Differential gene expression in progesterone-sensitive and progesterone-insensitive endometrial carcinoma cells.

High doses of progesterone are used in the treatment of advanced and recurrent endometrial cancer. Unfortunately the response rate is relatively low: 10-30%. The mechanisms involved in the development of insensitivity to progesterone treatment of endometrial cancer tissue are largely unknown. As tumour development is thought to be associated with a cascade of genetic alterations, it can be expected that genetic changes are involved in the development of progesterone insensitivity in endometrial carcinomas. We therefore started an investigation to identify, isolate and characterise progesterone-regulated genes involved in progesterone-induced growth inhibition in endometrial carcinoma cells. Using differential display PCR eight progesterone-regulated cDNA clones were identified in endometrial carcinoma cell lines. Four of these progesterone-regulated cDNA clones were regulated in the for growth progesterone-sensitive cell line IK-3H12 and not regulated in the for growth-insensitive cell line ECC-1. This indicates that these four cDNA clones represent potentially important genes, which could be involved in inhibition of growth of endometrial carcinoma tissue by progesterone.