SMARCA4 and ovarian small cell carcinoma: Notably, the loss of SMARCA2 has been observed in some tumors with SMARCA4 deficiency, such as 90-100% of small cell carcinoma of the ovary (hypercalcemic type) (28, 29), 67-80% of thoracic SMARCA4-deficient undifferentiated tumors (14, 30), 15-30% of SMARCA4-deficient non-small cell lung cancer (20, 21), 11% of SMARCA4-deficient gastric adenocarcinoma (23), 15% of SMARCA4-deficient colorectal cancer (25), 70% of undifferentiated endometrial carcinoma (31).