Circulating Tumor Cells in Breast Cancer: A Step Toward Precision Medicine for Real-Time Monitoring of Metastasis

Tumor metastasis involves the dissemination of malignant cells into the basement membrane and vascular system contributes to the circulating pool of these markers. In this context our aim has been focused on development of a non-invasive score based on degradation of glycosaminoglycans in the extracellular matrix for assessment of metastasis in patients with breast cancer. Circulating tumor cells (CTCs) represent a unique liquid biopsy carrying comprehensive biological information of the primary tumor. Herein, we sought to develop a novel score based on the combination of the most significant CTCs biomarkers with and routine laboratory tests for accurate detection of Metastases in patients with breast cancer. Cytokeratin 18 (CK18), Cytokeratin 19 (CK19) and CA15.3 were assayed in metastatic breast cancer patients (88), non-metastatic breast cancer patients (129) and healthy control (32). Areas under receiving operating curve (AUCs) were calculated and used for construction on novel score. A novel score named CTC-MBS = CA15.3 (U/L) × 0.08 + CK 18 % × 2.9 + CK19 × 3.1. CTC-MBS score produces AUC of 1 for differentiate patients with metastatic breast cancer from those with non-metastatic breast cancer with sensitivity and specificity of a cut-off 0 (i.e., less than 0 the case is considered metastatic, whereas above 0 it is considered non-metastatic. CTC-MBS score is a novel, non-invasive and simple can applied to discriminate patients with metastatic breast cancer and could replace CA15.3 during screening and follow-up of breast cancer patients.