BRCA testing in metastatic castration-resistant prostate cancer: successes and troubles in a real world setting. An Italian Multicentric study.

Objective: Prostate cancer (PCa) is the most common cause of cancer-related deaths in men worldwide. BRCA1/2 genes are reported altered in approximately 1% and 8% of PCa cases, respectively. To date, formalin-fixed paraffin-embedded (FFPE) tissues have a consolidate use in the clinical practice, but with a significant drawback related to DNA/RNA degradation during the pre-analytical process. The purpose of this study is to evaluate the feasibility of detecting BRCA1/2 alterations in DNA extracted from FFPE tissues collected from PCa patients after various years of storage in seven Italian hospitals.

Methods: A total of 241 DNA samples were extracted from FFPE tissue with different storage times (1-12 y) and sequenced with NGS technology. BRCA1/2 evaluability was assessed performing data analysis with a chi-square test to study the impact of the storage time on the DNA degradation.

Results: The data collected showed a strict relation not only between the storage time and the BRCA1/2 evaluability, but even between the storage time and DNA degradation (DIN). Taken together, all the parameters considered decrease with an increase in the storage time.

Conclusions: Excessive FFPE tissues storage time (more than 3 years) can harshly affect DNA analysis and evaluability, hindering the achievement of a result useful in the clinical practice. Hence, it should be considered to perform the analysis as soon as possible to increase the evaluability of the test.