Switch/sucrose non-fermentable complex component (SMARCA2, SMARCA4, SMARCB1, ARID1A, and/or ARID1B) deficiency and loss of mismatch repair protein expression are common immunohistochemical features of undifferentiated endometrial carcinoma and the dedifferentiated component of dedifferentiated endometrial carcinoma 46–49. Here, SMARCA4 is linked to endometrial carcinoma.