Related Study Of EGFR MRNA In Peripheral Blood Of Breast Cancer Patients And EGFR Protein In Corresponding Tumor Tissues And Pilot Exploration Of Its Clinical Significance

BACKGROUND. Primary breast cancer is one of the commonest malignant tumors of women in the worldwide.Recurrence and metastasis are the most fatal factors of this cancer. There are lack of sensitive and specific indicators to detect early metastasis of breast cancer. By highly sensitive RT-PCR amplification of tumor-specific and tumor-specific mRNA ,we can identify 1 malignant cell mixed with 1 to 10 million normal cells.Therefore, RT-PCR assay is the most effective method to detect malignant tumor micrometastasis~[1]. The overexpression of EGFR takes part in the occurrence and development and metastasis of epithelial malignant tumors.It is reported that the positivity for EGFR protein in primary breast cancer tissues is 14-65%~[2] .CK-19 is the commonly used micrometastic marker of breast cancer in many literatures,but its specificity is still disputed'3 .AIM.To evaluate the feasibility of detecting Epidermal growth factor receptor (EGFR) mRNA by reverse transcription polymerase chain reaction(RT-PCR)in peripheral blood of patients with breast cancer and to explore its clinical significance and relation with treatments.To explore the value of detecting cytokeratin 19(CK-19) mRNA in peripheral blood of patients with breastcancer.To explore the relationship between EGFR mRNA in peripheral blood and EGFR protein in corresponding tumor tissues of breast cancer patients.METHODS.40 patients with breast cancer, 25 patients with benign breast diseases and 30 healthy donors were enrolled in the study.The peripheral mononuclear cells were fractionated using the Ficoll Hypaque gradient method. Then total RNA of mononuclear cells was extracted by TRIzol Reagent. RT-PCR assay was applied to detect the expression of EGFR mRNA of them. The detection of EGFR mRNA was compared with that of known markers of circulating epithelial cells:CK-19. Expression of EGFR protein in corresponding tumor tissues was detected by immunohistochemistry.RESULTS. None of EGFR mRNA was detected in both peripheral blood from 30 healthy donors and 25 patients with benign breast diseases, there is no statistical difference between the two groups above.In contrast ,EGFR mRNA was expressed in 13 of 40(32.5%)patients with breast cancer,compared with healthy donors P<0.01, compared with benign breast disease patients P<0.01,there is significant difference between two groups. On the other hand,expression of EGFR protein was detected in 25(62.5%) of corresponding tumor tissues of 40 breast cancer patients by immunohistochemistry. We found that all patients who expressed EGFR mRNA in peripheral blood were also expressing EGFR protein in primary tumors.Having graded the expression of EGFR protein in tumor tissues,we found that patients with high expression grade of EGFR protein displayed high expression rate of EGFR mRNA in peripheral blood as well(P<0.01). The expression of EGFR gene was significantly correlated with clinical stage , histological grading and ER(P <0.05), but had no coincidence with pathologic type, tumor size, lymph node metastasis ,PR and HER-2 (P >0.05) . EGFR mRNA was expressed in 5 of 26(19.2%) breast cancer patients without any...