OBJECTIVES:The aim of this study was to discover new potential biomarkers of breast cancer and investigate their cellular functions. MATERIALS AND METHODS:We analysed the gene expression profiles of matched pairs of breast tumour and normal tissues from 24 breast cancer patients. Tetracycline-inducible MAMDC2 expression system was established and used to evaluate cell proliferation in vitro and in vivo. MAMDC2-mediated signalling was determined using immunoblot analysis. RESULTS:We identified MAMDC2 as a down-regulated gene showing significant prognostic capability. Overexpression of MAMDC2 or treatment with MAMDC2-containing culture medium significantly inhibited the cell proliferation of T-47D cells. Furthermore, MAMDC2 expression reduced in vivo growth of T-47D xenograft tumours. MAMDC2 may exert its growth-inhibitory functions by attenuating the MAPK signalling pathway. CONCLUSION:We report that MAMDC2 has a tumour-suppressive role and, as a secretory protein, it might be useful as a biomarker for breast cancer treatment.
KEYWORDS: biomarkers, breast cancer, cell proliferation, tumour suppressor