Taking together the ER-negative patients, whose clinicopathologic features are detailed in Supplementary Table 4 (available online), dMMR tumors (n = 9) showed a better prognosis both in terms of overall and disease-free survival compared with pMMR (n = 33) and hMMR (n = 7) neoplasms (P < .001), with 87 months of median survival (range = 73–123 months) for the former compared with 79 months (range = 8–113 months) for the latter two categories (P < .001). This evidence concerns the gene ESR1 and neoplasm.