Somatic mutational analysis of MED12 exon 2 in uterine leiomyomas of Iranian women.

Uterine leiomyomas are steroid-hormone dependent tumors of myometrial smooth muscle cells that affect numerous women throughout the world. Based on previous studies, we evaluated the mutations of MED12 gene which encodes a co-activator protein involved in transcription regulation of the vast majority of RNA polymerase II-dependent genes. Exon 2 of MED12 gene was genotyped by PCR-sequencing method. To determine the proportion of mutation-containing transcripts, RNA was extracted from the tissue samples and the corresponding amplified cDNA was sequenced. We observed 11 mutation positive lesions, 7 of them were located in codon 44. The c.131G>A was found to be the most common somatic mutation in this study. Our investigation also demonstrated two unreported mutations , one large deletion and one insertion. cDNA analyzing revealed that the mutated transcripts were predominantly expressed in almost all changes including the new insertion mutation c.122-123ins15. Our study provides further evidence that the MED12 somatic mutations occur in a heterozygous manner and are mostly missense mutations in codon 44. The results displayed 47.8% mutation positive lesions in Iranian patients confirming the diversity between the populations.