Loss of MDA-7 expression with progression of melanoma.

PURPOSE: Ectopic transfer of the melanoma differentiation-associated gene-7 (mda-7) has been shown in vitro to suppress growth and induce apoptosis in a variety of human tumor cell lines; similar effects are not elicited in normal cells. Thus, the mda-7 gene seems to function as a novel tumor suppressor, and there is interest in the potential of mda-7 gene transfer as cancer therapy. The objective of this study was to determine if MDA-7 protein is lost during primary melanoma progression from superficial to invasive stages and from localized to metastatic tumor. As a secondary objective, we analyzed MDA-7 protein expression in primary melanomas for correlation with predictors of outcome and with survival. MATERIALS AND METHODS: MDA-7 protein expression was evaluated by immunohistochemistry in 41 primary melanomas and 41 metastases, including 24 paired samples. Each sample was scored for the percentage of positive cells and the overall intensity of immunolabeling. RESULTS: Significant decreases in MDA-7 immunostaining, reflected in both number and intensity scores, were observed when comparing the intraepidermal and superficially invasive portions with the deeply invasive portions of primary tumors. Significant differences were also observed when comparing primary tumors to paired metastases. CONCLUSION: Downregulation of MDA-7 expression in primary melanomas facilitates progression to invasive and metastatic stages. These data support the development of Ad-mda7 as gene therapy for advanced melanoma.

Expression of thyrotropin-releasing hormone by human melanoma and nevi.

PURPOSE: Thyrotropin-releasing hormone (TRH) is a tripeptide hormone produced by the hypothalamus in response to hypothyroidism. RNA transcripts for the TRH prohormone have recently been described in melanoma cell lines. To expand these findings, we have examined cultured melanoma cells and melanocytes, human melanoma tumors, and nevi for the expression of TRH. EXPERIMENTAL DESIGN: Five melanoma cell lines were analyzed by reverse transcription-PCR/Southern blotting for preproTRH message. The same melanoma lines and two melanocyte lines were examined by immunocytochemistry for TRH protein expression and for growth response to exogenous TRH. Immunohistochemistry was used to test for TRH protein in sections of 19 melanomas, 33 dysplastic nevi, and 27 benign nevi. RESULTS: TRH message and protein were detected in all melanoma cell lines examined. Melanocytes were also found to express TRH protein. Four of the five melanoma cell lines but neither melanocyte line responded with a increase in proliferation to low concentrations of exogenous TRH. TRH immunoreactivity was observed in 12 of 19 melanomas (63%), 23 of 33 (69.7%) dysplastic nevi, and 14 of 27 (51.9%) benign nevi. Expression in dysplastic nevi was significantly greater than in benign nevi. Upon separate analysis of nevi from melanoma patients, the difference between dysplastic and benign nevi was even more significant. However, in healthy individuals, no difference between dysplastic and benign nevi was observed. Furthermore, dysplastic nevi from melanoma patients had a significantly higher percentage of TRH-positive cells when compared with healthy individuals. CONCLUSIONS: TRH is commonly expressed by melanomas and dysplastic nevi and may function as a melanoma autocrine growth factor. The presence of TRH in dysplastic nevi may be predictive for the development of melanoma. Our findings have significant clinical and biological implications for future research into the early stages of melanoma initiation and progression.

Association between clinical characteristics and risk-reduction interventions in women who underwent BRCA1 and BRCA2 testing: a single-institution study.

BACKGROUND: Women who are at increased risk for breast and ovarian cancers, especially BRCA1 and BRCA2 mutation carriers, face a myriad of risk-reduction options, including increased surveillance, chemoprevention, prophylactic oophorectomy, and prophylactic mastectomy. However, little is known about which clinical, demographic, or cancer-related factors are associated with risk-reduction interventions. METHODS: The authors conducted a retrospective review of records for 554 women who had undergone testing at The University of Texas M. D. Anderson Cancer Center between 2000 and 2006 for deleterious BRCA1 and BRCA2 gene mutations. Data were collected on the risk-reduction interventions these women adopted after they underwent genetic testing. These data were tested for associations with demographic and clinical characteristics. RESULTS: Among the 554 women who underwent genetic testing for BRCA mutation, 78 were found to have a deleterious mutation in the BRCA1 gene, and 54 had a mutation in the BRCA 2 gene. Of the 554 women, 85 underwent prophylactic mastectomy, 30 prophylactic oophorectomy, and 52 both surgeries; 387 women opted for surveillance. Women who had BRCA mutations, a history of breast cancer or ductal carcinoma in situ (DCIS), or previous breast biopsies were more likely to have prophylactic surgery. Women with a family history of ovarian cancer were more likely to undergo prophylactic oophorectomy. Women with a personal history of ovarian cancer or advanced breast cancer were more likely to undergo surveillance only. Women with breast cancer who had had a total mastectomy as part of their prior breast cancer treatment underwent prophylactic mastectomy more frequently than women who either had breast-conserving surgery or no history of breast cancer. In multivariate analysis, only positive BRCA mutation carrier status was associated with having had prophylactic surgery. In addition, breast cancer history was significantly associated with prophylactic mastectomy. CONCLUSIONS: Women who were BRCA carriers, women who had a history of breast cancer, DCIS, or breast biopsy, or had a family history of ovarian cancer were more likely to have undergone surgery for cancer risk reduction. Women with ovarian cancer or advanced breast cancer were more likely to have undergone surveillance.