In such cases, the best immunohistochemistry panel is combining uroplakin III and CK20 (bladder), CK20 and CDX2 (colon), TTF-1 (lung), ER and mammaglobin (breast), and WT-1 and PAX8 (ovary) which can differentiate between primary cancers of urinary tract, lung, breast, ovary, and colon though pancreas and salivary gland are left with no specific markers [20]. The gene discussed is CDX2; the disease is cancer.