TP53 and cancer: TP53 was mutated in 96.6% tumors in this cohort, which is consistent with many earlier sequencing studies on HGSOC that established TP53 as the dominant mutation in this cancer.2, 3 Previously, the presence of mutations in TP53 had been proposed as a defining feature of HGSOC.7 The three tumors in our cohort which were TP53 mutation negative could possibly be explained by TP53 mutations outside the coding region with unknown function, or TP53 mutations at low frequency below our detection threshold.