Prevalence of RAS point mutations in papillary thyroid carcinoma; a novel mutation at codon 31 of K-RAS.

The aim of this study was to assess the incidence of point mutations in RAS oncogenes of papillary thyroid carcinoma (PTC). Tumour specimens were obtained from 29 PTCs. The fragments of exons 1 and 2 of RAS oncogenes family (H- RAS, K- RAS, N- RAS) were amplified and then, point mutations were detected by SSCP and/or by RFLP analysis. Several DNA samples were directly sequenced to confirm the results. Two mutations were found in this study (GAA/CAA at codon 31 of K- RAS and CAA/CAC at codon 61 of N- RAS oncogene). These data confirm the results of previous studies, showing that RAS mutations are more rarely found in PTC than in follicular neoplasms. The influence of a novel mutation at codon 31 of K- RAS oncogene on the development of PTC needs further studies.