IFITM3 and breast carcinoma: To explore the broader relevance of this association beyond SCLC, we performed pan-cancer analyses and found that IFITM3 expression was consistently positively correlated with key MHC-I genes in tumors characterized by low baseline MHC-I expression, including neuroblastoma, prostate cancer, low-grade gliomas, and breast cancer [28–31] (Supplementary Figs. 2F).