Utility of ankyrin 3 as a prognostic marker in androgen-receptor-positive breast cancer

Purpose: Androgen receptor (AR) and AR signaling pathways are thought to play a role in breast cancer (BC) and are potentially related to treatment responses and outcomes. Ankyrin 3 (ANK3) is associated with AR stability in cancer cells. In the present study, we investigated the clinicopathological utility of ANK3 expression with emphasis on AR and its associated signalling pathway at transcriptomic and proteomic phases. Patients and methods: The Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) cohort (n = 1980) and The Cancer Genome Atlas (TCGA) dataset (n = 1039) were used to assess the expression and significance of ANK3 mRNA and other AR signalling pathway-associated gene signature. Using immunohistochemistry, ANK3 protein expression was evaluated in large (n = 982) cohort of early-stage BC with long-term follow-up and compared with clinicopathological characteristics and its prognostic value in the whole cohort and the subgroups stratified by AR protein expression. Results: An AR-related gene signature was developed, comprising 20 genes, which included ANK3. This AR-related gene signature was significantly associated with AR mRNA expression, oestrogen receptor, human epidermal growth factor receptor 2 (HER2) status and the patients’ outcomes. In tumours with high AR protein expression (n = 614), high ANK3 protein expression was significantly associated with progesterone receptor positivity and it was independently associated with the good outcomes (p = 0.025). Conclusions: This study indicates that ANK3 is related to AR signalling pathway and is associated with BC prognosis.