[show abstract][hide abstract] ABSTRACT: Oncogenic mutations in BRAF and NRAS occur in 70% of melanomas. In this study, we identify a microRNA, miR-146a, that is highly upregulated by oncogenic BRAF and NRAS. Expression of miR-146a increases the ability of human melanoma cells to proliferate in culture and form tumors in mice, whereas knockdown of miR-146a has the opposite effects. We show these oncogenic activities are due to miR-146a targeting the NUMB mRNA, a repressor of Notch signaling. Previous studies have shown that pre-miR-146a contains a single nucleotide polymorphism (C>G rs2910164). We find that the ability of pre-miR-146a/G to activate Notch signaling and promote oncogenesis is substantially higher than that of pre-miR-146a/C. Analysis of melanoma cell lines and matched patient samples indicates that during melanoma progression pre-miR-146a/G is enriched relative to pre-miR-146a/C, resulting from a C-to-G somatic mutation in pre-miR-146a/C. Collectively, our results reveal a central role for miR-146a in the initiation and progression of melanoma. DOI: http://dx.doi.org/10.7554/eLife.01460.001.
[show abstract][hide abstract] ABSTRACT: The histopathologic distinction between primary adnexal carcinomas and metastatic adenocarcinoma to the skin from sites such as the breast, lung, and others often presents a diagnostic dilemma. Current markers of diagnostic utility include p63 and cytokeratin 5/6; however, their expression has been demonstrated in 11%-22% and 27% of cutaneous metastases, respectively. Furthermore, the immunoreactivity of p40 and GATA3 in various cutaneous adnexal carcinomas has not been previously reported. In the present study, we compared the expression of p40, p63, cytokeratin 5/6, and GATA3 in a total of 143 cases, including 67 primary adnexal carcinomas and 76 cutaneous metastases. p40, p63, cytokeratin 5/6, and GATA3 expression was observed in 80%, 84%, 86% and 47% of primary adnexal carcinoma, respectively; and in 8%, 17%, 26% and 40% of cutaneous metastases, respectively. Chi-square analysis revealed statistically significant p-values (<0.0001) for p40, p63, and cytokeratin 5/6 in distinguishing primary adnexal carcinoma from cutaneous metastases. In summary, while p63 and cytokeratin 5/6 have similar sensitivity (84% and 86%, respectively) in detecting primary adnexal carcinomas, p40 appeared to be the most specific marker (92%) with the best positive predictive value (90%). Since breast and lung are the most common sites of origin for cutaneous metastases, p40 is the best distinguishing marker in these settings. None of the four studied markers (p40, p63, cytokeratin 5/6, and GATA3) are helpful in distinguishing between primary adnexal carcinomas from cutaneous metastases of salivary gland or bladder malignancies.
[show abstract][hide abstract] ABSTRACT: Background/Aims. Given the defining histopathologic architecture of keratoacanthoma (KA), the aim of this study was to measure the crateriform orifice ("orificial size") in histopathologically crateriform lesions to ascertain its utility as an objective diagnostic histopathologic adjunct. Methods. This cross-sectional, retrospective study included 97 cases with a histopathologic diagnosis of KA. We measured the "orificial size" using the ocular micrometer in a BH-2 Olympus microscope at 4× magnification, in a blinded manner with respect to information. Frequency of histopathologic features observed was also recorded. Results. The average orificial size for different groups was as follows: 2.3 ± 0.2 mm for cases with a clinical presentation of KA/keratotic papule (KP) (n = 30) versus 2.9 ± 0.3 mm for other (n = 67), P = .18. Histopathologic findings in the 2 groups were as follows: crateriform architecture/epithelial lip and sharp demarcation of tumor from stroma (100% in both groups), fibrosis (29/30 vs 64/67), apoptotic keratinocytes (27/30 vs 56/67), dermal islands of "glassy" keratinocytes (26/30 vs 54/67), entrapped elastic fibers (26/30 vs 49/67), and neutrophilic abscesses (11/30 vs 21/670 [P = not significant for all]. Conclusion. Our findings indicate that, in the appropriate clinical setting, a smaller orificial size, although predictive of a KA, in itself is not sufficient for a definitive diagnosis. Given that a major limitation is that this is a function of age of the lesion as orificial size depends on the evolution stage of the neoplasm with the largest diameter often evident in lesions at early stages of regression, for now correlation with histopathologic features such as presence of an epithelial lip, sharp demarcation of tumor from stroma, and fibrosis (present in >95% of cases of KAs) is required.
International Journal of Surgical Pathology 11/2013; · 0.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Cancer cells acquire several traits that allow for their survival and progression, including the ability to evade the host immune response. However, the mechanisms by which cancer cells evade host immune responses remain largely elusive. Here we study the phenomena of immune evasion in malignant melanoma cells. We find that the tumor suppressor phosphatase and tensin homolog (PTEN) is an important regulator of the host immune response against melanoma cells. Mechanistically, PTEN represses the expression of immunosuppressive cytokines by blocking the phosphatidylinositide 3-kinase (PI3K) pathway. In melanoma cells lacking PTEN, signal transducer and activator of transcription 3 activates the transcription of immunosuppressive cytokines in a PI3K-dependent manner. Furthermore, conditioned media from PTEN-deficient, patient-derived short-term melanoma cultures and established melanoma cell lines blocked the production of the interleukin-12 (IL-12) in human monocyte-derived dendritic cells. Inhibition of IL-12 production was rescued by restoring PTEN or using neutralizing antibodies against the immunosuppressive cytokines. Furthermore, we report that PTEN, as an alternative mechanism to promote the host immune response against cancer cells, represses the expression of programmed cell death 1 ligand, a known repressor of the host immune response. Finally, to establish the clinical significance of our results, we analyzed malignant melanoma patient samples with or without brisk host responses. These analyses confirmed that PTEN loss is associated with a higher percentage of malignant melanoma samples with non-brisk host responses compared with samples with brisk host responses. Collectively, these results establish that PTEN functions as a melanoma tumor suppressor in part by regulating the host immune response against melanoma cells and highlight the importance of assessing PTEN status before recruiting melanoma patients for immunotherapies.Oncogene advance online publication, 21 October 2013; doi:10.1038/onc.2013.409.
[show abstract][hide abstract] ABSTRACT: Multiple endocrine neoplasia type 1 is a familial cancer syndrome resulting from loss-of-function mutations in the MEN1 gene. We previously identified the tumor suppressor MEN1 as a gene required for oncogene-induced senescence in melanocytes, raising the possibility that MEN1 is a melanoma tumor suppressor. Here we show that MEN1 expression is lost in a high percentage of human melanomas and melanoma cell lines. We find that melanocytes depleted of MEN1 are deficient in homologous recombination (HR)-directed DNA repair, which is accompanied by increased non-homologous end joining activity. Following DNA damage, MEN1 levels increase resulting from phosphorylation by the DNA damage kinase ATM/ATR. Most importantly, we show that MEN1 functions by directly stimulating transcription of several genes, including BRCA1, RAD51 and RAD51AP1, that encode proteins involved in HR. MEN1 and its coactivator, the histone methyltransferase MLL, are recruited to the BRCA1, RAD51 and RAD51AP1 promoters by estrogen receptor 1, resulting in increased histone H3-lysine 4 trimethylation and transcription. Collectively, our results indicate that MEN1 is a melanoma tumor suppressor that functions by stimulating transcription of genes involved in HR-directed DNA repair.
Molecular and cellular biology 05/2013; · 6.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Evidence favoring a critical role for mast cells (MC) in cutaneous malignancies is conflicting. METHODS: Using the immunohistochemical stain tryptase, MC counts were performed in the following tumor categories: epithelial (basal cell carcinoma [BCC]: nodular [N], n = 10, infiltrative [I], n = 10; squamous cell carcinoma [SCC]: well differentiated [W], n = 9, moderate/poorly differentiated [MP], n = 15); melanocytic (intradermal nevus, n = 10, malignant melanoma in situ [MMIS], n = 8, invasive melanoma, n = 15); vascular (hemangioma [HEM], n = 11, Kaposi's sarcoma [KS], n = 14, angiosarcoma [AS] n = 8); and fibrohistiocytic (dermatofibroma [DF], n = 7, atypical fibroxanthoma [AFX], n = 5, dermatofibrosarcoma protuberans [DFSP], n = 5). MC (intra- and peritumoral) were expressed as cells per 10 high-power fields. RESULTS: Mean MC counts were: BCCN 166.30; BCCI 130; SCCW 167.22; SCCMP 133.80; nevus 156.40; MMIS 93; MM radial growth phase 73.86; MM vertical growth phase 82.13; HEM 165.18; KS 120.57; AS 168.13; DF 247.86; AFX 280.20; and DFSP 83.60. Using a one-way analysis of variance, statistically significant differences were observed in the following pairs: AFX and DF vs. DFSP, nevus vs. melanoma, AS and HEM vs. KS. CONCLUSIONS: Our findings appear to point towards a dichotomous role for mast cells in fibrohistiocytic and vascular neoplasms and argue against their preferential recruitment in epithelial malignancies and malignant melanoma. The value of mast cell counts as a prognostic index appears to be limited in most cutaneous malignancies.
International journal of dermatology 04/2013; · 1.18 Impact Factor
[show abstract][hide abstract] ABSTRACT: : In vitro evidence indicates that the E6 protein of human papillomavirus (HPV) targets Bak, a proapoptotic protein, expression of which is enhanced in epidermal keratinocytes in response to ultraviolet B radiation. Given this, our aim was to ascertain Bak expression and prevalence of beta-HPV (β-HPV) in cutaneous squamous cell carcinoma (SCC) from sun-exposed sites to test our hypothesis that the virus plays a role in the neoplastic process by suppressing UV-induced apoptosis. This retrospective study included 30 cases of cutaneous SCC and 30 cases of SCC in situ (SCCIS) from sun-exposed sites. Immunohistochemical staining for Bak protein was performed on all, and β-HPV subtyping on 10 randomly selected cases from each group, using a broad-spectrum polymerase chain reaction-reverse hybridization assay. A semiquantitative scoring system for immunohistochemical expression of Bak was used based on the percentage positivity of the cells. Of cases studied, 30 of 30 (100%) of SCCIS and SCC (mean score 4.2 and 4.6, respectively, demonstrated immunopositivity, albeit to varying degrees, with Bak. Of the selected cases studied with reverse hybridization assay, 7 of 10 (70%) of SCCIS and 3 of 10 (30%) of SCC had β-HPV with HPV-5 being the most common subtype detected. Enhanced Bak immunoexpression confirms the presence of UV-induced apoptosis in both in situ as well as invasive epithelial malignancies, although the lack of differences in expression of Bak between both groups studied suggests that its relevance in disease progression is minimal. Expression of Bak in 100% of HPV-containing lesions from sun-exposed sites suggests that the virus does not abrogate UV-induced apoptosis.
The American Journal of dermatopathology 02/2013; · 1.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: The grenz zone is a narrow area of the papillary dermis uninvolved by underlying pathology. Historically believed to be a feature unique to granuloma faciale, this feature has also been observed in other cutaneous inflammatory conditions, infectious entities, and neoplastic benign and malignant tumors. This review attempts to enumerate cutaneous entities commonly displaying a grenz zone with an emphasis on histopathological features that help in their differentiation. It also attempts to answer the obvious question of why select entities have this histopathologic feature by ascertaining the defining structure of a grenz zone.
The American Journal of dermatopathology 02/2013; 35(1):83-91. · 1.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: The c-myc proto-oncogene is involved in various cellular processes including cell growth, proliferation, and apoptosis. Overexpression and deregulated expression of the gene have been previously linked to several lineage-unrelated, aggressive, and poorly differentiated tumors. The expression of c-myc has also been implicated in hematopoiesis and has been shown to play a crucial role in angiogenesis via a vascular endothelial growth factor-dependent mechanism. This gives c-myc a dual oncogenic function in that tumor growth requires both cell proliferation and angiogenesis to ensure survival and confer an effective malignancy. Amplification of c-myc has been recently reported to be a recurrent genetic alteration in angiosarcomas secondary to irradiation and/or chronic lymphedema. Of note, however, no c-myc gene abnormalities have been demonstrated in cases of primary angiosarcomas or postradiation atypical vascular lesions. More recently, our own experience indicates that c-myc amplification is not normally found in the Kaposi sarcoma and cannot be correlated with expression of the c-Myc protein. This comprehensive review outlines the structure, normal functions, and effects of the deregulated expression of c-myc with particular emphasis on its role in angiogenesis and select cutaneous vascular neoplasms.
The American Journal of dermatopathology 12/2012; · 1.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: The V600E mutation of BRAF has emerged as both an effective biomarker and therapeutic target for select benign and malignant cutaneous and non-cutaneous human tumors and is typically determined using DNA-based techniques that include allele-specific PCR and direct DNA sequencing. Recently however, the development of new antibodies directed against the V600E protein has opened the door for an easier and more efficient strategy for identifying this mutation. Our present aim was to determine the efficacy of one such antibody, anti-B-Raf (V600E), a mouse monoclonal antibody in which the immunogen is a synthetic peptide derived from the internal region of BRAFV600E. A total of 35 cases of primary cutaneous melanoma were evaluated using a combination of DNA-based techniques that included allele-specific PCR and/or direct DNA sequencing and immunohistochemistry. Cases of papillary thyroid carcinomas (n=5) and colorectal carcinomas (n=5), known to harbor the BRAFV600E mutation, served as positive controls for the study. DNA analyses revealed that 6 of 35 (17%) cases of the primary cutaneous malignant melanoma possessed the BRAFV600E mutation. For immunohistochemical analyses, cytoplasmic positivity with anti-B-Raf was noted in 7 of 35 (20%) cases of primary melanoma and in all 10 positive controls. Statistical analyses of the data demonstrated that the sensitivity of the immunohistochemistry was 100% and specificity was 97%. Findings from the current study support the potential use of immunohistochemistry as an ancillary screening tool to assess the BRAFV600E mutation status in primary cutaneous melanoma.Modern Pathology advance online publication, 5 October 2012; doi:10.1038/modpathol.2012.168.
[show abstract][hide abstract] ABSTRACT: Background: The incidence of psoriatic alopecia in psoriatic patients is underwhelming, given the prevalence of psoriasis in the North American population. Recently, a 60-year-old Albanian female, lacking a significant medical history for psoriasis, presented to our clinic with a 1-year history of "dandruff" associated with itch, hair thinning, and histopathologic evidence consistent with prior reports of "psoriatic alopecia." Aims: The absence of preceding or concomitant psoriasis suggests that the patient's alopecia is an antecedent manifestation of psoriasis, thus prompting this retrospective study to ascertain better the relationship between alopecia and psoriasis. Methods: We performed a retrospective review of 33 scalp biopsies on 31 patients having histopathologic diagnosis of psoriasis belonging to 31 patients seen between 2007 and 2010. Results: Alopecia was a presenting feature in 48% of cases with definitive clinical and/or histopathologic diagnosis of psoriasis (scale crust with neutrophils, psoriasiform epidermal hyperplasia, and hypogranulosis). The most common follicular-related changes were infundibular dilatation (87%) followed by perifollicular fibrosis (77%), perifollicular lymphocytic inflammation (68%), thinning of the follicular infundibulum (55%), and fibrous tracts (28%). Of interest, sebaceous glands were absent in 60% and atrophic in 25% of cases. Conclusion: While a major limitation of this study is that it is a retrospective one, given that these changes are common to varying degrees in all lymphocytic scarring alopecias, we posit that psoriatic alopecia likely represents a secondary clinical change to a primary process and is not a unique histopathologic entity. A prospective study with a control group that includes lymphocytic scarring alopecias from non-psoriatic patients is required to support our findings.
Indian journal of dermatology, venereology and leprology 09/2012; 78(5):611-9. · 0.98 Impact Factor
[show abstract][hide abstract] ABSTRACT: Matrix metalloproteinases, a group of over 26 zinc-dependent enzymes, share a similar structure to each other and functionally are capable of degrading almost every component of the extracellular matrix. They are essential to normal development during embryogenesis and extracellular matrix remodeling and, given this, understandably enough have been implicated in multiple pathologic processes that encompass the inflammatory and neoplastic spectrum of disease. This review attempts to define roles of matrix metalloproteinases of relevance in normal skin and to elucidate their roles in inflammatory dermatoses and benign and malignant neoplasms.
The American Journal of dermatopathology 08/2012; 34(6):565-79. · 1.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Distinct ABCB5 forms and ABCF2, members of the ATP-binding cassette (ABC) superfamily of transporters, are normally expressed in various tissues and cells, and enhanced expression of both has been demonstrated in select cancers. In melanoma cell lines, gene expression profiling of ABC transporters has revealed enhanced expression of melanocyte-specific ABCB5 and ABCF2 proteins. Given this, our primary aim was to ascertain immunohistochemical expression of the ABC transporters ABCB5 and ABCF2 and, the stem cell marker, nestin in a spectrum of benign and malignant nevomelanocytic proliferations, including nevi (n=30), in situ (n=31) and invasive (n=24) primary cutaneous melanomas to assess their role in the stepwise development of malignancy. In addition, their expression was compared with established melanoma prognosticators to ascertain their utility as independent prognosticators. A semiquantitative scoring system was utilized by deriving a cumulative score (based on percentage positivity cells and intensity of expression) and statistical analyses was carried out using analysis of variance with linear contrasts. Mean cumulative score in nevi, in situ and invasive melanoma were as follows: 3.8, 4.4 and 5.3 for ABCB5, respectively (P<0.005 for all), and 4.6, 4.6 and 5.3 for nestin, respectively (P=not significant for all). No appreciable expression of ABCF2 was noted in any of the groups. While ulcerated lesions of melanoma demonstrated lower levels of expression of ABCB5 and nestin than non-ulcerated lesions, and nestin expression was lower in lesions with mitoses >1, after controlling for the presence of ulceration and mitotic activity, the expression of both proteins did not significantly correlate with known melanoma prognosticators. The gradual increase in the expression of ABCB5 from benign nevus to in situ to invasive melanoma suggests that it plays a role in melanomagenesis. On the basis of our findings, a prospective study with follow-up data is required to ascertain the utility of ABCB5 as a therapeutic target.
Modern Pathology 05/2012; 25(8):1169-75. · 5.25 Impact Factor
[show abstract][hide abstract] ABSTRACT: Cutaneous clear cell neoplasms represent a heterogenous group of several primary and metastatic tumors with diverse histogenesis. Tumors with widespread clear cell change can seem strikingly similar under the microscope resulting in diagnostic difficulties. Although most cases are idiopathic, intracytoplasmic accumulation, artifact of tissue processing, and degenerative phenomenon have been cited as possible causes of clear cell change. An awareness of the various entities demonstrating this attribute, judicious use of ancillary techniques, and knowledge of the clinical setting are crucial to the accurate diagnosis. This review details the histological features of clear cell neoplasms of the skin with particular emphasis on the discriminating features.
The American Journal of dermatopathology 05/2012; 34(3):237-54. · 1.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: We present an unusual case of a CD56-positive T-cell lymphoma exhibiting immunophenotypic characteristics of both γδ T-cell lymphoma and extranodal NK/T-cell lymphoma, nasal-type. The patient presented with a 2-month history of rapidly progressive, pruritic and cutaneous nodules on his arms. A biopsy showed a dense pan-dermal infiltrate of markedly atypical CD3-positive lymphocytes, compatible with tumor stage cutaneous T-cell lymphoma. Retrospective review of a preceding biopsy and flow cytometric analysis, performed at an outside institution, showed strong expression of surface CD3, CD7, CD43 and γδ T-cell receptor (TCR), findings consistent with a diagnosis of cutaneous γδ T-cell lymphoma. In light of these data, we performed additional studies that showed diffuse positive staining of the atypical lymphocytes for CD56, CD4 and CD43 as well as Epstein-Barr virus-encoded small nonpolyadenylated RNA (EBER). Interestingly, this case displays characteristic features of γδ T-cell lymphoma, with strong surface expression of CD3 and γδ-TCR, as well as characteristics of natural killer (NK)/T-cell lymphoma, including expression of CD4 and EBER positivity, that represent two separate categories in the current classification of cutaneous lymphomas. Taken together, these findings underscore the difficulty of rendering an unambiguous classification of the presented neoplasm given the close ontogenetic relationship between NK and cytotoxic T-cells and highlight the need for continued reevaluation of the current classification system.
Journal of Cutaneous Pathology 05/2012; 39(5):540-4. · 1.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: A reactive histiocytic infiltrate can be seen as an incidental finding in a lymph node biopsy from a patient with a history of joint arthroplasty. We report the case of a 74-year-old female who underwent surgical revision of a polyethylene-based right total knee prosthesis due to chronic wear. At the time of surgery, a soft tissue mass adjacent to the tibial prosthetic insert was noted and excised. Histopathologic examination revealed a sheet-like proliferation of large, histiocytoid cells within the subcutis and superficial fascia. The cells showed abundant eosinophilic, granular cytoplasm and small round bland nuclei. Immunohistochemical evaluation revealed the cells to be positive only for CD68. In addition, abundant PAS-positive cytoplasmic granules were found, and minute particles of polarizable material were noted intracellularly and scattered throughout the interstitium of the infiltrate. These findings were interpreted as consistent with a reactive, non-Langerhans cell histiocytosis secondary to the patient's polyethylene knee prosthesis. This finding appears to be a local correlate of the process previously described in regional lymph nodes as reactive granular histiocytosis. Dermatopathologists should be cognizant of this uncommon reaction pattern to avoid mistaking it for a neoplastic process.
Journal of Cutaneous Pathology 05/2012; 39(5):558-61. · 1.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: Pagetoid reticulosis or Woringer-Kolopp disease (WKD) is a rare variant of mycosis fungoides, consisting of localized patches or plaques containing intraepidermal proliferations of neoplastic T cells in a pagetoid distribution (similar to that of the adenocarcinomatous cells found in Paget disease of the nipple), which typically affects middle-aged and elderly men. We report a trial of photodynamic therapy (PDT) with topical aminolaevulinic acid (ALA), carried out on a 10-year-old boy with a solitary lesion of WKD on his foot, to avoid the long-term problems associated with the typical treatments for WKD of surgery and/or local irradiation. The plaque progressively flattened during treatment, and after nine PDT sessions over 13 months, the patient was clinically free of disease. PDT may be a viable alternative to surgery and local irradiation for localized cutaneous T-cell lymphoma, including WKD, especially in younger patients.
Clinical and Experimental Dermatology 04/2012; 37(7):759-61. · 1.33 Impact Factor