Although TP53, CDKN2A, NOTCH1, FAT1 and CASP8 are consistently identified as key genes involved in the pathogenesis of oral squamous cell carcinoma, their precise biological and clinical roles, particularly their prognostic value, remain partly controversial, due to differences in genetic alteration, population background, tumor subsite and methodological settings. This evidence concerns the gene NOTCH1 and neoplasm.