F2RL1 and non-small cell lung carcinoma: Our findings showed that a synergic effect of the PAR2 inhibitor and gefitinib in preventing cell viability in gefitinib-sensitive cell PC-9, acquired resistant cell PC-9-GR and primary resistant cell A549 (Figures 1I–K), revealing targeting PAR2 could sensitive NSCLC responses to gefitinib.