Detection of specific biomarker hSBEM in breast cancer and its clinical significance

Objective To explore the possibility of human small breast epithelial mucin(hSBEM)as a metastasis marker of breast cancer through blood route by detecting the expression of hSBEM in benign and malignant tumours and peripheral blood.Methods The expression of hSBEM was detected with nested reverse transcription polymerase chain reaction(nested RT-PCR)in 67 samples of breast cancer and adjacent normal breast tissue,16 samples of breast benign lesion tissue,and 67 specimens of peripheral blood from patients with breast cancer,16 specimens of benign breast lesions,and 20 specimens of healthy volunteers,meanwhile the hSBEM expressions tested by nested RT-PCR in 25 other carcinomas tissue samples,including gastric carcinoma(n=5),colorectal carcinoma(n=5),esophageal carcinoma(n=5),lung carcinoma(n=5),and ovary carcinoma(n=5)were also analyzed.Results hSBEM expression was observed in 92.54%(62/67)of breast cancer,87.50%(14/16)of breast benign lesions and 88.05%(59/67)of normal breast tissue,with no significant differences between them(P0.05).None of the samples from the 25 other cancer tissues were positive.In peripheral blood the expression of hSBEM was detected in 50.75%(34/67)patients with breast cancer,with significant increase(P0.05)in the cases of metastatic disease and those with lymph node metastasis compared with localized disease and without lymph node metastasis,but the expression was not found in peripheral blood of patients with benign breast lesions and healthy volunteers.The expression of hSBEM had no correlation with the age of the patients,size of primary tumor,histological type and estrogen or progestin receptor status(P0.05).Conclusions hSBEM,as assessed by nested RT-PCR,shows a mammary-specific and mammary-sensitive expression,and is a sensitive indicator of hematogeneous spread of breast cancer cell.hSBEM is a promising molecular biomarker in detecting breast cancer micrometastases.