Overexpression of Aldo-keto reductase family 1 B10 protein in ductal carcinoma in situ of the breast correlates with HER2 positivity

Ductal carcinoma in situ of the breast constitutes the early stage of breast cancer when cancer cells are confined by the intact myoepithelial cell layer. Transition from DCIS to invasive carcinoma is a process yet poorly understood. By liquid chromatography (LC) and mass spectrometry (MS/MS) methods, we analyzed this early event using paired samples of micro-dissected cells overlaid with focally disrupted myoepithelial layers and their adjacent counterparts within the intact duct from formalin-fixed paraffin-embedded blocks. AKR1B10, a member of Aldo-keto reductase family, was shown to be abundantly located in the filtering cells among a catalog of proteins. Moreover, strong correlation between AKR1B10 and HER2 positivity was found in an independent cohort of DCIS samples. AKR1B10 could become a potential diagnosis and therapeutic marker for early breast cancers with HER2 overexpression and poor prognosis.