GENETIC BASES OF CUTANEOUS TUMORS

Carcinogenesis is a multigenic phenomenon where 3 prevailing types of genes are involved: oncogenes which stimulate the cell proliferation, tumor suppressor genes which act as inhibitors and metastagenes which contribute to the tumor progress. In animal models it has been shown t hat epithelial skin carcinogenesis proceeds stepwise: initiation, prom otion, premalignant progression and finally malignant conversion. The oncogene c-H-ras and the tumor suppressor gene P53 are the genes whose involvement in these steps of epithelial skin cancers are duly establ ished. Less experimental data are available concerning melanoma. The r ole of the oncogene N-ras, the tumor suppressor gene MTS-1 (encoding f or protein p16) ans the metastagene nm 23 has recently be emphasized. Some cytogenetic abnormalities on chromosomes 1, 6, 9, 10, 11 and 17 h ave also been observed and incite to look for other genes potentially involved in the development of this tumor.