SMARCA4 and sarcomatoid carcinoma: SMARCA4-UT is strongly associated with smoking and displays a molecular profile similar to that of smoking-related non-small cell lung carcinoma (NSCLC) and also exhibits a focal expression of NSCLC markers such as TTF1 and p40, as reported by Rekhtman et al. suggesting that SMARCA4 deficient thoracic sarcomas are conceptually similar to sarcomatoid carcinomas and have undergone epithelial-mesenchymal transition (2).