Abstract 721: Multiplexed systems pathology for in-depth analysis of the tumor microenvironment: a strong correlation between pAkt and androgen receptor in the epithelial component of prostate cancer.

Abstract

Abstract It is important to understand the heterogeneity across the cancer tissue as well as the spatial interactions and signaling between the different components that constitute the tumor microenvironment; epithelium, stroma, inflammatory cells, etc. The state of the tumor microenvironment and its variability within and in between tumors may give important insights on cancer initiation and progression, diagnostics, prognostics and therapeutic assessment. Thus, there is a major need to assess multiple molecular targets simultaneously, quantitatively, and within the specific tumor sub-compartments. Here, we demonstrate a systems pathology approach for quantitative detection of multiple proteins in formalin-fixed paraffin-embedded patient tissue samples using a combination of immunohistochemistry and high-throughput fluorescence imaging. The study cohort consisted of 50 prostate cancer tissue samples from 25 patients exhibiting different disease stages in a tissue microarray (TMA) format. We developed a multiplexed assay for detecting pAkt, AR, and cytokeratin 8 (CK8) simultaneously using fluorescent nanoparticle labeling and high-throughput quantitative imaging. Fluorescent signals of pAkt and AR were automatically quantified within the segmented CK8-positive prostate epithelium. The stromal compartment and the non-malignant prostate tissue were analysed separately. Our results showed that the expression of pAkt and AR correlated strongly in the prostate cancer epithelium (Pearson correlation coefficient 0.89, p < 0.001). This suggests that the androgen-dependent signaling is strongly associated with the pAkt signaling in cancer, with potential ramifications for administrating and monitoring anti-androgens and/or Akt-inhibitor therapy. The systems pathology approach enables quantitative in situ multianalyte detection for any key cancer signaling proteins. The analyses can be readily expanded to TMAs of large prospective or clinical trial cohorts with automated imaging. The ability to quantitatively study the spatial arrangement of the tumor microenvironment could have decisive advantages and improve the diagnostic and therapeutic predictions. Citation Format: Sami Blom, Petra Mäki-Teeri, Tuomas Mirtti, Antti Rannikko, Jenni Säilä, Teijo Pellinen, Olli Kallioniemi. Multiplexed systems pathology for in-depth analysis of the tumor microenvironment: a strong correlation between pAkt and androgen receptor in the epithelial component of prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 721. doi:10.1158/1538-7445.AM2013-721