PTEN and head and neck squamous cell carcinoma: The most obvious effects on outcome for HemDel PTEN losses were observed in head and neck squamous cell carcinomas (HNSCC) harboring a mono-allelic somatic loss-of-function mutation in TP53. For this type, the hemizygous loss was associated with a less favorable overall survival with a significant HR of 1.67 (P = 0.023) (Fig. 3, Supplementary Table 2).