Association of cachexia with loss of function mutations in STK11/LKB1 for NSCLC.

e15099 Background: Cancer cachexia (CC), a wasting syndrome of muscle and adipose tissue resulting in weight loss, occurs in 50% of non-small cell lung cancer (NSCLC) patients. Management of CC is limited by the absence of biomarkers and knowledge of molecules that drive its phenotype. The evolving landscape of increased genomic testing of human tumors and derived cell lines has further given us an opportunity to leverage these findings to identify a genetic biomarker that regulates CC development through a novel in vivo human NSCLC cachexia screen. Methods: To identify such molecules, we injected 54 human non-small cell lung cancer (NSCLC) lines into immunodeficient mice, 17 of which produced an unambiguous phenotype of cachexia (n = 10) or non-cachexia (n = 7). Whole exome sequencing of tumors was conducted to identify candidate cachexia-associated genes and gene variant analysis was conducted to identify gene variants that associated with NSCLC-associated CC. CRISPR/Cas9 targeted gene silencing in human NSCLC and mouse cancer lines verified if target genes conferred the cachexia phenotype. Circulating tumor DNA analysis of a 246 NSCLC patient cohort was used to confirm candidate gene variants association with cancer-related weight loss. Results: Whole exome sequencing revealed that 8 of 10 cachexia lines, but none of the non-cachexia lines, possessed mutations in STK11/LKB1 (p = 2x10 -12 ), a regulator of nutrient sensor AMP kinase. Silencing of STK11/LKB1 in human NSCLC and murine colorectal carcinoma lines conferred a cachexia phenotype after cell transplantation into immunodeficient and immunocompetent models, respectively. This host wasting was associated with an alteration in the immune cell repertoire of the tumor microenvironments that led to increases in local mRNA expression and serum levels of CC-associated cytokines resulting in host adipose and muscle tissue wasting. Mutational analysis of circulating tumor DNA from 246 NSCLC patients identified 89% concordance between STK11/LKB1 mutations and weight loss at cancer diagnosis (OR = 17 ± 1, p = 0.004). Conclusions: The current data provides evidence that tumor STK11/LKB1 loss of function is a driver of CC in NSCLC, simultaneously serving as the first genetic biomarker for this wasting syndrome.