SMARCA2 and ovarian small cell carcinoma: For example, SMARCA4 deficiency was the most common driver in small cell carcinoma of the ovary hypercalcemic type (SCCOHT) [22] and thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-DUT) [23], while the role of SMARCA2 in the development and progression of undifferentiated carcinomas has been neglected, and more studies are needed in the future.