In lung adenocarcinoma, the genetic background seems to affect the relationship between MET and PD-L1; thus, in tumors with KRAS mutation or those lacking EGFR mutation/KRAS mutation/ALK translocation (so called triple-negative), but not EGFR-mutated tumors, there was a strong positive correlation between MET and PD-L1. Here, ALK is linked to lung adenocarcinoma.