In supporting out speculation, the different expression patterns of FPRs were observed in 6 GC cells (5 cell lines and a primary GC cell) and 6 fresh GC specimens, in which all 6 cells and specimens expressed FPRs, but the expression levels of FPR2 in 5 of 6 cells and specimens were much higher than that of FPR1 and FPR3 (Fig. S4A and B). Here, FPR3 is linked to gastric cancer.