Blute, Michael L.

Abstract DNA methylation profiles could signify the risk of prostate cancer and predict the progression of cancer before the appearance of clinical symptoms. Specific CpG sites methylation of genes identified in our study could be used to improve the sensitivity and specificity for early diagnosis and to predict the risk of prostate cancer recurrence. To identify methylation changes associated with prostate cancer, we measured gene methylation using the Infinium Human Methylation27 bead chips. Tissue DNA isolation and bisulfite conversion was done using ZR Genomic DNA kit and EZ methylation kit. The methylation27 microarrays was used to analyze methylation of 27,578 CpG sites of 14,495 genes in 198 tumor tissues and 40 matched normal tissues. Methylation data was processed using the Genome Studio software, differentially methylated genes identified using one-way analysis of variance, and correction for multiple testing done using the false discovery rate q-value. To identify putative diagnostic and prognostic biomarkers we performed four subgroup comparisons: tumor vs. matched normal, recurrent tumors vs. non-recurrent tumors, clinical recurrence vs. biochemical recurrence, and systemic recurrence vs. local recurrence. Clinicopathological and molecular features including patient preoperative PSA levels, Gelason score, TNM stage, GPSM, recurrence type, were also evaluated for subgroup discrimination. Discriminative subgroup candidate methlyation markers were selected using a p value <0.05 and a mean difference between two contrast groups >0.05. Between the tumor and matched normal tissue samples, 164 CpG sites representing 147 genes were identified as significantly differentially methylated (p<9.99E-25, fold change>2.0). Between recurrent tumor and non-recurrent tumor tissues there were 78 CpG sites representing 75 genes that were significantly differentially methylated (p <0.002, fold change >1.5). Between clinically recurrent and biochemically recurrent tumors, 16 CpG sites representing 16 genes were significantly differentially methylated (p <0.05, fold change >1.5). Between systemic recurrent and local recurrent tumors there were 73 CpG sites representing 68 genes that were significantly differentially methylated (p <0.01, fold change >1.5) Our analysis revealed differential methylation of the genes, implicating their role in prostate cancer development and progression. We demonstrated that the hypermethylation of genes could be used as a sensitive molecular tool in detection of prostate tumorigenesis and prediction of tumor progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 109. doi:10.1158/1538-7445.AM2011-109

Abstract Purpose: Release of inhibitory coregulatory proteins into the circulation may represent one mechanism by which tumors thwart immune responses. Our objective was to determine whether soluble B7-H1 (sB7-H1) levels in patients with clear cell renal cell carcinoma (ccRCC) are associated with pathologic features and patient outcome. Experimental Design: We developed an ELISA for quantification of sB7-H1 in biological fluids. Biochemical confirmation of the measured analyte as sB7-H1 was done by protein microsequencing using supernates from tumor cell lines. Biological activity of sB7-H1 was assessed in vitro utilizing T-cell apoptosis assays. We tested sB7-H1 levels in the sera from 172 ccRCC patients and correlated sB7-H1 levels with pathologic features and patient outcome. Results: sB7-H1 was detected in the cell supernatants of some B7-H1–positive tumor cell lines. Protein sequencing established that the measured sB7-H1 retained its receptor-binding domain and could deliver proapoptotic signals to T cells. Higher preoperative sB7-H1 levels were associated with larger tumors (P < 0.001), tumors of advanced stage (P = 0.017) and grade (P = 0.044), and tumors with necrosis (P = 0.003). A doubling of sB7-H1 levels was associated with a 41% increased risk of death (P = 0.010). Conclusion: Our observations suggest that sB7-H1 may be detected in the sera of ccRCC patients and that sB7-H1 may systemically impair host immunity, thereby fostering cancer progression and subsequent poor clinical outcome. Clin Cancer Res; 17(7); 1915–23. ©2011 AACR.