A Retrospective Quality Audit of a Prostate Cancer Biobank Reveals Procurement Method as the Critical Determinant of Biospecimen Fitness-for-Purpose

The "fitness-for-purpose" of biospecimens is paramount for reproducible genomic and proteomic research, yet is frequently compromised by preanalytical variability. To identify key determinants of sample quality in prostate cancer (PCa), a disease characterized by challenging tissue procurement, we conducted a retrospective quality audit of 300 radical prostatectomy specimens. Biospecimens were stratified based on Tumor Nuclei Percentage (TNP) against established thresholds for proteomic (TNP ≥ 20%) and genomic (TNP ≥ 50%) applications, revealing significant heterogeneity in the cohort's overall quality. Subsequent analysis of preanalytical data revealed that the tissue procurement method-conventional macroscopic inspection, preoperative magnetic resonance imaging (MRI)-guidance, or biopsy-guidance-was the single most significant factor associated with achieving high-quality strata. For the stringent genomics-grade threshold (TNP ≥ 50%), guided procurement methods (MRI: 60.00%; Biopsy: 56.00%) more than doubled the yield of qualifying samples compared with conventional inspection (28.00%; p < 0.0001). This work establishes guided procurement not merely as a superior technique, but as an essential quality assurance standard for modern PCa biobanking, ensuring the collection of biospecimens that are truly "fit-for-purpose" in the era of precision medicine.