Real-World Comprehensive Genomic Profiling Success Rates in Tissue and Liquid Prostate Carcinoma Specimens

Blood-based liquid biopsy in advanced prostate cancer

Prostate cancer is characterized by several genetic alterations which could impact prognosis and therapeutic decisions in the advanced disease. Tissue biopsy is still considered the gold standard approach for molecular characterization in prostate cancer, but it has several limitations, including the possibility of insufficient/inadequate tumor tissue to be analyzed. Blood-based liquid biopsy is a non-invasive method to investigate tumor cell derivatives in the bloodstream, being a valid alternative to tissue biopsy for molecular characterization but also for predictive and/or prognostic purposes. In this review, we analyze the most relevant evidence in this field, focusing on clinically relevant targets such as HRD genetic alterations and also focusing on the differences between tissue and liquid biopsy in light of the data from the latest clinical trials.

Genetic and Genomic Testing for Prostate Cancer: Beyond DNA Repair

Significant progress has been made in genetic and genomic testing for prostate cancer across the disease spectrum. Molecular profiling is increasingly relevant for routine clinical management, fueled in part by advancements in testing technology and integration of biomarkers into clinical trials. In metastatic prostate cancer, defects in DNA damage response genes are now established predictors of benefit to US Food and Drug Administration-approved poly (ADP-ribose) polymerase inhibitors and immune checkpoint inhibitors, and trials are actively investigating these and other targeted treatment strategies in earlier disease states. Excitingly, opportunities for molecularly informed management beyond DNA damage response genes are also maturing. Germline genetic variants (eg, BRCA2 or MSH2/6) and polygenic germline risk scores are being investigated to inform cancer screening and active surveillance in at-risk carriers. RNA expression tests have recently gained traction in localized prostate cancer, enabling patient risk stratification and tailored treatment intensification via radiotherapy and/or androgen deprivation therapy for localized or salvage treatment. Finally, emerging minimally invasive circulating tumor DNA technology promises to enhance biomarker testing in advanced disease pending additional methodological and clinical validation. Collectively, genetic and genomic tests are rapidly becoming indispensable tools for informing the optimal clinical management of prostate cancer.

Minimizing Sample Failure Rates for Challenging Clinical Tumor Samples

Identification of somatic variants in cancer by high-throughput sequencing has become common clinical practice, largely because many of these variants may be predictive biomarkers for targeted therapies. However, there can be high sample quality control (QC) failure rates for some tests that prevent the return of results. Stem-loop inhibition mediated amplification (SLIMamp) is a patented technology that has been incorporated into commercially available cancer next-generation sequencing testing kits. The claimed advantage is that these kits can interrogate challenging formalin-fixed, paraffin-embedded tissue samples with low tumor purity, poor-quality DNA, and/or low-input DNA, resulting in a high sample QC pass rate. The study aimed to substantiate that claim using Pillar Biosciences oncoReveal Solid Tumor Panel. Forty-eight samples that had failed one or more preanalytical QC sample parameters for whole-exome sequencing from the Australian Translational Genomics Center's ISO15189-accredited diagnostic genomics laboratory were acquired. XING Genomic Services performed an exploratory data analysis to characterize the samples and then tested the samples in their ISO15189-accredited laboratory. Clinical reports could be generated for 37 (77%) samples, of which 29 (60%) contained clinically actionable or significant variants that would not otherwise have been identified. Eleven samples were deemed unreportable, and the sequencing data were likely dominated by artifacts. A novel postsequencing QC metric was developed that can discriminate between clinically reportable and unreportable samples.