Development of a multigenomic liquid biopsy (PROSTest) for prostate cancer in whole blood

Prostate. 2024 Jun;84(9):850-865. doi: 10.1002/pros.24704. Epub 2024 Apr 3.


Introduction: We describe the development of a molecular assay from publicly available tumor tissue mRNA databases using machine learning and present preliminary evidence of functionality as a diagnostic and monitoring tool for prostate cancer (PCa) in whole blood.

Materials and methods: We assessed 1055 PCas (public microarray data sets) to identify putative mRNA biomarkers. Specificity was confirmed against 32 different solid and hematological cancers from The Cancer Genome Atlas (n = 10,990). This defined a 27-gene panel which was validated by qPCR in 50 histologically confirmed PCa surgical specimens and matched blood. An ensemble classifier (Random Forest, Support Vector Machines, XGBoost) was trained in age-matched PCas (n = 294), and in 72 controls and 64 BPH. Classifier performance was validated in two independent sets (n = 263 PCas; n = 99 controls). We assessed the panel as a postoperative disease monitor in a radical prostatectomy cohort (RPC: n = 47).

Results: A PCa-specific 27-gene panel was identified. Matched blood and tumor gene expression levels were concordant (r = 0.72, p < 0.0001). The ensemble classifier ("PROSTest") was scaled 0%-100% and the industry-standard operating point of ≥50% used to define a PCa. Using this, the PROSTest exhibited an 85% sensitivity and 95% specificity for PCa versus controls. In two independent sets, the metrics were 92%-95% sensitivity and 100% specificity. In the RPCs (n = 47), PROSTest scores decreased from 72% ± 7% to 33% ± 16% (p < 0.0001, Mann-Whitney test). PROSTest was 26% ± 8% in 37 with normal postoperative PSA levels (<0.1 ng/mL). In 10 with elevated postoperative PSA, PROSTest was 60% ± 4%.

Conclusion: A 27-gene whole blood signature for PCa is concordant with tissue mRNA levels. Measuring blood expression provides a minimally invasive genomic tool that may facilitate prostate cancer management.

Keywords: PCa; PSA; adenocarcinoma; biomarker; diagnosis; liquid biopsy; mRNA; prostate cancer; qPCR; whole blood.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biomarkers, Tumor* / blood
  • Biomarkers, Tumor* / genetics
  • Humans
  • Liquid Biopsy / methods
  • Machine Learning
  • Male
  • Middle Aged
  • Prostatectomy
  • Prostatic Neoplasms* / blood
  • Prostatic Neoplasms* / diagnosis
  • Prostatic Neoplasms* / genetics
  • Prostatic Neoplasms* / pathology
  • Prostatic Neoplasms* / surgery
  • RNA, Messenger / blood
  • RNA, Messenger / genetics
  • Sensitivity and Specificity


  • Biomarkers, Tumor
  • RNA, Messenger