STK11 and head and neck squamous cell carcinoma: Furthermore, our data and results from other studies (c-Bioportal, MSKCC) show that tumors with a clear environmental component including, melanoma, head an neck squamous cell carcinoma, lung squamous cell carcinoma and endometrial squamous cell carcinoma, alterations in LKB1 or NUAK1 are mutually exclusive, reinforcing the role of this molecular axis in DNA damage and genomic instability.