DIFFERENT RAS GENE MUTATIONAL FREQUENCIES IN THYROID PAPILLARY CARCINOMAS IN JAPAN AND THAILAND

The incidence and pattern of ras oncogene mutations in human malignanc ies demonstrate geographic and racial differences. For example, specif icity of alterations is found in cholangiocellular carcinomas in Thai patients with a different etiology from those in Japanese patients. In the present study, a comparison of ras gene mutations in thyroid papi llary carcinomas from Japanese and Thai patients was performed using s ingle-strand conformation polymorphism and direct sequencing analyses. The incidence of ras mutation differed markedly in Japanese (two of 2 4 carcinomas, 8.3%) and Thai (five of 10 carcinomas, 50%) patients. In addition, all but one ras mutation occurred at codon 12 of the K-ms g ene in the Thai cases. These results suggest that thyroid cancers in T hailand may be due to specific genetic and/or environmental factors. ( C) 1998 Elsevier Science Ireland Ltd. All rights reserved.