LACK OF P16 CDKN2 ALTERATIONS IN THYROID CARCINOMAS/

Exons 1-3 of the p16/CDKN2 gene and exons 4-9 of the p53 gene were scr eened for mutations by single-strand conformation polymorphism (SSCP) analysis and direct sequencing of PCR-amplified DNA from human primary thyroid carcinomas and thyroid carcinoma cell lines. The samples incl uded 21 papillary carcinomas, 2 undifferentiated carcinomas, 1 follicu lar carcinoma, 1 medullary carcinoma and 2 cell lines originating from thyroid undifferentiated carcinomas. No homozygous deletions and muta tions in the p16/CDKN2 were observed in any of the primary tumors or c ell lines. In contrast, one of the two undifferentiated carcinomas and both cell lines demonstrated point mutations in the p53 gene. These r esults suggest that p16/CDKN2 gene alteration is not required for mali gnant transformation in the thyroid, while p53 gene mutations may play a role in the progression from differentiated to undifferentiated car cinoma.