Aromatase cytochrome P450 gene expression in endometrial carcinoma.

We analysed aromatase gene expression and its regulation in seven cases of endometrioid endometrial carcinoma. Immunohistochemistry revealed the presence of strong aromatase immunoreactivity in the stromal cells of carcinoma in five out of seven cases. A polymerase chain reaction after reverse transcription (RT PCR) revealed varying levels of aromatase transcripts (0.1-27.0 amol ng(-1) total mRNA) in five cases. The alternative use of multiple exons 1 was also examined by identifying various human aromatase transcripts specific for exons 1 in RT-PCR products. Gonadal type or exon 1d was primarily used in three cases in which aromatase overexpression was not detected. The two cases in which fibroblasts type or exon 1b was used with other exons 1 as minor transcripts demonstrated aromatase overexpression in immunohistochemistry and RT PCR analysis. Further studies are required, but alternative splicing as well as use of multiple exons 1 transcripts may result in increased aromatase expression in stromal cells observed in endometrial carcinoma.