The CK7 and CK20 immunoprofile is useful in differentiating pulmonary, ovarian, and breast carcinomas (CK7+/CK20−) from colon (CK7−/CK20+), urothelial (CK7+/CK20+), and renal or prostatic carcinomas (CK7−/CK20−) [17]. The gene discussed is KRT7; the disease is breast carcinoma.