Lela Buckingham

Rush University Medical Center, Chicago, Illinois, United States

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Publications (15)69.51 Total impact

  • Molly Steele · Amy Liu · Kate Bernhardt · Jennifer McCall · Brett Mahon · Lela Buckingham ·
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    ABSTRACT: Tyrosine kinase inhibitors (TKI) have significantly improved the prognosis for chronic myelogenous leukemia (CML) patients. Several mechanisms of resistance have been identified, however. BCR-ABL-dependent resistance is the most frequently occurring, usually as mutations preventing therapeutic drug interaction. This study addresses a mechanism of resistance observed in the absence of mutations. During TKI challenge, of downstream dephosphorylators such as Protein-Tyrosine Phosphatase, Nonreceptor-Type 6 (PTPN6 or SHP1) may supplement oncogenic activation. We retrospectively examined expression and control of SHP1 in TKI sensitive and resistant cases of CML in 122 North American patients of European and African ancestry employing mutation detection, methylation analysis and gene expression. Mean SHP1 gene expression was lower in CML cases (SHP1/beta2 microglobulin% = 399.4) than in nonleukemic samples (SHP1/beta2 microglobulin% = 704.5). Mutations were detected in 16/28, 26/47 and 5/18 of TKIresistant cases by standard PCR, quantitative PCR and sequencing, respectively. Expression of SHP1 was slightly lower in cases of drug-resistant CML than in drug sensitive CML (SHP1/beta 2 microglobulin% = 382 vs 422). Methylation of the SHP1 promoter at CpG site at -456 was significantly higher in cells from CML patients than in cells from normal patients (p=0.023). Depressed expression and increased methylation of SHP1 in CML cells are consistent with a role of tumor suppressor of SHP1, with its loss contributing to malignant cellular phenotypes. Although no significant differences were observed in SHP1 expression and methylation in TKI-resistant and TKI sensitive CML, expression was consistently lower and methylation higher in cases of TKI-resistant CML without detectable ABL kinase mutations. Methylation as the cause of SHP1 (or other tumor suppressor gene) suppression would offer new therapeutic strategies for treating CML.
    Current Pharmacogenomics and Personalized Medicine (Formerly Current Pharmacogenomics) 05/2015; 13(999):1-1. DOI:10.2174/1875692113666150513002248
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    ABSTRACT: Approximately 70% of lung adenocarcinomas express TTF-1. EGFR mutations are present in 13-15% of Western adenocarcinoma patients. This paper investigates TTF1 as a negative predictor of mutant EGFR in lung adenocarcinomas. In the pilot cohort (N = 301) two of 224 specimens positive for EGFR mutations had negative TTF-1 expression (sensitivity 99.1%, 95% confidence interval (CI) 96.8-99.9%). Estimated negative predictive values (NPV) for EGFR mutation prevalence rates of 13% and 15% are 99.5% (95% credible interval (CRI) 98.6%-99.9%) and 99.4% (CRI - 98.4%-99.9%). For EGFR mutation rates of 13% and 15%, using validation cohort data (211 patients), the estimated NPVs were 97% (95% CRI 92%-99%) and 96% (95% CRI 91%-99%). Formalin-fixed paraffin-embedded tumors from lung adenocarcinoma patients were analyzed for EGFR mutations by allele-specific PCR in the 'pilot cohort'. TTF-1 status was documented as positive or negative. Negative predictive value (NPV) for a range of true prevalence of EGFR mutation (1%-50%) was estimated using Bayesian modeling. The hypothesis was validated in a separate 'validation' cohort using the same modeling. An overwhelming majority of TTF-1 negative adenocarcinomas will be negative for EGFR mutations. This finding allows for earlier initiation of chemotherapy in newly diagnosed TTF-1 negative adenocarcinomas of the lung with stage IV disease.
    08/2014; 1(8):522-8. DOI:10.18632/oncoscience.72
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    ABSTRACT: High-grade malignancies are the leading cause of death from gynecological tumors. Unfortunately, no efficient screening method is available for these tumors. In this paper we report the results of a pilot study based on the frequency of TP53 mutations in these cancers. Mucus from the cervix of 32 hysterectomy specimens with no grossly visible cervical or serosal involvement were included in this study. TP53 exons 5-9 mutations were screened for mutations using single strand conformation polymorphism (SSCP). Immunostain for p53 protein was performed in all fallopian tubes and in a sample from the tumors that were identified prospectively. A total of 32 cases including 19 malignant, and 13 benign cases were included. P53 immunostain was positive in only 5 cases including 3 high grade malignant tumors and 2 precancerous lesions (serous tubal intraepithelial lesion or p53 signature) in the fallopian tubes. A TP53 mutation band pattern was detected by SSCP in 2/3 and 2/2 cases respectively. Twenty-seven cases were negative for p53 imunostain, 4 of which were positive for TP53 mutation by SSCP including 3 low-grade malignancies. The results of this study provide evidence that DNA from precursor lesions of high grade ovarian, fallopian tube and endometrial carcinomas can be detected in cervical mucus. Further studies using different markers, in preoperative setting and large scale screening studies will determine the utility of using cervical mucus to screen for gynecological malignancies.Modern Pathology advance online publication, 14 June 2013; doi:10.1038/modpathol.2013.92.
    Modern Pathology 06/2013; 26(11). DOI:10.1038/modpathol.2013.92 · 6.19 Impact Factor
  • Lela Buckingham · Philip Bonomi ·

    02/2013; 2(1):9-12. DOI:10.2217/lmt.12.59
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    ABSTRACT: Purpose: Non-small cell lung cancer (NSCLC) occurs most frequently in individuals older than 60 years of age. Currently, no biological indicators associated with NSCLC in younger patients (30 to 60 y) have been identified. To explore epigenetic influences, promoter methylation of selected tumor suppressor genes was analyzed in early-stage NSCLC patients ranging in age from 30 to 87 years at diagnosis. Experimental design: The analysis was performed on formalin-fixed tumor tissue from 193 surgically treated NSCLC patients (127, older than 60 y; 66, 60 y and younger). Methylation was quantified in p16, MGMT, DAPK, RASSF1, CDH1, LET7-3-a, NORE1(RASSF5), and PTEN promoters by pyrosequencing. p16 protein expression was assessed by immunohistochemistry (IHC). Outcome, defined by time to recurrence and overall survival, was evaluated by Kaplan-Meier analysis. Results: Promoter methylation levels were generally higher in patients older than 60 years of age than in patients 60 years or younger at diagnosis. Of the genes tested, methylation levels of the p16 promoter showed age-related differences. Although p16 promoter methylation was significantly lower using cut-points of 50 years or younger and 40 years or younger (P=0.001 to 0.012, respectively), p16 protein expression increased with age. Patients 60 years or younger with p16 promoter hypermethylation had a significantly shortened time to recurrence (P=0.002) and a shortened survival time (P=0.011). No effect of p16 hypermethylation was seen in patients older than 60 years. Conclusions: p16 promoter hypermethylation was associated with a worse outcome in patients with age at diagnosis of 60 years or younger, but was not associated with the outcome in the older than 60-year age group. Overall, these data support methylation-dependent and methylation-independent age-related regulation of p16 expression with differential effects on the outcome after surgical resection for early-stage NSCLC.
    Diagnostic molecular pathology: the American journal of surgical pathology, part B 10/2012; 21(4). DOI:10.1097/PDM.0b013e31825554b2 · 2.28 Impact Factor
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    ABSTRACT: Insulin-like growth factor receptor 1 (IGF1R) is a proposed mechanism of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors. Newer agents targeting this pathway make it of clinical interest. This study evaluates the IGF1R expression in regard to outcomes and molecular markers of EGFR activity in lung cancer patients treated with gefitinib. Gefitinib-treated patients with sufficient archived tissue were included. The IGF1R activity was measured by immunohistochemistry and the EGFR by immunohistochemistry, fluorescent in situ hybridization, and gene mutation testing. Logistic regression and cox proportional hazards models were used. A total of 83 patients were included in the study: 71% were positive for IGF1R expression which was not associated with EGFR parameters or clinical outcomes. Exploratory analyses showed counter-intuitive improved outcomes with co-expression of IGF1R and EGFR. IGF1R expression measured by immunohistochemistry does not appear to be related to gefitinib resistance.
    Anticancer research 05/2012; 32(5):1705-10. · 1.83 Impact Factor
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    ABSTRACT: Fluorescent in situ hybridisation analyses of PTEN, PIK3CA, EGFR and CEN7 were performed on tumour specimens from patients treated on the expanded access gefitinib trial. Progression-free survival (PFS) and overall survival (OS) were correlated with outcomes in all patients and EGFR wild-type patients. Progression-free survival (hazard ratio=2.54, P<0.001) and OS (hazard ratio=4.04, P<0.001) were significantly shorter in patients whose tumours had all of the following molecular patterns: CEN7 <4 copies per cell, PTEN loss (<2 copies in at least 20% of cells), and PIK3CA gain (>2 copies in at least 40% of cells) both in all and EGFR wild-type only patients. The combination of low CEN7 copy number, PTEN loss, and PI3KCA gain may be useful for identifying NSCLC patients unlikely to benefit from treatment with EGFR (TKIs), specifically in wild-type EGFR cases.
    British Journal of Cancer 11/2011; 105(12):1920-6. DOI:10.1038/bjc.2011.494 · 4.84 Impact Factor
  • Janet Plate · Philip Bonomi · John Coon · Lela E. Buckingham ·

    Cancer Research 07/2011; 71(8 Supplement):3831-3831. DOI:10.1158/1538-7445.AM2011-3831 · 9.33 Impact Factor
  • Lela E. Buckingham · Philip Bonomi · John Coon · Janet Plate ·

    Cancer Research 01/2011; 70(8 Supplement):4120-4120. DOI:10.1158/1538-7445.AM10-4120 · 9.33 Impact Factor
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    ABSTRACT: The primary objective of this study is to identify prognostic site-specific epigenetic changes in surgically treated Stage I and II nonsmall cell lung cancer (NSCLC) patients by quantifying methylation levels at multiple CpG sites within each gene promoter. Paraffin-embedded tumors from stage Ib, IIa and IIb in training and validation groups of 75 and 57 surgically treated NSCLC patients, respectively, were analyzed for p16, MGMT, RASSF1, RASSF5, CDH1, LET7, DAPK and PTEN promoter hypermethylation. Hypermethylation status was quantified individually at multiple CpG sites within each promoter by pyrosequencing. Molecular and clinical characteristics with time to recurrence (TTR) and overall survival (OS) were evaluated. Overall average promoter methylation levels of MGMT and RASSF1 were significantly higher in smokers than in nonsmokers (p = 0.006 and p = 0.029, respectively). Methylation levels of the p16 promoter were significantly higher in squamous cell carcinoma than in adenocarcinoma (p = 0.020). In univariate analysis, hypermethylation of RASSF1 at CpG sites -53 and -48 and PTEN at CpG site -1310 were the significantly associated with shorter TTR (p = 0.002 and p < 0.000, respectively). Hypermethylation of PTEN at -1310 and DAPK at -1482 were most significantly associated with outcome in multivariate analysis. These results show that methylation of specific promoter CpG sites in PTEN, RASSF1 and DAPK is associated with outcome in early stage surgically treated NSCLC.
    International Journal of Cancer 04/2010; 126(7):1630-9. DOI:10.1002/ijc.24896 · 5.09 Impact Factor
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    ABSTRACT: Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, potentiates antitumor effects of erlotinib in preclinical studies, and COX-2 is frequently expressed in non-small cell lung cancer (NSCLC). With these observations, we designed a phase II trial to evaluate the efficacy and safety of erlotinib plus celecoxib in advanced NSCLC. Previously treated stage IIIB/IV NSCLC patients were given celecoxib at 400 mg orally twice daily and erlotinib at 150 mg orally daily until disease progression. Planned accrual was 40 patients. Tissue was collected for epidermal growth factor receptor (EGFR) analysis and COX-2 immunohistochemistry. Twenty-six patients were enrolled (17 men, 9 women; median age, 66 years). Eighteen and 21 patients had tissue available for EGFR analysis and COX-2 immunohistochemistry, respectively. The median progression-free survival (PFS) and overall survival were 2.0 and 9.2 months, respectively. Eleven of 21 patients tested had increased tumor COX-2 expression, which was strongly associated with prolonged PFS (P=0.048). Four patients on anticoagulation or with a history of peptic ulcer disease had grade 3/grade 4 upper gastrointestinal bleeding (GIB), prompting early study closure. Three patients with GIB had endoscopy that found peptic ulcers. The combination of erlotinib and celecoxib does not seem superior to erlotinib alone in unselected patients. However, longer PFS with high-tumor COX-2 expression suggests that trials of EGFR and COX-2 inhibitors may be warranted in this patient subset. GIB observed in our trial supports excluding patients with a history of peptic ulcer disease or those requiring therapeutic anticoagulation from future EGFR and COX-2 inhibitor studies.
    Clinical Cancer Research 05/2008; 14(7):2088-94. DOI:10.1158/1078-0432.CCR-07-4013 · 8.72 Impact Factor
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    Philip D Bonomi · Lela Buckingham · John Coon ·
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    ABSTRACT: Identification of objective tumor regressions with epidermal growth factor receptor tyrosine kinases (EGFR TKI) in non-small cell lung cancer (NSCLC) patients has resulted in intense, worldwide clinical and basic research directed toward finding the optimal use of EGFR TKIs in NSCLC. EGFR TKI clinical trials have shown that higher response rates and longer survival are associated with specific patient characteristics and that using conventional chemotherapy simultaneously with EGFR TKIs in unselected patients does not increase survival. Molecular studies have revealed that EGFR-activating mutations and high EGFR gene copy number are frequently found in patients who have the best outcomes with EGFR TKIs. More recent studies suggest that KRAS mutations may identify the subset of patients who have the worst outcome with the EGFR TKI treatment. Currently, investigators are trying to determine the optimal approach to selecting patients for treatment with EGFR TKIs. Studies that have evaluated the potential predictive value of clinical features and/or molecular profiles in EGFR TKI-treated NSCLC patients are discussed in this review.
    Clinical Cancer Research 09/2007; 13(15 Pt 2):s4606-12. DOI:10.1158/1078-0432.CCR-07-0332 · 8.72 Impact Factor

  • Journal of Thoracic Oncology 08/2007; 2(Supplement 4). DOI:10.1097/01.JTO.0000284043.40963.fd · 5.28 Impact Factor
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    V. Villaflor · L. Buckingham · M. Gale · J. Coon · A. Mauer · T. Muzzafar · K. Kaiser · T. Zusag · L. Faber · P. Bonomi ·

    Lung Cancer 07/2005; 49. DOI:10.1016/S0169-5002(05)80244-2 · 3.96 Impact Factor

  • Lung Cancer 08/2003; 41. DOI:10.1016/S0169-5002(03)91832-0 · 3.96 Impact Factor