Proteogenomic characterization of pulmonary large-cell neuroendocrine carcinoma identifies molecular features and therapeutic strategy.

Pulmonary large-cell neuroendocrine carcinoma (LCNEC) is a rare yet highly aggressive subtype of non-small cell lung carcinoma (NSCLC) with limited therapeutic options. We conduct a comprehensive proteogenomic analysis of LCNEC using tumors and paired normal adjacent tissues from 107 patients (81 pure LCNEC and 26 combined LCNEC). APOBEC mutational signatures strongly correlate processes of tumor initiation and immune suppression, and KEAP1 mutations correlate with metabolic reprogramming in LCNEC combined with NSCLC. A conflicting relationship is observed between neuroendocrine and immune phenotypes. We identify three LCNEC subtypes with unique prognosis features, microenvironment dysregulation, genetic alterations, and potential therapeutic targets. Interleukin-33 (IL-33) emerges as a critical therapeutic biomarker associated with enhanced T cell infiltration and antitumor activity. We further optimize recombinant IL-33 (rIL33) with site-directed mutagenesis and develop PEGylated rIL33, demonstrating its prolonged circulation time in cynomolgus monkeys and superior immune agonist activity in mouse models. Overall, this study offers insights into LCNEC biology and provides promising innovative immunoagonist therapy strategies for lung cancer.