Co-Occurring Mutations in NSCLC: Influence on Prognosis and Immunotherapy Response

In this segment, Dr. Jani and Dr. Singhi discuss how co-occurring genetic alterations beyond classic driver mutations influence prognosis and treatment expectations in NSCLC. Dr. Singhi explains that co-alterations such as STK11, KEAP1, MTAP loss, and TP53 are increasingly recognized as modifiers of immunotherapy response and prognosis. He emphasizes these are not standalone treatment selectors like EGFR or ALK, but they shape expectations and guide decisions about combination therapies or clinical trials.

Dr. Singhi highlights STK11-mutant NSCLC, noting it frequently co-occurs with KRAS-altered disease and is associated with reduced responsiveness to single-agent immune checkpoint blockade. Even when PD-L1 is higher than expected, he remains cautious and considers dual immunotherapy strategies or trial enrollment. Dr. Jani adds that growing meta-analysis data are clarifying the role of dual checkpoint inhibition in this setting.

On MTAP loss, Dr. Singhi notes it occurs in approximately 10–15% of NSCLC overall and up to 40% of ALK-positive cases. MTAP loss may qualify patients for PRMT5 inhibitor trials, which exploit a metabolic vulnerability created by the loss. He stresses that NGS and IHC provide complementary assessments: NGS can miss MTAP loss when tumor content is low, while IHC captures protein-level heterogeneity. Dr. Jani draws a parallel to HER2, where IHC and mutation testing similarly complement each other.

In the next episode, "EGFR-Targeted Therapy Sequencing in NSCLC: Navigating Resistance," the experts discuss sequencing therapies after progression on EGFR-directed treatment.