Abstract: Background and purpose: Triple negative breast cancer (TNBC) is with high invasion, poor prognosis and lack of usefull treatment. This study investigated expression status of ICAM-1 protein in TNBC in order to explore its relationship with clinicopathological features and outcome in patients. Methods: Fifty-nine tissue samples of TNBC were collected while 50 cases of para-carcinoma tissue samples were used as negative controls. Immunohistochemical staining was conducted to detect expression level of ICAM-1 protein. The relationship of ICAM-1 protein expression with clinicopathological features (age, tumor size, subtype, grade, status of lymph node metastasis, TNM stage, vascular tumor thrombus, nerve infiltration, Ki-67, p53 and E-cadherin expression) and outcome in patients were analyzed. Results: The ICAM-1 protein expression of TNBC was significantly higher than that in adjacent tissues (P=0.000). ICAM-1 expression was related to status of lymph node metastasis, grade and TNM stage (with a P-value of 0.036, 0.027 and 0.048, respectively), while demonstrated an undefined relationship with tumor size, subtype, vascular tumor thrombus and expression of Ki-67, p53 and E-cadherin. The disease-free survival (DFS) of ICAM-1 high expression set was shorter than that of the lower one but has nothing to do with overall survival (OS). In addition, Cox proportional hazards model showed that ICAM-1 expression and lymph node metastasis were independent risk factors of DFS in patients (HR=3.2, 95%CI: 1.6 to 6.4, HR=2.7, 95%CI: 1.28 to 5.9, P<0.05). Conclusion: ICAM-1 could serve as a predictive factor for differentiation status of TNBC. The high expression of ICAM-1 in TNBC may indicate poorer prognosis.

Key words: Triple-negative breast cancer, Intercellular adhesion molecule-1, Immunohistochemistry, Prognosis