Colorectal cancers are typically characterized by a cytokeratin 7-negative/cytokeratin 20-positive (CK7−/CK20+) profile in 65.8% of cases, whereas primary breast cancers predominantly exhibit a CK7-positive/CK20-negative (CK7+/CK20-) pattern [5,9]. The gene discussed is KRT7; the disease is breast cancer.