FOXP4 and cancer: High expression of FOXP4-AS1 was predictive of a larger tumor size (OR = 3.82, 95% CI 2.3-6.3, <i>P</i> < 0.001).<h4>Conclusions</h4>Overexpression of FOXP4-AS1 correlates with poor prognosis of cancer patients, and is a potential prognostic biomarker and therapeutic target.<h4>Systematic review registration</h4>PROSPERO, identifier CRD42021245267.