Expression of reactive oxygen species-related proteins according to androgen and HER-2 status in estrogen receptor-negative breast cancer.

Objective: The purpose of the current study is to understand the clinicopathological implications of redox proteins in association with androgen receptor (AR) and HER-2 status in estrogen receptor (ER)-negative breast cancers through evaluation of the expression patterns of redox proteins, such as catalase, thioredoxin reductase (TxNR), glutathione S-transferase π (GSTπ), thioredoxin interacting protein (TxNIP), and manganese superoxide dismutase (MnSOD).

Methods: Two hundred cases of ER-negative breast cancer samples were collected as a tissue microarray. Immunohistochemical staining was done for redox-related proteins, after which the resulting data set was organized by AR and HER-2 status.

Results: The redox proteins that had a significant association with AR and HER-2 status were tumoral catalase (p < 0.001) and stromal GSTπ (p < 0.001). Tumoral catalase was least expressed in the AR-/HER-2- group, while stromal GSTπ was least expressed in both the AR+/HER-2- and the AR-/HER-2- groups. Stromal GSTπ was highly expressed in HER-2 positive groups (p < 0.001). Stromal GSTπ negativity and tumoral MnSOD positivity were associated with a shorter disease-free survival (p = 0.041 and p = 0.007, respectively) in univariate analysis.

Conclusion: ER-negative breast cancers showed different expressions of redox-related proteins according to AR and HER-2 status. Catalase expression was high in AR-negative groups, while stromal GSTπ expression was high in HER-2-positive groups.