In endometrial adenocarcinoma (UCEC), 3/321 (0.9%) MSS samples, 4/44 (9.1%) MSI-L samples, and 79/169 (46.7%) MSI-H samples had a frameshift alteration in JAK1, which was statistically significant when comparing MSS and MSI-H (Fig 2F, P < 0.0001, Fisher’s exact test). The gene discussed is JAK1; the disease is endometrium adenocarcinoma.