Simultaneously, results generated from PrognoScan based on the GEO dataset of GSE31210 indicated that decreased mRNA expression of TCF21 is not only an unfavorable prognostic factor for lung adenocarcinoma patients’ relapse-free survival (HR = 0.59; 95% CI: 0.46–0.76; P = 0.000032; n = 204) (Fig. 7a) but also for overall survival (HR = 0.71; 95% CI: 0.55–0.91; P = 0.006584; n = 204) (Fig. 7b). Here, TCF21 is linked to lung adenocarcinoma.