RANKL acts an unfavorable prognostic biomarker and potential target in advanced KRAS-mutated lung adenocarcinoma.

OBJECTIVE: Advanced lung cancers carrying Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation remain a group that lacks effective treatments. Receptor activator of nuclear factorκB ligand (RANKL) has been demonstrated to drive malignant phenotypes in lung cancer; however, its role in KRAS-mutant (mt) lung adenocarcinoma (LUAD) is not yet fully elucidated. MATERIALS AND METHODS: The data used to explore expression and prognosis were obtained from The Cancer Genome Atlas, Genotype-Tissue Expression databases, and from our hospital. The proliferation, invasion, and migration capacities of KRAS-mt LUAD cells were evaluated. The prediction model was established via Lasso regression method. RESULTS: RANKL is strongly expressed in advanced KRAS-mt LUAD, and significantly distinct association exists between high RANKL expression and poor survival. The enriched expression of RANKL in advanced KRAS-mt LUAD was confirmed by specimens from our hospital. Further, although not statistically significant, our clinical cohort (n = 57) revealed a longer median progression-free survival in advanced KRAS-mt LUAD patients treated with RANKL inhibitor than those without (300 vs. 133 days, p = 0.210), but not in KRAS-wt ones (208 vs. 250 days, p = 0.334). Decrease of KRAS-mt LUAD cells' capacity for proliferation, invasion, and migration was observed when RANKL was knocked down. Enrichment analysis suggested distinct roles of RANKL between KRAS-mt and KRAS-wt LUAD, with adhesion-related pathways and molecules significantly downregulated in the KRAS-mt RANKL-high tumors. Finally, a model for predicting overall survival of KRAS-wt LUAD was established according to four related key genes (BCAM, ICAM5, ITGA3, and LAMA3), which had good performance in prediction concordance. CONCLUSIONS: RANKL acts as an unfavorable prognostic biomarker for patients with advanced KRAS-mt LUAD. Inhibition of RANKL may be a feasible strategy for this subset of patients.