Alpha-methylacyl-CoA racemase (AMACR/P504S) protein expression in urothelial carcinoma of the upper urinary tract correlates with tumour progression

Screening of differentially expressed genes and identification of AMACR as a prognostic marker in prostate cancer

Prostate cancer, the second most common cancer found in male over the world, was estimated to have 191,930 new cases and 33,330 deaths in 2020 in the United States. Prostate cancer is very common in male, about 12.1% of men will acquire this cancer in their lifetime, and a higher risk was reported in older men and African American men. Gene deregulations have been found to be extensively associated with cancer development. To gain further insight into how gene deregulation affects prostate cancer, we analysed three gene profiling datasets of prostate cancer from Gene Expression Omnibus (GEO) applying bioinformatic tools in our study. Firstly, we identified common differently expressed genes (DEGs) shared by the three gene profiling datasets, constructed protein-protein interaction network and determined top 10 hub genes. Further DEGs validation in TCGA and Human Protein Atlas Database identified AMACR as the core gene. We then analysed the role of AMACR in prostate cancer cell lines and found that AMACR-knockdown resulted in the decreased cell proliferation and increased apoptosis. These results suggest an oncogenic role of AMACR in prostate cancer, and it could be a potential biomarker for the diagnosis of prostate cancer.

Diagnostic roles of proliferative markers in pathological Grade of T1 Urothelial Bladder Cancer

The stage T1 urothelial bladder cancer (T1 UBC) tumor grade classification is important for prognosis and clinical management. However, the reproducibility of this two-grade classification system is limited in regards to pathological diagnosis, and there is lack of ideal, objective and easily detected markers for pathological diagnosis. In our study, bladder urothelial lesions from a total of 124 patients diagnosed pathologically after transurethral resection of the bladder tumor (TURBT) were collected, including non-cancerous lesions from 33 patients and lesions from 91 T1 UBC patients. A series of previous studies have suggested some common and valuable factors in the diagnosis and prognosis of UBC, but there are still some controversial factors, such as the mitotic figure (MF) of tumor cell, cell proliferation index Ki-67, graded differentiation marker CK20, P53, P504S and carcinogenesis associated telomerase reverse transcriptase (TERT) promoter mutations. The purpose of this study was to evaluate the value of these factors in the pathological grading diagnosis of T1 UBC. The results showed that gender, lesion size, mitotic index (MI), CK20, P53, Ki-67, P504S and TERT promoter hot spot mutations (C228T and C250T) were correlated with T1 UBC diagnosis (P<0.05). The MI, Ki-67 and P504S were correlated with the pathological grade of T1 UBC (P<0.05). Logistic regression analysis showed that the MI and Ki-67 were independent risk factors for high-grade (HG) of T1 UBC (P<0.05). The combined detection of the MI, Ki-67 and P504S in a multivariate diagnostic model improved the diagnostic accuracy of assigning the T1 UBC pathological grade (AUC=0.904, 95%CI: 0.824~0.956, P<0.05). In conclusion, MI and Ki-67, as important markers of histopathology and cell proliferation, can be easily measured and have good reproducibility. These markers may be meaningful parameters for assigning the pathological grade of UBC.

CK20 versus AMACR and p53 immunostains in evaluation of Urothelial Carcinoma in Situ and Reactive Atypia

Ancillary testing with immunohistochemistry has shown recent promise in the workup of equivocal bladder lesions. We read with interest the recent findings of Alston et al., who assessed the diagnostic utility of alpha-methylacyl-CoA racemase (AMACR) in comparison to cytokeratin 20 (CK20) in evaluation of atypia in challenging flat urothelial lesions in the differential between carcinoma in situ (CIS) and reactive atypia. AMACR was reported to be a somewhat more specific but less sensitive marker for CIS than CK20, though showing weaker intensity. Spurred by their report, with the knowledge that we had consistently and consecutively performed AMACR, CK20, and p53 on flat urothelial lesions challenging enough to reach intradepartmental consensus, we performed a retrospective review. Similarly, we found that AMACR was less sensitive (80%) and more specific (100%) than CK20, with the same caveat of less staining intensity. Additionally, our p53 review identified a significant rate (~ 27%) of equivocal/non-informative findings. Taken together, our experience in this consecutive cohort confirms the impression of Alston et al. regarding the utility and challenges of AMACR use, while highlighting challenges with p53, which we plan to use more sparingly prospectively.

The Biology of Myxofibrosarcoma: State of the Art and Future Perspectives

BACKGROUND

Myxofibrosarcoma (MFS) is among the most highly complex sarcoma types. Molecular cytogenetic studies have identified a high level of genomic complexity.

SUMMARY

This review provides an update of the current research related to MFS, with particular emphasis on emerging mechanisms of tumorigenesis and their potential therapeutic impact. Many novel possible molecular markers have been identified, not only for prognostication in MFS, but also to serve as possible therapeutic targets, and thereby improve clinical outcomes. However, the molecular pathogenesis of MFS remains incompletely understood. Key Messages: Patients suffering from advanced MFS might benefit from expanded molecular evaluation in order to detect specific expression profiles and identify drug-able targets. Moreover, immunotherapy represents an intriguingly perspective due to the presence of "T-cell inflamed" tumor microenvironment.

Does the addition of AMACR to CK20 help to diagnose challenging cases of urothelial carcinoma in situ?

Background

Urothelial carcinoma in situ (CIS) in the bladder can be difficult to diagnose due to factors including procedural artifact, minimal tissue sampled, therapy-related changes, and various CIS growth patterns. Prior data has demonstrated an increase in alpha-methylacyl-CoA-racemase (AMACR) in urothelial CIS, but there is no information on its utility for diagnosing difficult cases. The aim of this investigation was to assess the expression of AMACR that was ordered on equivocal bladder cases during clinical practice.

Methods

Transurethral resections of the bladder in which AMACR and CK20 were performed during diagnostic workup were identified and cases with a final diagnosis of CIS (n = 22) or non-neoplastic urothelium (n = 30) were selected. Additionally, cases in which a diagnosis of CIS was rendered without IHC (n = 20) were selected and tested for AMACR expression.

Results

Sensitivity of AMACR for CIS diagnosed with IHC during clinical practice was 73% and specificity was 97%, while CK20 was 95% sensitive and 80% specific. Sensitivity of AMACR in CIS diagnosed without IHC was 100%. In all groups, AMACR had inconsistent intensity, compared to CK20 which had consistent, strong intensity.

Conclusions

AMACR was usually positive in urothelial CIS and negative in non-neoplastic urothelium. However, it is important to note that AMACR was less sensitive in difficult cases, while CK20 was more sensitive with more consistent, strong staining compared to AMACR.

A Novel Monoclonal Antibody Against Alpha-Methylacyl-CoA Racemase Applicable for Paraffin-Embedded Tissues and Diagnostics of Prostate Cancer

AMACR (alpha-methylacyl-CoA racemase) has been recently described as a prostate cancer-specific gene that encodes a protein involved in the beta-oxidation of branched chain fatty acids. Expression of AMACR protein is found in prostatic adenocarcinoma, but not in benign prostatic tissue. Thus, monoclonal antibodies (mAbs) for AMACR detection are an important tool for the diagnosis of AMACR-positive cancers. However, only a few mAbs, especially those applicable for immunohistochemistry (IHC), have been established to date. In this study, we describe the generation of a new hybridoma clone G8 producing anti-AMACR antibodies. G8 mAb specifically binds human AMACR and was successfully used in immunoblotting and immunofluorescence on paraformaldehyde-fixed cells and in IHC of paraffin-embedded tumor specimens. These results indicate that this new anti-AMACR mAb G8 would be useful in the diagnosis of AMACR-related cancers and would be a strong tool in both basic and clinical research on AMACR.

High alpha-methylacyl-CoA racemase (AMACR) is associated with ERG expression and with adverse clinical outcome in patients with localized prostate cancer

Alpha-methylacyl-CoA racemase (AMACR) is a well-characterized marker extensively utilized in prostate cancer (PCA) diagnosis. However, the prognostic value of AMACR expression and its relation to TMPRSS2-ERG gene rearrangement as one of the most common molecular alterations in PCA is not fully explored. AMACR expression was investigated in a cohort of 218 men with localized PCA treated by radical prostatectomy and correlated with ERG and various clinical and pathological parameters. In vitro studies assessed AMACR changes to ERG knockdown and other related genes. In addition, bioinformatics validated the significance of AMACR/ERG expression and assessed relevant genetic signatures in relation to AMACR/ERG expression. AMACR expression was significantly associated with disease progression and with ERG (p ∼0). Seventeen percent of cancer foci showed negative/weak AMACR expression while being ERG positive. High AMACR expression was significantly associated with positive surgical margins (p = 0.01), specifically in tumors with lower Gleason score <7, with ∼95 % exhibiting positive surgical margin (p = 0.008). High AMACR showed marginal association with PSA biochemical recurrence (BCR) (p = 0.06) which was slightly more pronounced in ERG-positive tumors (p = 0.04). This was validated in other public cohorts. However, in this cohort, the association with BCR was not statistically significant in multivariate analysis (p = 0.09). Using in vitro cellular models, AMACR messenger RNA (mRNA) expression, but not protein levels, showed an association with ERG expression. We report for the first time a significant association between AMACR and ERG with prognostic implication. Patients with high AMACR/ERG-positive PCA may be at higher risk for disease progression, and additional studies in larger cohorts are needed to confirm the above findings. Functional studies investigating the molecular pathways connecting AMACR and ERG may provide an additional insight into PCA progression pathways.

[Metastatic lymph node collision of a prostatic adenocarcinoma and an urothelial carcinoma and review of the literature]

INTRODUCTION

Tumor collision is the encounter of two tumors from two different topographical sites. Cases of metastatic lymph node collision are exceptional. We report the case of a metastatic lymph node collision of an urothelial carcinoma and a prostatic adenocarcinoma.

OBSERVATION

A 61-year-old man was hospitalized for a right nephroureterectomy with peri-ureteral lymph node dissection. He was followed since 2004 for prostatic adenocarcinoma and treated with radical prostatectomy then radiation therapy 4 years later due to a new increase of PSA. In the follow-up, an urothelial carcinoma of the lower right ureter was discovered in 2014. Histological analysis of a peri-ureteral lymph node showed a double metastasis of urothelial and prostatic origin. The prostatic adenocarcinoma was composed of acinar and ductal subtypes. Immunohistochemical study including CK7, CK20, PSA, GATA3, P63 antibodies confirmed the distinct phenotype of the 2 tumors.

DISCUSSION

Metastatic collision of urothelial carcinoma and prostatic adenocarcinoma has been reported in 4 cases only. Our review of literature shows that prostatic adenocarcinoma always precedes the urothelial carcinoma. Immunohistochemical study, when carried out for distinguishing both tumors, should include CK7, CK20 and PSA. GATA3, androgen receptor and P63 could be added in a second time.

AMACR amplification and overexpression in primary imatinib-naïve gastrointestinal stromal tumors: a driver of cell proliferation indicating adverse prognosis

Non-random gains of chromosome 5p have been observed in clinically aggressive gastrointestinal stromal tumors, whereas the driving oncogenes on 5p remain to be characterized. We used an integrative genomic and functional approach to identify amplified oncogenes on 5p and to evaluate the relevance of AMACR amplification at 5p13.3 and its overexpression in gastrointestinal stromal tumors. Thirty-seven tumor samples, imatinib-sensitive GIST882 cell line, and imatinib-resistant GIST48 cell line were analyzed for DNA imbalances using array-based genomic profiling. Forty-one fresh tumor samples of various risk categories were enriched for pure tumor cells by laser capture microdissection and quantified for AMACR mRNA expression. AMACR-specific fluorescence in situ hybridization and immunohistochemistry were both informative in tissue microarray sections of 350 independent primary gastrointestinal stromal tumors, including 213 cases with confirmed KIT /PDGFRA genotypes. To assess the oncogenic functions of AMACR, GIST882 and GIST48 cell lines were stably silenced against their endogenous AMACR expression. In 59% of cases featuring 5p gains, two major amplicons encompassed discontinuous chromosomal regions that were differentially overrepresented in high-risk cases, including the one harboring the mRNA-upregulated AMACR gene. Gene amplification was detected in 19.7% of cases (69/350) and strongly related to protein overexpression (p<0.001), although 52% of AMACR-overexpressing cases exhibited no amplification. Both gene amplification and protein overexpression were significantly associated with epithelioid histology, larger size, increased mitoses, higher risk levels, and unfavorable genotypes (all p≤0.03). They were also independently predictive of decreased disease-free survival (overexpression, p<0.001; amplification, p=0.020) in the multivariate analysis. Concomitant with downregulated cyclin D1, cyclin E, and CDK4, AMACR knockdown suppressed cell proliferation and induced G₁-phase arrest, but did not affect apoptosis in both GIST882 and GIST48 cells. In conclusion, AMACR amplification is a mechanism driving increased mRNA and protein expression and conferring aggressiveness through heightened cell proliferation in gastrointestinal stromal tumors.

AMACR amplification in myxofibrosarcomas: a mechanism of overexpression that promotes cell proliferation with therapeutic relevance

PURPOSE

Myxofibrosarcomas frequently display arm-level gains on 5p. We characterized the pathogenetic and therapeutic relevance of the α-methylacyl coenzyme A racemase (AMACR) at 5p13.3.

EXPERIMENTAL DESIGN

AMACR mRNA expression in myxofibrosarcomas was analyzed using the public transcriptome and laser-microdissected sarcoma cells. We performed florescence in situ hybridization (FISH) and immunohistochemistry in independent samples for clinical correlates. In AMACR-overexpressing myxofibrosarcoma cells and xenografts, we elucidated the biologic function of AMACR using RNA interference and explored the therapeutic effect and mechanism of an AMACR inhibitor, ebselen oxide.

RESULTS

AMACR protein overexpression and gene amplification were significantly associated with each other (P < 0.001), with higher tumor grades (both P ≤ 0.002), and univariately with worse metastasis-free survival (MFS; both P < 0.0001) and disease-specific survival (DSS; P = 0.0002 for overexpression; P = 0.0062 for amplification). AMACR protein overexpression also independently portended adverse outcome (DSS, P = 0.007; MFS, P = 0.001). However, 39% of AMACR-overexpression cases did not show gene amplification, implying alternative regulatory mechanisms. In myxofibrosarcoma cell lines, stable AMACR knockdown suppressed cell proliferation, anchorage-independent growth, and expression of cyclin D1 and cyclin T2. These growth-promoting attributes of AMACR were corroborated in the AMACR-silenced xenograft model and AMACR-underexpressed myxofibrosarcomas, showing decreased labeling for cyclin D1, cyclin T2, and Ki-67. Compared with fibroblasts, AMACR-expressing myxofibrosarcoma cells were more susceptible to ebselen oxide, which not only decreased viable cells, promoted proteasome-mediated degradation of AMACR protein, and induced cellular apoptosis in vitro, but also dose-dependently suppressed xenografted tumor growth in vivo.

CONCLUSIONS

Overexpressed AMACR in myxofibrosarcomas can be amplification-driven, associated with tumor aggressiveness, and may be relevant as a druggable target.

Dysregulation of mammalian target of rapamycin pathway in upper tract urothelial carcinoma

Upper tract urothelial carcinoma (UTUC) accounts for 5% to 10% of all urothelial carcinomas. Despite many shared features, key clinical and molecular genetic differences between upper tract and bladder urothelial carcinomas are becoming apparent. We have previously demonstrated alterations of mammalian target of rapamycin (mTOR) pathway in bladder carcinoma with a potential impact on biological behavior. In the current study, we evaluated the expression status and prognostic significance of mTOR pathway members in UTUC. Archival formalin-fixed and paraffin-embedded tissues from 99 primary UTUCs were retrieved from one of the authors' institution. Tissue microarrays were constructed with triplicate tumor samples and paired nonneoplastic urothelium. Tissue microarrays were analyzed using immunohistochemistry for mTOR pathway members: PTEN, phos-AKT, phos-mTOR, phos-S6, phos-4EBP1, and related markers p27 and c-MYC; correlation with clinicopathologic parameters and outcome was performed. We found significantly lower expression of PTEN, phos-AKT, phos-mTOR, phos-S6, phos-4EBP1, p27, and c-MYC in UTUC compared with paired benign urothelium (P < .0005). We found a strong positive correlation between PTEN and phos-AKT. Moderate correlation was observed between phos-mTOR and phos-S6, PTEN and p27, phos-AKT and p27, phos-S6 and p27, phos-mTOR and c-MYC, phos-S6 and c-MYC, and p27 and c-MYC. None of the evaluated biomarkers were associated with increased hazard ratios for tumor recurrence or for cancer-specific mortality, when adjusting for relevant clinicopathologic variables. Dysregulation of the mTOR pathway was observed in UTUC compared with normal urothelium, implicating a potential pathogenic role in tumor development. In our cohort, expression of the evaluated biomarkers had no prognostic value.

Differential diagnosis of renal tumors with clear cytoplasm: clinical relevance of renal tumor subclassification in the era of targeted therapies and personalized medicine

CONTEXT

The World Health Organization classification of renal tumors synthesizes morphologic, immunohistochemical, and molecular findings to define more than 40 tumor types. Of these, clear cell (conventional) renal cell carcinoma is the most common malignant tumor in adults and-with the exception of some rare tumors-the most deadly. The diagnosis of clear cell renal cell carcinoma on morphologic grounds alone is generally straightforward, but challenging cases are not infrequent. A misdiagnosis of clear cell renal cell carcinoma has clinical consequences, particularly in the current era of targeted therapies.

OBJECTIVE

To highlight morphologic mimics of clear cell renal cell carcinoma and provide strategies to help differentiate clear cell renal cell carcinoma from other renal tumors and lesions. The role of the pathologist in guiding treatment for renal malignancies will be emphasized to stress the importance of proper tumor classification in patient management.

DATA SOURCES

Published literature and personal experience.

CONCLUSIONS

In challenging cases, submission of additional tissue is often an inexpensive and effective way to facilitate a correct diagnosis. If immunohistochemical stains are to be used, it is best to use a panel of markers, as no one marker is specific for a given renal tumor subtype. Selection of limited markers, based on a specific differential diagnosis, can be as useful as a large panel in reaching a definitive diagnosis. For renal tumors, both the presence and absence of immunoreactivity and the pattern of labeling (membranous, cytoplasmic, diffuse, focal) are important when interpreting the results of immunohistochemical stains.

Cancer biomarker discovery: the entropic hallmark

Background

It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods.

Methodology/Principal Findings

Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer.

Conclusions/Significance

We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-througput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases.

Clear cell adenocarcinoma of urinary bladder and urethra: another urinary tract lesion immunoreactive for P504S

CONTEXT

Clear cell carcinoma of the urinary bladder/ urethra is a rare tumor histologically resembling the neoplasms in the female genital tract. Adequate characterization of this tumor has been hampered by its rarity. alpha-Methylacyl-CoA racemase (AMACR)/P504S has been reported to be positive in prostatic adenocarcinoma, papillary renal cell carcinoma, and gastrointestinal neoplasmas; however, it has never been studied in clear cell carcinoma of the lower urinary tract.

OBJECTIVE

To investigate the immunohistochemical staining profile in 4 primary clear cell carcinomas of the urinary tract, including P504S, which has not been previously evaluated in these tumors.

DESIGN

Four cases of clear cell adenocarcinoma were retrieved from our archives: 2 cases from the urinary bladder (one each from a man and a woman) and 2 cases from the urethra (both from women, 1 in a diverticulum). Immunohistochemistry performed on the cases were P504S, K903, cytokeratin (CK) 7, CK20, CA 125, and p63.

RESULTS

We found that clear cell carcinomas had a distinct immunoreactive profile: strongly positive for P504S, K903, and CK7, and negative for p63. Two cases were also positive for CA 125 and CK20.

CONCLUSION

The immunohistochemical profile of clear cell carcinomas shares some similarity to conventional urothelial carcinoma; however, it deviates from those tumors in being positive for P504S and negative for p63. This staining profile may suggest a nonurothelial origin for these tumors, may serve as a useful tool in the differential diagnosis of this tumor, and may reflect its etiology. Because similar expression of P504S is also seen in nephrogenic adenomas, this marker should not be used to differentiate nephrogenic adenomas from clear cell adenocarcinomas.

Alpha-methylacyl CoA racemase in pulmonary adenocarcinoma, squamous cell carcinoma, and neuroendocrine tumors: expression and survival analysis

CONTEXT

Alpha-methylacyl CoA racemase (AMACR) is an oxidative enzyme involved in isomeric transformation of fatty acids entering the beta-oxidation pathway. AMACR serves as a useful marker in establishing a diagnosis of prostatic malignancy; however, limited information is available in regard to its presence in pulmonary neoplasms.

OBJECTIVE

To investigate AMACR expression within a spectrum of lung carcinomas and its correlation with patients' survival.

DESIGN

Four hundred seventy-seven pulmonary carcinomas, including 150 squamous cell carcinomas, 150 adenocarcinomas, 46 typical carcinoids, 31 atypical carcinoids, 28 large cell neuroendocrine carcinomas, and 72 small cell carcinomas, were studied immunohistochemically using tissue microarray-based samples.

RESULTS

Overall, pulmonary tumors were positive for AMACR in a significant percentage (47%) of cases. Among tumor types, 22% of squamous cell carcinoma, 56% of adenocarcinoma, 72% of typical carcinoid, 52% of atypical carcinoid, 70% of large cell neuroendocrine carcinoma, and 51% of small cell lung carcinoma were positive for AMACR. Furthermore, the Kaplan-Meier analysis revealed that the patients with AMACR-positive small cell carcinoma had better survival (19% vs 5% after 5 years, P = .04) than patients with AMACR-negative tumors. Such survival advantage was seen for patients with stage I-II (P = .01) but not stage III-IV small cell carcinomas (P = .58).

CONCLUSIONS

These results indicate that, similar to prostate cancer, the overexpression of AMACR frequently occurs in pulmonary carcinomas. Additionally, its positive correlation with outcome of stage I-II small cell lung carcinoma warrants further investigation of the AMACR role in the prognosis of this tumor.

α-Methylacyl-CoA-Racemase Expression in Adenocarcinoma, Dysplasia and Non-Neoplastic Epithelium of the Stomach

Alpha-methylacyl-CoA-racemase (AMACR) is an essential enzyme in the oxidation of bile acid intermediates and branched-chain fatty acids. This study aims to examine the expression pattern, as well as diagnostic and prognostic significance, of AMACR in carcinoma, dysplasia and non-neoplastic epithelium of the stomach. A total of 158 cases, including 66 cases of gastric carcinoma (GC), 48 cases of dysplasia and 44 cases of non-neoplastic gastric mucosa, were examined by immunohistochemistry for AMACR. AMACR expression was divided into two categories: negative (negative-weak staining intensity) and positive (moderate-strong staining intensity). AMACR immunoreactivity was detected in only 2 of 44 (4.5%) cases of non-neoplastic epithelium. A significantly high frequency of AMACR expression was found in 40 of 48 (83.3%) cases of dysplasia and 34 of 66 (51.5%) carcinoma cases compared with cases of non-neoplastic epithelium (p < 0.05). The frequency of AMACR expression was significantly higher in dysplasia than in carcinoma cases (p < 0.05). AMACR expression was higher in intestinal- than diffuse-type GC (p < 0.05). In conclusion, this study suggests that AMACR immunostaining aids in distinguishing malignant or precancerous lesions from reactive epithelial atypia in gastric biopsy specimens. It also suggests that AMACR expression is more likely to be associated with intestinal-type adenocarcinoma in gastric carcinogenesis.

CD24 expression in urothelial carcinoma of the upper urinary tract correlates with tumour progression

Expression of the mucin-like adhesion molecule CD24 has been implicated in the progression of several types of cancer and has been identified as new prognostic factor. We evaluated CD24 expression in 268 consecutive cases of upper urinary tract urothelial carcinoma with respect to associations with tumour stage, grade, angioinvasion and infiltrative growth pattern using a tissue microarray technique and correlated data with patient outcome. CD24 expression was demonstrated in 161/259 (62%) evaluable tumours and was associated with high tumour stage [77/139 (55%) pTa/pT1 vs 84/120 (70%) pT2-pT4; P=0.02] and high tumour grade [68/139 (49%) low vs 93/120 (78%) high grade; P<0.001] as well as presence of angioinvasion (P=0.002) and infiltrative pattern of invasion (P=0.007). Patients with CD24-positive tumours tended to have a higher risk of disease progression (P=0.065). Multivariate analysis, however, proved pT stage >1 [P<0.001, risk ratio (RR)=5.87, 95% confidence interval (CI)=2.88-11.95] and high tumour grade (P<0.001, RR=3.30, 95% CI 1.75-6.22) as only independent predictors of metastatic disease. In conclusion, CD24 expression in upper urinary tract urothelial cancer is associated with advanced tumour stage and high tumour grade as well as histopathological features indicative of aggressive tumour behaviour, but it lacks independent impact on patient outcome.