As a side note, unique sets of genes up or down-regulated by PRA-PRA, PRB-PRB, and PRA-PRB have been mapped in Hec50co endometrial cancer cells and, from these, endometrial cancer cells expressing both PR isoforms (where heterodimers are possible) have reportedly shown about a tenfold more robust genomic response to progesterone, with over 10× genes found to be regulated by PRA + PRB when compared to the number of genes regulated by PRB and PRA alone (communications with Dr. K. Leslie, also see12 and references therein). This evidence concerns the gene PGR and endometrial cancer.