Publications (21)83.08 Total impact
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Article: Triaging Pap cytology negative, HPV positive cervical cancer screening results with p16/Ki-67 Dual-stained cytology.
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ABSTRACT: Testing for human papillomavirus (HPV) has been shown to increase the sensitivity and negative predictive value for detection of high-grade cervical intraepithelial neoplasia (CIN2+), either when used in conjunction with Pap cytology testing or alone. However, there is no satisfying clinical management algorithm for women testing Pap negative/HPV positive. We therefore evaluated the clinical utility of a novel dual biomarker-based approach (p16/Ki-67 Dual-stained cytology) for the identification of CIN2+ in women with Pap negative/HPV positive screening results, without the need to refer all women to immediate colposcopy. All women aged ≥30 enrolled during 2007/2008 into a regional prospective Pap/HPV co-testing screening pilot project and tested Pap negative, but positive for HPV (n=425) were included in the analysis. p16/Ki-67 Dual-stained cytology was performed from residual cellular material available from the liquid-based cytology vial collected during the initial Pap/HPV co-testing screening visit. Results were correlated to the presence of CIN2+ confirmed during preliminary follow-up. p16/Ki-67 Dual-stained cytology tested positive at baseline in 108 out of 425 (25.4%) Pap negative/HPV positive cases. Sensitivity of Dual-stain testing for the detection of biopsy-confirmed CIN2+ during preliminary follow-up within the group of Pap negative/HPV positive women was 91.9% for CIN2+ (34/37 cases), and 96.4% for CIN3+ (27/28 cases). Specificity was 82.1% for CIN2+ on biopsy, and 76.9% for CIN3+, respectively. Triaging Pap negative/HPV positive screening test results with p16/Ki-67 Dual-stained cytology may identify women with a high probability of underlying CIN2+ and may efficiently complement HPV-based screening programs to prevent cervical cancer.Gynecologic Oncology 03/2011; 121(3):505-9. · 3.89 Impact Factor -
Article: p16/ki-67 dual-stain cytology in the triage of ASCUS and LSIL papanicolaou cytology: results from the European equivocal or mildly abnormal Papanicolaou cytology study.
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ABSTRACT: The objective of this study was to analyze the diagnostic performance of a newly established immunocytochemical dual-stain protocol, which simultaneously detects p16(INK4a) and Ki-67 expression in cervical cytology samples, for identifying high-grade cervical intraepithelial neoplasia (CIN2+) in women with Papanicolaou (Pap) cytology results categorized as atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesions (LSIL). Residual liquid-based cytology material from 776 retrospectively collected ASCUS/LSIL cases that were available from a recent study evaluating p16 cytology and HPV testing were subjected to p16/Ki-67 dual staining. The presence of 1 or more double-immunoreactive cell(s) was regarded as a positive test outcome, irrespective of morphology. Test results were correlated to histology follow-up. Sensitivity of p16/Ki-67 dual-stain cytology for biopsy-confirmed CIN2+ was 92.2% (ASCUS) and 94.2% (LSIL), while specificity rates were 80.6% (ASCUS) and 68.0% (LSIL), respectively. Similar sensitivity/specificity profiles were found for both age groups of women aged <30 years versus women aged ≥30 years. Dual-stain cytology showed comparable sensitivity, but significantly higher specificity, when compared with human papillomavirus (HPV) testing. The results of this study show that p16/Ki-67 dual-stain cytology provided a high sensitivity for the detection of underlying CIN2+ in women with ASCUS or LSIL Pap cytology results, comparable to the rates previously reported for HPV testing and p16 single-stain cytology. However, the specificity of this morphology-independent interpretation of p16/Ki-67 dual-stain cytology testing was further improved compared with the earlier p16 single-stain cytology approach, which required morphology interpretation, and it is significantly higher when compared with HPV testing.Cancer Cytopathology 03/2011; 119(3):158-66. · 3.33 Impact Factor -
Article: Evaluation of cervical cone biopsies for coexpression of p16INK4a and Ki-67 in epithelial cells.
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ABSTRACT: Diffuse overexpression of p16(INK4a) in basal and parabasal cells of cervical epithelium is a hallmark of human papillomavirus-mediated transformation. Focal p16(INK4a) expression is occasionally observed in nondysplastic epithelium. In normal cells, expression of p16(INK4a) triggers cell cycle arrest. However, cells undergoing transformation in intraepithelial lesions actively proliferate. To prove that the different expression patterns of p16(INK4a) , i.e., focal versus diffuse, reflect biologically different entities, we hypothesized that p16(INK4a) -positive cells in epithelia displaying focal p16(INK4a) expression pattern do not coexpress proliferation-associated Ki-67 protein, while p16(INK4a) -positive cells in lesions with diffuse p16(INK4a) expression may do. A total of 138 cervical cone biopsies were stained for the expression of p16(INK4a) and Ki-67 using a primary antibody cocktail. All metaplastic lesions (n = 21) displayed focal staining for p16(INK4a) , and in all of these lesions p16(INK4a) -positive cells were found to be negative for Ki-67 expression. Diffuse expression of p16(INK4a) was observed in 12/21 (57.1%) cervical intraepithelial neoplasia (CIN) 1 lesions, all of them simultaneously showed Ki-67 immunoreactivity in a large proportion of p16(INK4a) -positive cells. Seventeen of 23 (73.9%) CIN2 lesions and all 27 (100%) CIN3/carcinoma in situ (CIS) as well as all 46 (100%) carcinoma cases displayed diffuse and combined expression of p16(INK4a) and Ki-67. Coexpression of Ki-67 and p16(INK4a) in the same cell is entirely restricted to cervical lesions displaying diffuse p16(INK4a) expression, whereas in lesions with focal p16(INK4a) expression, p16(INK4a) -expressing cells are negative for Ki-67. Thus, diffuse expression of p16(INK4a) reflects lesions with proliferation-competent cells, while p16(INK4a) -expressing cells associated with focal expression patterns are cell cycle arrested.International Journal of Cancer 03/2011; 130(2):388-94. · 5.44 Impact Factor -
Article: The sensitivity and specificity of p16(INK4a) cytology vs HPV testing for detecting high-grade cervical disease in the triage of ASC-US and LSIL pap cytology results.
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ABSTRACT: We analyzed the performance of p16(INK4a) immunocytochemistry on a series of 810 retrospectively collected atypical squamous cells of undetermined significance (ASC-US) and low-grade squamous intraepithelial lesion (LSIL) cases with available biopsy follow-up data, including 94 cases of cervical intraepithelial neoplasia (CIN) 2 and 128 cases of CIN 3. Human papillomavirus (HPV) testing was performed from the same residual liquid-based cytologic specimen, and results for both tests were correlated with histologic follow-up data. Sensitivity values for high-grade CIN (HGCIN) confirmed on biopsy within 6 months were 92.6% (ASC-US) and 92.2% (LSIL) for cytotechnologists' reviews of p16 cytology and 90.1% (ASC-US) and 95.7% (LSIL) for HPV testing. Sensitivity rates of initial pathologists' reviews were slightly lower, 76.4% to 80.1%, with levels comparable to cytotechnologists' results after adjudication. The specificity of p16 cytology for HGCIN detection was significantly higher than for HPV testing for cytotechnologists and pathologists: 63.2% to 71.1% (p16 cytology) vs 37.8% for HPV in ASC-US (P < .001) and 37.3% to 53.3% (p16 cytology) vs 18.5% for HPV in LSIL (P < .001). This evaluation of the diagnostic performance of p16 cytology confirms the potential of this stain for the efficient triage of ASC-US and LSIL cytologic results.American Journal of Clinical Pathology 07/2010; 134(1):12-21. · 2.60 Impact Factor -
Article: Conjunctive p16INK4a testing significantly increases accuracy in diagnosing high-grade cervical intraepithelial neoplasia.
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ABSTRACT: The histopathologic interpretation of cervical intraepithelial neoplasia (CIN) is subject to a high level of interobserver variability and a substantial number of false-positive and false-negative results. We assessed the impact of the conjunctive interpretation of p16(INK4a)-immunostained slides on the accuracy of community-based pathologists in diagnosing high-grade cervical intraepithelial neoplasia (CIN; CIN 2 and CIN 3) in biopsy specimens. Twelve pathologists rendered independent diagnoses on a set of 500 H&E-stained cervical punch and conization specimens. Results were compared with a dichotomized "gold standard" established by consensus of 3 gynecopathology experts. When p16(INK4a)-immunostained slides were added and conjunctively interpreted with the H&E-stained slides, a significant increase in diagnostic accuracy for the detection of high-grade CIN was observed (P = .0004). Sensitivity for high-grade CIN was increased by 13%, cutting the rate of false-negative results in half. Agreement of community-based pathologists in diagnosing high-grade CIN was significantly improved (mean kappa values advanced from 0.566 to 0.749; P < .0001). Reproducibility of p16(INK4a) stain interpretation was excellent (kappa = 0.899). Our results show that conjunctive interpretation of p16(INK4a)-stained slides could significantly improve the routine interpretation of cervical histopathology.American Journal of Clinical Pathology 03/2010; 133(3):395-406. · 2.60 Impact Factor -
Article: Evaluation of an ELISA for p16INK4a as a screening test for cervical cancer.
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ABSTRACT: The low sensitivity of cytology and low specificity of human papillomavirus testing prompts searching for more accurate cervical cancer screening strategies. Our goal was to evaluate an ELISA-based test for p16(INK4a). 1,781 women undergoing routine screening provided cervical specimens for p16(INK4a) ELISA (original and enhanced versions of a prototype), liquid-based cytology, and Hybrid Capture II (hc2) testing. All women with a positive result and a random sample of those with negative results on all tests were referred for histologic diagnosis. Cervical intraepithelial neoplasia grade >or=3 (>or=CIN3) was the main outcome. The original analysis included all >or=CIN3 outcomes (n = 28). The a posteriori analysis was used to represent clinically relevant results with >or=CIN3 as outcomes only when detected after a positive screening test (n = 27). Participants had a median age of 23 years. The prevalence of high-risk human papillomavirus DNA was 30.6%. In a posteriori analyses, the sensitivity and specificity for p16(INK4a) ELISA (>or=8 pg/mL cut-point), cytology, and hc2 were 50.9%, 58.1%, and 100.0%, respectively, and 90.4%, 89.3%, and 69.2%, respectively. Referral to colposcopy of women with positive results for hc2 and p16(INK4a) (enhanced ELISA, >or=6 pg/mL cut-point) had a sensitivity of 91.8% (95% confidence interval, 79.1-100.0%) and specificity of 86.0% (95% confidence interval, 82.0-89.0%). Results of the original analyses had similar specificity but substantially lower sensitivity due to the strong influence of the single CIN3 case with completely negative screening results. An enhanced version of this prototypic p16(INK4a) ELISA showed promise in screening, particularly when combined with hc2.Cancer Epidemiology Biomarkers & Prevention 11/2009; 18(11):3008-17. · 4.12 Impact Factor -
Article: Immunostaining for p16INK4a used as a conjunctive tool improves interobserver agreement of the histologic diagnosis of cervical intraepithelial neoplasia.
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ABSTRACT: The quality of cervical histopathology is critical to cervical cancer prevention, cancer treatment, and research programs. On the basis of the histology results further patient management is determined. However, the diagnostic interpretation of histologic hematoxylin-eosin (H&E)-stained slides is affected by substantial rates of discordance among pathologists. Overexpression of the cyclin-dependent kinase inhibitor p16INK4a, a cell cycle regulating protein, has been shown to be strongly correlated with dysplastic lesions of the cervix uteri. In this study, we assessed whether p16INK4a immunohistochemistry may increase the performance of pathologists in diagnosing squamous lesions in cervical punch and cone biopsies. When using a consecutive p16INK4a-stained slide in conjunction to the H&E-stained slide, interobserver agreement between 6 pathologists improved significantly for both cervical punch and cone biopsies (P < 0.001). For punch biopsies (n = 247), kappa value increased from 0.49 (moderate agreement) to 0.64 indicating substantial agreement, and interobserver agreement for cone biopsies (n = 249) improved from 0.63 (conventional H&E slide reading) to 0.70 when H&E-stained slides were read conjunctively with p16INK4a-stained slides. In comparison to a common consensus diagnosis established by 3 independent experts, 4 pathologists reached an improvement with the conjunctive p16INK4a test, 2 of them showing significantly better agreement (P < 0.001 and P = 0.002, respectively), p16INK4a immunohistochemistry as an adjunct to conventional H&E-stained specimens thus contributes to a more reproducible diagnosis of cervical intraepithelial neoplasia and may be a valuable aid for the interpretation of cervical histology.American Journal of Surgical Pathology 05/2008; 32(4):502-12. · 4.35 Impact Factor -
Article: Evaluation of a new p16(INK4A) ELISA test and a high-risk HPV DNA test for cervical cancer screening: results from proof-of-concept study.
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ABSTRACT: p16(INK4a), a cell cycle regulation protein, accumulates in abnormal epithelial cells infected with high-risk human papilloma virus (HPV). In immunostaining studies, p16(INK4a) has shown potential as a marker of high grade cervical intraepithelial neoplasia (CIN) and invasive cervical cancer. To evaluate its potential use in cervical cancer screening, we conducted a feasibility study to compare the performance of a new enzyme linked immunosorbant assay (ELISA) for p16(INK4a) (mtm laboratories, Heidelberg, Germany) to that of the Hybrid Capture 2 (hc2) test for high-risk HPV DNA for the detection of CIN3. Three hundred and nineteen women were referred from Western Washington Planned Parenthood clinics for colposcopy examination and cervical biopsy because of abnormal Pap test results. Cervical samples were obtained from study participants for p16(INK4a) ELISA, liquid-based cytology and hc2. The order (first and second) for obtaining samples for cervical cytology and p16(INK4a) ELISA changed with every other subject. Concentrations of p16(INK4a) protein were higher when the sample was taken before the cytology. The sensitivity of p16(INK4a) ELISA (concentration > or = 8 units/ml) taken as first sample was 90.0% for CIN3, and the sensitivity of HC2 taken as a second sample was 85%. In the same group, the specificity of p16(INK4a) ELISA (46.9%) was slightly better than hc2 (35.4%) Results from this proof-of-concept study suggest that p16(INK4a) ELISA has a similar sensitivity and slightly better specificity for CIN3 compared to hc2. These findings support proceeding with a larger study with samples from a population of women presenting for routine cytology screening.International Journal of Cancer 07/2007; 120(11):2435-8. · 5.44 Impact Factor -
Article: Identification of high-grade cervical dysplasia by the detection of p16INK4a in cell lysates obtained from cervical samples.
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ABSTRACT: Current cervical cancer screening approaches are based on cytology supplemented by human papillomavirus (HPV) testing in some settings. Whereas cytology is laborious and depends on the cytologists' experience, HPV testing has limited specificity when it is used to detect high-grade lesions. A dichotomous test to identify high-grade lesions with greater specificity may be a useful tool for cervical cancer screening. p16(INK4a) is a cell-cycle regulator that has demonstrated strong overexpression in cervical precancer cells and cervical cancer induced by the deregulated expression of HPV oncogenes. The authors used a sandwich enzyme-linked immunosorbent assay (ELISA) to quantify the amount of solubilized p16(INK4a) protein in lysates that were prepared from cervical samples to detect high-grade cervical lesions. In total, 187 specimens that were obtained after sampling for conventional cytology in women who attended a cervical colposcopy clinic were analyzed. Seventy-six women underwent a biopsy, and 45 of those women showed histologically confirmed, high-grade cervical intraepithelial neoplasia. For 76 women with biopsy-proven diagnoses, receiver operating characteristic (ROC) analysis of different cutoff values showed an area under the ROC curve of 0.89 for the detection of high-grade cervical dysplasia. At a cutoff value of 8 U/mL, the sensitivity of the p16(INK4a) ELISA for detecting high-grade dysplastic cervical lesions was 96%. The data obtained in this study suggested that ELISA-based quantification of solubilized p16(INK4a) protein may have high sensitivity for detecting cervical precancer. Further population-based studies will be necessary to analyze the specificity and predictive values of p16(INK4a) protein quantification in cervical samples.Cancer 12/2006; 107(9):2307-13. · 4.77 Impact Factor -
Article: Cross-reactivity of Trichomonas in cervical p16INK4a immunocytochemistry is dependent on antibody, not antigen.
Diagnostic Cytopathology 08/2006; 34(7):512-4; author reply 515. · 1.16 Impact Factor -
Article: Comparable transforming capacities and differential gene expression patterns of variant FUS/CHOP fusion transcripts derived from soft tissue liposarcomas.
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ABSTRACT: The chromosomal translocation t(12;16)(q13;p11) is a common genetic alteration in myxoid and round-cell liposarcomas. It results in transcription of various chimeric FUS/CHOP fusion transcripts that encode different oncogenic proteins. Recent reports suggest that these may have different neoplastic transformation activities. To audit this hypothesis, we transfected expression plasmids for the two major variant FUS/CHOP transcripts I and II in NIH 3T3 cells and determined the number of outgrowing foci as well as their growth potential in soft agar. In addition, we compared tumour growth in nude mice upon subcutaneous injection of the respective transfectants. No significant differences in transformation assays in vitro and in vivo were observed, suggesting that both variant transcripts confer comparable transforming activities. The histopathological picture of tumours derived from both cell populations resembles high-grade spindle cell sarcomas. This suggests that both FUS/CHOP variants cause similar patterns of differential gene expression. This hypothesis was confirmed by mRNA-expression profiles of the respective cell clones. Strong overexpression of the pentaxin-related gene (PTX), the osteoblast-specific factor 2 (osf-2), the basic Kruppel-like factor (bklf), the leucoprotease inhibitor, and the cyclophilin B were observed in both types of FUS/CHOP-transfected cell clones. Taken together, our data suggest that different FUS/CHOP variants cause transformation of mesenchymal cells via the same pathways with comparable efficacy.Oncogene 10/2004; 23(40):6798-805. · 6.37 Impact Factor -
Article: Validation of p16INK4a as a marker of oncogenic human papillomavirus infection in cervical biopsies from a population-based cohort in Costa Rica.
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ABSTRACT: Due to the high prevalence of cancer-associated types of human papillomavirus (HPV) and the poorly reproducible histologic classification of low-grade lesions, identifying infected women at highest risk for cancer prior to neoplastic progression remains a challenge. We therefore explored the utility of p16INK4a immunostaining as a potential diagnostic and prognostic biomarker for cervical neoplasia using paraffin-embedded tissue blocks (punch biopsies and loop electrosurgical excision procedures) obtained from women referred to colposcopy during the enrollment phase of the Guanacaste Project (1993 to 1994). All blocks from 292 women selected by HPV status (HPV negative, nononcogenic HPV positive, or oncogenic HPV positive) and representing the diagnostic spectrum of the population [normal to precancer: cervical intraepithelial neoplasia (CIN) 3] were immunostained for p16INK4a using the p16INK4a research kit based on the monoclonal antibody clone E6H4 (MTM Laboratories, Heidelberg, Germany). For CIN3, the sensitivity of diffuse p16INK4a immunostaining was 100% and the specificity was 95%. For CIN2, the sensitivity and specificity for diffuse staining were 81.1% and 95.4%, respectively. Generalized to the 10,000-woman cohort, this translated to positive predictive value and negative predictive value of 13.9% and 100% for CIN3, respectively, and 20.4% and 99.7% for CIN2 or CIN3, respectively. Of women with an initial diagnosis of less than CIN2 for whom follow-up data for up to 5 to 7 years were available, 44% with diffuse staining developed persistent infection (CIN2 or CIN3). Whereas our data support the diagnostic potential for p16INK4a, further prospective studies with detailed follow-up determining the prognostic capacity of this marker are needed.Cancer Epidemiology Biomarkers & Prevention 09/2004; 13(8):1355-60. · 4.12 Impact Factor -
Article: Correlation of p16INK4A overexpression with human papillomavirus infection in cervical adenocarcinomas.
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ABSTRACT: As human papillomavirus (HPV) infection is the main risk factor for squamous cell carcinoma of the cervix and overexpression of p16INK4a occurs when retinoblastoma protein is inactivated by high-risk HPV, the authors studied the association of HPV infection and expression of p16INK4a in cervical adenocarcinomas. Specimens of cervical glandular neoplasias were immunostained with a p16INK4a-specific monoclonal antibody (clone E6H4). Approximately 80% of glandular neoplasms showed overexpression of p16INK4a. Exfoliated cells from 14 adenocarcinomas were further examined by p16INK4a-specific immunocytochemistry, and 12 cases showed overexpression of p16INK4a, suggesting that immunostaining for p16INK4a may be a useful diagnostic tool for cervical adenocarcinomas. The authors further examined HPV DNA in cervical adenocarcinomas with the polymerase chain reaction method. Overexpression of p16INK4a was positive in 94% of cases in which HPV16 or 18DNA was positive, a finding suggesting that HPV16 or 18 may play an important role in cervical adenocarcinomas. Overexpression of p16INK4a may be an indicator of pathogenic activity of high-risk HPVs.International Journal of Gynecological Pathology 11/2003; 22(4):378-85. · 1.45 Impact Factor -
Article: Identification and characterization of UEV3, a human cDNA with similarities to inactive E2 ubiquitin-conjugating enzymes.
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ABSTRACT: Recent studies have shown that ubiquitination is an essential factor in endosomal sorting and virus assembly. The human TSG101 gene has been demonstrated to belong to a group of genes coding for apparently inactive E2 ubiquitin-conjugating enzymes, which exert regulatory effects on E2 activity in cellular ubiquitination processes. In this study, a novel human cDNA (UEV3) encoding a putative protein of 379 amino acids was isolated from a human placenta library that may represent a partial paralogue of human TSG101. The predicted protein contains an N-terminal domain homologous to the catalytic domain of ubiquitin-conjugating enzymes (Ubc), which is fused to a sequence showing significant homology to members of the lactate dehydrogenase protein family. The UEV3 gene is located on chromosome 11 closely adjacent to TSG101 and LDH-C. Northern blot and UEV3-specific reverse transcription/polymerase chain reaction (RT/PCR) analyses of various colon carcinoma cell lines as well as both normal and tumor samples from colon revealed an expression of the UEV3 cDNA in all tested samples.Biochimica et Biophysica Acta 01/2003; 1579(2-3):219-24. · 4.66 Impact Factor -
Article: Prevention of chemotherapy-related toxic side effects by infection with adeno-associated virus type 2.
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ABSTRACT: Drug resistance and toxic side effects are major limiting factors in the clinical use of antineoplastic chemotherapy. Patients with pancreatic cancer generally do not benefit from chemotherapy. The nonpathogenic adeno-associated virus type 2 (AAV-2) has been shown to sensitize human tumor cells to gamma irradiation and chemotherapeutic drugs. In the present study, we characterized the therapeutic role of AAV-2 infection in combination with 5-fluorouracil (5-FU)-based chemotherapy on pancreatic cancer cells in an animal model. In Lewis rats bearing s.c. implants of syngeneic DSL6A pancreatic cancer cells, intratumoral infection with AAV-2 (MOI 10E8 i.u.) in combination with 5-FU (5 or 50 mg/kg body weight) resulted in significantly reduced tumor growth and prolonged survival time compared with 5-FU single therapy. Most surprisingly, AAV-2-infected rats remained in a much better physical condition compared to their noninfected counterparts. While rats treated with 5-FU single therapy lost weight, were sluggish and died within 4 months after tumor implantation, animals infected with AAV showed much better vigilance, with body weight, leukocyte number and hemoglobin levels similar to healthy rats. In particular, 5-FU-related side effects like thrombocytopenia and leukopenia were significantly reduced in animals treated with the combination regimen. By in vitro analysis, human (Capan-1 and DANG) pancreatic cancer cell lines were shown to be sensitized to 5-FU chemotherapy to an extent similar to DSL6A cells. AAV-2 infection enhanced 5-FU-induced apoptosis by a factor of 8 to 14 in both human and rat pancreatic cancer cell lines. The data suggest that infection with the nonpathogenic AAV-2 significantly improves both chemotherapy efficacy and physical appearance and offers a novel strategy in cancer treatment.International Journal of Cancer 09/2002; 100(5):606-14. · 5.44 Impact Factor -
Article: Sensitization of sarcoma cells to doxorubicin treatment by concomitant wild-type adeno-associated virus type 2 (AAV-2) infection.
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ABSTRACT: Doxorubicin-based chemotherapy is used in the treatment of sarcomas. Toxic side effects and poor response rates underline the demand for an improvement in current chemotherapeutic protocols. Recently, it has been reported that parvoviruses confer various antineoplastic properties to infected cells, and that adeno-associated virus type 2 (AAV-2) infection sensitizes malignant epithelial cells to radiation- or chemotherapy-based genotoxic treatment. Thus, we analyzed whether AAV-2 infection leads to an improved efficacy of doxorubicin chemotherapy in malignant mesenchymal cells, using 13 human sarcoma cell lines. Therapeutic effects were analyzed by measuring cell viability and proliferation (WST-1, colony forming, and propidium iodide assays). Additionally, permissivity for AAV-2 infection was determined by Southern dot blot analysis. AAV-2 infection strongly increased the efficacy of doxorubicin treatment in rhabdomyo-, fibro-, osteo- and chondrosarcoma cells in a dose-dependent manner. This effect was not observed in liposarcoma and synovial sarcoma cells, although a susceptability to AAV-2 infection was documented. Our results indicate that the sensitization effects towards genotoxic treatment exerted by non-pathogenic AAV-2 infection are not restricted to epithelial malignancies but may also be exploited for the improvement of chemotherapy in patients suffering from rhabdomyo-, fibro-, osteo-, or chondrosarcomas.International Journal of Oncology 07/2002; 20(6):1211-8. · 2.40 Impact Factor -
Article: Characterization of viral-cellular fusion transcripts in a large series of HPV16 and 18 positive anogenital lesions.
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ABSTRACT: Persistent high risk type human papillomavirus (HR-HPVs) infections induce dysplasia or cancer of the anogenital tract, most notably of the uterine cervix. The viral genome usually persists and replicates as an episomal molecule in early dysplasia, whereas in advanced dysplasia or cervical cancer HPV genomes are frequently integrated into the chromosomal DNA of the host cell. Previous studies suggested that modification of critical cellular sequences by integration of HPV genomes might significantly contribute to the neoplastic transformation of anogenital epithelia (insertional mutagenesis). This prompted us to characterize the integration loci of high risk HPV genomes in a large set of genital lesions. We amplified E6/E7 oncogene transcripts derived from integrated HPV16 and HPV18 genomes and characterized in detail the co-transcribed cellular sequences of 64 primary genital lesions and five cervical cancer cell lines. Database analyses of the cellular parts of these fusion transcripts revealed 51 different integration loci, including 26 transcribed genes (14 known genes, 12 EST sequences with unknown gene function). Seventeen sequences showed similarity to repetitive elements, and 26 sequences did not show any database match other than genomic sequence. Chromosomal integration loci were distributed over almost all human chromosomes. Although we found HPV sequences integrated into cancer related genes and close to fragile sites, no preferential site or integration motif could be identified. These data demonstrate that target directed insertional mutagenesis might occur in few HPV-induced anogenital lesions, however, it is rather the exception than the rule.Oncogene 02/2002; 21(3):419-26. · 6.37 Impact Factor -
Article: Systematic identification of genes with coding microsatellites mutated in DNA mismatch repair‐deficient cancer cells
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ABSTRACT: Microsatellite instability (MSI) caused by deficient DNA mismatch-repair functions is a hallmark of cancers associated with the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome but is also found in about 15% of all sporadic tumors. Most affected microsatellites reside in untranslated intergenic or intronic sequences. However, recently few genes with coding microsatellites were also shown to be mutational targets in MSI-positive cancers and might represent important mutation targets in their pathogenesis. The systematic identification of such genes and the analysis of their mutation frequency in MSI-positive cancers might thus reveal major clues to their functional role in MSI-associated carcinogenesis. We therefore initiated a systematic database search in 33,595 distinctly annotated human genes and identified 17,654 potentially coding mononucleotide repeats (cMNRs) and 2,028 coding dinucleotide repeats (cDNRs), which consist of n ≥ 6 and n ≥ 4 repeat units, respectively. Expression pattern and mutation frequency of 19 of these genes with the longest repeats were compared between DNA mismatch repair-deficient (MSI+) and proficient (MSS) cancer cells. Instability frequencies in these coding microsatellite genes ranged from 10% to 100% in MSI-H tumor cells, whereas MSS cancer cells did not show mutations. RT-PCR analysis further showed that most of the affected genes (10/15) were highly expressed in tumor cells. The approach outlined here identified a new set of genes frequently affected by mutations in MSI-positive tumor cells. It will lead to novel and highly specific diagnostic and therapeutic targets for microsatellite unstable cancers. © 2001 Wiley-Liss, Inc.International Journal of Cancer 06/2001; 93(1):12 - 19. · 5.44 Impact Factor -
Article: Overexpression of p16INK4A as a specific marker for dysplastic and neoplastic epithelial cells of the cervix uteri
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ABSTRACT: Cytological screening for cervical cancer or its precursors using Papanicolaou's smear test (Pap test) has been highly efficient to reduce the morbidity and mortality of cervical cancer. However, evaluation of the Pap test relies on subjective diagnostic parameters and is affected by a high rate of false-positive and false-negative results. More objective diagnostic parameters to identify truly dysplastic or neoplastic cells in cervical smears as well as in cervical biopsy samples would therefore avoid insecurity for many patients and the high screening costs associated with repeated testing. Cervical dysplasia is induced by persistent infections through high-risk types of human papillomaviruses (HPVs). Outgrowth of dysplastic lesions is triggered by increasing expression of two viral oncogenes, E6 and E7, which both interact with various cell cycle-regulating proteins. Among these is the retinoblastoma gene product pRB, which is inactivated by E7. pRB inhibits transcription of the cyclin-dependent kinase inhibitor gene p16INK4a. Increasing expression of the viral oncogenes in dysplastic cervical cells might thus be reflected by increased expression of p16INK4a. In line with this hypothesis, we observed marked overexpression of p16INK4a in all cervical intraepithelial neoplasm (CIN) I lesions (n = 47) except those associated with low-risk HPV types (n = 7), all CIN II lesions (n = 32), all CIN III lesions (n = 60) and 58 of 60 invasive cervical cancers. In contrast, no detectable expression of p16INK4a was observed in normal cervical epithelium (n = 42), inflammatory lesions (n = 48) and low-grade cervical lesions (CIN I) associated with low-risk HPV types (n = 7). Dysplastic cells could also be identified in cervical smears using a specific p16INK4a monoclonal antibody. These data demonstrate that p16INK4a is a specific biomarker to identify dysplastic cervical epithelia in sections of cervical biopsy samples or cervical smears. © 2001 Wiley-Liss, Inc.International Journal of Cancer 04/2001; 92(2):276 - 284. · 5.44 Impact Factor -
Article: Identical variant TSG101 transcripts in soft tissue sarcomas and various non‐neoplastic tissues
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ABSTRACT: Inactivation of the TSG101 gene was recently shown to induce malignant transformation of NIH/3T3 fibroblasts. Abnormal TSG101 transcription profiles were observed in various human cancers, and large intragenic deletions of the TSG101 gene were reported for a series of human breast cancer specimens, pointing to a potential tumor-suppressive activity of TSG101. However, subsequent more detailed studies on a large panel of breast carcinoma samples did not confirm the tumor-associated genomic deletions. Here we analyzed the transcription patterns of the TSG101 gene in soft-tissue sarcomas and non-neoplastic human tissues. Forty-five of 71 soft tissue sarcoma samples (63%) displayed variant transcripts; however, identical aberrant transcripts were also detected in seven of 15 non-neoplastic control tissues. Restriction fragment length polymorphism analysis of the TSG101 gene excluded major genomic rearrangements in the soft tissue sarcoma samples. Northern blot analysis revealed a very low abundance of variant transcripts as compared with the wild-type TSG101 transcript. These data point to aberrant splicing of the TSG101 mRNA in normal and transformed human mesenchymal tissues rather than tumor specific alterations of the TSG101 gene. In summary, this analyses does not support a pathogenic role for altered TSG101 expression in human soft tissue sarcomas. Mol. Carcinog. 23:195–200, 1998. © 1998 Wiley-Liss, Inc.Molecular Carcinogenesis 01/1999; 23(4):195 - 200. · 3.16 Impact Factor
Top co-authors
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Institutions
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1999–2011
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Universität Heidelberg
- Institute of Pathology (Mannheim)
Heidelberg, Baden-Wuerttemberg, Germany
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2010
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North Bristol NHS Trust
Bristol, ENG, United Kingdom -
Laboratoire CERBA
Saint-Ouen-l'Aumône, Ile-de-France, France
-
-
2004
-
National Cancer Institute (USA)
Bethesda, MD, USA
-
-
2001
-
Max Delbrück Centrum für Molekulare Medizin
Berlin, Land Berlin, Germany
-
