F2RL1 and non-small cell lung carcinoma: The inhibition of PAR2 also notably facilitated gefitinib to slow down and block PC-9-GR tumor growth, while phosphorylation of ERK was markedly attenuated in tumor tissues from the combination treatment group, in vivo confirming targeting PAR2 could overcome gefitinib in NSCLC via ERK signaling pathway (Figure 5).