CLDN3 and breast cancer: Low-level expression of claudins 3, 4 and 7 together in cytoplasm was connected with higher grade (p = 0.013), larger primary tumor (p = 0.0074), a non-TNBC phenotype (p = 0.0033), and within TNBCs it was strongly connected with basal-like breast cancers (p = 0.0050).