The highest rates of Upk3b positivity were seen in epithelioid (82.1%) and biphasic mesotheliomas (30.8%; positivity always limited to epithelioid cells), followed by various categories of urothelial tumors (10.8–45.7%) including Brenner tumors of the ovary (10.8%) as well as four other subtypes of ovarian cancers (0.9–10.6%). The gene discussed is UPK3B; the disease is mesothelioma.