Marius Lund‐Iversen

Abstract Pulmonary large-cell neuroendocrine carcinomas (LCNECs) have similarities with other lung cancers, but their precise relationship has remained unclear. Here we perform a comprehensive genomic ( n = 60) and transcriptomic ( n = 69) analysis of 75 LCNECs and identify two molecular subgroups: “type I LCNECs” with bi-allelic TP53 and STK11 / KEAP1 alterations (37%), and “type II LCNECs” enriched for bi-allelic inactivation of TP53 and RB1 (42%). Despite sharing genomic alterations with adenocarcinomas and squamous cell carcinomas, no transcriptional relationship was found; instead LCNECs form distinct transcriptional subgroups with closest similarity to SCLC. While type I LCNECs and SCLCs exhibit a neuroendocrine profile with ASCL1 high / DLL3 high / NOTCH low , type II LCNECs bear TP53 and RB1 alterations and differ from most SCLC tumors with reduced neuroendocrine markers, a pattern of ASCL1 low / DLL3 low / NOTCH high , and an upregulation of immune-related pathways. In conclusion, LCNECs comprise two molecularly defined subgroups, and distinguishing them from SCLC may allow stratified targeted treatment of high-grade neuroendocrine lung tumors.

PURPOSE: Immunoscore is a prognostic tool defined to quantify in situ immune cell infiltrates, which appears to be superior to the tumor-node-metastasis (TNM) classification in colorectal cancer. In non-small cell lung cancer (NSCLC), no immunoscore has been established, but in situ tumor immunology is recognized as highly important. We have previously evaluated the prognostic impact of several immunological markers in NSCLC, yielding the density of stromal CD8(+) tumor-infiltrating lymphocytes (TIL) as the most promising candidate. Hence, we validate the impact of stromal CD8(+) TIL density as an immunoscore in NSCLC. EXPERIMENTAL DESIGN: The prognostic impact of stromal CD8(+) TILs was evaluated in four different cohorts from Norway and Denmark consisting of 797 stage I-IIIA NSCLC patients. The Tromso cohort (n = 155) was used as training set, and the results were further validated in the cohorts from Bodo (n = 169), Oslo (n = 295), and Denmark (n = 178). Tissue microarrays and clinical routine CD8 staining were used for all cohorts. RESULTS: Stromal CD8(+) TIL density was an independent prognostic factor in the total material (n = 797) regardless of the endpoint: disease-free survival (P < 0.001), disease-specific survival (P < 0.001), or overall survival (P < 0.001). Subgroup analyses revealed significant prognostic impact of stromal CD8(+) TIL density within each pathologic stage (pStage). In multivariate analysis, stromal CD8(+) TIL density and pStage were independent prognostic variables. CONCLUSIONS: Stromal CD8(+) TIL density has independent prognostic impact in resected NSCLC, adds prognostic impact within each pStage, and is a good candidate marker for establishing a TNM-Immunoscore.