Quantitative proteomic profiling of breast cancers using a multiplexed microfluidic platform for immunohistochemistry and immunocytochemistry

This paper describes a multiplexed microfluidic immunohistochemistry (IHC)/immunocytochemistry (ICC) platform for quantitative proteomic profiling in breast cancer samples. Proteomic profiling via ICC was examined for four breast cancer cell lines (AU-565, HCC70, MCF-7, and SK-BR-3). The microfluidic device enabled 20 ICC assays on a biological specimen at the same time and a 16-fold decrease in time consumption, and could be used to quantitatively compare the expression level of each biomarker. The immunohistochemical staining from the microfluidic system showed an accurate localization of protein and comparable quality to that of the conventional IHC method. Although AU-565 and SK-BR-3 cell lines were classified by luminal subtype and adenocarcinomas and were derived from the same patient, weak p63 expression was seen only in SK-BR-3. The HCC70 cell line showed a triple-negative (estrogen receptor-negative/progesterone receptor-negative/human epidermal growth factor receptor 2-negative) phenotype and showed only cytokeratin 5 expression, a representative basal/myoepithelial cell marker. To demonstrate the applicability of the system to clinical samples for proteomic profiling, we were also able to apply this platform to human breast cancer tissue. This result indicates that the microfluidic IHC/ICC platform is useful for accurate histopathological diagnoses using numerous specific biomarkers simultaneously, facilitating the individualization of cancer therapy.