PITX1 and head and neck squamous cell carcinoma: Furthermore, the methylation levels of the homeobox gene PITX1 (exon 3) and the adjacent long transgenic non-coding RNA C5orf66-AS1 (lincRNA) are remarkably higher in the tumor tissue than in the adjacent healthy tissue in the samples of HNSCC patients, with subsequent silencing of transcriptional expression, while hypermethylation of both genes has been correlated with an increased risk of mortality [40].