Verhandlungen der Deutschen Gesellschaft fur Pathologie最新文献

Amplification of 6 p22.3 is one of the most frequent chromosomal alterations in high grade and invasive urinary bladder cancer. In order to determine amplification levels of all known genes inside the 1.6 kb core amplicon, we constructed a small tissue microarray (TMA) from 9 primary bladder cancers and 4 bladder cancer cell lines with known 6p22 amplification, and analyzed it with a panel of 16 overlapping FISH probes constructed from bacterial artificial chromosomes (BACs). The highest amplification rates were observed for the transcription factor E2F3 and the adjacent gene NM_017774, the function of which is not known. For a more detailed analysis of these genes, additional large section analysis was done in 19 primary bladder cancers and 18 bladder cancer cell lines. It showed that E2F3 and NM 017774 were always coamplified, but amplification levels in terms of the number of gene copies were slightly higher (16-19 copies per nucleus) for E2F3 as compared to NM_017774 (13-15 gene copies). Our study demonstrates that E2F3 and NM_017774 are located on the top of the 6p22.3 amplicon in bladder cancer. It remains to be studied which one of the two genes drives 6p22 amplification, or if both genes contribute jointly to the aggressive features of 6p22 amplified bladder cancers.

Aims: The clonality of multiple urothelial carcinomas (UC) is subject to debate and affects treatment. Evidence derived from X-chromosome mosaicism and patterns of molecular alterations supports both a mono- and polyclonal relationship. In contrast to most UC, tumours with the mutator phenotype have frequent mutations in repetitive sequences (MSI) and promoter methylation. The aim of this study was to investigate the clonality of multifocal UC with MSI.

Methods: We have screened 400 UC for MSI and found it to occur in 1% of bladder and 15% of upper tract UC. Of these, 9 patients, whose tumours had MSI, developed or presented with multiple UC. A total of 32 UC (occurring over 0-6 years, 2-12 TCC per patient), 2 cases of CIS and 9 normal urothelial samples were screened for MSI at 17 loci and aberrant promoter methylation at 7 genes.

Results: In 8 of 9 patients, the pattern of microsatellite mutation and promoter methylation suggested that the multiple tumours had a clonal origin. Patterns of aberrant methylation in multiple tumours were more similar than microsatellite mutations, suggesting an earlier carcinogenic timing. MSI and promoter methylation were present in macroscopically normal urothelium from these patients.

Conclusions: Aberrant promoter methylation occurs before microsatellite alteration in UC with mutator phenotype. The majority of recurrent UC with MSI are monoclonal in origin and macroscopically normal urothelium harbours multiple molecular abnormalities. Thus, at the time of apparently successful treatment, there is molecular evidence of residual tumour that subsequently develops into recurrent disease.

Anaplastic large cell lymphoma (ALCL) designates a heterogeneous group of CD30+ (systemic or primary cutaneous) peripheral T-cell lymphomas (PTCLs). A subgroup of systemic ALCL is transformed by anaplastic lymphoma kinase (ALK). We compared 46 ALCL with 22 PTCLs in terms of T-cell receptor (TCR) rearrangements, expression of TCRs and TCR-associated molecules [CD3, ZAP-70 (zeta-associated protein 70)]. Despite their frequent clonal rearrangement for TCRbeta, only 4% of ALCLs expressed TCRbeta protein, whereas TCRs were detected in 86% of PTCLs. Moreover, both TCRbeta+ ALCLs lacked CD3 and ZAP-70 (ie, molecules indispensable for the transduction of cognate TCR signals). Defective expression of TCRs is a common characteristic of all types of ALCL, which may contribute to the dysregulation of intracellular signaling pathways controlling T-cell activation and survival. This molecular hallmark of ALCL is analogous to defective immunoglobulin expression distinguishing Hodgkin lymphoma from other B-cell lymphomas.

Aims: The potential role of adult stem cells in the regeneration of beta cells in diabetes is still controversial. Although islet cell transplantation is currently the most pursued field of research, we have investigated the capacity of multipotent adult stem cells to correct hyperglycaemia in an experimental murine diabetes model.

Methods: Cloned stem cells were labelled with eGFP or transfected with a pTie2-RFP construct to show endothelial differentiation in vivo. The beta cell toxin alloxan was injected intravenously and all mice became hyperglycaemic (> 400 mg/dl) within two days and lost more than 90 % of their beta cell mass. Stem cells were then injected either directly into the pancreas or given systemically.

Results: Mice that received stem cell transplantation reached normal blood glucose levels within 14 days and the beta cell mass fully recovered within one month after treatment, regaining normal body weight soon after stem cell infusion. The host pancreas then dissociated and further analysed. The eGFP+ donor cells did not express insulin and other endocrine markers, but showed a red fluorescence (RFP+) and CD31 expression instead, characteristics of endothelial cells after pTie2 activation. It was further shown that remaining (eGFP-) beta cells showed increased cell cycle activity.

Conclusions: Endothelial differentiation from transplanted stem cells, induced by the environment of an injured pancreas, allows the regeneration of insulin production either through proliferation of still existing and residual beta cells in the islet or the recruitment and differentiation of beta cell progenitors mostly from the duct region via enhanced vasculogenesis and microcirculation.

Aims: The oncogenic potential of the high-risk human papillomavirus (HR-HPV) genotypes depends on the expression of the viral oncogenes E6 and E7. Thus, the detection of these transcripts could serve as a factor in the evaluation of a woman's risk of development of cervical intraepithelial neoplasia (CIN).

Methods: A nested RT-PCR assay for the detection of E6/E7 oncogene transcripts of all known HR-HPV genotypes was established. Cervical scrapes of 779 HR-HPV-DNA-positive women exhibiting all grades of CIN were examined.

Results: Spliced E6/E7 oncogene transcripts of all the HR-HPVs were detected in numerous samples. In 459 cases with agreement between the cytologic and histologic findings, the prevalence increased with lesion severity: CIN 0, 18%; CIN I, 58%; CIN II, 77%; CIN III, 84%. While sensitivity and negative predictive value of HR-HPV DNA-positivity for the detection of a CIN lesion were significantly (p < 0.0001) higher than those of E6/E7 mRNA positivity (90.3% vs. 65.5% and 93% vs. 83.1%), the opposite was true for the specificity and positive predictive value (72.8 % vs. 95.2%) and 65.1% vs. 88.5%, p < 0.0001). Preliminary follow-up data in 120 initially HPV-16 DNA-positive women revealed the development, persistence or progression of a CIN lesion in 33% (8/24) of HR-HPV DNA-positive and E6/E7 mRNA-negative women, compared to 93% (66/71, p < 0.0001) in women in whom transcriptional activity of the E6/E7 oncogenes was detectable.

Conclusions: Besides the identification of HPV DNA, the detection of HR-HPV E6/E7 oncogene transcripts may serve as a valuable tool in increasing the specificity of HPV testing.

When considering typical features of malignant lesions, the radiologist must differentiate between invasive cancers consisting of mass lesions and ductal carcinoma in situ, typically appearing as microcalcifications. Common malignant features of invasive cancers include irregular shape and indistinct or spiculated margins. In microcalcifications, segmental distribution and pleomorphic shape are the features with the highest predictive value of malignancy. However, there is a broad spectrum of findings that confound the reliable differentiation between benign and malignant lesions. The American College of Radiology has established the Breast Imaging Reporting and Data System (BI-RADS) for standardizing radiological terms and reports in mammography screening. The Breast Imaging Reporting and Data System provides diagnostic categories that have implications for guidance regarding follow-up or biopsy of mammographic breast lesions. BI-RADS 3 lesions are considered probably benign with a malignancy risk < 2%. These findings can be followed up at predetermined intervals according to current recommendations. Suspicious lesions with a substantial probability, but without the classic appearance of malignancy, are classified as BI-RADS 4. Minimal invasive biopsy should be considered in patients with these lesions. BI-RADS 5 lesions are highly suggestive of malignancy. It is recommended that appropriate action should be taken for these most suspicious lesions. The accuracy of the mammography as the primary diagnostic tool can be increased by the use of ultrasound and physical examination. In some situations, MRI is helpful for further evaluation. However, classifying the lesions with precision is not trivial since overlap exists between malignant and benign features.

During the last decade significant progress in molecular genetics and cell biology was made and numerous signal transduction pathways regulating cell growth, differentiation and survival were identified. It is now fairly well understood how accumulation of multiple genetic aberrations lead to deregulation of these signal transduction pathways and cause malignant transformation and tumour progression. Therefore, in many cases specific tumour phenotypes can be linked to specific genetic changes. As a result molecular diagnostics has become an important tool for tumour diagnositics that helps to discriminate specific entities. Further, determination of critical mutations leading to activation of important growth and survival signals can identify targets for specific tumour therapies. Gastrointestinal stromal tumours (GISTs) provide an excellent example of how activating mutations in receptor tyrosine kinases can be used as a tool to predict tumour biology and response to therapy by receptor inhibitors. During therapy secondary receptor mutations may cause resistance to therapy and thus may require additional combinatorial therapies. Therefore, predictive pathology and monitoring response to novel targeted therapies provide new challenges for pathologists and require a broad spectrum of techniques in molecular pathology.

Biochips are collections of miniaturized test sites (microarrays) arranged on a solid substrate onto which a large number of biomolecules are attached with high density. Like a computer chip performing millions of mathematical operations in a few split seconds, a biochip allows for simultaneous analyses of thousands of biological reactions, such as decoding genes, in a few seconds. Biochip technologies can be applied to numerous fields including genomic, proteomic, and glycomic research, as well as pharmacology and toxicology. However, one of the most common applications is in the determination of gene expression in human cells and tissues. Global gene expression analysis has helped to identify important genes and signalling pathways in human malignant tumors. And there is hope that microarrays will make the step from "the (laboratory) bench to the bedside (of the patient)". Recent studies have indeed revealed that analysis of differential gene expression by microarrays may help to identify subtypes of malignant tumors, that allow a risk stratification of the patients. However, there are several issues that need to be addressed before microarrays may become a tool for routine diagnostics, such as problems with bioinformatic analysis, construction of disease or tissue specific microarrays with only limited numbers of genes of interest, standard operation procedures for tissue preparation to prevent RNA degradation, etc.. In this article, an overview over of the multifarious biochip applications and technologies, its limitations, challenges and future developments is provided.

Autoimmune liver diseases encompass autoimmune hepatitis, primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) as lesions of the biliary tract. The term autoimmune cholangitis has not been generally accepted, so it remains an entitiy waiting for precise definition. AIH is a chronic progressive necroinflammatory liver disease mostly occuring in female individuals and leading to ultimate autodestruction of the liver if not treated. Histopathology of the liver reflects the gerneral understanding of the underlying immune especially self reactive CD4 + T-helper cells mediated mechanisms in destruction of liver cells displaying a typical but by no means pathognomonic histopathological pattern. Since there are no specific and generally valid tests the diagnosis should be confirmed by a scoring system including histopathology. Variants of autoimmune hepatitis cover seronegative cases, acute onset autoimmune hepatitis and autoimmune hepatitis with centrilobular necrosis. Differential diagnosis of autoimmune hepatitis includes drug induced chronic hepatitis that may mimick autoimmune hepatitis by clinical course and serology. Histopathology may give helpful hints for the correct diagnosis. Autoimmune lesions of the biliary tract are PBC in the first line. The target antigen of the autoimmune response has been identified, natural history of the diseases is well known and histopathology is pathognomonic in about a third of the cases. In clinical practice liver biopsy is taken to exclude other etiologies when AMA is present in the serum, staging the disease at first diagnosis and to establish diagnosis in cases of AMA negativity. The autoimmune nature of PSC has been discussed in the literature ever since the first description and the answer in not settled yet. Histopathology is relevant for the diagnosis in excluding other etiologies and confirming the diagnosis of small duct PSC. The term autoimmune cholangitis has been used to designate AMA-negative PBC, however, based on research experience and the clinical data it should be reserved to the overlap syndrome of AIH and PSC in children that seem to make up a disease entitiy of its own.

The majority of patients with epithelial ovarian cancer (EOC) are diagnosed with advanced disease involving sites such as the upper abdomen, pleural space, and paraaortic lymph nodes. The standard therapy for advanced disease requires maximal cytoreductive surgery followed by postoperative platinum- and taxane-based chemotherapy. Despite maximal primary surgical effort and postoperative standard chemotherapy long-term survival of patients with advanced stage III or IV disease ranges from 30% to less than 10% due to early and late relapse or primary progressive disease. Facing the highly lethal nature of epithelial ovarian carcinoma, the clinical course of advanced disease is difficult to predict in an individual patient. This heterogeneity of clinical outcome in patients with ovarian carcinoma suggests that reliable prognostic and/or predictive factors would be of potential clinical value and new treatment options are warranted in the future. In the light of recently published studies we summarize the clinical features and the diagnostic, operative and postoperative management of epithelial ovarian carcinoma. We furthermore address the importance of the pathologist during the clinical course of patients with ovarian carcinoma. The issue of timing between surgery and chemotherapy in the setting of neoadjuvant chemotherapy treatment of advanced ovarian carcinoma is being highlighted as well as the significance of new diagnostic and therapeutic options with regard to accurate predictive markers, that might identify patients who are appropriate candidates for novel therapeutic approaches.