Conversely, several of the SCLC-Y lines that we now identify to be SMARCA4-UT have previously been shown to be sensitive to CDK4/6 inhibitors (25), and consistent with this SMARCA4-deficiency, has been shown to be a strong predictor of sensitivity to CDK4/6 inhibitors in NSCLC and SCCOHT tumor models (51, 52). Here, CDK4 is linked to small cell lung carcinoma.