Supplementary Material for: High Inner Centromere Protein (INCENP) expression correlates with aggressive features and predicts poor prognosis in patients with invasive breast cancer

Background: Inner centromere protein (INCENP) is a member of the chromosomal passenger complex (CPC) and plays a key role in mitosis and cell proliferation. This study aims to evaluate the clinical and prognostic significance of INCENP in invasive breast cancer (BC). Material and Methods: INCENP protein expression was evaluated on a tissue microarray of a large BC cohort (n=1295) using immunohistochemistry. At the mRNA level, INCENP expression was assessed using the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) (n=1980) and Cancer Genome Atlas (TCGA) BC cohorts (n=854). The correlations between INCENP expression, clinicopathological parameters and patient outcome were investigated. Results: INCENP protein expression was detected in the nucleus and cytoplasm of the tumour cells. Its expression was significantly associated with features characteristic of aggressive BC behaviour including high tumour grade, larger tumour size and high Nottingham Prognostic Index scores. High INCENP nuclear expression was a predictor of shorter BC-specific survival (BCSS) in the whole cohort, as well as in the luminal subtype (p<0.001). High INCENP nuclear expression was predictive of poor prognosis in BC patients who received hormone treatment or chemotherapy. Conclusion: High INCENP expression is a poor prognostic biomarker in BC with potential therapeutic benefits.