However, concurrent loss of both SMARCA4 and SMARCA2 (referred to as SMARCA4/2 thereafter) characterizes small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), a rare but lethal ovarian cancer affecting young women without other recurrent genetic alterations9–14 and also occurs in other highly aggressive human malignancies, including non-small cell lung cancers (NSCLCs)15,16, undifferentiated thoracic sarcoma17,18, undifferentiated uterine sarcoma19, and dedifferentiated/undifferentiated carcinoma of various organs20–23. The gene discussed is SMARCA4; the disease is undifferentiated carcinoma.