High expression of cytoplasmic FOXO3 protein associated with poor prognosis of rectal cancer patients: A study from Swedish clinical trial of preoperative radiotherapy to big database analysis

•High FOXO3 expression was strongly associated with late TNM stages, distant recurrence, and poor prognosis in RT patients.•The FOXO3 and FOXM1 protein levels increased from the normal mucosa to the primary cancer.•FOXO3 is closely related to metabolism-related signalling pathway which is in turn associated with cancer radioresistance.•FOXO3 may be a key predictive biomarker to optimise RT for rectal cancer patients to improve prognosis.