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Purpose: This paper describes a process for the identification of genes that can report on the aggressiveness of prostate tumors and thereby add to the information provided by current pathologic analysis. Materials and Methods: Expression profiling data from over 100 laser capture microdissection derived samples from nonneoplastic epithelium; Gleason patterns 3, 4, and 5 and node metastasis prostate cancer were used to identify genes at abnormally high levels in only some tumors. These variably overexpressed genes were stratified by their association with aggressive phenotypes and were subsequently filtered to exclude genes with redundant expression patterns. Selected genes were validated in a case-control study in which cases (systemic progression within 5 years) and controls (no systemic progression at 7 years of follow-up) were matched for all clinical and pathologic criteria from time of prostatectomy (n = 175). Both cases and controls, therefore, could have nodal invasion or seminal vesicle involvement at the time of initial treatment. Results: A number of candidate variably overexpressed genes selected for their association with aggressive prostate cancer phenotype were evaluated in the case control study. The most prominent candidates were SSTR1 and genes related to proliferation, including TOP2A. Conclusions: The process described here identified genes that add information not available from current clinical measures and can improve the prognosis of prostate cancer.

Tumor-associated hypoxia has been associated with malignant progression, metastasis and resistance to therapy. We studied the role of oxygen tension (pO2) in modulating the properties of cultured human prostate cancer (CaP) cells. In air, where oxygen tension (pO2) is approximately 20 kPa, cultured CaP cells expressed lower levels of transcripts associated with cancer and urologic disease; reducing pO2 to 2 kPa made these levels comparable to those in surgical CaP specimens suggesting that hypoxically cultured cells, rather than normoxically cultured cells, express genes at levels akin to those in tumor cells in situ. In human primary CaP tissue, transcripts of hypoxia-associated genes DLG7, CCNB1 and HMMR were overexpressed and associated with Gleason score and disease prognosis; this implies the potential prognostic value of these transcripts. While hypoxia affected the CaP cell proteome mostly quantitatively, it did affect expression of tumor–associated antigens and suggested the potential therapeutic relevance of the hypoxic antigenic landscape. Overall, our results suggest that hypoxia modifies cellular properties of cultured CaP cells towards a phenotype more similar to tumor cells in situ. Introduction of pO2 as a variable can constitute a tool for the identification of more effective prognostic biomarkers and development of better therapy for CaP and, possibly, other tumors. Citation Format: Christian R. Gomez, Stanimir Vuk-Pavlovic, Farhad Kosari, Jan Marie Munz, Claire Schreiber, Gaylord Knutson, Cristine Charlesworth, R. Jeffrey Karnes, John Cheville, George Vasmatzis. Prognostic value of hypoxia-associated genes in prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C43.

Tumor-associated hypoxia has been associated with malignant progression, metastasis, resistance to therapy, and poor clinical outcome in prostate cancer (CaP). Prompted by the evidence that hypoxia affects CaP, we studied global gene expression in 100 CaP tissues and 71 samples of adjacent benign tissues. RNA was extracted from cancer cells isolated by laser-capture microdissection (LCM) or without isolation (“bulk tissue”). We found 24 hypoxia-associated genes significantly overexpressed in CaP (p≤0.02), both in bulk tissue and LCM. Among hypoxia-associated genes, the disc large (drosophila) homolog-associated protein 5 (DLG7), hyaluronan-mediated motility receptor (HMMR) and cyclin B1 (CCNB1) were associated with Gleason score and systemic progression. Since the products of HMMR and CCNB1 have been recently identified as molecular markers of CaP progression, we postulated that DLG7 has prognostic value also. To test this hypothesis we measured transcript levels for DLG7 in a 150-pair case-control cohort. The cases (progression to systemic disease within five years of surgery) and controls (no progression within seven years) were matched for clinical and pathologic prognostic variables, including grade, stage, and preoperative serum levels of PSA. The overall prognostic ability of DLG7, as tested in receiver operating characteristic analysis was of 0.74 (95% CL, 0.68 to 0.8), independent of the for ERG status. Overall, our data indicate that DLG7, a hypoxia-controlled gene have a prognostic value in high-risk CaP. To better define the value of DLG7 as a molecular predictor of CaP progression, we are currently assessing DLG7 protein levels by immunohistochemistry. Then we will analyze the association of DLG7 levels with clinical parameters. Introduction of oxygen tension as a variable may constitute a tool for the identification of novel biomarkers for CaP. Present address CRG: University of Mississippi Cancer Institute, Jackson, MS, USA. Support: DOD PC094680 (CRG), PCF Creativity Award (CRG), Mayo Clinic Prostate SPORE 5P50CA091956 (SV-P); Mrs. Adelyn L. Luther, Singer Island, Florida and Mayo Clinic Cancer Center (SV-P). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 116. doi:1538-7445.AM2012-116