ABSTRACT
Medullary Thyroid Carcinoma [MTC] occurs in either sporadic or hereditary forms. The susceptibility gene for hereditary MTC is the RET proto-oncogene. The aim of this study was to evaluate the prevalence of common germline RET mutations in exons 10 and 11 among Iranian MTC patients. 57 non-related MTC patients were examined in this survey [F: M=1.2:1.0, 40.0 +/- 11.5 years]. Genomic DNA was extracted from their peripheral blood samples and exons 10 and 11 of the RET proto-oncogene were amplified using polymerase chain reaction [PCR]. The PCR products were then digested by specific restriction enzymes and the Restriction Fragment Length Polymorphism [RFLP] patterns were analyzed for common RET mutations in exons 10 and 11. Only the MEN2A patient displayed a C634W mutation in exon 11. Three of the six first-degree relatives of the MEN2A evaluated patient had the same mutation. Among apparently sporadic MTC patients [53 cases], one patient showed a C620R mutation in exon 10 and two other patients displayed C634Y mutations in exon 11 of the RET proto-oncogene. Neither were the only MEN2B patient nor the two FMTC patients found to carry germline mutations in exons 10 and 11 of the RET proto-oncogene. It seems that the prevalence of germline RET mutations in exons 10 or 11 is prominent [5.7%] among Iranian, apparently sporadic, MTC patients. We conclude that a routine germline mutation analysis of the RET proto-oncogene should be advised for apparently sporadic MTC patients. Hereditary forms of MTC require a more extended investigation for RET mutations