BID expression determines the apoptotic fate of cancer cells after abrogation of the spindle assembly checkpoint by AURKB or TTK inhibitors.

BACKGROUND: Drugs targeting the spindle assembly checkpoint (SAC), such as inhibitors of Aurora kinase B (AURKB) and dual specific protein kinase TTK, are in different stages of clinical development. However, cell response to SAC abrogation is poorly understood and there are no markers for patient selection. METHODS: A panel of 53 tumor cell lines of different origins was used. The effects of drugs were analyzed by MTT and flow cytometry. Copy number status was determined by FISH and Q-PCR; mRNA expression by nCounter and RT-Q-PCR and protein expression by Western blotting. CRISPR-Cas9 technology was used for gene knock-out (KO) and a doxycycline-inducible pTRIPZ vector for ectopic expression. Finally, in vivo experiments were performed by implanting cultured cells or fragments of tumors into immunodeficient mice. RESULTS: Tumor cells and patient-derived xenografts (PDXs) sensitive to AURKB and TTK inhibitors consistently showed high expression levels of BH3-interacting domain death agonist (BID), while cell lines and PDXs with low BID were uniformly resistant. Gene silencing rendered BID-overexpressing cells insensitive to SAC abrogation while ectopic BID expression in BID-low cells significantly increased sensitivity. SAC abrogation induced activation of CASP-2, leading to cleavage of CASP-3 and extensive cell death only in presence of high levels of BID. Finally, a prevalence study revealed high BID mRNA in 6% of human solid tumors. CONCLUSIONS: The fate of tumor cells after SAC abrogation is driven by an AURKB/ CASP-2 signaling mechanism, regulated by BID levels. Our results pave the way to clinically explore SAC-targeting drugs in tumors with high BID expression.

Mechanical properties and defect sensitivity of diamond nanothreads.

One of the newest carbon allotropes synthesized are diamond nanothreads. Using molecular dynamics, we determine the stiffness (850 GPa), strength (26.4 nN), extension (14.9%), and bending rigidity (5.35 × 10(-28) N·m(2)). The 1D nature of the nanothread results in a tenacity of 4.1 × 10(7) N·m/kg, exceeding nanotubes and graphene. As the thread consists of repeating Stone-Wales defects, through steered molecular dynamics (SMD), we explore the effect of defect density on the strength, stiffness, and extension of the system.

Immunologic correlates of the abscopal effect in a patient with melanoma.

The abscopal effect is a phenomenon in which local radiotherapy is associated with the regression of metastatic cancer at a distance from the irradiated site. The abscopal effect may be mediated by activation of the immune system. Ipilimumab is a monoclonal antibody that inhibits an immunologic checkpoint on T cells, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4). We report a case of the abscopal effect in a patient with melanoma treated with ipilimumab and radiotherapy. Temporal associations were noted: tumor shrinkage with antibody responses to the cancer-testis antigen NY-ESO-1, changes in peripheral-blood immune cells, and increases in antibody responses to other antigens after radiotherapy. (Funded by the National Institutes of Health and others.).

Differences in prevalence of inflammatory bowel disease in Puerto Rico between commercial and government-sponsored managed health care insured individuals.

BACKGROUND: Evaluation of ethnic and racial patterns of Inflammatory Bowel Disease (IBD) has demonstrated a higher incidence of IBD in Jews, and lower rates in blacks and Hispanics when compared to whites. There is limited data describing incidence and prevalence among Hispanics, the fastest growing minority in the United States. METHODS: To estimate the prevalence of IBD computerized records of all physicians billing and hospital discharges classified with ICD-9-CM IBD related codes were searched. Prevalence was estimated by age group, sex, and type of insurance (commercial versus government-sponsored managed care). RESULTS: Of 1,248,993 insured individuals in 2005, 186 had a diagnosis of Crohn's disease and 291 of ulcerative colitis. The estimated prevalence per 100,000 was 14.9 for Crohn's disease, 23.3 for ulcerative colitis, and 38.2 cases for IBD. The most significant difference was found when comparing insurance type, with a total IBD prevalence rate of 61.75 cases among commercial versus 14.36 cases among government-sponsored insured. CONCLUSIONS: The prevalence of IBD in this insured population in Puerto Rico places it among the highest described in a Hispanic population. Given the continued rise in prevalence of IBD and the limited studies describing the epidemiology of IBD in Hispanics, further studies which may provide important clues to the etiology of the disease as well as valuable information for appropriate health care planning are important.

Reference standards for gene fusion molecular assays on cytological samples: an international validation study.

AIMS: Gene fusions assays are key for personalised treatments of advanced human cancers. Their implementation on cytological material requires a preliminary validation that may make use of cell line slides mimicking cytological samples. In this international multi-institutional study, gene fusion reference standards were developed and validated. METHODS: Cell lines harbouring EML4(13)-ALK(20) and SLC34A2(4)-ROS1(32) gene fusions were adopted to prepare reference standards. Eight laboratories (five adopting amplicon-based and three hybridisation-based platforms) received, at different dilution points two sets of slides (slide A 50.0%, slide B 25.0%, slide C 12.5% and slide D wild type) stained by Papanicolaou (Pap) and May Grunwald Giemsa (MGG). Analysis was carried out on a total of 64 slides. RESULTS: Four (50.0%) out of eight laboratories reported results on all slides and dilution points. While 12 (37.5%) out of 32 MGG slides were inadequate, 27 (84.4%) out of 32 Pap slides produced libraries adequate for variant calling. The laboratories using hybridisation-based platforms showed the highest rate of inadequate results (13/24 slides, 54.2%). Conversely, only 10.0% (4/40 slides) of inadequate results were reported by laboratories adopting amplicon-based platforms. CONCLUSIONS: Reference standards in cytological format yield better results when Pap staining and processed by amplicon-based assays. Further investigation is required to optimise these standards for MGG stained cells and for hybridisation-based approaches.

Clinicopathological and molecular characterization of colorectal micropapillary carcinoma.

Invasive micropapillary carcinoma is associated with frequent lymph node metastasis and adverse clinical outcome. Initially described as a variant of breast and ovarian carcinoma, it has subsequently been found in other organs, most recently the colon. Reports of colorectal micropapillary carcinoma to date are limited in number, and their molecular profile has not been established. The aims of the present study were to analyze their clinicopathological features and molecular profile, and compare them with those of conventional adenocarcinoma. Clinicopathological features of a cohort of 379 patients with primary colorectal cancer were retrospectively reviewed for the presence of the pattern characteristic of micropapillary carcinoma. We also assessed the expression of KRT7, KRT20, CEACAM5, MUC1 (EMA, clone E29), MUC1 (clone MA695), MLH1, MSH2, MSH6 and TP53 by immunohistochemistry. Genetic assessments of microsatellite instability, chromosomes 17p and 18q, and mutations in TP53, BRAF and KRAS were performed using DNA extracted from formalin-fixed, paraffin-embedded sections. In all, 60 of the reviewed cases (16%) had a micropapillary component that ranged from 5 to 95% of the tumor, characterized by a higher frequency of an infiltrative pattern, lymphovascular and perineural invasion, a higher depth of invasion and more positive lymph nodes than conventional adenocarcinoma. Immunohistochemistry for MUC1 (clone MA695) and MUC1 (EMA, clone E29) enhanced the characteristic inside-out staining pattern of the micropapillary carcinoma component, whereas the rest of the tumor showed luminal staining patterns. KRT7 expression was slightly increased in micropapillary carcinoma, but did not reach significance (17-3%, P=0.1967). The molecular parameters showed a higher frequency of TP53 alterations and a low incidence of microsatellite instability and RER phenotype (loss of mismatch repair protein) in micropapillary carcinoma. With regard to the histological parameters, micropapillary carcinoma appears to be more aggressive than conventional colorectal adenocarcinoma. The molecular profile supports the hypothesis that micropapillary carcinoma carcinogenesis develops through the classical chromosomal instability pathway.

CTLA-4 blockade enhances polyfunctional NY-ESO-1 specific T cell responses in metastatic melanoma patients with clinical benefit.

Blockade of inhibitory signals mediated by cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) has been shown to enhance T cell responses and induce durable clinical responses in patients with metastatic melanoma. The functional impact of anti-CTLA-4 therapy on human immune responses is still unclear. To explore this, we analyzed immune-related adverse events and immune responses in metastatic melanoma patients treated with ipilimumab, a fully human anti-CTLA-4 monoclonal antibody. Fifteen patients were selected on the basis of availability of suitable specimens for immunologic monitoring, and eight of these showed evidence of clinical benefit. Five of the eight patients with evidence of clinical benefit had NY-ESO-1 antibody, whereas none of seven clinical non-responders was seropositive for NY-ESO-1. All five NY-ESO-1 seropositive patients had clearly detectable CD4(+) and CD8(+) T cells against NY-ESO-1 following treatment with ipilimumab. One NY-ESO-1 seronegative clinical responder also had a NY-ESO-1 CD4(+) and CD8(+) T cell response, possibly related to prior vaccination with NY-ESO-1. Among five clinical non-responders analyzed, only one had a NY-ESO-1 CD4(+) T cell response and this patient did not have detectable anti-NY-ESO-1 antibody. Overall, NY-ESO-1-specific T cell responses increased in frequency and functionality during anti-CTLA-4 treatment, revealing a polyfunctional response pattern of IFN-gamma, MIP-1beta and TNF-alpha. We therefore suggest that CTLA-4 blockade enhanced NY-ESO-1 antigen-specific B cell and T cell immune responses in patients with durable objective clinical responses and stable disease. These data provide an immunologic rationale for the efficacy of anti-CTLA-4 therapy and call for immunotherapeutic designs that combine NY-ESO-1 vaccination with CTLA-4 blockade.

KIT as a therapeutic target in metastatic melanoma.

CONTEXT: Some melanomas arising from acral, mucosal, and chronically sun-damaged sites harbor activating mutations and amplification of the type III transmembrane receptor tyrosine kinase KIT. We explored the effects of KIT inhibition using imatinib mesylate in this molecular subset of disease. OBJECTIVE: To assess clinical effects of imatinib mesylate in patients with melanoma harboring KIT alterations. DESIGN, SETTING, AND PATIENTS: A single-group, open-label, phase 2 trial at 1 community and 5 academic oncology centers in the United States of 295 patients with melanoma screened for the presence of KIT mutations and amplification between April 23, 2007, and April 16, 2010. A total of 51 cases with such alterations were identified and 28 of these patients were treated who had advanced unresectable melanoma arising from acral, mucosal, and chronically sun-damaged sites. INTERVENTION: Imatinib mesylate, 400 mg orally twice daily. MAIN OUTCOME MEASURES: Radiographic response, with secondary end points including time to progression, overall survival, and correlation of molecular alterations and clinical response. RESULTS: Two complete responses lasting 94 (ongoing) and 95 weeks, 2 durable partial responses lasting 53 and 89 (ongoing) weeks, and 2 transient partial responses lasting 12 and 18 weeks among the 25 evaluable patients were observed. The overall durable response rate was 16% (95% confidence interval [CI], 2%-30%), with a median time to progression of 12 weeks (interquartile range [IQR], 6-18 weeks; 95% CI, 11-18 weeks), and a median overall survival of 46.3 weeks (IQR, 28 weeks-not achieved; 95% CI, 28 weeks-not achieved). Response rate was better in cases with mutations affecting recurrent hotspots or with a mutant to wild-type allelic ratio of more than 1 (40% vs 0%, P = .05), indicating positive selection for the mutated allele. CONCLUSIONS: Among patients with advanced melanoma harboring KIT alterations, treatment with imatinib mesylate results in significant clinical responses in a subset of patients. Responses may be limited to tumors harboring KIT alterations of proven functional relevance. Trial Registration clinicaltrials.gov Identifier: NCT00470470.

Multiplex RNA-based detection of clinically relevant MET alterations in advanced non-small cell lung cancer.

MET inhibitors have shown activity in non-small-cell lung cancer patients (NSCLC) with MET amplification and exon 14 skipping (METΔex14). However, patient stratification is imperfect, and thus, response rates have varied widely. Here, we studied MET alterations in 474 advanced NSCLC patients by nCounter, an RNA-based technique, together with next-generation sequencing (NGS), fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and reverse transcriptase polymerase chain reaction (RT-PCR), exploring correlation with clinical benefit. Of the 474 samples analyzed, 422 (89%) yielded valid results by nCounter, which identified 13 patients (3%) with METΔex14 and 15 patients (3.5%) with very-high MET mRNA expression. These two subgroups were mutually exclusive, displayed distinct phenotypes and did not generally coexist with other drivers. For METΔex14, 3/8 (37.5%) samples positive by nCounter tested negative by NGS. Regarding patients with very-high MET mRNA, 92% had MET amplification by FISH and/or NGS. However, FISH failed to identify three patients (30%) with very-high MET RNA expression, among which one received MET tyrosine kinase inhibitor treatment deriving clinical benefit. Our results indicate that quantitative mRNA-based techniques can improve the selection of patients for MET-targeted therapies.

Correlation of clinical and immunological data in a metastatic melanoma patient with heterogeneous tumor responses to ipilimumab therapy.

Melanoma patients treated with anti-CTLA-4 have shown a range of anti-tumor responses. In this report, we describe the response of a single patient to anti-CTLA-4, with individual lesions disappearing, others stabilizing, and others progressing. These responses can be viewed as a clear manifestation of cancer immunoediting and its three phases of elimination, equilibrium and escape, with each tumor in this patient being at a discrete stage in the process. The patient's course and associated immunological monitoring and other laboratory data are presented in an immunogram, a way to visualize temporal associations between the multiple clinical and laboratory parameters.

RNA-Based Multiplexing Assay for Routine Testing of Fusion and Splicing Variants in Cytological Samples of NSCLC Patients.

The detection of ALK receptor tyrosine kinase (ALK), ROS proto-oncogen1, receptor tyrosine kinase (ROS1), ret proto-oncogen (RET), and MET proto-oncogen exon 14 skipping (METΔex14) allows for the selection of specific kinase inhibitor treatment in patients with non-small cell lung cancer (NSCLC). Multiplex technologies are recommended in this setting. We used nCounter, a multiplexed technology based on RNA hybridization, to detect ALK, ROS1, RET, and METΔex14 in RNA purified from cytological specimens (n = 16) and biopsies (n = 132). Twelve of the 16 cytological samples (75.0%) were evaluable by nCounter compared to 120 out of 132 (90.9%) biopsies. The geometrical mean (geomean) of the housekeeping genes of the nCounter panel, but not the total amount of RNA purified, was significantly higher in biopsies vs. cytological samples. Among cytological samples, we detected ALK (n = 3), METΔex14 (n = 1) and very high MET expression (n = 1) positive cases. The patient with METΔex14 had a partial response to tepotinib, one of the patients with ALK fusions was treated with crizotinib with a complete response. Cell blocks and cytological extensions can be successfully used for the detection of fusions and splicing variants using RNA-based methods such as nCounter.

AURKB as a target in non-small cell lung cancer with acquired resistance to anti-EGFR therapy.

Non-small cell lung cancer (NSCLC) tumors harboring mutations in EGFR ultimately relapse to therapy with EGFR tyrosine kinase inhibitors (EGFR TKIs). Here, we show that resistant cells without the p.T790M or other acquired mutations are sensitive to the Aurora B (AURKB) inhibitors barasertib and S49076. Phospho-histone H3 (pH3), a major product of AURKB, is increased in most resistant cells and treatment with AURKB inhibitors reduces the levels of pH3, triggering G1/S arrest and polyploidy. Senescence is subsequently induced in cells with acquired mutations while, in their absence, polyploidy is followed by cell death. Finally, in NSCLC patients, pH3 levels are increased after progression on EGFR TKIs and high pH3 baseline correlates with shorter survival. Our results reveal that AURKB activation is associated with acquired resistance to EGFR TKIs, and that AURKB constitutes a potential target in NSCLC progressing to anti-EGFR therapy and not carrying resistance mutations.

[Overlap syndrome. LEOPARD and neurofibromatosis. A case report]. / Síndrome de superposición. LEOPARD con neurofibromatosis. Reporte de caso.

We expose a clinical case of a 43-year-old patient who was attended at the Dermatology service in a general hospital of the Instituto Mexicano del Seguro Social, with a disseminated pattern of lentigines, psychomotor retardation and electrocardiographic abnormalities. Afterwards, we made an analysis of the literature.

Se presenta el caso de un paciente varón de 43 años de edad, que fue atendido en el servicio de Dermatología de un hospital general de zona del Instituto Mexicano del Seguro Social, con lesiones lentiginosas diseminadas, retraso psicomotor y alteraciones electrocardiográficas. Posteriormente, realizamos un análisis de la literatura.

[Validation: reliable instruments needed. Attitude scale and an opinion poll]. / Validación: se necesitan instrumentos fiables.

The use of the scientific method in research and investigation in nursing requires avoiding subjectivity at all times. Professionals obtain data by means of instruments which must be operative, valid and reliable. The authors develop and verify two instruments: a nine question opinion poll which uses tests and retests, having a 93-40% concordance proportion. A Likert type attitude scale, applying the "t" in Student to 59 initial propositions, obtaining a definitive scale having 7 positive items and 7 negative ones which gave a 95% confidence level of statistical meaning for a bilateral test and which had 22 degrees of liberty. This study took place using a pilot group of 43 nurses, it was a practical shop exercise on research in nursing occurred in the Hospital, organized by the Nursing Administration and taught by the group coordinator.

A novel multiplexing, polymerase chain reaction-based assay for the analysis of chromosome 18q status in colorectal cancer.

Chromosome 18q allelic loss has been reported to have prognostic significance in stage II colorectal carcinoma. We have developed a fluorescent multiplex polymerase chain reaction assay to analyze five microsatellite markers (D18S55, D18S58, D18S61, D18S64, and D18S69) for allelic loss at the long arm of chromosome 18. Amplicon detection and evaluation was accomplished by capillary electrophoresis using an ABI 310 genetic analyzer. Robustness of the assay when performed on DNA extracted from formalin-fixed, paraffin-embedded tissue sections was confirmed by analyzing its repeatability and reproducibility. Allelic loss was assessed in 61 stage II colorectal tumors and was detected in 58% (31 of 53) of tumors not showing instability. As part of the study, results of 207 previous polymerase chain reaction/polyacrylamide-based assays were re-evaluated by two independent observers to determine the degree of concordance of visual evaluation. In the case of stage II colorectal tumors, when electropherogram results were compared with those obtained from visual evaluation of the same markers after polyacrylamide gel electrophoresis, discrepancies between observers were detected in 16.4% of determinations. In conclusion, we have developed a robust and reliable assay for multiplexed loss of heterozygosity determination that improves assessment of chromosome 18q allelic loss in colorectal tumors processed as routine formalin-fixed, paraffin-embedded specimens.

A novel logistic model based on clinicopathological features predicts microsatellite instability in colorectal carcinomas.

High-frequency microsatellite instability has been reported to be associated with good prognosis in colorectal adenocarcinoma. However, methods to assess microsatellite instability (MIN) are based on genetic assays and are not ideally suited to most histopathology laboratories. The aim of the present study was to develop a model for prediction of MIN status in colorectal cancer based on phenotypic characteristics. Clinicopathological features of a cohort of 204 patients with primary colon cancer were retrospectively reviewed following predetermined criteria. Genetic assessment of MIN status was performed on DNA extracted from sections of formalin-fixed, paraffin-embedded specimens by testing a panel of 11 microsatellite markers. Logistic regression analysis generated a mathematical tool capable of identifying colorectal tumors displaying MIN status with a sensitivity of 77.8% and a specificity of 96.8%. Features associated with instability included the proximal location of the lesions, occurrence of solid and/or mucinous differentiation, absence of cribriform structures, presence of peritumoral Crohn-like reaction, expansive growth pattern, high Ki67 proliferative index, and p53-negative phenotype. This approach predicts microsatellite instability in colorectal carcinoma with an overall assigned accuracy of 95.1% and a negative predictive value of 97.8%. Implementation of this tool to routine histopathological studies could improve the management of patients with colorectal cancer, especially those presenting with stage II and III of the disease. It will also assist in identifying a subset of patients likely to benefit from adjuvant chemotherapy.

Cross-reactivity of EGFR mutation-specific immunohistochemistry assay in HER2-positive tumors.

The coexpression of HER2 and EGFR L858R in a solitary nodule removed from the lung, whose mutation was not confirmed by molecular techniques, made us think about the possible existence of a cross-reaction between HER2 and the EGFR L858R-specific antibody. Our study was designed to further analyze the existence of this cross-reaction and stress the need to exclude a metastatic breast cancer when dealing with EGFR L858R-positive cases. The series consists of 42 primary breast carcinomas, 22 HER2 positive for overexpression and amplification, and 20 negative for both. EGFR mutations were studied by immunohistochemistry and confirmed using real-time PCR when positive. Immunohistochemistry assay with EGFR L858R was positive in 19 (86%) of the HER2-positive breast carcinomas and negative in all HER2-negative carcinomas. The EGFR L858R antibody gives false-positive results in most of the breast carcinomas with HER2 overexpression/amplification. As a consequence, it is essential to confirm any EGFR L858R-positive cases by molecular methods or at least discard the presence of HER2 overexpression/amplification before rendering a diagnosis. It is also important to consider that HER2 has been described in other carcinomas such as urothelial, gastric or ovarian, as well as lung, although infrequently.

Genetic and immunophenotype analyses of TP53 in bladder cancer: TP53 alterations are associated with tumor progression.

Altered p53 status is a frequent event in bladder cancer and reported to have prognostic significance. We studied the TP53 gene and its product in 76 patients affected with urinary bladder carcinomas by immunohistochemistry (mAb DO-7), polymerase chain reaction single-strand conformational polymorphism (exons 4-8) followed by direct sequencing of shifted bands, and loss of heterozygosity in 17p (p53CA). H-RAS mutations were also studied. The receiver operating characteristic curve and the logistic-regression analysis were used to evaluate the validity of immunohistochemistry in predicting TP53 mutations. A p53-positive nuclear phenotype was defined by a cutoff of 20% tumor cells being immunoreactive and was found in 23 cases, while TP53 mutations were detected in 22 cases, four of them with a negative p53 phenotype. TP53 deletions were identified in 23 cases. No H-RAS gene mutations were observed. There was a significant association between phenotype and genotype results. Moreover, a significant association was observed between p53 status and tumor stage and grade, being alterations more common in high-stage and high-grade tumors (both chi2 test; P < .01). Deletion of 17p significantly correlated with tumor stage (P < .01) and grade (P = .01), allelic losses being more common in advanced disease. Data from these studies suggest that genetic assays are necessary for the optimal determination of TP53 alterations, mainly in tumors with a p53 negative phenotype, and especially in early stage tumors for which p53 status may assist in determining its progression to invasive disease. Since p53 alterations are significantly associated to clinicopathological features of poor prognosis, the inclusion of both p53 phenotype and TP53 mutation status into a predictive panel of tumor markers for bladder cancer is recommended.

Lack of p53 nuclear immunostaining is not indicative of absence of TP53 gene mutations in colorectal adenocarcinomas.

Multiple studies using primary tumors have reported that alterations in p53 expression and detection of TP53 mutations are associated with clinical aggressiveness and poor response to specific therapies. However, there is no general agreement regarding the optimal technical approach to the analysis of p53. We have studied a series of 100 primary colorectal adenocarcinomas by immunohistochemistry with the monoclonal antibody PAb1801, and single-stranded conformation polymorphism (PCR-SSCP, exons 4-8) followed by direct sequencing of shifted bands. p53 Nuclear staining was undetectable (score 0) in 29 of 100 cases. However, gene mutations were detected in 15 of these cases, with all of these mutations leading to abnormal proteins. p53 Nuclear staining was detectable and scored as less than 10% tumor cells positive in 15 of 100 cases but was still considered to be displaying a p53-negative phenotype because the cut-off value for positivity was 10% positive tumor cells. Nevertheless, TP53 gene mutations were detected in 2 of these cases. p53 Nuclear immunoreactivities were detectable and scored as more than 10% tumor cells positive in 56 cases, considered the p53-positive phenotype. TP53 gene mutations were identified in 51 of these 56 cases. These results reveal that immunohistochemical assessment does not predict TP53 mutation status in colorectal adenocarcinoma, mainly in cases displaying absence of nuclear staining. It is thus concluded that molecular profiling should be conducted in parallel with immunophenotyping when analyzing colorectal tumors for p53 status.

ERG expression and prostatic adenocarcinoma.

ERG gene rearrangement has been identified as a highly specific alteration that is present in 40-50 % of prostate carcinomas. The standardization of an immunohistochemical assay with a novel anti-ERG antibody recently described would have significant diagnostic value. The aims of this study were to identify the incidence of this rearrangement in a Spanish population and to test the specificity of immunohistochemical ERG evaluation for prostate carcinomas. Three prostate tissue microarrays were constructed using radical prostatectomy specimens and related to grade, local invasion, and regional invasion. In addition to samples from malignant cases (160), specimens of prostatic hyperplasia (26) and high-grade prostatic intraepithelial neoplasia (10) were included. Tissue microarrays of 270 samples from most common malignant tumors (breast, colon, lung, and bladder) were also tested. All were analyzed by immunohistochemistry. Seventy-five out of 154 evaluable cases (49 %) of prostate carcinoma showed ERG expression; 52/75 showed strong staining. No ERG expression was observed in any of the high-grade prostatic intraepithelial neoplasia. ERG expression was independent of Gleason score (p = 0.160), extent of invasion (p = 0.517), and regional lymph node involvement (p = 0.816). No ERG expression was found in any other type of tumor, with the exception of one bladder cancer sample that showed focal and weak expression. The frequency of ERG detected in our study correlated with the results published for other Caucasian populations. Strong ERG protein expression was exclusively detected in prostate carcinomas, corroborating the specificity of ERG rearrangements for these tumors. Thus, detecting ERG using immunohistochemistry may be useful in routine practice in pathology departments.