Overexpression of L1 cell adhesion molecule correlates with aggressive tumor progression of patients with breast cancer and promotes motility of breast cancer cells

L1 cell adhesion molecule (L1CAM) has been observed to be aberrantly expressed and implicated in progression of several types of human cancers. However, its roles in breast cancer have not been fully elucidated. In this study, we aimed to investigate the clinical significance of L1CAM in human breast cancer and to validate whether it participates in cancer cell migration and invasion. Immunohistochemical analysis of 100 breast cancer and matched non-cancerous breast tissues was performed to detect the expression and sub-cellular localization of L1CAM protein. Its associations with clinicopathological characteristics of breast cancer patients were statistically analyzed and its phenotypic effects were also evaluated in vitro. Of the 100 breast cancer patients, 89 (89.0%) were positive for L1CAM immunostaining localized in the membrane of cancer cells. The immunoreactive scores of L1CAM protein in breast cancer tissues were significantly higher than those in matched non-cancerous breast tissues (P