TJP1 and breast cancer: Immunohistochemical staining showed that a high expression rate of ZO-1 existed in 10/23 (43.5%) muscle-invasive BC tissues, and a negative correlation between high expression rate of ZO-1 and muscle-invasiveness was found in BC tissues (Spearman's rank order correlation coefficient: -0.303, P < 0.05, Table 1).