Effect of thalidomide in different tumors in rodents.

This study investigated the effects of chronic administration of thalidomide on three different neoplasms of ectodermic origin in rodents: 1) chemically induced tumors of the nervous system of rats by transplacental exposure to ethylnitrosourea; 2) transplanted RPMI-1846 melanoma in hamsters and 3) transplanted C6 glioblastoma in rats. No effects were seen on thalidomide-treated rats on the frequency- and time of tumor development induced by ethylnitrosourea. In contrast, a reduction in tumoral growth and mitotic-index was obtained in animals treated with thalidomide in transplanted tumors, melanoma and glioblastoma, when compared with controls (P < 0.001 and 0.025, respectively). These results suggest that, although thalidomide is not a cytotoxic drug for neoplastic cells, it might partially inhibit the tumoral growth through any of its pharmacological actions; by blockage of cell-surface adhesion receptors induction of DNA oxidation, or inhibition of angiogenesis. Further investigations on the use of thalidomide perhaps associated to cytotoxic drugs, for treatment of ectodermic neoplasms seem guaranteed.