ABSTRACT
Background and purpose:Aberrant DNA methylation that leads to the inactivation of tumor suppressor genes plays important roles in development and progression of breast cancer. Clinically, related gene methylation is considered to be a promising biomarker for tumor diagnosis and prognosis. This study aimed to investigate the methylation status ofSox17 gene in breast cancer tissue and its corresponding plasma circulating DNA, as well as to investigate its value in breast cancer early diagnosis and prognosis.Methods:TheSox17 gene promoter methylation status was detected by MSP in 86 cases of breast cancer, 36 normal breast tissues and its paired plasma DNA, the results were analyzed with corresponding clinical and pathological features.Results:The frequency ofSox17 gene methylation rate among 86 breast cancer tissues was 77.9%(67/86), and was 61.6%(53/86)in plasma circulating DNA, however, noSox17 gene methylation was found in normal breast tissues.Sox17 gene promoter methylation in plasma circulating DNA was signiifcantly associated with the methylation status in tumor tissues (r=0.502,P=0.000). In breast cancer tissue specimens,Sox17 methylation status was significantly correlated with tumor stage (χ2=6.18,P=0.041) and lymph node metastasis (χ2=13.54,P=0.001);Sox17 gene methylation rate was signiifcantly correlated with tumor stage (χ2=27.06,P=0.000), tumor size (χ2=9.65,P=0.007) and lymph node metastasis (χ2=20.80,P=0.000) in plasma samples, and there was no signiifcant difference ofSox17 gene methylation between patient age, histological grade and ER, PR, HER-2/neu status.Conclusion:Sox17 gene promoter methylation plays an important role in the carcinogenesis and development of breast cancer, and may be associated with the prognosis of breast cancer. Furthermore, methylatedSox17 gene may be a useful tumor biomarker in plasma circulating DNA for breast cancer detection and disease monitoring.
ABSTRACT
Objective To establish an isolation method for solid GTC in peripheral blood using EpCAM antibody-linked nanobeads and evaluate the sensitivity of the method and its application significance. Methods Five, ten, twenty, fifty and one hundred MCF7 (breast cancer), KYSE70 (esophageal cancer), BxPC-3 (pancreatic cancer) and 9811P (stomach cancer) cells were added into 7. 5 ml erythrocyte lysed peripheral blood obtained from healthy volunteers respectively. EpCAM antibodylinked nanobeads were used to enrich cancer cells. The recovery rates of the in vitro added cancer cells were evaluated by fluorescence microscopy. Then, the untreated thirty cases of esophageal cancer (six cases at stage Ⅰ and Ⅱ, twenty-four cases at stage Ⅲ and Ⅳ), thirty-five cases of breast cancer (fifteen cases at stage Ⅰ and Ⅱ , twenty cases at stage Ⅲ and Ⅳ), thirty cases of pancreatic cancer (five cases at stage Ⅰ and Ⅱ , twenty-five cases at stage Ⅲ and Ⅳ), thirty-three gastric cancer (thirteen cases for stage Ⅰ and Ⅱ ,twenty cases at stage Ⅲ and Ⅳ) were enrolled to enrich the peripheral blood CTC. Thirty healthy volunteers and thirty gastritis patients served as two groups of control. Meanwhile the enriched CTC was identified by IF and HE staining. FISH was used to analyze the copy number of chromosome 8 and chromosome 20 in two hundred esophageal cancer, breast cancer, pancreatic caner and gastric cancer CTC. Results After DAPI staining and mixing with 7.5 ml peripheral blood from healthy donors, the average cell recovery rates of KYSE70, MCF7, BxPC-3 and 9811P cells evaluated under fluorescence microscope were 87%, 87%, 86% and 88% (within group), and the recovery rates of 5 gradient dilution levels were 88%, 85%, 87%, 88% and 87% (intergroup). With a high sensitivity, this method was able to isolate one cancer cell in 107 white blood cells of peripheral blood. The positive rates of more than 2 CTC in the peripheral blood detected by this method were 50% (15/30) of esophageal cancer, 63% (22/35) of breast cancer, 70% (21/30) of pancreatic cancer and 61% (20/33) gastric cancer patients respectively,but no CTC was detected in the peripheral blood of healthy volunteers and gastritis patients (P = 0. 000).The aneusomy of chromosome 8 and chromosome 20 were found in 80% esophageal cancer, 75% breast cancer, 65% pancreatic cancer and 59% gastric cancer. Conclusions The CTC isolation technique with EpCAM antibody-linked nanobeads is sensitive and accurate. The aneusomy of chromosome 8 and 20 is frequent in CTC from esophageal cancer, breast cancer, pancreatic cancer and gastric cancer.