Results of our bioinformatics analysis showed that of the 131 mutated/mutant cancer drivers detected in the TCGA HNSC cohort, the most mutated drivers included TP53, FAT1, NOTCH1, CDKN1, CDKN2A and PIK3CA, in decreasing order of mutational frequency (Figure 1A). The gene discussed is PIK3CA; the disease is cancer.