Anti-TTF is a marker that is both sensitive and specific for primary adenocarcinomas, bronchoalveolar carcinomas, and small cell carcinomas when a thyroid primary is ruled out [24], whereas CK7+/20 is a marker that is sensitive but not specific for primary adenocarcinomas and bronchoalveolar carcinomas [24–26]. This evidence concerns the gene RHOH and small cell carcinoma.