Unsurprisingly, the combination of P2pal-18S and gefitinib notably restricted protein levels of phospho-ERK (∼2.5 fold) in PC-9-GR tumors compared to gefitinib alone detected by western blot analysis (Figure 5D), suggesting that PAR2 inhibition may reactivate gefitinib to block PC-9-GR tumor growth via limiting ERK activation, which consistent with previous in vitro results. Here, F2RL1 is linked to neoplasm.