The prognostic impact of FOXM1 immunohistochemical staining in endometrial cancer

To investigate the relationship between FOXM1 immunohistochemical (IHC) staining and recurrence-free survival (RFS) and disease-specific survival (DSS) in patients with endometrial cancer. A retrospective screening of 567 endometrial cancer patients who underwent surgery at Kocaeli University Hospital between January 2017 and December 2023 was performed. IHC analysis for FOXM1 was performed on tissue samples. Cases with no nuclear staining were classified as FOXM1-negative, whereas cases showing any distinct nuclear staining were classified as FOXM1-positive; staining intensity was independently scored as absent, weak, or moderate. Kaplan–Meier and log-rank tests were applied to each prognostic marker for RFS and DSS, and Cox regression was used for the multivariate analysis. Four hundred and three patients were analysed, and FOXM1-positive IHC staining was associated with a worse prognosis in terms of RFS compared to patients with negative staining: 82.3 months ( ± 2.0, 95% CI: 78.4–86.3) versus 89.7 months ( ± 1.3, 95% CI: 87.1–92.4) ( p = 0.001). Similarly, patients with moderate FOXM1 IHC staining had a worse prognosis in terms of RFS than those with weak staining: 65.5 months ( ± 5.4, 95% CI: 54.8–76.2) versus 87.8 months ( ± 1.8, 95% CI: 84.1–91.4) ( p < 0.001). The recurrence risk was found to increase 3.9-fold ( p = 0.034, 95% CI: 1.109-13.749) with weak FOXM1 staining and 13.3-fold ( p < 0.001, 95% CI: 3.746-47.279) with moderate FOXM1 staining when analyzed together with other multiple variables using Cox regression analysis. Estimated DSS was 90.8 months ( ± 1.1, 95% CI: 88.6–93.1) in the FOXM1-negative group and 87.7 months ( ± 1.6, 95% CI: 84.6–90.9) in the FOXM1-positive group ( p = 0.064). Similarly, no significant statistical relationship was found between weak and moderate FOXM1 IHC positivity in terms of DSS, 88.7 months ( ± 1.7, 95% CI: 85.3-92.1) versus 84 months ( ± 4.1, 95% CI: 75.8-92.2), ( p = 0.290). FOXM1 IHC positivity is associated with poor prognosis for RFS in patients with endometrial cancer. Furthermore, the degree of IHC staining was identified as a critical factor in the recurrence of the disease.