Adenocarcinomas of the esophagogastric junction are more likely to respond to preoperative chemotherapy than distal gastric cancer.

BACKGROUND: Preoperative chemotherapy has been shown to improve outcome of patients with adenocarcinoma of the esophagogastric junction (AEG) and gastric cancer (GC), and histopathologic response has been identified as an independent prognostic parameter in these patients. A recent meta-analysis has identified patients with AEG as benefiting more from preoperative chemotherapy than patients with GC. The aim of this retrospective analysis was to prove these findings in an experienced single-center large patient cohort because there are currently no recruiting prospective clinical trials. METHODS: In a single center, 551 patients underwent preoperative platin-based chemotherapy followed by oncologic surgery for locally advanced AEG and GC. Pretherapeutic clinical parameters were correlated with histopathologic response to preoperative chemotherapy. RESULTS: Histopathologic response (<10% of residual tumor) was found in 130 patients (24%) and was significantly correlated with overall survival (P<0.0001). Tumor localization at the esophagogastric junction (GE junction), lower baseline cT stage, and baseline cN0 stage were significantly associated with histopathologic response (P=0.034, P=0.015, and P=0.002, respectively). In subgroup analyses, the latter two predictive parameters were confirmed only for AEG (n=378) but not for other GC (n=173). AEG patients who were pretherapeutically staged as having cT3/4, cN0 disease (n=73) were identified as the subgroup with the highest rate of histopathologic response (48%). CONCLUSIONS: AEG is more likely to respond to preoperative chemotherapy than GC, a finding that might help identify patients who would benefit from preoperative chemotherapy.

Long-term outcome of 2920 patients with cancers of the esophagus and esophagogastric junction: evaluation of the New Union Internationale Contre le Cancer/American Joint Cancer Committee staging system.

OBJECTIVE: We analyzed the long-term outcome of patients operated for esophageal cancer and evaluated the new seventh edition of the tumor-node-metastasis classification for cancers of the esophagus. BACKGROUND: Retrospective analysis and new classification. METHODS: Data of a single-center cohort of 2920 patients operated for cancers of the esophagus according to the seventh edition are presented. Statistical methods to evaluate survival and the prognostic performance of the staging systems included Kaplan-Meier analyses and time-dependent receiver-operating-characteristic-analysis. RESULTS: Union Internationale Contre le Cancer stage, R-status, histologic tumor type and age were identified as independent prognostic factors for cancers of the esophagus. Grade and tumor site, additional parameters in the new American Joint Cancer Committee prognostic groupings, were not significantly correlated with survival. Esophageal adenocarcinoma showed a significantly better long-term prognosis after resection than squamous cell carcinoma (P < 0.0001). The new number-dependent N-classification proved superior to the former site-dependent classification with significantly decreasing prognosis with the increasing number of lymph node metastases (P < 0.001). The new subclassification of T1 tumors also revealed significant differences in prognosis between pT1a and pT1b patients (P < 0.001). However, the multiple new Union Internationale Contre le Cancer and American Joint Cancer Committee subgroupings did not prove distinctive for survival between stages IIA and IIB, between IIIA and IIIB, and between IIIC and IV. CONCLUSION: The new seventh edition of the tumor-node-metastasis classification improved the predictive ability for cancers of the esophagus; however, stage groups could be condensed to a clinically relevant number. Differences in patient characteristics, pathogenesis, and especially survival clearly identify adenocarcinomas and squamous cell carcinoma of the esophagus as 2 separate tumor entities requiring differentiated therapeutic concepts.

The sensitivity of [11C]choline PET/CT to localize prostate cancer depends on the tumor configuration.

PURPOSE: To evaluate the dependency of the sensitivity of [(11)C]choline positron emission tomography/computed tomography (PET/CT) for detecting and localizing primary prostate cancer (PCa) on tumor configuration in the histologic specimen. EXPERIMENTAL DESIGN: Forty-three patients with biopsy-proven PCa were included. They underwent radical prostatectomy within 31 days after [(11)C]choline PET/CT. The transaxial image slices and the histologic specimens were analyzed by comparing the respective slices. Maximum standardized uptake values (SUV(max)) were calculated in each segment and correlated with histopathology. The tumor configuration in the histologic specimen was grouped as: I, unifocal; II, multifocal; III, rind-like shaped; IV, size <5 mm. Data analysis included the investigation of detection of PCa by SUV(max), the assessment of the influence of potential contributing factors on tumor prediction, and the evaluation of whether SUV could discriminate cancer tissue from benign prostate hyperplasia (BPH), prostatitis, HGPIN (high-grade prostate intraepithelial neoplasm), or normal prostate tissue. General estimation equation models were used for statistical analysis. RESULTS: Tumor configuration in histology was classified as I in 21 patients, as II in 9, as III in 5, and as IV in 8. The prostate segment involved by cancer is identified in 79% of the patients. SUV(max) was located in the same side of the prostate in 95% of patients. Tumor configuration was the only factor significantly negatively influencing tumor prediction (P < 0.001). PCa-SUV(max) (median SUV(max) = 4.9) was not significantly different from BPH-SUV (median SUV(max) = 4.5) and prostatitis-SUV (median SUV(max) = 3.9), P = 0.102 and P = 0.054, respectively. CONCLUSIONS: The detection and localization of PCa in the prostate with [(11)C]choline PET/CT is impaired by tumor configuration. Additionally, in our patient population, PCa tissue could not be distinguished from benign pathologies in the prostate.

Germline mutation of the E-cadherin gene in three sibling cases with advanced gastric cancer: clinical consequences for the other family members.

BACKGROUND AND AIMS: Germline mutations in the E-cadherin (CDH1) gene have been found in families with hereditary diffuse gastric cancer (HDGC). These families are characterized by a highly penetrant susceptibility to diffuse gastric cancer with an autosomal dominant pattern of inheritance. We describe the clinical presentation of three sibling cases with advanced gastric cancer, the way of confirming the suspicion of underlying HDGC and the clinical management of the other healthy family members. METHODS: Screening for CDH1 germline mutation was carried out by denaturing high-performance liquid chromatography and automated DNA sequencing. The clinical suspicion of HDGC has been confirmed by identifying a frameshift mutation in exon 9 (1302_1303insA, 1306_1307delTT) of the E-cadherin gene. RESULTS: Eight of nine tested family members were positive for the CDH1 germline mutation. Prophylactic laparoscopic gastrectomies were performed in five mutation carriers. After pathological examination, we could identify intramucosal malignant signet-ring cell carcinoma in all resected stomachs. CONCLUSION: This report underlines that prophylactic gastrectomy remains the only option to eliminate the high risk for gastric cancer in CDH1 mutation carriers.

Role of the epithelial-mesenchymal transition regulator Slug in primary human cancers.

Epithelial-mesenchymal-transition (EMT) is a crucial process during morphogenesis of multi-cellular organisms. EMT not only is a normal developmental process but also plays a role in tumor invasion and metastasis. Indeed, molecules involved in EMT, such as the transcription factor and E-cadherin repressor Slug (SNAI2), have recently been demonstrated to be important for cancer cells to down-regulate epithelial markers and up-regulate mesenchymal markers in order to become motile and invasive. Here we summarize major studies focusing on Slug expression in human tumor samples. We review a total of 13 studies involving 1150 cases from 9 different types of tumors. It is becoming clear that this transcription factor plays a role in the progression of some tumor types, including breast and gastric cancer. Interestingly, Slug expression is not always associated with down-regulation of E-cadherin. The mode of action, the signaling pathways involved in its regulation, and the interplay with other EMT regulators need to be addressed in future studies in order to fully understand Slug's role in tumor progression.

Sensitivity and specificity of oral brush biopsy.

The aim of this study was to evaluate the advantage of computer-assisted analysis of the oral brush biopsy compared with synchronous scalpel biopsy in the early detection of oral lesions. In this prospective, randomized, controlled study, brush and scalpel biopsies were performed on 75 patients. Six patients had to be excluded due to inadequate results, and 43 were shown to have dysplastic epithelium, 15 carcinoma, and 11 suspicious lesions. Therefore, the sensitivity for the detection of abnormal cells by means of OralCDx was 52%, specificity 29%, and the positive predictive value 63%. According to our results, the use of oral brush biopsy as a standardized, minimally invasive method of screening oral lesions should be reconsidered.

Expression profiling identifies genes that predict recurrence of breast cancer after adjuvant CMF-based chemotherapy.

Cyclophosphamide, methotrexate and 5-fluorouracile (CMF)-based chemotherapy for adjuvant treatment of breast cancer reduces the risk of relapse. In this exploratory study, we tested the feasibility of identifying molecular markers of recurrence in CMF-treated patients. Using Affymetrix U133A GeneChips, RNA samples from 19 patients with primary breast cancer who had been uniformly treated with adjuvant CMF chemotherapy were analyzed. Two supervised class prediction approaches were used to identify gene markers that can best discriminate between patients who would experience relapse and patients who would remain disease-free. An additional independent validation set of 51 patients and 21 genes were analyzed by quantitative RT-PCR. Applying different algorithms to evaluate our microarray data, we identified two gene expression signatures of 21 and 12 genes containing eight overlapping genes, that predict recurrence in 19 cases with high accuracy (94%). Quantitative RT-PCR demonstrated that six genes from the combined signatures (CXCL9, ITSN2, GNAI2, H2AFX, INDO, and MGC10986) were significantly differentially expressed in the recurrence versus the non-recurrence group of the 19 cases and the independent breast cancer patient cohort (n = 51) treated with CMF. High expression levels of CXCL9, ITSN2, and GNAI2 were associated with prolonged disease-free survival (DFS) (P = 0.029, 0.018 and 0.032, respectively). When patients were stratified by combined CXCL9/ITSN2 or CXCL9/FLJ22028 tumor levels, they exhibited significantly different disease-free survival curves (P = 0.0073 and P = 0.005, respectively). Finally, the CXCL9/ITSN2 and CXCL9/FLJ22028 ratio was an independent prognostic factor (P = 0.034 and P = 0.003, respectively) for DFS by multivariate Cox analysis in the 70-patient cohort. Our data highlight the feasibility of a prognostic assay that is applicable to therapeutic decision-making for breast cancer. Whether the biomarker profile is chemotherapy-specific or whether it is a more general indicator of bad prognosis of breast cancer patients remains to be explored.

Pathology as the cornerstone of human tissue banking: European consensus expert group report.

Aside from ethical considerations, the primary requirement for usage of human tissues in basic or translational research is the thorough characterization of tissues. The second, but equally essential, requirement is that tissues be collected, processed, annotated, and preserved in optimal conditions. These requirements put the pathologist at the center of tissue banking activities and of research aimed at discovering new biomarkers. Pathologists not only provide information identifying the specimen but also make decisions on what materials should be biobanked, on the preservation conditions, and on the timeline of events that precede preservation and storage. This central position calls for increased recognition of the role of the pathologist by the biomolecular community and places new demands on the pathologist's workload and scope of scientific activities. These questions were addressed by an Expert Group Meeting of the European Biological and Biomolecular Research Infrastructure (BBMRI). While detailed recommendations are published elsewhere (Bevilacqua et al., Virchows Archivs, 2010, in press), this article outlines the strategic and technological issues identified by the Expert Group and identifies ways forward for better integration of pathology in the current thrust for development of biomarker-based "personalized medicine."

Expression and clinical significance of glucose regulated proteins GRP78 (BiP) and GRP94 (GP96) in human adenocarcinomas of the esophagus.

BACKGROUND: Glucose regulated proteins (GRPs) are main regulators of cellular homeostasis due to their role as molecular chaperones. Moreover, the functions of GRPs suggest that they also may play important roles in cancer biology. In this study we investigated the glucose regulated proteins GRP78 (BiP) and GRP94 (GP96) in a series of human esophageal adenocarcinomas to determine their implications in cancer progression and prognosis. METHODS: Formalin-fixed, paraffin-embedded tissues of primary resected esophageal (Barrett) adenocarcinomas (n = 137) and corresponding normal tissue were investigated. mRNA-gene expression levels of GRP78 and GRP94 were determined by quantitative real-time RT-PCR after mRNA extraction. Protein expression analysis was performed with immunohistochemical staining of the cases, assembled on a tissue micorarray. The results were correlated with pathologic features (pT, pN, G) and overall survival. RESULTS: GRP78 and GRP94 mRNA were expressed in all tumors. The relative gene expression of GRP78 was significantly higher in early cancers (pT1m and pT1sm) as compared to more advanced stages (pT2 and pT3) and normal tissue (p = 0.031). Highly differentiated tumors showed also higher GRP78 mRNA levels compared to moderate and low differentiated tumors (p = 0.035). In addition, patients with higher GRP78 levels tended to show a survival benefit (p = 0.07). GRP94 mRNA-levels showed no association to pathological features or clinical outcome.GRP78 and GRP94 protein expression was detectable by immunohistochemistry in all tumors. There was a significant correlation between a strong GRP78 protein expression and early tumor stages (pT1m and pT1sm, p = 0.038). For GRP94 low to moderate protein expression was significantly associated with earlier tumor stage (p = 0.001) and less lymph node involvement (p = 0.036). Interestingly, the patients with combined strong GRP78 and GRP94 protein expression exclusively showed either early (pT1m or pT1sm) or advanced (pT3) tumor stages and no pT2 stage (p = 0.031). CONCLUSION: We could demonstrate an association of GRP78 and GRP94 mRNA and protein expression with tumor stage and behaviour in esophageal adenocarcinomas. Increased expression of GRP78 may be responsible for controlling local tumor growth in early tumor stages, while high expression of GRP78 and GRP94 in advanced stages may be dependent from other factors like cellular stress reactions due to glucose deprivation, hypoxia or the hosts' immune response.

Genetic alterations in the tyrosine kinase transcriptome of human cancer cell lines.

Protein tyrosine kinases (PTKs) play a critical role in the manifestation of cancer cell properties, and respective signaling mechanisms have been studied extensively on immortalized tumor cells. To characterize and analyze commonly used cancer cell lines with regard to variations in the primary structure of all expressed PTKs, we conducted a cDNA-based sequence analysis of the entire tyrosine kinase transcriptome of 254 established tumor cell lines. The profiles of cell line intrinsic PTK transcript alterations and the evaluation of 155 identified polymorphisms and 234 somatic mutations are made available in a database designated "Tykiva" (tyrosine kinome variant). Tissue distribution analysis and/or the localization within defined protein domains indicate functional relevance of several genetic alterations. The cysteine replacement of the highly conserved Y367 residue in fibroblast growth factor receptor 4 or the Q26X nonsense mutation in the tumor-suppressor kinase CSK are examples, and may contribute to cell line-specific signaling characteristics and tumor progression. Moreover, known variants, such as epidermal growth factor receptor G719S, that were shown to mediate anticancer drug sensitivity could be detected in other than the previously reported tumor types. Our data therefore provide extensive system information for the design and interpretation of cell line-based cancer research, and may stimulate further investigations into broader clinical applications of current cancer therapeutics.

Microfluidic deletion/insertion analysis for rapid screening of KIT and PDGFRA mutations in CD117-positive gastrointestinal stromal tumors: diagnostic applications and report of a new KIT mutation.

Gastrointestinal stromal tumors (GISTs) frequently harbor mutations in the KIT and PDGFRA genes, the presence and type of which correlate with the response to the kinase inhibitor imatinib mesylate. Because most GIST mutations are deletions/insertions, we used a microfluidic apparatus to detect these size variations in polymerase chain reaction-amplified DNA. This approach, termed microfluidic deletion/insertion analysis (MIDIA), identified mutations in 30 of 50 DNA samples from paraffin-embedded CD117-positive GISTs (60%), comprising 25 deletions and five insertions. Sequencing of 14 MIDIA-positive samples confirmed the deletions/insertions, including two 3-bp alterations. Sequencing of all 20 MIDIA-negative samples also showed highly consistent results with MIDIA because 10 cases were wild type and eight displayed a single base substitution in which detection by MIDIA was not expected. Sequencing also revealed a 3-bp deletion undetected by MIDIA, thus establishing the resolution limit of MIDIA at deletions/insertions >or=3 bp. Denaturing high-pressure liquid chromatography analysis confirmed all mutations detected by MIDIA and sequencing. We pro-pose MIDIA as the first step in mutational screening of GIST because it allowed the detection of 75% of mutated cases (94% of deletions/insertions) in less than 30 minutes after polymerase chain reaction amplification and at a lower cost compared with denaturing high-pressure liquid chromatography and sequencing, which might then be used only for MIDIA-negative cases.

Variability in the diagnosis of dysplasia in ulcerative colitis by dynamic telepathology.

Telepathology (TP) is the practice of evaluating pathology cases by the digital transmission of diagnostic slides as either static pictures (static TP) or by a continuous flow of pictures from a robotic microscopy (dynamic TP). The diagnostic efficacy of dynamic TP-based consultation services has not been widely tested. Dysplasia arising in association with chronic ulcerative colitis (CUC) is, at present, the most important marker for an increased risk of malignancy in patients with this disease. However, the diagnosis of dysplasia suffers from a significant degree of intra- and interobserver variability which usually necessitates a second opinion prior to definitive treatment. Thus, it is often necessary to obtain expert consultation of potential dysplasia cases by dedicated gastrointestinal pathologists. The aim of this study was to evaluate the utility and interobserver variability of diagnosing dysplasia in CUC with the use of dynamic TP. Dynamic TP was used to evaluate digitalized images of 38 CUC cases with areas considered negative, indefinite, or positive for dysplasia (low or high grade) independently by seven pathologists. Subsequently, all cases were graded by each of the pathologists by light microscopic examination of the H&E-stained glass slides. The degree of intra- and interobserver variability was determined by Kappa statistics. Overall, there was a poor degree of interobserver agreement (K=0.32) among the seven pathologists after analysis of the cases by dynamic TP. The poorest level of agreement was in the indefinite and low-grade dysplasia categories, whereas the highest level was in the negative and high-grade dysplasia categories. Grouping together several diagnostic categories (for instance: Indefinite and low, or low- and high-grade dysplasia) had no significant effect on the level of agreement. The degree of variability in interpretation of cases by microscopic slide analysis was similar (K=0.35). After reviewing all the cases by microscopic analysis of the glass slides, the diagnosis was changed in 51% of the observations; in the majority of these (61%), the grade of dysplasia was decreased. In summary, the use of dynamic TP for consultation in CUC-associated dysplasia has a poor level of interobserver agreement, but does not differ significantly from that obtained by the evaluation of the cases by microscopic slide analysis. Diagnoses rendered by dynamic TP tend to be of a higher grade compared to that obtained by microscopic slide analysis. Thus, although dynamic TP may be used for the consultation of CUC dysplasia cases, more specific criteria are needed in the general categorization of dysplasia in CUC.

PTP-PEST phosphatase variations in human cancer.

Signal transduction via tyrosine phosphorylation, normally fine-tuned by the concerted action of both protein tyrosine kinases and protein tyrosine phosphatases (PTPs), is a key mechanism in tumorigenesis. PTP-PEST, a ubiquitously expressed cytoplasmic tyrosine phosphatase, is thought to play an important role in cell adhesion and motility, and may be involved in metastasis. A search for sequence variations within the gene PTPN12 (alias PTP-PEST) was performed in breast cancer cell lines, leading to the identification of three amino acid substitutions at positions 322, 573, and 709. These alterations were also found in squamous cell carcinoma cell lines and could be verified in primary human breast and kidney tumor samples. Analysis of peripheral blood samples confirmed the germline origin of these alterations. Furthermore, functional characterization of the Ile322 and Ala573 PTP-PEST mutants revealed an enhancement of in vitro phosphatase activity, whereas the Lys709 variant showed reduced catalytic activity. These data demonstrate the existence of PTP-PEST variants that might be meaningful for human cancer and underscore the need for further characterizing PTP-PEST and its signaling pathways in context of this disease.

FGFR4 Arg388 allele is associated with resistance to adjuvant therapy in primary breast cancer.

PURPOSE: A recent study presented first evidence that a single nucleotide polymorphism (SNP) at codon 388 of fibroblast growth factor receptor 4 (FGFR4) gene, causing a transmembrane domain missense mutation (Gly388Arg), is associated with disease outcome in node-positive breast cancer. This article addresses the clinical relevance of this SNP, FGFR4 genotype, phenotype, and HER2 regarding patient outcome and influence of adjuvant systemic therapy in a substantial primary breast cancer collective (n = 372; median follow-up, 94.5 months). METHODS: Polymerase chain reaction restriction fragment length polymorphism analysis of germ-line polymorphism was performed in uninvolved lymph nodes; FGFR4 and HER2 expression were assessed immunohistochemically in tissue microarrays. RESULTS: In 51% of patients, homo- or heterozygous Arg388 allele was present. No correlation existed between FGFR4 genotype and expression or HER2 status. In node-negative patients, FGFR4 genotype was not correlated with disease outcome. In node-positive patients, however, FGFR4 Arg388 was significantly associated with poor disease-free survival (DFS; P = .02) and overall survival (OS; P = .04). Notably, this association seems to be attributable to relatively poor therapy response in Arg388 carriers, reflected in their significantly shorter DFS (P = .02) and OS (P = .045) among patients receiving adjuvant systemic therapy. It is also seen as a significant interaction term in a multivariate proportional hazards model with Arg388 carriers having only about half as much benefit from adjuvant systemic therapy as wild-type carriers. CONCLUSION: According to this study, FGFR4 Arg388 genotype is a marker for breast cancer progression in patients with adjuvant systemic therapy, particularly chemotherapy, and thus may indicate therapy resistance.

Multicenter validation of a gene expression-based prognostic signature in lymph node-negative primary breast cancer.

PURPOSE: We previously identified in a single-center study a 76-gene prognostic signature for lymph node-negative (LNN) breast cancer patients. The aim of this study was to validate this gene signature in an independent more diverse population of LNN patients from multiple institutions. PATIENTS AND METHODS: Using custom-designed DNA chips we analyzed the expression of the 76 genes in RNA of frozen tumor samples from 180 LNN patients who did not receive adjuvant systemic treatment. RESULTS: In this independent validation, the 76-gene signature was highly informative in identifying patients with distant metastasis within 5 years (hazard ratio, [HR], 7.41; 95% CI, 2.63 to 20.9), even when corrected for traditional prognostic factors in multivariate analysis (HR, 11.36; 95% CI, 2.67 to 48.4). The actuarial 5- and 10-year distant metastasis-free survival were 96% (95% CI, 89% to 99%) and 94% (95% CI, 83% to 98%), respectively, for the good profile group and 74% (95% CI, 64% to 81%) and 65% (53% to 74%), respectively for the poor profile group. The sensitivity for 5-yr distant metastasis-free survival was 90%, and the specificity was 50%. The positive and negative predictive values were 38% (95% CI, 29% to 47%) and 94% (95% CI, 86% to 97%), respectively. The 76-gene signature was confirmed as a strong prognostic factor in subgroups of estrogen receptor-positive patients, pre- and postmenopausal patients, and patients with tumor sizes 20 mm or smaller. The subgroup of patients with estrogen receptor-negative tumors was considered too small to perform a separate analysis. CONCLUSION: Our data provide a strong methodologic and clinical multicenter validation of the predefined prognostic 76-gene signature in LNN breast cancer patients.

Distribution of p53 mutations in esophageal and gastric carcinomas and the relationship with p53 expression.

Mutations of p53, a tumor suppressor gene, are known to be involved in the pathogenesis of a number of neoplasms. This study investigated the distribution of p53 mutations within both esophageal and gastric adenocarcinomas. The correlation between p53 mutations and an overexpression of p53, which has been reported by other researchers, was also explored. Samples were taken from 17 patients following a surgical resection of the tumor. The patients included 8 cases of adenocarcinoma from the cardia (esophagogastric junction) and 9 cases of gastric carcinoma. Two or three samples were taken from each tumor, plus samples of normal tissue from the patient. Denaturing high pressure liquid chromatography (DHPLC) was employed to detect p53 mutations, and samples found to have mutations were then sequenced. The expression of p53 was determined by immunohistochemistry. DHPLC demonstrated that 37.5% (3/8) of esophageal carcinomas and 44.4% (4/9) of gastric carcinomas have p53 mutations. DNA sequencing showed the same mutation to be present in all of the samples from each tumor, while the corresponding normal tissue was free from mutations (except for 2 cases of polymorphism). The results of immunohistochemistry did not demonstrate a relationship between p53 mutations and the expression of p53 protein, and only 4 of the 7 tumors with p53 mutations showed a positive result. These findings support the hypothesis that p53 mutations are homogeneous throughout a tumor and may thus be a more useful diagnostic and prognostic indicator than the expression of p53, which does not reliably correlate with p53 mutations.

Pathbase: a new reference resource and database for laboratory mouse pathology.

Pathbase (http://www.pathbase.net) is a web accessible database of histopathological images of laboratory mice, developed as a resource for the coding and archiving of data derived from the analysis of mutant or genetically engineered mice and their background strains. The metadata for the images, which allows retrieval and interoperability with other databases, is derived from a series of orthogonal ontologies and controlled vocabularies. One of these controlled vocabularies, MPATH, was developed by the Pathbase Consortium as a formal description of the content of mouse histopathological images. The database currently has over 1000 images on-line with 2000 more under curation and presents a paradigm for the development of future databases dedicated to aspects of experimental biology.

Pathbase: a database of mutant mouse pathology.

Pathbase is a database that stores images of the abnormal histology associated with spontaneous and induced mutations of both embryonic and adult mice including those produced by transgenesis, targeted mutagenesis and chemical mutagenesis. Images of normal mouse histology and strain-dependent background lesions are also available. The database and the images are publicly accessible (http://www.pathbase.net) and linked by anatomical site, gene and other identifiers to relevant databases; there are also facilities for public comment and record annotation. The database is structured around a novel ontology of mouse disorders (MPATH) and provides high-resolution downloadable images of normal and diseased tissues that are searchable through orthogonal ontologies for pathology, developmental stage, anatomy and gene attributes (GO terms), together with controlled vocabularies for type of genetic manipulation or mutation, genotype and free text annotation for mouse strain and additional attributes. The database is actively curated and data records assessed by pathologists in the Pathbase Consortium before publication. The database interface is designed to have optimal browser and platform compatibility and to interact directly with other web-based mouse genetic resources.