We determined the concentrations of immunoreactive epidermal growth factor in the urine (U-irEGF) of 97 adult patients with various malignancies, including carcinomas of the urinary bladder, kidney, stomach, colon, rectum, breast, endometrium, uterine cervix, ovary, vagina, prostate, pancreas and thyroid, liposarcoma and skin melanoma. The relative U-irEGF concentrations (ng m-1 creatinine) were higher (P = 0.002) for the whole series of female patients than for healthy controls matched for sex and age. Such difference did not appear for male patients. The only specific group with a statistically supranormal U-irEGF concentration (P = 0.0005) comprised women with endometrial carcinoma of the uterus.