Mutational analyses of candidate genes in human squamous cell carcinomas

A. Petroianu, M.D., Ph.D., L.A.C. DeMarco M.D., Ph.D., W.L.C.M. Bozon M.D.

Medical School of the Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil

AIM: The molecular mechanisms involved in tumorigenesis of squamous cell carcinomas remain largely unknown, but sequence alterations have been identified in coding regions of several genes. The aim of the present work was to examine whether several specific mutations are present in primary squamous cell carcinomas from a variety of tissues in a cohort of consecutive Brazilian patients. METHODS: We analyzed primary squamous cell carcinomas of various tissues (skin, head and neck, esophagus, lung, penis, uterus and vagina) from 52 patients for the presence of mutations within: Gs (&alpha), Gi2(α), N-terminal SH2 region of GTPase activating protein (GAP), and patched (PTCH) genes. Mutational assessment scheme included PCR, DGGE, SSCP and selected sequence analysis. RESULTS We could not demonstrate mutations in any of the potential candidate genes that we analyzed. No atypical migration patterns or sequence alterations were detected when all exons were studied, indicating that the investigated DNA apparently does not contain point mutations or sequence alterations in these regions in any of the present genes. CONCLUSIONS: Our data suggest that GTPase activating protein (GAP), PTCH, Gs(α) and Gi2(α) genes are not responsible for the development of human squamous cell carcinoma. Mutations looked for within these genes do not occur frequently in an unselected population of patients with this tumor.

KEY WORDS: Gs(&alpha, Gi_(2)(&alpha, .

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Carcinogenesis.