PPP1R13L and head and neck squamous cell carcinoma: Since its discovery, iASPP was shown to be encoded by the Protein Phosphatase 1 Regulatory Subunit 13-Like (PPP1R13L) gene, which is overexpressed in many tumors including acute leukemia [12], breast cancer [1], glioblastoma [13], ovarian cancer [14], and head and neck squamous cell carcinoma [15].