The expression of CK-19 gene in circulating tumor cells of blood samples of metastatic breast cancer women

Breast cancer is the most common cancer in women worldwide. Breast cancer in one third of all patients will go on to metastasis, which is the main cause of mortality in cancer cases. Tumor cells detach from primary tumor and enter into the circulation as circulating tumor cells (CTCs) which can form metastatic lesions. In this study, the expression of CK-19 gene in blood samples of metastatic breast cancer women was investigated and compared to control group. Twenty one patients with metastatic breast cancer and 20 healthy female volunteers enrolled in this study. For every patient and healthy donor 10 ml peripheral blood was collected. Peripheral blood mononuclear cells were isolated by gradient density centrifugation using Ficoll Hypaque. CK-19 gene expression was evaluated using SYBR green-based real-time quantitative polymerase chain reaction assays. The relative expression level of CK-19 was calculated using the 2(−ΔΔCt) analysis method. The mean of CK-19 expression was increased in metastatic breast cancer when compared to those of normal women (1.50 fold). 38.1% of the metastatic breast cancer patients showed CK-19 mRNA-detectable CTCs in their blood samples. There was no statistically significant difference between the relative expression level of CK-19 and the patient's clinicopathological characteristics. According to our knowledge, no study for determining CTC biomarkers in Iranian breast cancer women patients has yet been established. Our results suggest that the CK-19 mRNA expression investigation may be useful for monitoring CTCs in the blood of metastatic breast cancer patients, predicting early metastatic relapse or monitoring of anti-metastasis treatments.