L1 Cell Adhesion Molecule and Its Soluble Form sL1 Exhibit Poor Prognosis in Primary Breast Cancer Patients

In the present study, the expression of L1 cell adhesion molecule (L1-CAM) and the serum levels of its soluble form, sL1, were analyzed in 162 primary breast cancer (PBC) patients. Overexpression of L1-CAM in cancer tissues and higher levels of sL1 were associated with worse clinicopathologic characteristics and a poor prognosis. L1-CAM and sL1 might be useful as a biomarker and target for PBC. Introduction: The L1 cell adhesion molecule (L1-CAM) and its soluble form sL1 play a prominent role in invasion and metastasis in several cancers. However, its association with breast cancer is still unclear. Patients and Methods: We analyzed L1-CAM expression and serum sL1 levels in cancer and para-carcinoma tissues from 162 consecutive patients with primary invasive breast cancer (PBC) using immunohistochemistry and an enzyme-linked immunosorbent assay, respectively. The serum sL1 levels were also examined in 38 patients with benign breast disease and 36 healthy controls. Results: L1-CAM was expressed more frequently in cancer tissues than in para-carcinoma tissues (24.1% vs. 5.6%; P < .001), and the mean sL1 levels were significantly greater in PBC than in those with benign breast disease and healthy controls (P = .027). Both L1-CAM(+) thorn expression and higher mean sL1 levels correlated significantly with larger tumor size, lymph node involvement, higher histologic grade, advanced TNM stage, and shorter disease-free survival for PBC patients. Moreover, higher mean sL1 levels were also significantly associated with estrogen receptor-alpha-negative expression, human epidermal growth factor receptor 2-positive (HER2(+)) expression, HER2-enriched and triple-negative molecular subtypes, and L1-CAM(+) thorn expression (P < .05). On multivariate analysis, larger tumor size, nodal involvement, HER2(+) thorn, and higher sL1 levels (>= 0.7 ng/ mL) were independent factors associated with L1-CAM(+) thorn expression (P < .05). No association was found between L1- CAM expression or sL1 level with age, gender, histologic type, or expression of progesterone receptor, Ki- 67, p53, or vascular endothelial growth factor C (P >.05). Conclusion: These results indicate that L1-CAM and sL1 are elevated in PBC and both might affect the prognosis of PBC patients. In addition, sL1 might be a useful marker for screening and diagnosis. (C) 2017 The Authors. Published by Elsevier Inc.