SMAD4 and head and neck squamous cell carcinoma: Among oncogenes and TSG that have been implicated in HNSCC, we found copy number gain and loss of EGFR (36% and 1.3% of the samples, respectively), ERBB2 (21.3% and 4% of the samples, respectively), FAT1 (5.3% and 27% of the samples, respectively), SMAD4 (1.3% and 41% of the samples, respectively); and CDKN2A (8% and 54.7% of the samples, respectively).