Using mp-MRI guided prostate needle biopsy samples to improve prostate cancer diagnosis.


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Jonathan Olivier1,Jonathan Kay1,Alex Freeman1,Hashim Ahmed1,Caroline Moore1,Mark Emberton1,Hayley Whitaker1
1University College London

Abstract

Background

Prostate cancer is a heterogeneous disease both in terms of clinical presentation and pathology which can lead to very different clinical outcomes. Conventional prognostic factors, including serum PSA levels, Gleason score and pathological stage are often inaccurate so histological biomarkers could be useful in distinguishing indolent from aggressive prostate cancers. Tissue microarrays (TMAs) are useful for validating protein biomarker expression in large cohorts of patient samples using immunohistochemistry (IHC) but are often created from radical prostatectomy specimens which do not accurately represent diagnostic biopsies which are 1.5mm long and 0.5mm wide. This limiting amount of tumour has led us to develop an improved method for constructing TMAs to study multiple biomarkers simultaneously on biopsy tissue.

Method

UCLH patients with suspected prostate cancer routinely undergo a diagnostic mp-MRI scan to enable an image-guided biopsy which is analysed by a pathologist to confirm tumour Grade based on cellular architecture and morphology. We have devised a method of extracting the regions of tumour within biopsy samples and re-embedded them so that they can easily be repositioned into a recipient TMA block. The blocks were then sectioned and stained using automated IHC.

Results

We have successfully produced TMA blocks containing representative regions of benign and tumour samples for over 250 patients and analysed the expression of a panel of established prostate cancer biomarkers including p63, AMACR and PSA to validate our method. Novel markers for diagnosing aggressive prostate cancer are also being tested.

Conclusion

This new method of constructing TMA blocks allows multiple biomarkers to be assessed quickly in a large cohort of biopsy samples that accurately represent the tissue routinely used for diagnosis.