Abstract
The frequency and prognostic relevance of RET proto-oncog.somatic mutations in sporadic medullary thyroid carcinoma(MTC)remain controversial.In order to study somatic mutations in the RET proto-oncog.in sporadic MTCs found in the Czech population and to correlate these mutations with clinical and patholog.characteristics,we investigated 48 truly sporadic MTCs by sequencing classical risk exons 10.11,13,14,15 and 16.From the 48 tumors studied,23(48%) had somatic mutation in the RET proto-oncolog.in exons 10,11,15 or 16.The classical somatic mutation Met918Thr in exon 16 was only found in 13 tumors(27%).In five cases, multiple somatic mutations and deletions were detected.A statistically significant correlation between the presence of somatic mutation with more advanced patholog.TNM stages was observed.Other clinical and pathological characteristics did not show any statist.significant association with the presence or absence of somatic mutation.