TFF1 and small cell lung carcinoma: We also observed that previously proposed NE and non-NE markers (e.g., CHGA, SYP and REST) as well as SCLC subtype-specific markers (e.g., MYC, BCL2, DLL3, and TFF1) showed variable expression across SCLC subtypes, suggesting that these are not suitable for distinguishing between SCLC-M and SCLC-I tumors as single markers.