CTNNB1 and endometrial endometrioid carcinoma: SPNs displayed low mutational burdens (median: 19, range: 7–50) compared to β‐catenin wild‐type pancreatic tumors (median: 50, range: 1–185; P < 0.0001, Mann–Whitney U) (Bailey et al., 2018; Gao et al., 2013; Jiao et al., 2014; Scarpa et al., 2017; Wu et al., 2011), which is consistent with the finding that a subset of endometrioid endometrial carcinomas driven by CTNNB1 mutations and Wnt pathway activation are characterized by a relatively low tumor mutational burden (Liu et al., 2014).