A new method to provide a fresh frozen prostate slice suitable for gene expression study and MR spectroscopy

Bertilsson, Helena; Angelsen, Anders; Viset, Trond; Skogseth, Haakon; Tessem, May‐Britt; Halgunset, Jostein

doi:10.1002/pros.21260

Cited by 41 publications

(75 citation statements)

References 31 publications

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“…Several samples from each slice were selected from locations corresponding to cancerous and noncancerous areas identified in the adjacent paraffin sections. For finding these areas, a fused image of the digital photo of the fresh slice and the adjacent HES section are overlaid on the frozen slice (16). Cryosections (4 mm) from each sample were stained with HES and evaluated by a pathologist trained in uropathology.…”

Section: Patients and Tissue Samplesmentioning

confidence: 99%

Changes in Gene Transcription Underlying the Aberrant Citrate and Choline Metabolism in Human Prostate Cancer Samples

Bertilsson

Tessem

Flatberg

et al. 2012

Clinical Cancer Research

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Purpose: Low concentrations of citrate and high concentrations of choline-containing compounds (ChoCC) are metabolic characteristics observed by magnetic resonance spectroscopy of prostate cancer tissue. The objective was to investigate the gene expression changes underlying these metabolic aberrations to find regulatory genes with potential for targeted therapies.Experimental design: Fresh frozen samples (n ¼ 133) from 41 patients undergoing radical prostatectomy were included. Histopathologic evaluation was carried out for each sample before a metabolic profile was obtained with high-resolution magic angle spinning (HR-MAS) spectroscopy. Following the HR-MAS, RNA was extracted from the same sample and quality controlled before carrying out microarray gene expression profiling. A partial least square statistical model was used to integrate the data sets to identify genes whose expression show significant covariance with citrate and ChoCC levels.Results: Samples were classified as benign, n ¼ 35; cancer of low grade (Gleason score 6), n ¼ 24; intermediate grade (Gleason score 7), n ¼ 41; or high grade (Gleason score !8), n ¼ 33. RNA quality was high with a mean RNA Integrity Number score of 9.1 (SD 1.2). Gene products predicting significantly a reduced citrate level were acetyl citrate lyase (ACLY, P ¼ 0.003) and m-aconitase (ACON, P < 0.001). The two genes whose expression most closely accompanied the increase in ChoCC were those of phospholipase A2 group VII (PLA2G7, P < 0.001) and choline kinase a (CHKA, P ¼ 0.002).Conclusions: By integrating histologic, transcriptomic, and metabolic data, our study has contributed to an expanded understanding of the mechanisms underlying aberrant citrate and ChoCC levels in prostate cancer.

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Section: Patients and Tissue Samplesmentioning

confidence: 99%

Changes in Gene Transcription Underlying the Aberrant Citrate and Choline Metabolism in Human Prostate Cancer Samples

Bertilsson

Tessem

Flatberg

et al. 2012

Clinical Cancer Research

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“…Using fresh frozen radical prostatectomy prostate tissue material [16], we have previously analyzed gene expression profiles in 156 samples (116 PCa and 40 normal) from 41 patients using microarray technology [17]. All analyzed tissue samples were proven to be of high molecular quality, and thorough histopathological evaluation to characterize the composition of the relative amounts of cancer and normal tissue was performed.…”

Section: Introductionmentioning

confidence: 99%

Gene signatures ESC, MYC and ERG-fusion are early markers of a potentially dangerous subtype of prostate cancer

et al. 2014

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BackgroundGood prognostic tools for predicting disease progression in early stage prostate cancer (PCa) are still missing. Detection of molecular subtypes, for instance by using microarray gene technology, can give new prognostic information which can assist personalized treatment planning. The detection of new subtypes with validation across additional and larger patient cohorts is important for bringing a potential prognostic tool into the clinic.MethodsWe used fresh frozen prostatectomy tissue of high molecular quality to further explore four molecular subtype signatures of PCa based on Gene Set Enrichment Analysis (GSEA) of 15 selected gene sets published in a previous study. For this analysis we used a statistical test of dependent correlations to compare reference signatures to signatures in new normal and PCa samples, and also explore signatures within and between sample subgroups in the new samples.ResultsAn important finding was the consistent signatures observed for samples from the same patient independent of Gleason score. This proves that the signatures are robust and can surpass a normally high tumor heterogeneity within each patient. Our data did not distinguish between four different subtypes of PCa as previously published, but rather highlighted two groups of samples which could be related to good and poor prognosis based on survival data from the previous study.The poor prognosis group highlighted a set of samples characterized by enrichment of ESC, ERG-fusion and MYC + rich signatures in patients diagnosed with low Gleason score,. The other group consisted of PCa samples showing good prognosis as well as normal samples. Accounting for sample composition (the amount of benign structures such as stroma and epithelial cells in addition to the cancer component) was important to improve subtype assignments and should also be considered in future studies.ConclusionOur study validates a previous molecular subtyping of PCa in a new patient cohort, and identifies a subgroup of PCa samples highly interesting for detecting high risk PCa at an early stage. The importance of taking sample tissue composition into account when assigning subtype is emphasized.

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“…Bertlisson et al 10 describe a method where a whole slice of prostate is taken intact for research. This technique requires a specialised plastic rack and cryoclamp to cut and freeze the slice.…”

Section: Discussionmentioning

confidence: 99%

The handling and sampling of radical prostatectomy specimens for reporting and research: the Oxford approach

Gill¹,

Roberts²,

Browning³

et al. 2012

J Clin Pathol

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This article reviews previously described methods of fresh tissue sampling from radical prostatectomy specimens for research and describes a method used in Oxford which is simple, logical and cost effective. The method utilises a systematic zonal approach to tissue procurement in order to meet the increasing requirement for research samples with detailed morphological information such as zone of origin, tumour stage and Gleason grade.The described method involves punch biopsy sampling from a 4mm thick transverse slice cut 8mm superior to the apex. 9 biopsies are taken from each specimen in the following zonal distribution: Mid anterior, right lateral, right peripheral zone lateral, right peripheral zone mid, left peripheral zone mid, left peripheral zone lateral, left lateral, left transition zone and right transition zone.The method was validated by successfully sampling tumour in 7 out of 8 cases (88%). In 6 of the positive cases, tumour was present in more than 1 punch biopsy. The mean time from receipt of the specimen to completion of the biopsy freezing was 23.5 minutes. Tumour stage, zone and Gleason grade were determined for all positive biopsies. All cases were reported to RCPath guidelines with no compromising of margins.A logical systematic method of fresh tissue sampling from radical prostatectomy specimens is presented, which balances the need for accurate routine histopathological reporting with the requirement for increasingly complex research samples to be taken with attention to morphological details such as zone and stage.

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A new method to provide a fresh frozen prostate slice suitable for gene expression study and MR spectroscopy

Abstract: We present a safe and standardized method for procurement of a high quality fresh frozen prostate slice, suitable for gene expression analysis and MR spectroscopy.

Cited by 41 publications

References 31 publications

Changes in Gene Transcription Underlying the Aberrant Citrate and Choline Metabolism in Human Prostate Cancer Samples

Changes in Gene Transcription Underlying the Aberrant Citrate and Choline Metabolism in Human Prostate Cancer Samples

Gene signatures ESC, MYC and ERG-fusion are early markers of a potentially dangerous subtype of prostate cancer

The handling and sampling of radical prostatectomy specimens for reporting and research: the Oxford approach

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