Faculty Bibliography

African American (AA) men with prostate cancer (PCa) have worse disease, with a higher incidence, younger age and more advanced disease at diagnosis, and a worse prognosis, compared to Caucasian (CA) men. In addition to socioeconomic factors and lifestyle differences, molecular alterations contribute to this discrepancy. In this review, we summarize molecular genetics research results interrelated with the biology of PCa racial disparity. Androgen and androgen receptor (AR) pathways have long been associated with prostate growth. Racial differences have also been found among variants of the genes of the enzymes involved in androgen biosynthesis and metabolism, such as SRD5A2, CYP17, and CYP3A4. The levels of expression and CAG repeat length of AR also show racial divergence and may be critical molecular alterations for racial disparity. Growth factors and their receptors, which promote cancer cell growth, are another potential cause of the disparity; both EGFR and EPHB2, two of the most studied receptors, show interethnic differences. Differences have also been found among genes regulating cell apoptosis, such as BCL2, which is increased in PCa in the AA population. Recent developments in genetics, proteomics, and genomics, among other molecular biotechnologies, will greatly aid the advancement of translational research on PCa racial disparity, hopefully culminating in the discovery of novel mechanisms of disease, in addition to prognostic markers and novel therapeutic approaches

Several challenges face the development and operation of a biospecimen bank linked to clinical information, a critical component of any effective translational research program. Melanoma adds particular complexity and difficulty to such an endeavor considering the unique characteristics of this malignancy. We describe here a review of biospecimen bank and our experience in establishing a multi-disciplinary, prospective, integrated clinicopathological-biospecimen database in melanoma. The Interdisciplinary Melanoma Cooperative Group (IMCG), a prospective clinicopathological and biospecimen database, was established at the New York University (NYU) Langone Medical Center. With patients' informed consent, biospecimens from within and outside NYU, clinicopathological data, and follow-up information are collected using developed protocols. Information pertaining to biospecimens is recorded in 35 fields, and clinicopathological information is recorded in 371 fields within 5 modules in a virtual network system. Investigators conducting research utilizing the IMCG biospecimen resource are blind to clinicopathological information, and molecular data generated using biospecimens are linked independently with clinicopathological data by biostatistics investigators. This translational research enterprise acts as a valuable resource to efficiently translate laboratory discoveries to the clinic

Histone deacetetylases (HDACs) are a group of corepressors of transcriptional activators and their levels of expression are potentially dysregulated in prostate cancer. Certain inhibitors of histone deacetylases show anti-tumor activity in prostate cancer cell lines. Here, we systemically studied the expression of HDACs in human prostate cancer and the suppression of prostate cancer growth and invasion by HDAC inhibitor SAHA. HDAC1-5 showed increased expression using a combination of DNA microarray, in-situ hybridization, and immunohistochemistry in benign and malignant human prostate tissue as well as RT-PCR and Western blot analysis on various PCa cell lines. Importantly, HDAC inhibitor SAHA suppressed, in particular, prostate cancer cell growth and invasion determined using cell proliferation and Matrigel invasion assays. The findings of this study show that the expression of HDACs and their associated corepressors are increased in prostate cancer in humans and HDAC inhibitor SAHA could serve as a potential therapeutic agent in prostate cancer in addition to anti-androgens

PURPOSE: Activation of the mitogen-activated protein kinase (MAPK) pathway and the phosphatidylinositol 3-kinase/AKT pathway seems to be critical for melanoma proliferation. Components of these pathways are client proteins of heat-shock protein 90 (hsp90), suggesting that inhibition of hsp90 could have significant antimelanoma effects. We conducted a phase II trial using the hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) in melanoma patients. The primary end points were clinical responses and whether treatment inhibited MAPK pathway activity. EXPERIMENTAL DESIGN: Melanoma patients with measurable disease were stratified on the basis of whether or not their tumor harbored a V600E BRAF mutation. The hsp90 inhibitor 17-AAG was administered i.v. once weekly x 6 weeks at 450 mg/m2. Tumor biopsies were obtained pretreatment and 18 to 50 hours after the first dose of 17-AAG, and were snap-frozen. RESULTS: Fifteen evaluable patients were treated; nine had BRAF mutations and six were wild-type. No objective responses were observed. Western blot analysis of tumor biopsies showed an increase in hsp70 and a decrease in cyclin D1 expression in the posttreatment biopsies but no significant effect on RAF kinases or phospho-extracellular signal-regulated kinase expression. Plasma analyzed by mutant-specific PCR for V600E BRAF showed 86% sensitivity and 67% specificity in predicting tumor DNA sequencing results. CONCLUSIONS: At this dose and schedule of 17-AAG, the effects of 17-AAG on RAF kinase expression were short-lived, and no objective antimelanoma responses were seen. Future trials in melanoma should focus on a more potent hsp90 inhibitor or a formulation that can be administered chronically for a more prolonged suppression of the MAPK pathway

BACKGROUND: Nodular melanoma (NM) may be biologically aggressive compared with the more common superficial spreading melanoma (SSM), with recent data suggesting underlying genetic differences between these 2 subtypes. To better define the clinical behavior of NMs, the authors compared their clinical and histopathologic features to those of SSMs at their institution, a tertiary referral center, over 3 decades. METHODS: A total of 1,684 patients diagnosed with 1,734 melanomas were prospectively enrolled. Of these, 1,143 patients (69% SSM, 11% NM, 20% other) were diagnosed between 1972 and 1982; 541 patients (54% SSM, 23% NM, 23% other) were diagnosed between 2002 and the present. Differences between the features of NM and SSM within each time period as well as changes over time were analyzed. RESULTS: The authors found that SSMs are now diagnosed as thinner lesions (P < .0001) with a low incidence of histologic ulceration (P < .0001), whereas there was no significant change in the median tumor thickness or ulceration status of NMs over time (P = .10, P = .30, respectively). The median age at diagnosis of NM, however, did significantly increase over time (51 years to 63 years, P < .01). The median duration of NMs was reported to be only 5 months compared with 9 months in SSM patients. CONCLUSIONS: The authors' data suggest that improvements have been made in the early detection of SSM but not NM. Modifications of current screening practices, including increased surveillance of high-risk patients with an emphasis on the 'E' for 'evolution' criterion of the ABCDE acronym used for early detection of melanoma, are thus warranted

Despite the increasing use of gene transfer strategies in the study of cellular and molecular biology, melanoma cells have remained difficult to transfect in a safe, efficient, and reproducible manner. In the present study, we report the successful use of nucleofector technology to transfect human melanoma cell lines. This technology uses an empirically derived combination of cell line-specific solutions and nucleofector programmes to electroporate nucleic acid substrates directly into the cell nucleus. Using a colorimetric beta-galactosidase assay, we optimized nucleofection parameters for 13 melanoma cell lines, leading to maximum transfection efficiency and cell survival. The combinations of cell solutions NHEM or T and nucleofector programmes A-24 or U-20 produced the best results. We compared nucleofection with two commercially available lipid-based gene transfer systems, effectene and lipofectamine 2000 using a green fluorescent protein reporter vector. Nucleofection demonstrated a 3- to 40-fold improvement in transfection efficiency when compared with the lipid-based counterparts. Nucleofection was also superior in transfecting small-interfering RNA (siRNA) as determined by Western blot analysis. Lastly, we applied nucleofection to the simultaneous transfection of a p53-dependent luciferase plasmid and p53-siRNA. Experiments using dual transfection showed knockdown of p53 expression and silencing of the reporter plasmid. In conclusion, nucleofection is highly effective for the transfer of nucleic acid substrates, singly or in combination, into human melanoma cell lines

OBJECTIVES: The role of socioeconomic factors in the worse outcome of black men with prostate cancer remains unclear. To determine whether socioeconomic factors affect prostate cancer outcomes, we studied a cohort of only black patients to minimize known confounding factors. METHODS: We studied black men treated with radical prostatectomy at New York Veterans Administration Medical Center and Memorial Sloan-Kettering Cancer Center between 1990 and 2005. A centralized pathology review process determined the Gleason score of all cases. Prostate-specific antigen (PSA) recurrence at both sites was defined as PSA of 0.2 or greater with a confirmatory rise. By matching patients' home zip codes to the U.S. Census Bureau database, we obtained corresponding socioeconomic data regarding median household income (income) and percentage of population with a high school (degree). We analyzed income, education, and clinical and pathological parameters for the whole cohort. RESULTS: We studied 430 black patients. They resided in neighborhoods where median household income was $41,498.10 and mean percentage of high school graduates was 73.4%. A total of 88 patients (20.9%) had PSA recurrence. Median follow-up for survivors was 37 months. Neither income nor education evaluated as continuous or categorical variables were predictors of PSA recurrence. When evaluated as composite categorical variable, the combination of greater income and education did not predict disease-free survival. CONCLUSIONS: Data suggest that socioeconomic factors have limited impact on PSA recurrence in black men treated with radical prostatectomy. Thus, biologic factors might have a role in the poor outcomes in this population

While epidermal growth factor receptor (EGFR) dysregulation is known to play a critical role in prostate carcinogenesis, there has been no direct evidence indicating EGFR mutations induce tumorigenesis in prostate cancer. We previously identified four novel EGFR somatic mutations in the EGFR tyrosine kinase domain of prostate cancer patients: G735S, G796S, E804G and R841K. In this study, we investigated the oncogenic potential of these somatic mutations by establishing stable clonal NIH3T3 cells expressing these four mutations and WT EGFR to determine their ability to increase cell proliferation and invasion. In the absence of the EGF ligand, cell proliferation was readily increased in G735S, G796S and E804G mutants compared to WT EGFR. The addition of EGF ligand greatly increased cell growth and transforming ability of these same EGFR mutants. Matrigel invasion assays showed enhanced invasion with G735S, G796S and E804G mutants. Western blot analysis showed that these EGFR mutations enhanced cell growth and invasion via constitutive and hyperactive tyrosine phosphorylation and led to the activation of mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3 (STAT3) and Akt pathways. Our findings demonstrate the oncogenic activation of three novel EGFR somatic missense mutations in prostate cancer. Molecules that regulate the mechanisms of their oncogenic activation represent novel targets for limiting tumor cell progression, and further elucidation of these mutations will have utility in prostate cancer treatment.Oncogene advance online publication, 14 January 2008; doi:10.1038/sj.onc.1210983

OBJECTIVE: To determine the utility of the current diameter criterion of larger than 6 mm of the ABCDE acronym for the early diagnosis of cutaneous melanoma. DESIGN: Cohort study. SETTING: Dermatology hospital-based clinics and community practice offices. Patients A total of 1323 patients undergoing skin biopsies of 1657 pigmented lesions suggestive of melanoma. MAIN OUTCOME MEASURE: The maximum lesion dimension (diameter) of each skin lesion was calculated before biopsy using a novel computerized skin imaging system. RESULTS: Of 1657 biopsied lesions, 853 (51.5%) were 6 mm or smaller in diameter. Invasive melanomas were diagnosed in 13 of 853 lesions (1.5%) that were 6 mm or smaller in diameter and in 41 of 804 lesions (5.1%) that were larger than 6 mm in diameter. In situ melanomas were diagnosed in 22 of 853 lesions (2.6%) that were 6 mm or smaller in diameter and in 62 of 804 lesions (7.7%) that were larger than 6 mm in diameter. Conclusion The diameter guideline of larger than 6 mm provides a useful parameter for physicians and should continue to be used in combination with the A, B, C, and E criteria previously established in the selection of atypical lesions for skin biopsy