CLDN4 and neoplasm: No significant differences were observed between the subgroups stratified by other clinicopathological parameters (age, histology grade, vascular involvement, and tumor size) and CLDNs expression, except CLDN4 expression was found to be significantly higher in TNBC patients ≤50 years old with a tumor grade 3 compared to TNBC patients >50 years old or having a tumor grade 2 (P = 0.012 and P = 0.003, respectively) (Table 2).