Development and Optimization of a Subtraction-Normalized Immunocyte Profiling Signature for Prostate Cancer Active Surveillance Risk Stratification.

PURPOSE: Less invasive decision support tools are desperately needed to identify occult high-risk disease in men with prostate cancer (PCa) on active surveillance (AS). For a variety of reasons, many men on AS with low- or intermediate-risk disease forgo the necessary repeat surveillance biopsies needed to identify potentially higher-risk PCa. Here, we describe the development of a blood-based immunocyte transcriptomic signature to identify men harboring occult aggressive PCa. We then validate it on a biopsy-positive population with the goal of identifying men who should not be on AS and confirm those men with indolent disease who can safely remain on AS. This model uses subtraction-normalized immunocyte transcriptomic profiles to risk-stratify men with PCa who could be candidates for AS. MATERIALS AND METHODS: Men were eligible for enrollment in the study if they were determined by their physician to have a risk profile that warranted prostate biopsy. Both training (n = 1017) and validation cohort (n = 1198) populations had blood samples drawn coincident to their prostate biopsy. Purified CD2+ and CD14+ immune cells were obtained from peripheral blood mononuclear cells, and RNA was extracted and sequenced. To avoid overfitting and unnecessary complexity, a regularized regression model was built on the training cohort to predict PCa aggressiveness based on the National Comprehensive Cancer Network PCa guidelines. This model was then validated on an independent cohort of biopsy-positive men only, using National Comprehensive Cancer Network unfavorable intermediate risk and worse as an aggressiveness outcome, identifying patients who were not appropriate for AS. RESULTS: The best final model for the AS setting was obtained by combining an immunocyte transcriptomic profile based on 2 cell types with PSA density and age, reaching an AUC of 0.73 (95% CI: 0.69-0.77). The model significantly outperforms (P < .001) PSA density as a biomarker, which has an AUC of 0.69 (95% CI: 0.65-0.73). This model yields an individualized patient risk score with 90% negative predictive value and 50% positive predictive value. CONCLUSIONS: While further validation in an intended-use cohort is needed, the immunocyte transcriptomic model offers a promising tool for risk stratification of individual patients who are being considered for AS.

Evaluation of an RNAseq-Based Immunogenomic Liquid Biopsy Approach in Early-Stage Prostate Cancer.

The primary objective of this study is to detect biomarkers and develop models that enable the identification of clinically significant prostate cancer and to understand the biologic implications of the genes involved. Peripheral blood samples (1018 patients) were split chronologically into independent training (n = 713) and validation (n = 305) sets. Whole transcriptome RNA sequencing was performed on isolated phagocytic CD14+ and non-phagocytic CD2+ cells and their gene expression levels were used to develop predictive models that correlate to adverse pathologic features. The immune-transcriptomic model with the highest performance for predicting adverse pathology, based on a subtraction of the log-transformed expression signals of the two cell types, displayed an area under the curve (AUC) of the receiver operating characteristic of 0.70. The addition of biomarkers in combination with traditional clinical risk factors (age, serum prostate-specific antigen (PSA), PSA density, race, digital rectal examination (DRE), and family history) enhanced the AUC to 0.91 and 0.83 for the training and validation sets, respectively. The markers identified by this approach uncovered specific pathway associations relevant to (prostate) cancer biology. Increased phagocytic activity in conjunction with cancer-associated (mis-)regulation is also represented by these markers. Differential gene expression of circulating immune cells gives insight into the cellular immune response to early tumor development and immune surveillance.

Development and clinical validation of an in situ biopsy-based multimarker assay for risk stratification in prostate cancer.

PURPOSE: Prostate cancer aggressiveness and appropriate therapy are routinely determined following biopsy sampling. Current clinical and pathologic parameters are insufficient for accurate risk prediction leading primarily to overtreatment and also missed opportunities for curative therapy. EXPERIMENTAL DESIGN: An 8-biomarker proteomic assay for intact tissue biopsies predictive of prostate pathology was defined in a study of 381 patient biopsies with matched prostatectomy specimens. A second blinded study of 276 cases validated this assay's ability to distinguish "favorable" versus "nonfavorable" pathology independently and relative to current risk classification systems National Comprehensive Cancer Network (NCCN and D'Amico). RESULTS: A favorable biomarker risk score of ≤0.33, and a nonfavorable risk score of >0.80 (possible range between 0 and 1) were defined on "false-negative" and "false-positive" rates of 10% and 5%, respectively. At a risk score ≤0.33, predictive values for favorable pathology in very low-risk and low-risk NCCN and low-risk D'Amico groups were 95%, 81.5%, and 87.2%, respectively, higher than for these current risk classification groups themselves (80.3%, 63.8%, and 70.6%, respectively). The predictive value for nonfavorable pathology was 76.9% at biomarker risk scores >0.8 across all risk groups. Increased biomarker risk scores correlated with decreased frequency of favorable cases across all risk groups. The validation study met its two coprimary endpoints, separating favorable from nonfavorable pathology (AUC, 0.68; P < 0.0001; OR, 20.9) and GS-6 versus non-GS-6 pathology (AUC, 0.65; P < 0.0001; OR, 12.95). CONCLUSIONS: The 8-biomarker assay provided individualized, independent prognostic information relative to current risk stratification systems, and may improve the precision of clinical decision making following prostate biopsy.

PCA3 urine mRNA testing for prostate carcinoma: patterns of use by community urologists and assay performance in reference laboratory setting.

OBJECTIVES: Multiple trials have shown the high specificity of urine prostate cancer gene 3 (PCA3) compared with serum prostate-specific antigen (PSA) for biopsy detection of prostate carcinoma. We characterized the patterns of use of PCA3 by community urologists and determined the performance of PCA3 testing as a laboratory-developed test in a reference laboratory setting. METHODS: The urine PCA3 and PSA mRNA levels after digital rectal examination were determined using transcription-mediated amplification. The cutoff for a positive PCA3 score (PCA3/PSA mRNA x 10(3)) were pre-established at > or = 35. The PCA3 results were correlated with the serum PSA level, previous biopsy history, and the prostate biopsy findings. RESULTS: A total of 278 PCA3 tests were performed from December 2006 to June 2007. Of the PCA3 tested patients, 55.5% had previously undergone > or = 1 prostate biopsy; 92.7% had a PSA level > or = 2.5 ng/mL. The PCA3 test informative rate was 97.5%. For 50 samples that were also analyzed at a separate laboratory, concordance was achieved in 94%. The mean and median PCA3 score was 44.3 and 21.1, respectively. No correlation was found with the serum PSA level. The PCA3 test was negative in 16 of 19 patients with negative concurrent biopsy findings and positive in 8 of 11 with positive concurrent biopsy findings (sensitivity 72.7% and specificity 84.2%). Of 32 patients (70% with previous biopsy) who had undergone biopsy an average of 56 days after positive PCA3 test results, prostate carcinoma was detected in 41%. CONCLUSIONS: Urine PCA3 testing on the transcription-mediated amplification platform performed well as a laboratory-developed test. The high specificity of PCA3 was confirmed. In patients with elevated PSA levels and negative biopsy findings, PCA3 testing might be useful in choosing between repeat biopsy and more conservative follow-up.

Significance of atypical and suspicious small acinar proliferations, and high grade prostatic intraepithelial neoplasia on prostate biopsy: implications for cancer detection and biopsy strategy.

PURPOSE: We reviewed our results from a urological pathology reference laboratory with respect to the incidence of HGPIN, and atypical and suspicious lesions in the spectrum of ASAP. Subsequent CaP findings on repeat biopsy with relevant clinical implications were assessed. MATERIALS AND METHODS: A review of 42,667 prostate biopsies was performed. We defined atypical and suspicious as variants of ASAP with suspicious being more worrisome for CaP. Findings were correlated with the location of CaP on repeat prostate biopsy. RESULTS: The rate of subsequent CaP detection was significantly higher for an initial diagnosis of suspicious findings (51% or 54 of 107 cases) than for atypical findings (34% or 39 of 116) or HGPIN (22% or 79 of 358, p < 0.001). CaP was found on the same side of the prostate in 61 of 78 (78%), 30 of 39 (77%) and 41 of 54 patients (76%) with initial HGPIN, atypical and suspicious biopsies, respectively. There was no significant difference among the 3 groups in the likelihood of future CaP at the same site or the same side of the prostate. CONCLUSIONS: Patients with a suspicious biopsy were significantly more likely to have CaP on future biopsy than those with atypical findings or HGPIN, suggesting that there may be divisions with prognostic significance in the larger category of ASAP. To our knowledge the reproducibility of recognizing such divisions remains to be established. Neither atypical nor suspicious lesions were more likely than HGPIN to predict CaP at the same site or side of the prostate as the original diagnosis. Repeat biopsy may be indicated in any patient with HGPIN, or atypical or suspicious lesions and this biopsy should not be limited to the site or side of the original pathological findings.

Integrin alpha(v) and coxsackie adenovirus receptor expression in clinical bladder cancer.

OBJECTIVES: To evaluate the expression of the coxsackie and adenovirus receptor (CAR) and alpha(v) integrins in clinical specimens of bladder cancer to determine the susceptibility to adenoviral gene therapy. Efficient adenovirus-based gene therapy requires binding of the virus to CAR and involves the alpha(v) integrins. Studies on bladder cancer cell lines have shown that low adenoviral transduction rates were associated with low-level expression of CAR. Integrin alpha(v) expression increases in various tumors suggest its importance in differentiation, proliferation, and migration. CAR is structurally a member of the Ig-type superfamily of cell-cell adhesion molecules, suggesting that its expression may also be related to the state of tumor differentiation. METHODS: We performed immunohistochemistry for CAR and integrin alpha(v) expression in bladder cancer specimens in 50 paraffin-embedded tumor-normal pairs and confirmed the results by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of 11 separate bladder tumors and 4 separate normal bladder controls. RESULTS: Immunochemistry demonstrated a stage and grade-dependent decrease in CAR expression (90.0%, 83.3%, and 31.3% of normal urothelium and superficial and invasive transitional cell carcinoma [TCC] and 83.3% and 39.5% of low and high-grade TCC, respectively). Furthermore, we found a stage and grade-dependent increase in alpha(v) integrin expression (13.3%, 46.0%, and 56.3% of normal urothelium, superficial TCC, and invasive TCC and 25% and 52.6% of low and high-grade TCC, respectively). Quantitative RT-PCR analysis confirmed a downregulation at the CAR gene expression level. CONCLUSIONS: This down-regulation may have a major impact on developing adenoviral-based gene therapy modalities. In addition, we propose that loss of CAR expression decreases rigid cell adhesion, possibly increasing the migratory potential. Loss of CAR expression correlates with the invasive phenotype in our analysis of bladder cancer. Simultaneously, the finding of increased alpha(v) expression in invasive cancer suggests a pathogenesis that involves heterophilic adhesion and migration of these cells on various extracellular ligands.