Global expression of AMACR transcripts predicts risk for prostate cancer – a systematic comparison of AMACR protein and mRNA expression in cancerous and noncancerous prostate

Abstract

Background: The high false negative rates for initial prostate biopsies refer a large number of the men for repeat biopsies each year. Therefore, biomarkers associated with high risk of the presence of malignancy in histologically benign biopsies could provide a tool to discriminate the patients who need repeat biopsy or intensive follow-up from those who do not. Here we examined the diagnostic applicability of alpha-methylacyl CoA racemase (AMACR) and androgen receptor (AR) mRNA expression and AMACR protein levels in benign and cancerous prostatic tissue. Methods: AMACR and AR mRNA levels were measured with quantitative, reverse-transcription PCR (qRT-PCR) assays in 79 radical prostatectomy (RP) cases (including 69 benign (RP-Be) and 69 cancerous (RP-PCa) samples) and 19 benign prostate samples obtained from cystoprostatectomies. To further determine the detailed areas of altered AMACR expression, AMACR mRNA level measurement and protein staining were performed for three cross-sectioned RP cases. Results: The median AMACR and AR expression levels were 194.6 (p < 0.0001) and 6.6 (p = 0.0004) times higher in RP-PCa samples than in the benign cystoprostatectomy (CP) samples, respectively. There was no statistically significant difference between RP-PCa and RP-Be samples, except for AMACR/KLK3 (Kallikrein-Related Peptidase 3) ratio, which was significantly higher in RP-PCa samples than in RP-Be samples (p = 0.016). In the systematic study of cross-sections, AMACR mRNA was detected in all of the studied areas including histologically benign tissue, but at significantly higher levels in carcinoma areas (p < 0.001). AMACR protein expression was detected in 80 % (28/35) of the areas that contained carcinoma and in 37 % (44/119) of the benign and PIN areas from the same patients. Conclusions: AMACR transcripts were detected in all RP-PCa and RP-Be samples but not in non-cancerous CP samples, which suggest a global increase of AMACR expression in cancerous prostates. Therefore patients with false negative biopsies might benefit from an AMACR mRNA measurement when assessing their cancer risk.

RNA‐based markers in biopsy cores with atypical small acinar proliferation: Predictive effect of T2E fusion positivity and MMP‐2 upregulation for a subsequent prostate cancer diagnosis

“…Recently, PC specific ERG rearrangements and altered epigenetic regulations of AMACR at the protein level were evaluated to allocate high PC risk in diagnostically challenging prostate cores including ASAP. [15][16][17][33][34][35][36][37][38][39][40] Although ERG and AMACR have stood out as PC indicators at the protein level in the literature, currently existing results are conflicting and should be validated as this is most likely due to methodological approaches (fluorescence in situ hybridization, immunohistochemistry [IHC] or qPCR), ethnic origin of the patients that is an important factor affecting the fusion frequency in the population of interest, and the differences in clinicopathological characteristics of patients. In the present study, we analyzed all PC-related markers using a RT-qPCR system which offers a more sensitive detection option.…”

“…In the literature, diagnostic utility of AMACR has been suggested in diagnostically challenging prostatic tissue samples due to altered expression in PC, and due to high specificity and sensitivity at both the transcriptional and translational level. 28,36,[38][39][40][41][42][43][44][45][46] AMACR expression at the RNA level, but not at the protein level, was also reported to be a predictive marker for PC risk in tissue samples of the patients with negative biopsies. 47 We emphasized in detail that the expression of AMACR should be assessed at the mRNA level, due to RNA/protein discordancy, when evaluating PC risk in biopsy samples.…”

Prostate Cancer Risk Stratification in Men With a Clinical Suspicion of Prostate Cancer Using a Unique Biparametric MRI and Expression of 11 Genes in Apparently Benign Tissue: Evaluation Using Machine‐Learning Techniques

“…The mRNA transcript expression of ACSM1, AMACR, CACNA1D, DLX1, PCA3, PLA2G7, RHOU, SPINK1, SPON2, TMPRSS2‐ERG, and TDRD1 genes were evaluated in the biopsy cores taken from the peripheral zone of the prostate without IMPROD bpMRI evidence of suspicious lesion. Total RNA was extracted from the tissues using RNeasy Mini kit (Qiagen, Chatsworth, CA) with the modification of adding a known, fixed amount of artificial internal control RNA to each sample after cell lysis as described previously . Total RNA was reverse transcribed into cDNA using the High Capacity cDNA Archive kit (Applied Biosystems, Foster City, CA) using the random primers provided in the kit.…”

“…In previous studies, expressions of 11 genes (ie, ACSM1, AMACR, CACNA1D, DLX1, PCA3, PLA2G7, RHOU, SPINK1, SPON2, TMPRSS2‐ERG, and TDRD1) in histologically benign prostate tissue from PCa patients were investigated to determine their diagnostic performance . Furthermore, it has been shown that the expression of TDRD1 and TMPRSS2‐ERG mRNA is significantly different ( P < 0.05) in men with PCa compared with men without PCa .…”

COMBO-FISH: A Versatile Tool Beyond Standard FISH to Study Chromatin Organization by Fluorescence Light Microscopy

“…The AMACR gene codes for an enzyme involved in peroxisomal beta oxidation of branched fatty acids [70,71] and is highly overexpressed in prostate cancer [72,73], the most prevalent cancer in the male population, and is used as a well-established diagnostic marker. However, the exact mechanisms causing dysregulation of AMACR expression remain elusive [74,75].…”