This isoform was previously reported as the PR-C isoform in human breast cancer cells [5,6,28], human fetal membranes [25], the rat decidua basalis [40] and the guinea pig cervix [27], suggesting that the ~60 kDa PR protein in the amniochorion and placenta is PR-C (Fig 5). The gene discussed is PPRC1; the disease is breast carcinoma.