MUC1 and endometrial cancer: By contrast, MUC1 IgM ab levels were significantly lower in patients with ovarian or endometrial cancer than in healthy controls (p < 0.001 and p = 0.001, respectively), in patients with endometriosis (p = 0.009 and p = 0.013, respectively), and in patients with benign ovarian tumors (p < 0.001 in both cases).