PMS2 and ovarian carcinoma: Subsequent work has shown partial down-regulation of PMS2 in human cancer cell lines WM9, MDA-MB-231 and MDA-MB-435.TO.1 grown as spheroids compared with sub-confluent monolayer cultures and substantial down-regulation of MLH1, PMS2 and, occasionally both genes, in human breast, prostate, and ovarian cancer cell lines [19].