Immunohistochemical biomarker validation in highly selective needle biopsy microarrays derived from mpMRI-characterized prostates

Intra-operative fluorescence-based detection of positive surgical margins during radical prostatectomy: Lessons learned from a pilot ex vivo translational study

OBJECTIVES

Nerve-sparing techniques during radical prostatectomy have been associated with an increased risk of positive surgical margins. The intra-operative detection of residual prostatic tissue could help mitigate this risk. The objectives of the present study were to assess the feasibility of using an anti-prostate-specific membrane antigen (anti-PSMA) antibody conjugated with a fluorophore to characterize fresh prostate tissue as prostatic or non-prostatic for intra-operative surgical margin detection.

METHODS

Fresh prostatic tissue samples were collected from transurethral resections of the prostate (TURP) or prostate biopsies, and either immunolabelled with anti-PSMA antibody conjugated with Alexa Fluor 488 or used as controls. A dedicated, laparoscopy-compliant fluorescence device was developed for real-time fluorescence detection. Confocal microscopy was used as the gold standard for comparison. Spectral unmixing was used to distinguish specific, Alexa Fluor 488 fluorescence from nonspecific autofluorescence.

RESULTS

The average peak wavelength of the immuno-labeled TURP samples (n = 4) was 541.7 ± 0.9 nm and of the control samples (n = 4) was 540.8 ± 2.2 nm. Spectral unmixing revealed that these similar measures were explained by significant autofluorescence, linked to electrocautery. Three biopsy samples were then obtained from seven patients and also displayed significant nonspecific fluorescence, raising questions regarding the reproducibility of the fixation of the anti-PSMA antibodies on the samples. Comparing the fluorescence results with final pathology proved challenging due to the small sample size and tissue alterations.

CONCLUSIONS

This study showed similar fluorescence of immuno-labeled prostate tissue samples and controls, failing to demonstrate the feasibility of intra-operative margin detection using PSMA immuno-labeling, due to marked tissue autofluorescence. We successfully developed a fluorescence device that could be used intraoperatively in a laparoscopic setting. Use of the infrared range as well as newly available antibodies could prove interesting options for future research.

Active Surveillance in Intermediate-Risk Prostate Cancer: A Review of the Current Data

Simple Summary

AS is an option for the initial management of selected patients with intermediate-risk PC. The proper way to predict which men will have an aggressive clinical course or indolent PC who would benefit from AS has not been unveiled. Genetics and MRI can help in the decision-making, but it remains unclear which men would benefit from which tests. In addition, there are several differences between AS protocols in inclusion criteria, monitoring follow-up, and triggers for active treatment. Large series and a few RCTs are under investigation, and more research is needed to establish an optimal therapeutic strategy for patients with intermediate-risk PC. This study summarizes the current data on patients with intermediate-risk PC under AS, recent findings, and discusses future directions.

Abstract

Active surveillance (AS) is a monitoring strategy to avoid or defer curative treatment, minimizing the side effects of radiotherapy and prostatectomy without compromising survival. AS in intermediate-risk prostate cancer (PC) has increasingly become used. There is heterogeneity in intermediate-risk PC patients. Some of them have an aggressive clinical course and require active treatment, while others have indolent disease and may benefit from AS. However, intermediate-risk patients have an increased risk of metastasis, and the proper way to select the best candidates for AS is unknown. In addition, there are several differences between AS protocols in inclusion criteria, monitoring follow-up, and triggers for active treatment. A few large series and randomized trials are under investigation. Therefore, more research is needed to establish an optimal therapeutic strategy for patients with intermediate-risk disease. This study summarizes the current data on patients with intermediate-risk PC under AS, recent findings, and discusses future directions.

Prognostic capabilities and clinical utility of cell cycle progression testing, prostate imaging reporting and data system, version 2, and clinicopathologic data in management of localized prostate cancer

OBJECTIVES

To compare the prognostic capabilities and clinical utility of the cell cycle progression (CCP) gene expression classifier test, multiparametric magnetic resonance imaging (mpMRI) with Prostate Imaging Reporting and Data System (PI-RADS) scoring, and clinicopathologic data in select prostate cancer (PCa) medical management scenarios.

PATIENTS AND METHODS

Retrospective, observational analysis of patients (N = 222) ascertained sequentially from a single urology practice from January 2015 to June 2018. Men were included if they had localized PCa, a CCP score, and an mpMRI PI-RADS v2 score. Cohort 1 (n = 156): men with newly diagnosed PCa, with or without a previous negative biopsy. Cohort 2 (n = 66): men who initiated active surveillance (AS) without CCP testing, but who received the test during AS. CCP was combined with the UCSF Cancer of the Prostate Risk Assessment (CAPRA) score to produce a clinical cell-cycle risk (CCR) score, which was reported in the context of a validated AS threshold. Spearman's rank correlation test was used to evaluate correlations between variables. Generalized linear models were used to predict binary Gleason score category and medical management selection (AS or curative therapy). Likelihood-ratio tests were used to determine predictor significance in both univariable and multivariable models.

RESULTS

In the combined cohorts, modest but significant correlations were observed between PI-RADS score and CCP (r_s = 0.22, P = 8.1 × 10^-4), CAPRA (r_s= 0.36, P = 4.8 × 10^-8), or CCR (r_s = 0.37, P = 2.0 × 10^-8), suggesting that much of the prognostic information captured by these measures is independent. When accounting for CAPRA and PI-RADS score, CCP was a significant predictor of higher-grade tumor after radical prostatectomy, with the resected tumor approximately 4 times more likely to harbor Gleason ≥4+3 per 1-unit increase in CCP in Cohort 1 (Odds Ratio [OR], 4.10 [95% confidence interval [CI], 1.46, 14.12], P = 0.006) and in the combined cohorts (OR, 3.72 [95% CI, 1.39, 11.88], P = 0.008). On multivariable analysis, PI-RADS score was not a significant predictor of post-radical prostatectomy Gleason score. Both CCP and CCR were significant and independent predictors of AS versus curative therapy in Cohort 1 on multivariable analysis, with each 1-unit increase in score corresponding to an approximately 2-fold greater likelihood of selecting curative therapy (CCP OR, 2.08 [95% CI, 1.16, 3.94], P = 0.014) (CCR OR, 2.33 [95% CI, 1.48, 3.87], P = 1.5 × 10^-4). CCR at or below the AS threshold significantly reduced the probability of selecting curative therapy over AS (OR, 0.28 [95% CI, 0.13, 0.57], P = 4.4 × 10^-4), further validating the clinical utility of the AS threshold.

CONCLUSION

CCP was a better predictor of both tumor grade and subsequent patient management than was PI-RADS. Even in the context of targeted biopsy, molecular information remains essential to ensure precise risk assessment for men with newly diagnosed PCa.

Molecular Biomarkers in Localized Prostate Cancer: ASCO Guideline

PURPOSE

This guideline provides recommendations for available tissue-based prostate cancer biomarkers geared toward patient selection for active surveillance, identification of clinically significant disease, choice of postprostatectomy adjuvant versus salvage radiotherapy, and to address emerging questions such as the relative value of tissue biomarkers compared with magnetic resonance imaging.

METHODS

An ASCO multidisciplinary Expert Panel, with representatives from the European Association of Urology, American Urological Association, and the College of American Pathologists, conducted a systematic literature review of localized prostate cancer biomarker studies between January 2013 and January 2019. Numerous tissue-based molecular biomarkers were evaluated for their prognostic capabilities and potential for improving management decisions. Here, the Panel makes recommendations regarding the clinical use and indications of these biomarkers.

RESULTS

Of 555 studies identified, 77 were selected for inclusion plus 32 additional references selected by the Expert Panel. Few biomarkers had rigorous testing involving multiple cohorts and only 5 of these tests are commercially available currently: Oncotype Dx Prostate, Prolaris, Decipher, Decipher PORTOS, and ProMark. With various degrees of value and validation, multiple biomarkers have been shown to refine risk stratification and can be considered for select men to improve management decisions. There is a paucity of prospective studies assessing short- and long-term outcomes of patients when these markers are integrated into clinical decision making.

RECOMMENDATIONS

Tissue-based molecular biomarkers (evaluating the sample with the highest volume of the highest Gleason pattern) may improve risk stratification when added to standard clinical parameters, but the Expert Panel endorses their use only in situations in which the assay results, when considered as a whole with routine clinical factors, are likely to affect a clinical decision. These assays are not recommended for routine use as they have not been prospectively tested or shown to improve long-term outcomes-for example, quality of life, need for treatment, or survival. Additional information is available at www.asco.org/genitourinary-cancer-guidelines.

The Oncogene Metadherin Interacts with the Known Splicing Proteins YTHDC1, Sam68 and T-STAR and Plays a Novel Role in Alternative mRNA Splicing

Oncogenic metadherin is a key contributor to tumourigenesis with metadherin expression and cytoplasmic localisation previously linked to poor survival. A number of reports have shown metadherin localises specifically to nuclear speckles known to be rich in RNA-binding proteins including the splicing proteins YTHDC1, Sam68 and T-STAR, that have been shown to select alternative splice sites in mRNA of tumour-associated proteins including BRCA, MDM2 and VEGF. Here we investigate the interaction and relationship between metadherin and the splice factors YTHDC1, T-STAR and Sam68. Using a yeast two-hybrid assay and immunoprecipitation we show that metadherin interacts with YTHDC1, Sam68 and T-STAR and demonstrate that T-STAR is significantly overexpressed in prostate cancer tissue compared to benign prostate tissue. We also demonstrate that metadherin influences splice site selection in a dose-dependent manner in CD44v5-luc minigene reporter assays. Finally, we demonstrate that prostate cancer patients with higher metadherin expression have greater expression of the CD44v5 exon. CD44v5 expression could be used to discriminate patients with poor outcomes following radical prostatectomy. In this work we show for the first time that metadherin interacts with, and modulates, the function of key components of splicing associated with cancer development and progression.

Overview of established and emerging immunohistochemical biomarkers and their role in correlative studies in MRI

Clinical practice in radiology and pathology requires professional expertise and many years of training to visually evaluate and interpret abnormal phenotypic features in medical images and tissue sections to generate diagnoses that guide patient management and treatment. Recent advances in digital image analysis methods and machine learning have led to significant interest in extracting additional information from medical and digital whole-slide images in radiology and pathology, respectively. This has led to significant interest and research in radiomics and pathomics to correlate phenotypic features of disease with image analytics in order to identify image-based biomarkers. The expanding role of big data in radiology and pathology parallels the development and role of immunohistochemistry (IHC) in the daily practice of pathology. IHC methods were initially developed to provide additional information to help classify tumors and then transformed into an indispensable tool to guide treatment in many types of cancer. IHC markers are used in daily practice to identify specific types of cells and highlight their distributions in tissues in order to distinguish benign from neoplastic cells, determine tumor origin, subclassify neoplasms, and support and confirm diagnoses. In this regard, radiomics, pathomics, and IHC methods are very similar since they enable the extraction of image-based features to characterize various properties of diseases. Due to the dramatic advancements in recent radiomics research, we provide a brief overview of the role of established and emerging IHC biomarkers in various tumor types that have been correlated with radiologic biomarkers to improve diagnostic accuracy, predict prognosis, guide patient management, and select treatment strategies. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:341-354.

Stroma in normal and cancer wound healing

It is currently believed that stroma, the connective framework of biological tissues, plays a central role in normal wound healing and in cancer. In both these contexts, stromal cellular components such as activated fibroblasts interact with complex protein networks that include growth factors, structural protein or proteinases in order to initiate and sustain an extensive remodelling process. However, although this process is usually spatially and temporally self-limited, it is unregulated in the case of cancer and leads to uncontrolled cell proliferation and invasion within tissues, metastasis and therapeutic resistance. In this review, we outline the role of stroma in normal healing, cancer and post radiotherapy, with a particular focus on the crosstalk between normal or cancer cells and fibroblasts. Understanding these mechanisms is particularly important as several stromal components have been proposed as potential therapeutic targets.

Can expressed prostatic secretions effect prostate biopsy decision of urologist?

Objectives:

To evaluate the frequency of NIH category IV prostatitis, and the use of expressed prostatic secretions tests in an effort to improve the reliability of prostate specific antigen as an indicator, to avoid unnecessary prostate biopsy.

Materials and Methods:

178 expressed prostatic secretion positive patients with serum prostate specific antigen levels of ≥ 2.5 ng / mL were included in present prospective study. The diagnostic evaluation included detailed history and physical examination, digital rectal examination, urine analysis, urine culture, and expressed prostatic secretions tests. Transrectal ultrasonography was used both to measure prostate volume and conduct 12 core prostate biopsy.

Results:

The prevalence of NIH category IV prostatitis was 36.9% (178 / 482) in our population of men. In our study patients (n: 178) prostate biopsy results were classified as; 66 prostatitis, 81 BPH, and 31 Pca. In asymptomatic prostatitis group, expressed prostatic secretion mean leucocyte ratio was higher compared to other two groups (p < 0.0001). The relation between number of expressed prostatic secretion leucocytes and prostatitis, benign prostate hyperplasia, and prostate cancer is analyzed. If 16 is taken as the cut of number for leucocyte presence, its sensitivity is 0.92 (AUC = 0.78 p = 0.01).

Conclusions:

The number of leucocytes in expressed prostatic secretion is higher in the chronic prostatitis group. If the leukocyte presence of 16 and above is taken as the cut off point, the sensitivity becomes 0.92 (AUC = 0.78). We firmly believe that our new cut off value may be used as to aid prostate specific antigen and derivates while giving biopsy decision.