SMAD4 and head and neck squamous cell carcinoma: A recent study demonstrated for the first time that RVT has anti-proliferative, DNA damaging, and apoptotic effects in HNSCC cells independent of Smad4 status, both in vitro and in vivo, implying that more research is needed to establish its potential utility against head and neck squamous cell carcinoma (HNSCC) [73].