Expression of small breast epithelial mucin (SBEM) protein in tissue microarrays (TMAs) of primary invasive breast cancers

G P Skliris (1) , F Hubé (2) , I Gheorghiu (1) , M M Mutawe (1) , C Penner (1) , P H Watson (1) , L C Murphy (1) , E Leygue (1) , Yvonne Myal (1)

1 University of Manitoba [Winnipeg]
2 EDC (UMR_7216) - Centre épigénétique et destin cellulaire

Expression of small breast epithelial mucin (SBEM) protein in tissue microarrays (TMAs) of primary invasive breast cancers Aims: Small breast epithelial mucin (SBEM) is a recently described gene product that shows promise as a new breast biomarker. The aim was to investigate for the first time SBEM protein expression in a large cohort (n = 300) of invasive breast cancers, its relationship to established clinical variables and its association with clinical outcome. Methods and results: Immunohistochemical analysis was performed on tissue microarrays consisting of 149 oestrogen receptor (ER) a) and 151 ERa+ breast cancers. Overall, 18% of tumours were SBEM+ (n = 53 ⁄ 300). However, SBEM protein was more frequently observed in ER) (22%) than in ER+ cancers (13%; P = 0.049). A significant association with psoriasin ⁄ S100A7 expression (P £ 0.0001) was observed in the entire cohort. SBEM was also positively associated with HER-2 (P = 0.046) in ER) cancers, and increased levels of SBEM were strongly associated with higher tumour grade (P = 0.0015). Furthermore, SBEM expression showed a trend towards an association with reduced overall survival and relapse-free survival in the ER+ cohort (P = 0.063 and P = 0.072, respectively). Conclusions: Our results suggest that SBEM may identify a unique subset of breast cancers with poor prognosis and may have future implications for therapeutic management of this disease.

Keywords: breast cancer; immunohistochemistry; small breast epithelial mucin; survival analysis; tissue microarrays; tumour biomarker

Domains: Life Sciences [q-bio]; Cancer; Life Sciences [q-bio]; Biochemistry, Molecular Biology; Genomics [q-bio.GN]

G P Skliris, F Hubé, I Gheorghiu, M M Mutawe, C Penner, et al.. Expression of small breast epithelial mucin (SBEM) protein in tissue microarrays (TMAs) of primary invasive breast cancers. Histopathology, 2008, 52 (3), pp.355-369. ⟨10.1111/j.1365-2559.2007.02955.x⟩. ⟨hal-02127337⟩