RB1 and uterine corpus sarcoma: Our study confirmed that the key mutant genes characterizing uLMS are TP53, RB1, ATRX and PTEN, which collectively account for 81% of the analyzed tumor samples, a fact that was already anticipated in previous studies [14,15,16,17] and in the recent Memorial Sloan Kettering study on uterine sarcomas [19], whose data were used in this analysis altogether with other data.