The detection of micrometastases in the peripheral blood of patients with breast cancer for hSBEM mRNA and CD44V6 mRNA

Abstract

ObjectiveSuccessful treatment of breast cancer greatly depends on the early detection of its metastasis, therefore a sensitive and
specific biomarker for detecting dissemination of the cancer cells will help to achieve this goal. This study was to evaluate
the prognostic significance of human small breast epithelial mucin (hSBEM) and CD44V6 in breast cancer.

MethodsThe expressions of hSBEM mRNA and CD44V6 mRNA were 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 lesions tissue, and
67 specimens of peripheral blood from patients with breast cancer, 16 specimens of benign breast lesions, 20 specimens of
healthy volunteers, and 25 (each five cases) other carcinomas tissue samples, including those of gastric carcinoma, colorectal
carcinoma, esophageal carcinoma, lung carcinoma, and ovary carcinoma, were analyzed for hSBEM mRNA expression by nested RT-PCR.

ResultshSBEM mRNA expression was observed in 62/67 (92.54%) of breast cancer, 14/16 (87.50%) of breast benign lesions and 59/67 (88.05%)
of normal breast tissue, with no significant differences between them (P > 0.05). None of the samples from other cancer tissues were positive. In peripheral blood the expression of hSBEM mRNA was
detected in 34/67 (50.75%) from patients with breast cancer, with significant increasing (P < 0.05) in the cases of metastatic disease (stage IV) and those with lymph node metastasis compared with localized disease
(stage I, II and III) and without lymph node metastasis, but its expression was not found in peripheral blood of patients
with benign breast lesions or healthy volunteers. Although CD44V6 mRNA was significantly higher in breast cancer than in benign
breast lesions tissue and normal breast tissue, its expression in peripheral blood show no significant difference (P > 0.05) in the patients with breast cancer (82.09%), benign breast lesion (75.00%), or healthy volunteers (70.00%). The expressions
of hSBEM mRNA and CD44V6 mRNA had no correlation with the age of the patients, size of primary tumor, histological type and
estrogen or progestin receptor status (P > 0.05).

ConclusionhSBEM mRNA, 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, while CD44V6 shows low sensitivity and specificity in detecting dissemination
of breast cancer cell in peripheral blood. hSBEM mRNA is a promising molecular biomarker for detecting breast cancer micrometastases.