Hermans BCM, et al. - In a well characterized stage IV large cell neuroendocrine carcinoma (LCNEC) cohort, researchers assessed the expression of PD-L1 and CD8, and compared the expression in the two subtypes of LCNEC, the co-mutated TP53 and RB1 group and the TP53 and STK11/KEAP1 group. Using immunohistochemical (IHC) analysis, they analyzed the expression on pathologically reviewed pretreatment tumor samples for 148 stage IV LCNEC. They found 16% of stage IV LCNEC tumors had positive PD-L1 expression. This was not dependent on molecular subtype, but was found to be related to CD8 expression. Superior overall survival was experienced by LCNEC patients with PD-L1 and/or CD8 expression.