Association Between The Expression Of CK-19 MRNA And Breast Cancer

Objective: Detect the expression of cytokeratin 19(CK-19) mRNA in peripheral blood of breast cancer patients by fluorescence quantitative polymerase chain reaction(FQ-PCR),in order to evaluate its clinical significance as well as relationship with surgery, chemotherapy and pathology.Methods: The sensitivity of this method were examined by using an established human metastatic breast cancer cell line (MCF-7) mixed with normal peripheral blood at various dilutions from 106/ml to 10/ml.Peripheral blood samples were analyzed from 60 patients with early breast cancer (stage II-III) at the times of pre-operation,in a week after operation and after one cycle of adjuvant chemotherapy (Patients accepted adjuvant chemotherapy from 7 to 20 days after operation.). Drew 10ml peripheral blood for detection. Peripheral blood samples from 20 patients of breast benign tumer as control group before operation were collected and processed in the same manner. FQ-PCR was used to detect the expression of cytokeratin 19 mRNA in peripheral blood and breast cancer cell line.Results: CK-19 mRNA were detected in models at dilutions of 106/ml to 102/ml.That means this method can detect a breast cancer cell in 107 blood cells.The detection for CK-19 mRNA in peripheral blood samples from 20 patients of breast benign tumer turned out to be negative. CK-19 mRNA were detected in 18 (30.0%) of 60 patients pre-operation (which had significant difference with control group ,P<0.05),15(25.0%) of 60 patients in a week after operation, 8(13.33%) of 60 patients after one cycle of adjuvant chemotherapy.There were significant difference between pre-operation and after one cycle of adjuvant chemotherapy in CK-19 mRNA.So as in a week after operation and after one cycle of adjuvant chemotherapy ( P﹤0.05).While, there were no significant difference between pre-operation and in a week after operation in CK-19 mRNA(P>0.05). The positive rates of the micrometastasis in stage III higher than stage II,there were significant difference between them(P﹤0.05). The expression of CK-19 mRNA had no relation to estrogen receptor (ER), progestogen receptor (PR) and HER2 status.Its expression had relation to invasion of blood vessel, nerve and metastasis in lymph nodes.The positive results of CK-19 mRNA would increase when there were invasion of blood vessel, nerve or metastasis in lymph nodes.Conclusions: Detecting CK-19 mRNA in peripheral blood by FQ-PCR is a sensitive mothod to detect micrometastasis in peripheral blood of breast cancer patients.It can detect a breast cancer cell in 107 blood cells. The expression of CK-19 mRNA has no relation to estrogen receptor (ER), progestogen receptor (PR) and HER2 status,but has relation to invasion of blood vessel, nerve and metastasis in lymph nodes. The positive rates of the micrometastasis increase with the level of tumor's staging. Postoperative adjuvant chemotherapy may lower the positive rates of the micrometastasis.