An analysis of the data sets shown in Fig. 1 revealed that GPR87 expression is significantly associated with both relapse and prognosis in stage I lung adenocarcinoma patients (Fig. 7a,b; relapse: P=4.0 × 10−3 for GSE13213 and P=7.8 × 10−4 for GSE31210, t-test; survival: P=9.0 × 10−3 for GSE13213, 3.1 × 10−2 for overall survival of GSE31210 and P=2.9 × 10−3 for relapse-free survival of GSE31210, log-rank test). This evidence concerns the gene GPR87 and lung adenocarcinoma.