TP53 and head and neck squamous cell carcinoma: Several genetic changes have been observed in HNSCC patients, including deletion of genetic material on 9p (which codes for p16), 17p (which codes for p53), 18q (which codes for DCC, Smad4, and Smad2,9, 10, 11 as well as the type II TGF‐ receptor (TGFBR2)).12