DDB2 and head and neck squamous cell carcinoma: Re-expression of DDB2 in mouse embryonic fibroblasts (MEFs) isolated from Ddb2 (−/−) knockout-mice resulted in repression of EMT-regulatory factors Zeb1, Snail and Tgfb2. Taken together, these results support the active role of DDB2 as a candidate suppressor of the EMT-process in HNSCC.