AMACR Research Articles

Partial Atrophy in Prostate Needle Biopsies: A Detailed Analysis of Its Morphology, Immunophenotype, and Cellular Kinetics

We systematically analyzed 73 prospectively collected partial atrophy (PA) foci from over 185 prostate needle biopsy cases to characterize them along 3 fronts: morphologic, as it can be a mimic of prostate cancer (PCa), immunohistochemical (basal cell markers and alpha-methyl acyl-CoA racemase), as it often shares the staining characteristics of PCa, and cellular kinetics (MIB-1 proliferation marker), as it belongs to the larger group of focal atrophy, some of which have been shown to be proliferative and associated with chronic inflammation. The following morphologic features were prominent at low magnification: small to mid-sized glands with circumscribed (70%) or disorganized growth pattern (30%), presence of stellate/undulated gland lumina (92%), associated few completely atrophic glands within the PA focus (97%), and scant apical but abundant lateral pale/clear cytoplasm similar to adjacent benign glands (100%). On higher magnification, 33% of foci contained micronucleoli, but all lacked nuclear enlargement (100%) or macronucleoli (100%), characteristic of PCa. No adjunctive features of PCa were seen. Patchy basal cell staining was observed in 52/71 (73%), whereas 4/71 (6%) were completely negative. alpha-methyl acyl-CoA racemase demonstrated variable expression, stronger than the benign glands in 7/72 (10%) foci. Associated pathology included PCa (42%), and complete atrophy (91%), distinct from PA foci. There was no difference between the mean proliferative index of the PA foci compared with the benign glands [5.5 (range 0 to 30) and 5.6 (range 0 to 31), respectively, P=0.97 by paired t test], as measured quantitatively by ChromaVision system. PA foci were rarely associated with inflammation (1%). Familiarity with these morphologic features and staining characteristics will allow its confident separation from cancer, especially in limited biopsy material. PA foci do not represent a spectrum of proliferative inflammatory atrophy, justifying its term.

Molecular cloning and preliminary analysis of the human α-methylacyl-CoA racemase promoter

Alpha-methylacyl-CoA racemase (AMACR) is an enzyme involved in beta-oxidation of branched-chain fatty acids and bile acid intermediates. Recent works have revealed that AMACR is overexpressed in prostate cancer and functionally important for the growth of prostate cancer cells. Despite the recent interest in AMACR as a diagnostic marker for prostate cancer, little is known about the transcriptional regulation of AMACR in prostate cancer. To elucidate the regulation of the AMACR gene, a 2.3-kb fragment of its 5' flanking region was cloned into pGL3-Basic, then using tansfection and Dual-luciferase reporter assay, a preliminary analysis on promoter activity and function of this 2.3-kb sequence was carried out. This 2.3-kb fragment represented promoter activity that consistent with the expression level in LNCaP and PC-3 cells respectively. Transfection experiments of 5'-deletion mutants into LNCaP cells revealed a positive-regulatory region located between nucleotides -423 and -93 that may be responsible for AMACR transactivation in LNCaP cells. Cotransfection experiments revealed that promoter activity of this 2.3-kb sequence was down-regulated by C/EBPalpha, p53, NF-kappaB p50. And data from luciferase-based reporter assays suggest that the promoter function of AMACR is independent of androgen receptor-mediated signaling.

Mechanisms of Disease: biomarkers and molecular targets from microarray gene expression studies in prostate cancer

Molecular biomarkers can serve as useful diagnostic markers, as prognostic markers for predicting clinical behavior, or as targets for new therapeutic strategies. Application of expression microarray technology, which allows the expression of all or most of the genes in the human genome to be analyzed simultaneously, has dramatically enhanced the discovery of prostate cancer biomarkers. The diagnostic markers identified include AMACR (alpha-methylacyl CoA racemase), a protein that has already been translated into clinical use as an aid in distinguishing prostate cancer from benign disease. Individual genes, such as the polycomb gene EZH2 whose expression indicates poor survival, have been identified. The power of microarray technology is that it has allowed the identification of gene signatures (each composed of multiple genes) that might provide improved prediction of clinical outcomes in human prostate cancer. The development of a new method for analyzing expression microarray data, called COPA, has led to the discovery of TMPRSS2-ERG gene fusion involvement in the development of prostate cancer, while expression analysis of castration-resistant prostate cancer has suggested the use of novel therapeutic approaches for advanced disease. Despite these successes, there are limitations in the application of microarray technology to prostate cancer; for example, unlike with other cancers, this approach has failed to provide a consistent unsupervised classification of the disease. Overcoming the reasons for these failures represents a major challenge for future research endeavors.

Sequence variation in α‐methylacyl‐CoA racemase and risk of early‐onset and familial prostate cancer

Expression of the alpha-methylacyl-CoA racemase (AMACR) gene has been established as a sensitive and specific biomarker for the diagnosis of prostate cancer. An initial study has also suggested that the risk of familial (but not sporadic) prostate cancer may be associated with germline variation in the AMACR gene. In a study of brothers discordant for the diagnosis of prostate cancer (including 449 affected and 394 unaffected men) from 332 familial and early-onset prostate cancer families, we used conditional logistic regression and family-based association tests to investigate the association between prostate cancer and five single nucleotide polymorphisms (SNPs) tagging common haplotype variation within the coding and regulatory regions of AMACR. The strongest evidence for prostate cancer association was for SNP rs3195676, with an estimated odds ratio of 0.58 (95% confidence interval = 0.38-0.90; P = 0.01 for a recessive model). This non-synonymous SNP (nsSNP) results in a methionine-to-valine substitution at codon 9 (M9V) in exon 2 of the AMACR gene. Three additional nsSNPs showed suggestive evidence for prostate cancer association (P < or = 0.10). Our results confirm an initial report of association between the AMACR gene and the risk of familial prostate cancer. These findings emphasize the value of studying early-onset and familial prostate cancer when attempting to identify genetic variation associated with prostate cancer.

Polymorphic variants in α‐methylacyl‐CoA racemase and prostate cancer

Alpha-methylacyl-CoA racemase (AMACR), which prepares branched chain fatty acids to be metabolized for energy and is implicated in the activation of the COX-inhibiting form of ibuprofen, is overexpressed in prostate cancer and its precursor lesions. Significant differences in AMACR allele frequencies have been reported for hereditary prostate cancer (HPC), but the relevance of AMACR in the context of its substrates have not been studied. We conducted a nested case-control study of 1,318 prostate cancer cases and 1,842 controls from the screening arm of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Five non-synonymous (nsSNP) and two intronic AMACR polymorphisms were genotyped. Conditional logistic regression models were used to evaluate the associations between the genetic variants and prostate cancer. Overall, prostate cancer was not related to AMACR gene variants; however, risks for prostate cancer were significantly reduced among regular ibuprofen users who carried allele variants at four nsSNP loci (M9V, D175G, S201L, and K277E; all P(trend) < 0.05) or carried the TGTGCG haplotype (OR = 0.65; 95% CI 0.44-0.97). No AMACR-related associations were noted among nonregular ibuprofen users (all P(interaction) > 0.33). AMACR gene variants were unrelated to prostate cancer overall in this study. The protective associations observed among ibuprofen users suggest that AMACR gene variants may enhance the chemopreventive effects of ibuprofen on prostate cancer risk.

Design, Synthesis, and In Vitro Testing of α-Methylacyl-CoA Racemase Inhibitors

The enzyme alpha-methylacyl-CoA racemase (AMACR) is overexpressed in prostate, colon, and other cancers and has been partially validated as a potential therapeutic target by siRNA knockdown of the AMACR gene. Analogs of the natural substrate branched chain alpha-methylacyl coenzyme A esters, possessing one or more beta-fluorine atoms, have been synthesized using Wittig, conjugate addition, and asymmetric aldol reactions and found to be reversible competitive inhibitors. Each diastereomer of the previously reported inhibitor ibuprofenoyl-CoA was also tested. The compounds had Ki values of 0.9-20 microM and are the most potent inhibitors yet known. The presence of beta-fluorine on the alpha-methyl group or the acyl chain results in a significant lowering of the Ki value compared with nonfluorinated analogs, and this is attributed to a lowering of the pKa of the alpha-proton, facilitating enolization and binding. Several of the CoA ester inhibitors were formed by incubating the free carboxylic acid precursors with cell free extracts and CoA. alpha-Trifluoromethyltetradecanoic acid, the precursor to the most potent inhibitor, was shown to inhibit growth of cancer cell lines PC3, CWR22 Rv1, and Du145 in a dose-dependent manner and could be related to the expression level of AMACR.

Sensitivity of P504S/??-Methylacyl-CoA Racemase (AMACR) Immunohistochemistry for the Detection of Prostate Carcinoma on Stored Needle Biopsies

Alpha methylacyl-CoA-racemase (AMACR), also known as P504S, has been widely used as a positive marker for the diagnosis of prostate carcinoma in clinical practice. The utility of this assay is highly dependent on the sensitivity of AMACR detection in routinely processed biopsies. It is common practice to store precut prostate biopsy sections. Hence, it is important to determine the effect on the immunoreactive of P504S/AMACR in stored, unstained glass slides as compared with freshly cut sections of paraffin-embedded tissue. The purpose of this study was to determine the sensitivity of AMACR immunostaining for the detection of prostate carcinoma on stored needle biopsies. A total of 63 prostate biopsies with prostate carcinoma were transferred onto glass slides, baked, and stored for 1.6 to 9.2 months. The Gleason scores were 3+3(6) (n=40) including 10 small focal carcinomas (< or = 1.0 mm), 4+3(7) (n=16), and 4+4(8) or higher (n=7). The slides were then stained with a monoclonal antibody to P504S, and the staining intensity was compared with sections cut from the same blocks just prior to immunostaining, without an intervening storage period. There was no loss of sensitivity of AMACR for prostate adenocarcinoma, regardless of the length of the storage interval. The sensitivity was preserved and was independent of Gleason scores. The sensitivity of AMACR for small foci of adenocarcinoma was also not affected by the length of storage. Overall, stored slides had no observable increase in nonspecific background staining over freshly cut sections. These results indicate that the time interval between mounting and staining does not affect the sensitivity of the AMACR immunohistochemistry (IHC) stain in the detection of prostate cancer even with small foci of carcinoma on needle biopsies.

Detection of prostate cancer by α‐methylacyl CoA racemase (P504S) in needle biopsy specimens previously reported as negative for malignancy

To investigate the possibility of detecting small focal prostatic cancer by alpha-methylacyl CoA racemase (AMACR)/P504S immunohistochemistry on needle biopsy specimens that were previously interpreted as negative for carcinoma on routine haematoxylin and eosin (H&E)-stained sections. Prostate needle biopsy specimens (n = 793) previously interpreted as benign prostatic tissue by conventional morphology from 239 patients with prostatic cancer diagnosed in other biopsy cores taken at the same biopsy session were stained with the P504S monoclonal antibody. If a biopsy specimen stained positively, two pathologists independently reviewed the original corresponding H&E-stained sections to establish the malignant diagnosis. Eighty-four of the 793 biopsy specimens showed AMACR immunoreactivity; nine of these (9/793, 1.1%) contained previously unrecognized small focal prostatic carcinoma (Gleason 6, N = 8; Gleason 8, N = 1). Six of nine (67%) carcinomas showed foamy/pseudohyperplastic (N = 3) or atrophic (N = 3) features. Additionally, five biopsy specimens (5/793, 0.6%) with positive AMACR staining that did not meet the criteria for prostatic cancer on the original H&E slides were considered to be atypia. In this study, we found a 1.1% false-negative rate for carcinoma on routine H&E-stained sections. AMACR immunohistochemical staining has shown the ability to improve detection of small focal prostatic carcinoma that could be missed by conventional histological examination.

Kinetic fluorescence reverse transcriptase-polymerase chain reaction for alpha-methylacyl CoA racemase distinguishes prostate cancer from benign lesions

Background: High-throughput gene expression profiling has recently shown that the mRNA for alpha-methylacyl CoA racemase (AMACR or P504S) is overexpressed in prostate carcinomas (PCa). Several immunohistochemical studies have reported the usefulness of anti-AMACR/P504S for detecting prostate cancer over the full range of prostate specimens encountered in surgical pathology. We tested real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for specific and sensitive detection of AMACR transcripts as a supplementary measure for discriminating between malignant and benign lesions in prostatic tissues. Methods: Total RNA was isolated from snap-frozen chips in 55 cases of benign prostatic hyperplasia (BPH) and from frozen sections in 57 prostatectomy cases. The latter were analyzed by an uropathologist (J.K.) and found to contain at least 50% malignant epithelia. Relative quantification of AMACR transcripts was performed by RT-PCR using hybridization probes for detection and PBGD for normalization. Results: Normalized AMACR transcript levels showed an average 3.75-fold increase in 57 prostate carcinomas cases when compared to 55 cases of BPH ( p < 0.0001). A 85.6% specificity and 64.9% sensitivity can be achieved if the cutoff is set at 12.95. AMACR expression levels among PCa cases were not statistically associated with the tumor and lymph node stage, the grading, the surgical margins, the Gleason score or progression. Discussion: The present study demonstrates the usefulness of quantitative AMACR-mRNA transcript detection in prostatic tissues as an alternative to immunological staining techniques. Since the latter clearly predominate in the laboratory routine, PCR-based detection of AMACR has the potential to gain widespread acceptance as a suitable future tool for monitoring prostate cancer patients.

Comparison of monoclonal antibody (P504S) and polyclonal antibody to alpha methylacyl‐CoA racemase (AMACR) in the work‐up of prostate cancer

Studies using a monoclonal (P504S) and a polyclonal antibody (p-AMACR) to alpha-methylacyl-CoA racemase (AMACR) have shown variable expression in prostate cancer (PCa). The goal is to compare the sensitivity of both antibodies in PCa and evaluate their utility in the work-up of atypical prostate needle biopsies (NBXs). A tissue microarray (TMA) with 248 samples of benign prostate, high-grade prostatic intraepithelial neoplasia (HGPIN) and PCa samples, 20 NBXs with minute PCa and 32 NBXs with 'atypical' foci were stained with P504S and p-AMACR. Ninety percent of PCa (76/76 TMA, 16/20 NBXs) showed predominantly strong p-AMACR expression while 87% (65/69 TMA, 16/20 NBXs) showed variable P504S expression (sensitivity 90% versus 87%, P = 0.10). In HGPIN, P504S and p-AMACR were positive in 77% and 91% of samples, respectively. In the 'atypical' NBXs group, 53% were classified as PCa, 12% benign and 35% atypical, suspicious for PCa, after review of the basal marker. Of atypical, suspicious for PCa, P504S/p-AMACR helped convert the diagnosis to PCa in 5/11 (45%) cases, where, despite negative basal cell markers, morphology was less than optimal. Differences between P504S and p-AMACR appear marginal and clinically insignificant. AMACR is negative in a subset of unequivocal minute PCa with both antibodies. However, when utilized in proper context, AMACR may offer significant advantage in converting an 'atypical' diagnosis to PCa where morphology and basal markers are less than optimal in resolving the diagnosis.

Extraction and processing of high quality RNA from impalpable and macroscopically invisible prostate cancer for microarray gene expression analysis.

Molecular analyses of early-stage prostate cancers are necessary to assess their potential clinical significance based on established and/or novel biomarkers for tailored clinical management. A prerequisite for the application of RNA-based analyses of such, mostly macroscopically-undetectable, small prostate carcinomas is the recovery and preservation of sufficient RNA quantities and quality. Furthermore, in prostate cancer, heterogeneity is a common phenomenon that includes a juxtaposition of different tissue compositions and variable histological grades within the same tumor focus. To better understand the molecular mechanisms of prostate cancer, it is essential to correlate molecular data with a specific cell type. Here, we present a tissue collecting protocol which is aligned with the preoperative evaluation of tumor localization. In combination with the technique of laser microdissection and pressure catapulting, we are able to preserve RNA of high quality from homogeneous cell populations of macroscopically-undetectable small prostate carcinomas. To obtain the necessary RNA quantities for whole genome cDNA microarrays, the isolated total RNAs were amplified by T7-based RNA-polymerase in vitro transcription. The microarray analyses (Human Unigene Set RZPD3.1) resulted in 216 differentially expressed genes (191 down-regulated, 25 up-regulated). Among these were several known prostate cancer relevant genes, such as AMACR, TARP, LIM, GPR160 (all up-regulated), CAV1, NTN1, MT1X; CLU, TRIM29, SPARCL1 and HSPB8 (all down-regulated).

A Variant of the alpha-methyl-acyl-CoA racemase gene created by a deletion in exon 5 and its expression in prostate cancer

Alpha-methylacyl-CoA racemase (AMACR) is a mitochondrial and peroxisomal enzyme that is overexpressed in prostate cancer. Alternatively spliced variants of AMACR have recently been reported, however, their role in prostate cancer pathogenesis is unclear. Using PCR techniques we have identified a novel variant of AMACR. This transcript arises by an alternative splicing event in the 5th exon of the gene whereby a 749 base sequence is deleted causing a shift in the reading frame. The protein encoded by this transcript has a predicted molecular weight of 43,833 kDa and a pI of 7.01 and therefore differs in size and physical characteristics from the main form of AMACR. The carboxyl terminus of this variant does not contain the peroxisomal targeting signal found in the main form of AMACR. Using real time PCR it was demonstrated that this transcript also occurs in normal prostate tissue and is elevated in prostate cancer. Coordinate expression of this transcript with the other forms of AMACR was shown. This transcript was expressed as a FLAG fusion protein in Cos-7 cells and probed with relevant antibodies. A deletion event in exon 5 of the AMACR gene creates a novel transcript that is coordinately expressed with the other forms of AMACR but with different biochemical characteristics. (c) 2005 Wiley-Liss, Inc.

Molecular Classification of Renal Tumors by Gene Expression Profiling

Renal tumor classification is important because histopathological subtypes are associated with distinct clinical behavior. However, diagnosis is difficult because tumor subtypes have overlapping microscopic characteristics. Therefore, ancillary methods are needed to optimize classification. We used oligonucleotide microarrays to analyze 31 adult renal tumors, including clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, oncocytoma, and angiomyolipoma. Expression profiles correlated with histopathology; unsupervised algorithms clustered 30 of 31 tumors according to appropriate diagnostic subtypes while supervised analyses identified significant, subtype-specific expression markers. Clear cell RCC overexpressed proximal nephron, angiogenic, and immune response genes, chromophobe RCC oncocytoma overexpressed distal nephron and oxidative phosphorylation genes, papillary RCC overexpressed serine protease inhibitors, and extracellular matrix products, and angiomyolipoma overexpressed muscle developmental, lipid biosynthetic, melanocytic, and distinct angiogenic factors. Quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry of formalin-fixed renal tumors confirmed overexpression of proximal nephron markers (megalin/low-density lipoprotein-related protein 2, alpha-methylacyl CoA racemase) in clear cell and papillary RCC and distal nephron markers (beta-defensin 1, claudin 7) in chromophobe RCC/oncocytoma. In summary, renal tumor subtypes were classified by distinct gene expression profiles, illustrating tumor pathobiology and translating into novel molecular bioassays using fixed tissue.

Serum levels of phytanic acid are associated with prostate cancer risk

Recent findings of over-expression of the AMACR gene in prostate cancer and association between sequence variants in the AMACR gene and prostate cancer risk, along with the well established findings of association between prostate cancer risk and over-consumption of dairy products and red meat, indirectly suggest that phytanic acid, which primarily comes from dietary intake of dairy and red meat and requires the AMACR enzyme for its metabolism, may be associated with prostate cancer risk. In this small case-control study, we assessed the association between phytanic acid levels and prostate cancer risk. One hundred and four prostate cancer patients and controls were recruited in North Carolina. Serum levels of phytanic acid were measured using a gas liquid chromatography/mass spectroscopy analysis, and a food frequency questionnaire was administered to each individual to assess dietary intake. Three key findings are reported. First, there was a high correlation between two independent measurements of phytanic acid levels from the same individuals and the levels of phytanic acid were within the expected range, suggesting that serum levels of phytanic acid levels can be reliably measured in large epidemiological studies. Second, serum levels of phytanic acid among prostate cancer patients were significantly higher than that of unaffected controls, suggesting an association between phytanic acid and prostate cancer risk. Lastly, there was a significantly positive correlation between serum levels of phytanic acid and dietary intake of dairy and red meat servings during the year prior to the serum measurement. Although the results from our study suggest phytanic acid levels may be associated with prostate cancer risk, they were based on a study with a small sample size. Much larger studies are required to confirm these important findings.

A Nonclassic CCAAT Enhancer Element Binding Protein Binding Site Contributes to α-Methylacyl-CoA Racemase Expression in Prostate Cancer

Alpha-methylacyl-CoA racemase (AMACR), an enzyme involved in branched-chain fatty acid beta-oxidation that is normally expressed at high levels in human liver, is specifically and consistently overexpressed at both mRNA and protein levels in human prostate cancer and potentially other cancer types. To characterize the mechanisms underlying transcriptional regulation of AMACR at the genetic and epigenetic levels, we performed a series of methylation and reporter assays in prostate cancer tissues and cell lines. The results ruled out altered methylation patterns as the cause of overexpression in prostate cancer cells. However, promoter deletion analysis identified an 8-bp nonclassic CCAAT enhancer element located approximately 80 bp upstream of the transcriptional initiation site that is responsible for AMACR expression in both prostate cancer cell lines and cell lines of liver origin. Deletion or mutation of this element completely abolished AMACR promoter activity. Ectopic expression of CCAAT/enhancer binding protein beta increased luciferase activity driven by a wild-type AMACR promoter sequence but not by the sequence in which the putative CCAAT/enhancer binding protein binding element had been mutated. These results implicate a nonclassic CCAAT enhancer element in the AMACR gene promoter as playing a critical role in the regulation of AMACR gene expression.

Diagnostic Utility of ??-Methylacyl CoA Racemase (P504S) on Prostate Needle Biopsy

Alpha-methylacyl CoA racemase (AMACR), also known as P504S, was identified by the analysis of cDNA library subtraction in conjunction with high throughput microarray screening from prostate tissue and has been proven to be one of the very few biomarkers that can distinguish cancer from benign cells with high sensitivity and specificity for prostate carcinoma. It is a successful example of the translation of molecular findings into clinical practice. This review focuses on the study of AMACR (P504S) expression in small focal prostate cancer and atypical small acinar proliferation (ASAP) on needle biopsies and emphasizes the utility of AMACR (P504S) in routine surgical pathology practice. We also discuss the potential pitfalls and caveats in the interpretation of immunostaining results.

Detection of P504S (alpha-methylacyl-CoA racemase) in prostatic adenocarcinomas

To evaluate the specificity and sensitivity of the monoclonal antibody P504S (AMACR) in detection of prostatic adenocarcinomas. 150 cases, including prostatic adenocarcinomas (n = 105), benign prostatic hyperplasia (BPH, n = 42) and atypical small acinar proliferation (ASAP, n = 3), were studied by immunohistiochemical analysis of P504S. The clinical data, HE, PSA and CK34betaE12 staining slides were reviewed in all of the cases. P504S was strongly and diffusely positive (> or = +++) in 97.1% cases of prostatic adenocarcinomas and focally positive (+) in 2 cases, regardless of Gleason score, age and serum PSA. However, P504S was also positive in high grade PIN that surrounded adenocarcinomas (n = 24) and weakly positive (+) in benign prostatic hyperplasia that surrounded adenocarcinomas (8 out of 82 cases). In 42 cases of BPH, 10 cases (23.8%) show (+) staining, and 1 case (2.4%) shows (++) staining. P504S was negative in entire 8 cases of basal cell hyperplasia (BCH) and in 3 cases of ASAP. P504S (AMACR), a recently established positive marker for prostatic adenocarcinomas, has good sensitivity (97.1%) and specificity (86.0%). It is crucial to correlate the P504S staining pattern with the findings of HE, PSA and CK34betaE12 (or p63) staining, as well as clinical information to reach a correct diagnosis.

Discovery and clinical application of a novel prostate cancer marker: alpha-methylacyl CoA racemase (P504S).

The recent discovery of the overexpression of P504S/alpha-methylacyl coenzyme A racemase (AMACR) in prostate cancer is a successful example of translating an advanced molecular finding into clinical practice. AMACR (P504S) has been proven to be one of the few biomarkers that can help distinguish cancer from benign cells, with high sensitivity and specificity for prostate carcinoma. It is the first gene identified by the analysis of complementary DNA microarray profiles from prostate tissue to be used as a tissue tumor marker in clinical practice and to improve the diagnosis of prostate cancer. This review focuses on the study of AMACR (P504S) expression in prostate cancer, premalignant lesions, benign prostate tissues, and other normal and malignant tissues and a discussion of its clinical usefulness. We emphasize the interpretation of the AMACR immunohistochemical results in routine surgical pathology practice and also discuss the potential future applications of this marker and the possible role of AMACR in the pathogenesis of cancer development.

A mouse model for alpha-methylacyl-CoA racemase deficiency: adjustment of bile acid synthesis and intolerance to dietary methyl-branched lipids.

alpha-Methylacyl-CoA racemase (Amacr) deficiency in humans leads to sensory motor neuronal and liver abnormalities. The disorder is recessively inherited and caused by mutations in the AMACR gene, which encodes Amacr, an enzyme presumed to be essential for bile acid synthesis and to participate in the degradation of methyl-branched fatty acids. To generate a model to study the pathophysiology in Amacr deficiency we inactivated the mouse Amacr gene. As per human Amacr deficiency, the Amacr(-/-) mice showed accumulation (44-fold) of C27 bile acid precursors and decreased (over 50%) primary (C24) bile acids in bile, serum and liver, however the Amacr(-/-) mice were clinically symptomless. Real-time quantitative PCR analysis showed that, among other responses, the level of mRNA for peroxisomal multifunctional enzyme type 1 (pMFE-1) was increased 3-fold in Amacr(-/-) mice. This enzyme can be placed, together with CYP3A11 and CYP46A1, to make an Amacr-independent pathway for the generation of C24 bile acids. Exposure of Amacr(-/-) mice to a diet supplemented with phytol, a source for branched-chain fatty acids, triggered the development of a disease state with liver manifestations, redefining the physiological significance of Amacr. Amacr is indispensable for the detoxification of dietary methyl-branched lipids and, although it contributes normally to bile acid synthesis from cholesterol, the putative pMFE-1-mediated cholesterol degradation can provide for generation of bile acids, allowing survival without Amacr. Based upon our mouse model, we propose elimination of phytol from the diet of patients suffering from Amacr deficiency.

Apport d’un cocktail d’anticorps anti-(p63 + p504s) dans le diagnostic de cancer de prostate

Numerous lesions of the prostate, such as atrophy, adenomatous atypical hyperplasia (adenosis) or PIN can be misdiagnosed with prostatic cancer, and confused with ASAP, leading to perform additional biopsies. In such lesions, the pathologist can perform an immunohistochemical study with the anti-high molecular weight cytokeratin antibody CK903 (34bE12), which confirms the absence of basal cells and supports the diagnosis of prostatic cancer. To compare markers of basal cells (cytokeratin 5/6, p63) and the marker of prostatic carcinomatous glands (p504s) or alpha methylacyl-CoA racemase (AMACR). Retrospective study of 44 cases of paraffin-embedded prostatic specimens (36 biopsies, 4 PER, 1 adenomectomy and 3 radical prostatectomies), consisting in 20 cases of prostatic carcinomas (2 intraductal, 12 Gleason 6 (3+3), 4 Gleason 7 (4+3), 2 Gleason 8 (4+4)), 11 ASAP, 9 PIN (2 low grade, 7 high grade (2 isolated)), and 10 benign lesions (8 atrophy, 1 atypical adenomatous hyperplasia and 1 case of clear cell cribriform hyperplasia). All cases were tested with antibodies to CK 5/6, and with a cocktail to p63 and p504s, after heat antigenic retrieval on NEXES Ventana processor. Basal cells of normal prostatic glands stained with CK5/6 and p63 in 91,3% and 100% of cases, independently from the fixation procedure (Bouin or Formalin). Carcinomas had a p63-/p504s+ profile, PIN were p63+/p504s+, and benign lesions were p63+/p504s-. We observed an increase in sensitivity: p63/p504s (100%), CK5/6 (80%), p63 (90%), p504s (95%), and specificity: p53/p504s (90%), CK5/6 (87.5%), p63 (90.5%), p504s (90.9%). Our results show that the use of a cocktail to p63/p504s is more specific than the use of CK5/6 alone this technique supports a diagnosis of prostatic cancer in 40% of cases previously considered as ASAP.