Prognostic value of decreased FOXP1 protein expression in various tumors: a systematic review and meta-analysis

The prognostic value of forkhead box protein P1 (FOXP1) protein expression in tumors remains controversial. Therefore, we conducted a systematic review and meta-analysis, searching the PubMed, Embase and Web of Science databases to identify eligible studies. In total, we analyzed 22 articles that examined 9 tumor types and included 2468 patients. Overall, decreased expression of FOXP1 protein was associated with favorable overall survival (OS) in lymphoma patients (HR = 0.38, 95% CI: 0.30-0.48, p < 0.001). In patients with solid tumors, decreased FOXP1 expression correlated with unfavorable OS (HR = 1.82, 95% CI: 1.18-2.83, p = 0.007). However, when FOXP1 protein expression was nuclear, decreased expression was also associated with favorable OS (HR = 0.53, 95% CI: 0.32-0.86, p = 0.011). Furthermore, decreased FOXP1 expression resulted in the best OS in patients with mucosa-associated lymphoid tissue (MALT) lymphomas (HR = 0.26, 95% CI: 0.11-0.59, p = 0.001), but the worst OS was observed in non-small cell lung cancer (NSCLC) patients (HR = 3.11, 95% CI: 1.87-5.17, p < 0.001). In addition, decreased FOXP1 expression was significantly correlated with an unfavorable relapse-free survival (RFS) in breast cancer patients (HR = 1.93, 95% CI: 1.33-2.80, p = 0.001).