Tracing TET1 expression in prostate cancer: discovery of malignant cells with a distinct oncogenic signature

Background

Ten–eleven translocation methylcytosine dioxygenase 1 (TET1) is involved in DNA demethylation and transcriptional regulation, plays a key role in the maintenance of stem cell pluripotency, and is dysregulated in malignant cells. The identification of cancer stem cells (CSCs) driving tumor growth and metastasis is the primary objective of biomarker discovery in aggressive prostate cancer (PCa). In this context, we analyzed TET1 expression in PCa.

Methods

A large-scale immunohistochemical analysis of TET1 was performed in normal prostate (NOR) and PCa using conventional slides (50 PCa specimens) and tissue microarrays (669 NOR and 1371 PCa tissue cores from 371 PCa specimens). Western blotting, RT-qPCR, and 450 K methylation array analyses were performed on PCa cell lines. Genome-wide correlation, gene regulatory network, and functional genomics studies were performed using publicly available data sources and bioinformatics tools.

Results

In NOR, TET1 was exclusively expressed in normal cytokeratin 903 (CK903)–positive basal cells. In PCa, TET1 was frequently detected in alpha-methylacyl-CoA racemase (AMACR)–positive tumor cell clusters and was detectable at all tumor stages and Gleason scores. Pearson’s correlation analyses of PCa revealed 626 TET1-coactivated genes (r > 0.5) primarily encoding chromatin remodeling and mitotic factors. Moreover, signaling pathways regulating antiviral processes (62 zinc finger, ZNF, antiviral proteins) and the pluripotency of stem cells were activated. A significant proportion of detected genes exhibited TET1-correlated promoter hypomethylation. There were 161 genes encoding transcription factors (TFs), of which 133 were ZNF-TFs with promoter binding sites in TET1 and in the vast majority of TET1-coactivated genes.

Conclusions

TET1-expressing cells are an integral part of PCa and may represent CSCs with oncogenic potential.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01201-7.

[HER2 testing in gastric cancer - results of a German expert meeting]

Valid HER2 testing is essential for optimal therapy of patients with HER2 positive gastric cancer and the correct use of first-line treatment. While each breast cancer is routinely being tested for the HER2 status, HER2 testing in gastric cancer has still not become part of the routine and is often only done upon request by the therapist. An interdisciplinary German expert group took the challenges of HER2 testing in gastric cancer as an opportunity to address essential aspects and questions for the practical use of HER2 testing in this indication from the perspective of pathologists and therapists. The recommendations made in this manuscript reflect the consensus of all participants and correspond to their opinions and long-term experience.

[The metastatic niche. Mechanisms and prognostic implications]

Disseminated tumor cells require a special microenvironment to form metastases. This metastatic niche is organ specific and forms prior to the establishment of visible metastases. The niche is characterized by vascular remodeling and bone marrow-derived cells which have migrated into it. Studies by other groups and our own results have already shown that intranodal lymphangiogenesis is an important prerequisite for regional lymph node metastases in rectal cancer patients, and can be used as a prognostic marker for progression-free survival. Niche cells such as endothelia secrete factors that attract tumor and bone marrow-derived cells. CXCL12 is one of these factors. CXCL12 activates the CXCR4 chemokine axis and induces migration along its gradient. Several factors, such as hypoxia, have been described to regulate CXCR4 function and surface expression on tumor cells. Low molecular weight agents have been used to block CXCR4 activation. This review focuses on the function and regulation of CXCR4 and its ligand CXCL12 in metastases formation. It also discusses potential options for therapeutic blockage.

Neuropilin-2 and its ligand VEGF-C predict treatment response after transurethral resection and radiochemotherapy in bladder cancer patients

The standard treatment for invasive bladder cancer is radical cystectomy. In selected patients, bladder-sparing therapy can be performed by transurethral resection (TURBT) and radio-chemotherapy (RCT) or radiotherapy (RT). Our published in vitro data suggest that the Neuropilin-2 (NRP2)/VEGF-C axis plays a role in therapy resistance. Therefore, we studied the prognostic impact of NRP2 and VEGF-C in 247 bladder cancer patients (cN0M0) treated with TURBT and RCT (n = 198) or RT (n = 49) and a follow-up time up to 15 years. A tissue microarray was analyzed by immunohistochemistry. NRP2 expression emerged as a prognostic factor in overall survival (OS; HR: 3.42; 95% CI: 1.48 - 7.86; p = 0.004) and was associated with a 3.85-fold increased risk of an early cancer specific death (95% CI: 0.91 - 16.24; p = 0.066) in multivariate analyses. Cancer specific survival (CSS) dropped from 166 months to 85 months when NRP2 was highly expressed (p = 0.037). Patients with high VEGF-C expression have a 2.29-fold increased risk of shorter CSS (95% CI: 1.03-5.35; p = 0.043) in univariate analysis. CSS dropped from 170 months to 88 months in the case of high VEGF-C expression (p = 0.041). Additionally, NRP2 and VEGF-C coexpression is a prognostic marker for OS in multivariate models (HR: 7.54; 95% CI: 1.57-36.23; p = 0.012). Stratification for muscle invasiveness (T1 vs. T2-T4) confirmed the prognostic role of NRP2 and NRP2/VEGF-C co-expression in patients with T2-T4 but also with high risk T1 disease. In conclusion, immunohistochemistry for NRP2 and VEGF-C has been determined to predict therapy outcome in bladder cancer patients prior to TURBT and RCT.

Abstract P6-06-48: Breast cancer subtypes and metastatic pattern at the Regional Breast Center Dresden

Background: Breast cancer is classified into the subtypes luminal A, luminal B (HER2 positive or negative), HER2 enriched (not luminal) and triple negative (St. Gallen International Breast Cancer Conference 2011). These breast cancer subtypes show differences in response to therapies and prognosis. Amongst others prognosis is depended on hormone receptor positivity, extent and localization of metastases. Routine screening for metastatic disease is not part of the guidelines for breast cancer aftercare although in oligometastatic disease surgery or local ablative therapies can be used to improve outcome. We evaluated if tumor aftercare should be individualized due to different patterns of metastases of the breast cancer subtypes.

Methods: Four hospitals incorporated into the Regional Breast Center Dresden as a certified center of excellence for treating breast cancer. We retrospectively evaluated sites and characteristics of metastases and survival data according to the intrinsic breast cancer subtypes from patients treated between 2006 and 2011. Immunohistochemical detection of estrogen and progesterone receptor, grading and overexpression of HER2 oncogene was used for identifying tumor subtypes. All data were collected at the Clinical Cancer Registry Dresden.

Results: In 2006 routinely identification of overexpression of HER2 started. Since that time 2334 patients had therapy for breast cancer- 12,4% (290/2334) with metastatic disease (7.2%; 168/2334 primary and 5.2%; 122/2334 relapse). Mean duration of follow up was 38 months. Metastatic disease was more frequently found in HER2 enriched, 27.2%; 30/110, and triple negative, 19.7%; 44/223, than in the luminal subtypes: luminal A 8.3%; 107/1284, luminal B HER2 negative 12.2%; 23/188, luminal B HER2 positive 16%; 36/225. Luminal A and B HER2 negative subtypes showed a preference for solely bone metastases (43%; 56/130) which was rare in triple negative breast cancer (6.8% 3/44). If bone metastases occurred in triple negative breast cancer they mostly appeared together with visceral and/or brain metastatic disease (27%; 12/44). Solely visceral metastases were found in the HER2 enriched subtype (46.7%; 14/30), luminal B HER2 positive (38.9%; 14/36), and triple negative breast cancer (20.2%; 19/44). Brain metastases were more frequently observed in triple negative breast cancer (22.7%; 10/44). Overall survival rate at 5 years for metastatic disease was 38.5% (95%CI 28.2-52.5) for luminal A, 23.1% (95%CI 12.0-44.5) for luminal B (HER2 negative), 11.9% (95%CI 5.5-25.7) for luminal B (HER2 positive), 27.6% (95%CI 14.4-52.8) for HER2 enriched and 6.5% (95%CI 2.4-17.1) for triple negative subtype.

Conclusion: Different patterns of metastatic disease were seen according to the subtypes of breast cancer. An individualized tumor aftercare that includes screening for visceral metastasis might improve prognosis of patients with luminal B HER positive, HER enriched and triple negative subtype. Further investigation on patients eligible for metastatic surgery should be performed with longer follow up and evaluated with respect to post-interventional survival.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-48.

Impact of the adaptor protein GIPC1/Synectin on radioresistance and survival after irradiation of prostate cancer

PURPOSE

Studies have shown that GIPC1/Synectin is an essential adaptor protein of receptors that play an important role in cancer progression and therapy resistance. This is the first study to explore the role of GIPC1/Synectin in radioresistance of prostate cancer and as a possible predictive marker for outcome of primary radiation therapy.

MATERIALS AND METHODS

The effect of RNA interference-mediated GIPC1/Synectin depletion on clonogenic cell survival after irradiation with 0, 2, 4, or 6 Gy was assayed in two different GIPC1/Synectin-expressing human prostate cancer cell lines. The clinical outcome data of 358 men who underwent radiotherapy of prostate cancer with a curative intention were analyzed retrospectively. Uni- and multivariate analysis was performed of prostate-specific antigen recurrence-free survival and overall survival in correlation with protein expression in pretreatment biopsy specimens. Protein expression was evaluated by standard immunohistochemistry methods.

RESULTS

In cell culture experiments, no change was detected in radiosensitivity after depletion of GIPC1/Synectin in GIPC1/Synectin-expressing prostate cancer cell lines. Furthermore, there was no correlation between GIPC1/Synectin expression in human pretreatment biopsy samples and overall or biochemical recurrence-free survival after radiotherapy in a retrospective analysis of the study cohort.

CONCLUSION

Our results do not show a predictive or prognostic function of GIPC1/Synectin expression for the outcome of radiotherapy in prostate cancer. Furthermore, our in vitro results do not support a role of GIPC1 in the cellular radiation response. However, the role of GIPC1 in the progression of prostate cancer and its precursors should be subject to further research.

[Barrett's esophagus. An update]

Barrett's esophagus (BE), a well-known complication of gastroesophageal reflux disease (GERD), constitutes a precancerous condition for adenocarcinoma of the distal esophagus. The so-called Barrett's carcinoma shows increasing incidences in countries of the western hemisphere; new data, however, indicate that the rise in incidence is not quite as dramatic as previously assumed. The definition of BE is currently changing: despite good reasons for a purely endoscopic definition of BE, goblet cells are still mandatory for this diagnosis in Germany and the USA. Dysplastic changes in the epithelium are the most important risk factor for the development of Barrett's adenocarcinoma and recently dysplasia was subclassified into a more frequent adenomatous (intestinal) and a non-adenomatous (gastric-foveolar) types. The gold standard for diagnosing dysplasia is still H&E staining. The histological diagnosis of dysplasia is still encumbered by a significant interobserver variability, especially regarding the differentiation between low grade dysplasia and inflammatory/reactive changes and the discrimination between high grade dysplasia and adenocarcinoma. Current data, however, show much higher interobserver agreement in endoscopic resection specimens than in biopsies. Nevertheless, the histological diagnosis of dysplasia should be corroborated by an external second opinion because of its clinical consequences. In endoscopic resections of early Barrett's adenocarcinoma, the pathological report has to include a risk stratification for the likelihood of lymphogenic metastases.

[Standardized and structured histopathological evaluation of colorectal polyps: a practical checklist against the background of the new WHO classification]

Gastroenterologists removing colorectal polyps expect standardized and well-structured pathological reports, providing them with all relevant data for the further clinical management of the patient. Over the last year, a task force of clinicians and pathologists has developed a checklist to improve and harmonize endoscopic and pathological reporting of colorectal polyps. This checklist concentrates more on concrete recommendations from evidence-based guidelines and established international classifications for daily practice rather than detailed molecular pathological pathways of carcinogenesis. These recommendations are based on the current S3 guidelines for colorectal cancer (the chapter entitled "Management of colorectal polyps"), the histomorphological consensus manuscript of the GI working group of the German Society for Pathology, as well as the current WHO classification for tumors of the digestive system.

[Nonbacterial colitides]

Aside from bacterial infections, viral, fungal, and parasitic infections are important differential diagnoses in inflammatory disorders of the colorectum. In contrast to bacterial infections, in which the causative organism can hardly ever be detected histologically, in non bacterial infections the germs can often be verified by either histology, immunohistochemistry, or at least by molecular pathology. This manuscript will give an overview of the spectrum of pathogenic germs, the clinical symptoms, and pathological findings of the most important infections.

[Bacterial colitis]

The question of whether there are inflammatory changes in colorectal biopsy specimens is frequently asked, especially when the patient reports diarrhea or when the mucosa is reddened on endoscopy. The pathologist first has to find out whether there is, in fact, an increase in the inflammatory infiltrate of the colorectal mucosa which warrants the diagnosis of inflammation. If so, the second challenge is to ascertain the etiology of these inflammatory changes, in particular to differentiate between infectious and non-infectious causes. In principle, we can distinguish forms of colitis with distinct morphological hallmarks confirming the diagnosis (e.g. microscopic detection of the causative organism, as well as lymphocytic or collagenous colitis) from other forms of colitis which have a characteristic pattern of findings not necessarily allowing to deduce the etiology (e.g. infectious colitis without microscopic evidence of the germ vs. inflammatory bowel disease). The present article discusses the pathomorphology and differential diagnosis of the most important forms of bacterial colitis.

[Serrated precursor lesions]

The so-called serrated pathway has in recent years been well established as a second route of colorectal carcinogenesis. Sessile serrated polyps, especially sessile serrated adenomas (SSA) and traditional serrated adenomas (TSA) were identified as precursor lesions of this pathway. Activating mutations in either the BRAF (in SSAs) or the KRAS oncogene (in TSAs) have been determined as the initiating molecular alterations, followed by epigenetic methylation of CpG islands in promoter regions of genes which are implicated in cell cycle control or DNA repair. These findings have led to a paradigm shift in gastrointestinal pathology as lesions without cytological dysplasia, such as SSAs and certain forms of hyperplastic polyps, are now accepted to be precancerous lesions. In addition, carcinomas that have developed through the serrated pathway of colorectal carcinogenesis show varying biological behavior relevant for the clinical management of these tumors depending on the molecular aberrations.

[GIPC: a new target for therapy in pancreatic adenocarcinoma?]

GIPC is highly expressed in human pancreatic adenocarcinoma and is a central protein for the stability of IGF-1R in pancreatic adenocarcinoma cell lines (15). The goal of this study was to prove the importance of GIPC in vivo and to evaluate possible therapeutic strategies that target this protein and its PDZ domain. In vivo effects of GIPC knockout were studied after lentiviral transduction of luciferase-expressing MiaPaCa2 pancreatic cancer cells with shRNA against GIPC; growth characteristics were monitored with bioluminiscence. Knockdown of GIPC led to a significant inhibition of pancreatic tumor cell growth in vivo in different mouse models. To test a possible therapeutic approach, the PDZ domain of GIPC was targeted by a short peptide composed of the amino acid sequence PSQSSSEA. This octapeptide was designed based on the C-terminal binding motif of GAIP. Targeting GIPC with this peptide inhibited the association between IGF-1R and GIPC. The subsequent downregulation of IGF-1R decreased proliferation in vitro and in vivo. In conclusion, our findings suggest that targeting GIPC and its PDZ domain-mediated interaction with the tyrosine kinase receptor IGF-1R could be a promising new treatment option for pancreatic cancer.

[Intraepithelial neoplasia in ulcerative colitis: on the way to more diagnostic confidence]

Ulcerative colitis (UC)-related intraepithelial neoplasia and its distinction from regenerative changes and sporadic adenomas occurring in UC is one of the greatest challenges in gastrointestinal pathology. Recently, the molecular changes in UC-related neoplastic progression have been determined and compared with the molecular changes in sporadic carcinogenesis. Diagnostically promising differences between sporadic and UC-related carcinogenesis are the advent of genetic changes in non-neoplastic UC-related mucosa and the early loss of 18q (harbouring SMAD2, SMAD4, and DCC) and 17p (site of p53) in UC-related tumorigenesis. These studies have given rise to a number of adjunct methods in the determination of UC-related neoplasia. Never the less, conventional histopathology still remains the gold standard in the diagnosis of UC-related neoplasia. Training of histopathologists therefore is one of the most important issues in conquering the diagnostic challenges of UC-related neoplasia. The working group "Gastrointestinal Pathology" of the German Society for Pathology set up a diagnostic multicenter trial which was open to everyone interested. The interobserver variability regarding ulcerative colitis-related neoplasia was quite promising (kappa = 0.63). A consensus diagnosis was reached for all the specimens and diagnostic criteria for UC-related neoplasia were discussed, reevaluated, and agreed on. Adjunct methods and emerging markers for the diagnosis of ulcerative colitis-related neoplasia (p53, Ki67, AMACR) and its distinction from regenerative changes and sporadic adenomas occurring in UC (ALM) will be presented and discussed.

Characterization of macrophage subpopulations in colon cancer using tissue microarrays

AIMS

To determine the pattern of macrophage infiltration in colon cancers and its correlation with clinicopathological characteristics.

METHODS AND RESULTS

Colon cancers from 100 patients were arrayed into a tissue microarray (TMA). Four cores per tumour were taken: three from the invasion front (IF) and one from the tumour surface (TS). Macrophages were quantified by immunohistochemistry with antibodies to the PG-M1, KP-1, MRP8, MRP14 and MRP8/14 antigens. The number of macrophages was significantly higher in the TS cores than in the IF cores and both tumour sites showed a higher number of macrophages than the normal mucosa. The number of macrophages decreased in higher stage tumours. The different tumour-associated macrophage (TAM) subpopulations were positively correlated with each other.

CONCLUSIONS

The increased number of macrophages in cancers compared with normal colon mucosa indicates that macrophages are attracted to the tumour site. However, decreasing macrophages in higher stage colon cancers suggest that this attraction decreases with tumour progression.

Prognostic relevance of 20q13 gains in sporadic colorectal cancers: a FISH analysis

BACKGROUND

Amplification of 20q13 is a frequent chromosomal alteration in solid tumors and harbors a number of putative oncogenes (CAS/CSE1-L, NABC1, or Aurora2). Amplifications on 20q13 have been identified as an independent prognostic marker indicating worse survival in breast and ovarian cancer. However, little is known about the prognostic significance of 20q13 gains in sporadic colorectal cancers. The aim of this study was to correlate 20q13 gains in sporadic colorectal cancers with other known prognostic factors, tumor progression, and overall survival.

METHODS

Nuclei were extracted from 146 paraffin-embedded colorectal cancers of different UICC stages and used for fluorescence in situ hybridization (FISH) with a directly labeled probe for 20q13.2 (VYSIS). Signals were counted in 120 nuclei per sample. 20q13 was considered gained when > or =40% of the nuclei showed 3 or more FISH signals. Statistical correlations were tested with log-rank tests and Kaplan-Meier survival curves.

RESULTS

Signal numbers for 20q13.2 were gained in 78 cases (53%). Cases with gains on 20q13.2 showed worse outcome than cases without: the gain of 20q13.2 was an independent prognostic marker for overall survival (P=0.006) as well as tumor progression (P=0.012) in univariate and multivariate analyses. Gains on 20q13.2 did not correlate with tumor stage. However, there was a significant association between 20q13.2 gains and tumor location in the left-sided colon and an inverse correlation between histologic grade and 20q13.2 gains.

CONCLUSION

These data indicate that gains on 20q13.2 correlate with faster tumor progression and worse patient survival independent from tumor size and lymph node involvement. Therefore, alterations on 20q13 are an important biological event in colorectal tumor progression with independent prognostic relevance.

Sustained elevation of NF-kappaB DNA binding activity in radiation-induced lung damage in rats

PURPOSE

To characterize the cellular distribution and DNA binding activity of the nuclear factor kappaB (NF-KappaB) in a model of radiation-induced lung damage in the rat.

MATERIAL AND METHODS

The right lung of Fischer rats was irradiated with a single dose of 20 Gy. The cellular distributions of NF-KappaB proteins and mRNA were detected with immunohistochemistry and in-situ hybridization respectively. The DNA binding activity of NF-KappaB, nuclear and cytoplasmic levels of NF-KappaB proteins, and kinase activity towards IkappaBalpha (IKappaBAlpha) were determined using electrophoretic mobility shift assays (EMSA), Western blots and kinase assays, respectively. The mRNA level of interleukin 6 (IL-6) was determined using quantitative room temperature polymerase chain reaction.

RESULTS

There was a continuous elevation of NF-KappaB DNA binding activity in the rat lung after ionizing irradiation over 6 months. The irradiated lung tissue exhibited an increased kinase activity towards IKappaBAlpha and a selective loss of nuclear IKappaBAlpha. The NF-KappaB-DNA binding complex switched from p50-p65 heterodimers in normal lung tissue to p50 homodimers in irradiated lung tissue. The increased level of IL-6 mRNA suggests transcriptional activation of NF-KappaB-dependent genes in the irradiated rat lung.

CONCLUSIONS

The DNA binding activity of NF-KappaB is continuously activated after irradiation of the rat lung by loss of nuclear IKappaBAlpha. This might play a role in sustaining chronic inflammation and hyperproliferation of mesenchymal cells after irradiation.

Cellular apoptosis susceptibility gene expression in endometrial carcinoma: correlation with Bcl-2, Bax, and caspase-3 expression and outcome

Deregulation of proliferation and apoptosis is known to contribute to neoplastic transformation and growth. Using specific antibodies for the cellular apoptosis susceptibility (CAS) gene, caspase-3, Bcl-2, and Bax, we examined the protein expression in 89 endometrial carcinomas and in 56 samples of nonneoplastic adjacent endometrium for comparison. Immunostaining results were scored with regard to approximate percentage of positive tumor cells (< 10%, 10% to 50%, > 50%) and relative immunostaining intensity (1+, 2+, 3+). In nonneoplastic endometrium, CAS protein was expressed in 70.6%, Bax in 64%, caspase-3 in 52%, and Bcl-2 in 87%. In neoplastic tissue, CAS was present in 93% of the tumors, Bax in 88%, caspase-3 in 77%, and Bcl-2 in 51%. Bcl-2:Bax ratio was > 1 in 9 cases (10%). In cases of atrophy (n = 24) and simple (n = 10) and complex (n = 22) hyperplasia in the adjacent endometrium, lower levels of expression compared with carcinoma were observed for CAS (p = 0.003), caspase-3 (p = 0.034), and Bax (p = 0.04) and higher levels for Bcl-2, although for this protein the results were not statistically significant (p = 0.32). There was no association between immunoscores and FIGO stage. High caspase-3 levels were seen in endometrioid tumor type (p = 0.017). CAS expression was higher in grade 3 tumors (p = 0.002) and older patients (p = 0.013). All tumors of younger patients (< 50 years) were Bcl-2 negative (p = 0.037). Caspase-3 correlated positively with CAS (p = 0.008), Bax (p = 0.04), and low Bcl-2:Bax ratio (p = 0.043), and inversely (as a trend) with Bcl-2 (p = 0.056). Survival analysis (Kaplan-Meier and Cox regression) established a strong association between prognosis and stage, grade, and histologic type (all p < or = 0.0036). In addition, shorter survival was observed for patients whose tumors contained > 50% of positive cells for caspase-3 (p = 0.024) or for CAS (p = 0.04). Age, Bcl-2, Bax, and Bcl-2:Bax ratio did not provide prognostic information. Our results suggest a role of CAS, Bcl-2, Bax, and caspase-3, which are apparently involved in the progressive deregulation of proliferation and apoptosis leading from simple and complex hyperplasia to carcinoma. In addition, CAS and caspase-3 protein levels may be useful markers in predicting the outcome of the patients.

Prognostic relevance of hMLH1, hMSH2, and BAX protein expression in endometrial carcinoma

Endometrial carcinoma is the most common gynecologic malignancy in perimenopausal and postmenopausal women. A role of mismatch repair genes, like hMLH1 and hMSH2 in their pathogenesis, has been suggested. Loss of their function leads to the accumulation of replication errors (mutator phenotype), which are responsible for further mutations in genes with microsatellite sequences in their coding region, such as Bax. We analyzed the expression of hMLH1, hMSH2, and Bax genes in 89 formalin-fixed paraffin-embedded endometrial carcinomas. The immunostains were scored with regard to percentage of positive tumor cells (0%, <10%, 10 to 50%, >50%), and relative staining intensity (1+, 2+, 3+). The staining results were correlated with clinicopathologic features and survival. Loss of hMSH2 expression (0% positive cells) was observed in 1.1% (1/89) of the tumors; loss of hMLH1 was seen in 12.4% (11/89) of the cases, particularly in endometrioid tumors with mucinous differentation (5/11; 45%; P =.03). No significant association was found between the immunoscores and grade, stage criteria of the International Federation of Obstetrics and Gynecology (FIGO), or age of the patients. Among 11 tumors with loss of Bax expression (12.4%), 4 had also loss of hMLH1 (4/11; 36.4%; P =.017). In multivariate analysis (Cox model), significantly longer survival was found for patients with tumors in FIGO Stage I-II (P <.0001), endometrioid type (P =.001), low grade (P =.001), and absence of hMLH1 expression (P =.027). Our results suggest that loss of function of hMLH1 and Bax occur in a subgroup of endometrial carcinoma. In addition to the classical prognostic factors, absence of hMLH1 expression is associated with better outcome of patients.

Cellular chimerism of the lung after transplantation. An interphase cytogenetic study

The present study evaluated the origin of endothelial and epithelial cells, as well as of lymphocytes and macrophages, after lung transplantation. Biopsy specimens from patients who underwent lung and heart-lung transplantation and received organs of sex-mismatched donors were studied by means of nonisotopic in situ hybridization with DNA probes of the X and Y chromosome. By means of monoclonal antibodies against leukocytes, T and B lymphocytes, and macrophages, the various infiltrating cell types were analyzed. In all allografted lungs, the endothelial cells and bronchial and alveolar epithelium retained the donor sex type. The lymphocytes of the donor were almost completely replaced by recipient cells 1 month after transplantation. Low numbers of alveolar macrophages of the donor were present during the entire period under study. Low numbers of donor lymphocytes and high numbers of donor alveolar macrophages in the allografted lung seem to be correlated with a worse clinical course.

Immunohistochemical analysis of drug resistance-associated proteins in ovarian carcinomas

Loss of function of the tumor suppressor gene p53, increased expression of glutathione-S-transferase pi (GST7pi) and the major vault protein are involved in drug resistance of ovarian carcinomas. However, a study comparing these factors has not yet been performed. Therefore, paraffin-embedded material of 213 ovarian tumors with well-documented follow-up was used for immunohistochemical analysis of p53 protein, GSTpi, and major vault protein (antibodies LRP-56, LMR-5). Forty-six percent of the cases showed nuclear p53 accumulation. Strong immunoreactivity for GSTpi, LRP-56, and LMR-5 was seen in 50%, 36%, and 47%, respectively. p53 positivity was most often found in serous carcinomas (p < 0.05). Strong GSTpi expression was the only factor that correlated with clinical resistance to chemotherapy (p = 0.04). In the whole group, as well as in FIGO III cases stratified for residual disease < or = and >2 cm, p53 and GSTpi correlated with an adverse outcome (p = 0.01 for p53 and p = 0.04 for GSTpi). Strong LRP-56 or LMR-5 staining was associated with a tendency towards poorer prognosis, without reaching statistical significance. In multivariate analysis for FIGO III, only residual disease and p53 proved to be independent prognostic factors. Our observations confirm the prognostic significance of p53 accumulation in ovarian carcinomas. Only GSTpi immunoreactivity was significantly correlated with drug resistance.

Altered distribution of beta-catenin, and its binding proteins E-cadherin and APC, in ulcerative colitis-related colorectal cancers

The beta-catenin pathway plays a central role in transcriptional signaling and cell-cell interactions in colonic epithelium. Alterations of the expression of beta-catenin, and its binding partners E-cadherin and the adenomatous polyposis coli protein (APC), are frequent events in sporadic colorectal cancer. Ulcerative colitis (UC)-related cancers originate in a field of chronic inflammation and therefore may have different alterations in the beta-catenin pathway than sporadic cancers. To test this hypothesis, expression and subcellular localization of beta-catenin, E-cadherin, and APC were detected by immunohistochemistry in paraffin sections from 33 UC-related and 42 sporadic colorectal cancers. Although beta-catenin and E-cadherin expression were predominantly limited to the lateral cell membrane in normal colonic epithelium, both tumor groups showed an overall shift from membranous to cytoplasmic expression for these proteins. An increase in nuclear localization of beta-catenin and a decrease in cytoplasmic APC expression also were seen in both cancer groups compared with normal epithelium. Abnormal beta-catenin expression was more closely linked to E-cadherin alterations in UC-related cancers than in sporadic cancers. In contrast, abnormal beta-catenin expression was more closely linked to APC alterations in sporadic cancers than in UC-related cancers. These data suggest that alterations of the beta-catenin pathway are important in both UC-related and sporadic colorectal cancers. However, differences in the expression patterns of beta-catenin, E-cadherin, and APC between UC-related and sporadic colorectal cancers suggest that the specific alterations in this pathway may differ in these two cancer groups.

FISH analysis of gene aberrations (MYC, CCND1, ERBB2, RB, and AR) in advanced prostatic carcinomas before and after androgen deprivation therapy

Genetic mechanisms leading to androgen-independent growth in advanced prostatic carcinomas (PC) are still poorly understood. Analysis of genes potentially involved in the regulation of tumor cell proliferation and apoptosis might confer better insight into this process and might lead to improved therapeutic strategies. Fluorescence in situ hybridization (FISH) analysis of dissociated nuclei with DNA probes for MYC (8q24)/#8, cyclin D1 gene (CCND1; 11q13)/#11, ERBB2 (17q13)/#17, the androgen receptor gene (AR; Xq12)/#X, and the retinoblastoma gene (RB; 13q14) was applied to formalin-fixed tissue from 63 patients with advanced PC after androgen deprivation therapy (ADT); matched tumor tissue before ADT was also available in 22 of these cases. The cut-points used were: "increased copy number," > or = 30% of all nuclei with increased FISH signals (centromere and/or gene); "amplification," > or = 15% of nuclei with "increased gene copy number." CCND1 and MYC gene "amplifications" were present before ADT in 25% and 33% of the cases, respectively; the frequency of these "amplifications" increased to 37% and 57% after ADT. Loss of the RB gene was nearly four times more frequent after ADT than before therapy (22% versus 6%). AR and ERBB2 gene "amplifications" occurred only after ADT in 36% and 30% of cases, respectively. With the exception of the AR gene, the copy number increase was low. After treatment, MYC and AR gene "amplifications" correlated with the proliferation rate (Ki-67/MIB1 index; p = 0.01 and p = 0.04), whereas ERBB2 "amplifications" were associated with increased apoptotic index (PCD/TUNEL; p = 0.016). However, no correlation between FISH results and clinical follow-up could be established. FISH analysis of genes putatively involved in PC progression revealed characteristic patterns of aberrations in advanced PC before and after ADT. Distinct changes in gene copy number before and after therapy suggests possible involvement of these genes in the escape from androgen control.

20q13 and cyclin D1 in ovarian carcinomas. Analysis by fluorescence in situ hybridization

In ovarian carcinomas, alterations of the chromosomal region 20q13 and the cyclin D1 gene have been described. This study has sought to determine their prognostic significance. Fluorescence in situ hybridization (FISH) on dissociated nuclei and paraffin sections with DNA probes for 20q13.2 and cyclin D1, as well as immunohistochemistry (cyclin D1), were applied to formalin-fixed tissue of 69 invasive ovarian carcinomas, mainly of serous type. On dissociated nuclei 33/47 cases (70%) and on tissue sections 13/66 cases (20%) demonstrated an increase of 20q13.2 copies. The presence of > or =4 copies per nucleus (isolated nuclei) and > or =3 copies per nucleus (sections) was associated with an adverse prognosis (Kaplan-Meier for FIGO stage III after stratification for residual tumour: p=0.0049 and p=0.03, respectively). Thirty-four out of 47 cases (72%) showed an increase of cyclin D1 copies. Kaplan-Meier analysis for FIGO stage III after stratification for residual tumour>2 cm or < or =2 cm revealed an unfavourable outcome for cases with more than two cyclin D1 copies (p=0.04). No correlation was seen between FISH and immunohistochemistry. Multivariate analysis identified residual tumour (p=0.0002), 20q13.2 gain (p=0.0004) and cyclin D1 gain (p=0.0343) as independent prognostic factors. It is concluded that gains of chromosomal region 20q13.2 and the cyclin D1 gene are frequent and biologically important events, with prognostic relevance, in advanced ovarian carcinomas.

[Molecular carcinogenesis in ulcerative colitis-associated and sporadic colorectal carcinoma--differences and similarities]

Like sporadic colorectal cancers, ulcerative colitis (UC)-related cancers are thought to evolve through a multistep progression pathway. The genomic alterations important in sporadic colorectal carcinogenesis are well characterized, with loss of APC function being a frequent and early event. However, the genomic alterations in UC-related carcinogenesis are yet unclear and the role of APC is controversial. In this study genomic alterations in UC-related cancers, dysplasias and nondysplasias were assessed by comparative genomic hybridization (CGH). Alterations of the APC/beta-catenin pathway were evaluated by immunohistochemistry. 32 cases of UC-related cancers (14 with synchronous dysplasias and nondysplasias) and 42 sporadic cancers were matched by UICC stage. CGH was performed using DOP-PCR amplification after microdissection. Expression of beta-catenin, E-cadherin and APC were detected by immunohistochemistry in paraffin sections. Chromosomal alterations were present in 90% of the sporadic and 94% of the UC-related cancers. 86% of the UC-related dysplasias and 36% of the nondysplasias showed changes by CGH. Chromosome 5q was lost in 56% of UC-related cancers and 36% of the dysplasias but in only 26% of the sporadic cancers. Other frequent alterations in both cancer groups were loss of 18q, 8p, 17p, and gain of 8q and 20q. Immunohistochemistry showed a decrease of membranous and an increase of cytoplasmic expression of E-cadherin and beta-catenin in UC-related and sporadic cancers. APC expression was significantly decreased in both tumor types. Clonal chromosomal alterations occur early in UC-related tumor progression. UC-related and sporadic cancers share a set of common clonal abnormalities. The frequent loss of 5q and the altered expression of APC, beta-catenin, and E-cadherin proteins in UC-related cancers indicate a critical role of the APC/beta-catenin pathway in UC-related carcinogenesis.

Cytokine profile of liver- and blood-derived nonspecific T cells after liver transplantation: T helper cells type 1/0 lymphokines dominate in recurrent hepatitis C virus infection and rejection

Orthotopic liver transplantation (OLT) is a successful treatment in patients with hepatitis C virus (HCV)-associated end-stage liver disease worldwide. T lymphocytes and their cytokines are believed to have a pivotal role in the defense against HCV and in allograft rejection. An immunosuppressive drug regimen may cause a cytokine imbalance toward a T helper (TH) cell type 2 profile that is associated with the persistence of infection and acceptance of the graft. The aim of this study is to assess whether cytokine imbalances toward a TH1- or TH2-type response may have a role in recurrent HCV infection and rejection after OLT. Twenty-one intrahepatic T-cell lines of 15 patients with recurrent HCV infection after OLT (group A) and 15 lines of 11 patients with rejection (group B) were studied. Both patient groups had received liver allografts because of HCV-associated end-stage liver disease. Patients with HCV-induced liver disease who did not undergo OLT served as controls: 17 patients with chronic hepatitis C (CH-C) and 8 patients with cirrhosis. At the time of liver biopsy, 14 blood-derived T-cell lines of 12 patients with recurrent HCV infection, 7 of 10 patients with rejection, and 18 of 18 control patients were also investigated. Regardless of the underlying disease (recurrent HCV infection, rejection, HCV-induced hepatitis, and cirrhosis), all liver tissue-derived T-cell lines produced interferon-gamma; some additionally produced interleukin-4 (IL-4), but none produced IL-10, indicating that the TH0/1 cytokine profile dominates. T-cell lines showing a TH1 cytokine profile derived from intrahepatic T cells could be established significantly more often in recurrent HCV infection and rejection than in controls with CH-C (Fisher's exact test, P <.05). The cytokine profile of intrahepatic T cells did not differ from that obtained in peripheral blood. TH0/1 cytokine profile dominates the intrahepatic and blood-derived immune response in recurrent HCV infection and rejection after OLT regardless of the mode of immunosuppression. The lymphokine profile of immunocompromised patients with recurrent HCV infection or rejection does not differ principally from that of patients with HCV-induced hepatitis and cirrhosis, but seems to show a TH1 profile significantly more often.

Chromosomal alterations in ulcerative colitis-related and sporadic colorectal cancers by comparative genomic hybridization

Both ulcerative colitis (UC)-related and sporadic colorectal cancers are thought to evolve through a multistep process of genomic instability, accumulation of genomic alterations, and clonal expansion. This process may involve different genomic changes in UC-related cancers than in sporadic cancers because of the origin of UC-related cancers in an inflammatory field. This study was designed to define the specific genomic events occurring in UC-related cancers. Comparative genomic hybridization (CGH) was performed on 32 UC-related and 42 stage-matched sporadic colorectal cancers. The mean number of chromosomal alterations per case was similar in the UC-related and sporadic tumor groups (8.6 in UC, 8.1 in sporadic). The 2 tumor groups shared many chromosomal alterations: losses on 18q (78% UC v69% sporadic), 8p (53% v50%), 17p (44% v57%), and gains on 8q (63% v45%), 20q (44% UC v67%), and 13q (44% UC v38%). However, differences in the frequency and timing of specific alterations were observed. Chromosome 5q was lost in 56% of UC-related but in only 26% of sporadic cancers. Alterations of chromosome 8 were associated with stage progression in UC-related, but not in sporadic cancers. In contrast, 18q loss was associated with stage progression in sporadic cancers only. Thus, differences in the frequency and timing of individual chromosomal alterations suggest that genetic progression in these 2 tumor groups may follow multiple pathways.

Sjögren's syndrome and MALT lymphomas of salivary glands: a DNA-cytometric and interphase-cytogenetic study

Few and conflicting cytogenetic data are available concerning the chromosomal constitution of (mainly gastric) extranodal marginal zone B-cell non-Hodgkin's lymphoma arising from mucosa-associated lymphoid tissue (MALT)-type lymphoma. The majority of salivary gland MALT lymphomas are thought to develop from longstanding Sjögren's syndrome/benign lymphoepithelial lesion (BLEL). We tried to achieve a better comprehension of related cytogenetic alterations by comparing DNA-ploidy and numerical chromosomal (#) aberrations, assessed by different techniques of DNA cytometry (image cytometry) and interphase cytogenetics using nonradiographic in situ hybridization (centromere specific probes for #3, 7, 12, 18) on 12 cases of BLEL, 13 low-grade MALT lymphomas (LG-MALT-L) and 4 high-grade MALT lymphomas (HG-MALT-L) of salivary gland. Both techniques were applied on tissue sections preferentially, enabling a reliable measurement of histomorphologically identified areas. No case of BLEL showed cytogenetic abnormalities. Three of 4 HG- and 2 of 13 LG-MALT-L exhibited complex chromosomal gains in nonisotopic in situ hybridization, which were reflected by DNA nondiploidy in image cytometry. In 6 of 13 LG- and lof 4 HG-MALT-L, one or two numerical chromosomal aberrations were demonstrated by nonisotopic in situ hybridization, which could not be resolved by image cytometry. In the 11 DNA-diploid LG-MALT-L, trisomies 18, 3, and 12 were found in 36, 12, and 9%, respectively. In conclusion, comparing BLEL, which showed no chromosomal aberrations, with LG- and HG-MALT-L, an increase in frequency and number of numerical aberrations and DNA nondiploidy was seen. Peritetraploid DNA nondiploidy might be characteristic for HG-MALT-L of salivary gland as it is a rare finding in MALT lymphomas of other sites. It is unclear whether the documented chromosomal aberrations in LG-MALT-L, especially increased rate of trisomy 18, indicate a pathogenic impact or merely reflect genetic instability.

Microsatellite instability and loss of heterozygosity in prostatic carcinomas: comparison of primary tumors, and of corresponding recurrences after androgen-deprivation therapy and lymph-node metastases

BACKGROUND

The molecular mechanisms leading to prostate cancer progression are poorly understood. In particular, those changes which are responsible for androgen-independent growth and metastatic spread in prostate cancer are an issue of current investigations.

METHODS

To gain more insight into these processes, paired microdissected samples from both untreated, locally advanced primary tumors (n = 20) and recurrences (n = 20) after conventional androgen-deprivation therapy (ADT) were analyzed retrospectively for microsatellite instability (MSI) and loss of heterozygosity (LOH) at nine loci on chromosomes 8, 18, and X by polymerase chain reaction. In parallel, 12 prostatic carcinomas treated by radical prostatectomy and nine corresponding lymph-node metastases were analyzed in the same way.

RESULTS

The group treated with ADT showed a total of 10 MSI in 7 of the primary tumors (35%): 4 of these (20%) at one locus, and 3 of these (15%) at two loci. In the recurrences, MSI was observed in 4 cases (20%): 3 of these at one locus (15%), and 1 of these (5%) at two loci. LOH was found in 8 cases (40%) before as well as after ADT. In the radically resected carcinomas, MSI could be detected at two chromosomal loci in one of the primary tumors (8%) and in one of the metastases (11%); LOH was found in 2 primaries (16%) and 3 metastases (33%).

CONCLUSIONS

Although MSI can be found in advanced prostatic carcinomas, it apparently does not play a major role in the progression of prostate cancer regarding androgen-independent growth or lymphogenous spread.

p53 gene mutations are not required for early dissemination of cancer cells

The p53 protein is involved in several central cellular processes, including gene transcription, DNA repair, cell cycling, genomic stability, chromosomal segregation, senescence, and apoptosis. p53 mutations frequently result in an immunocytochemically detectable accumulation of the p53 protein in tumor cells. To evaluate whether p53 gene mutations are required for the onset of hematogeneous tumor cell dissemination, we compared the p53 status of primary and micrometastatic tumor cells. Disseminated carcinoma cells could be detected in bone marrow aspirates obtained from 46 (40%) of 114 patients with various types of epithelial tumors without overt skeleton metastases. There was no correlation between the detection of p53 protein in primary lung carcinomas and the presence of tumor cells in bone marrow. Further analyses revealed that the disseminated carcinoma cells rarely accumulate mutated p53 protein and that 10 cell lines derived thereof did not harbor p53 mutations even in the presence of such mutations in the autologous primary tumors. These observations indicate that tumor cells can leave the primary tumor before mutations of the p53 gene occur and that these mutations are not essential for such early hematogeneous dissemination of cancer cells. Thus, the value of mutated p53 as a target for diagnosis and treatment of micrometastatic disease in cancer patients is questionable.

Proliferation- and apoptosis-associated factors in advanced prostatic carcinomas before and after androgen deprivation therapy: prognostic significance of p21/WAF1/CIP1 expression

The molecular mechanisms leading to androgen-independent growth in prostate cancer (PC) are poorly understood. Androgen deprivation therapy (ADT) results physiologically in a decrease in proliferation and an increase in programmed cell death (PCD)/apoptosis. The aim of our study was to get more insight into these processes in prostatic carcinomas before and after ADT. For this purpose, immunohistologic staining for the androgen receptor (AR) molecule, the Ki-67 antigen, the bcl-2 oncoprotein, the p53 protein and its physiologic effector, p21/WAF1, was performed on archival material. PCD was visualized by enzymatic detection of DNA fragmentation. Specimens from 69 PC patients after ADT were studied in correlation to histopathology and prognosis. In 42 cases, corresponding tumour tissue from the untreated primary tumours could be analysed comparatively. Before ADT, histologic grade was associated with Ki-67 index (P < 0.0001, Spearman correlation) and PCD rate (P < 0.05, Spearman correlation). Ki-67 index correlated with PCD rate (P < 0.05, Spearman correlation) and p21/WAF1 expression (P < 0.01, Fisher's exact test). p21/WAF1 expression was the only statistically significant prognostic factor for shorter survival (P < 0.002, log-rank test). All p21/WAF1-positive cases showed high Ki-67 index and high histologic grade. After ADT, loss of AR expression was associated with high Ki-67 index, whereas histologic signs of regression correlated negatively with Ki-67 index (P < 0.001, Pearson chi2 test). p21/WAF1 expression increased significantly (P < 0.02, McNemar test) and correlated with p53 accumulation (P < 0.0001, Pearson chi2 test). Most significant prognostic parameter after conventional ADT was high-rate p21/WAF1 expression (> 50% of tumour cells; P < 0.00001, log-rank test). This study demonstrates that p21/WAF1 overexpression before and after ADT characterizes a subgroup of advanced PC with paradoxically high proliferation rate and significantly worse clinical outcome. This finding might be clinically useful for planning therapy in these patients.

[TP53 gene aberrations in chondromatous neoplasms: correlation with immunohistochemical p53 accumulation and MDM2 expression]

Histological differentiation between chondroma and chondrosarcoma is a common problem in surgical pathology. In a former study (3) we were able to show, that immuno-histochemical p53-accumulation in chondromatous neoplasias might be an additional hint for malignancy. Now we tried to find out, whether p53-accumulation is caused by TP53-aberrations or functional inactivation of p53-wildtype protein by MDM2. For this purpose, paraffin-embedded material of 80 chondromatous neoplasms (18 chondromas, 18 chondromatous neoplasms of uncertain dignity (i.e. cytologically suspicious but without definite invasive growth), and 44 chondrosarcomas (24 GI, 13 GII, 7 GIII)) were screened for TP53 gene-aberrations by means of DGGE (denaturing gradient gel electrophoresis; exons 5-8). The results were correlated with immunohistochemical p53-accumulation (DO-7, DAKO) and MDM2-expression (AB-1, Oncogene). A total of 43% of all chondromatous neoplasms showed TP53-aberrations in DGGE-analysis, i.e. 27% of chondromas, 50% of chondromatous neoplasms of uncertain dignity, 46% of GI-, 46% of GII- and 71% of GIII-chondrosarcomas. Exon 6 (58% of all cases with aberrations) and exon 8 (47%) were affected most frequently. No significant correlation between TP53-aberration and either p53-accumulation or MDM2-expression was present. A statistically significant correlation could be found between p53-accumulation and MDM2-expression (p < 0.0001). Regarding histological tumor-classification, p53-accumulation and MDM2-expression discriminated between chondromas/chondromatous neoplasms of uncertain dignity and well differentiated chondrosarcomas in a statistically significant manner. In the subgroup of p53-positive and MDM2-negative cases significantly more TP53-aberrations were detected by DGGE-analysis than in the other groups. Interestingly, the subgroup of p53- and MDM2-negative cases showed the second highest rate of TP53-DGGE-aberrations. Nearly 50% of these aberrations, however, were localized in exon 8, a mutation that is known to cause no p53-protein-accumulation. In conclusion, TP53-aberrations occur frequently in chondromatous neoplasms and show no significant association to either immunohistochemical p53-accumulation or MDM2-expression. Functional inactivation of p53 wildtype protein by MDM2-expression seems to be the major cause of p53-accumulation in chondromatous neoplasms and emphasizes the role of these parameters as additional hint for malignancy.

[Chronic transplant reaction of the kidney. A interphase cytogenetic and immunohistologic characterization of the involved cells in relation to donor and recipient origin]

Chronic rejection is a major problem in contemporary kidney transplantation. The purpose of this study was to determine whether renal cells are repopulated by extra-renal cells over time or whether the graft remains permanently allogenic. We studied nine explanted allografted kidneys of sex-mismatched donors by means of non-isotopic in situ hybridization (NISH). We used biotinylated centromer-specific DNA probes of the human chromosomes Y and X. In a further step, monoclonal and polyclonal antibodies against CD45, CD3, CD20, CD31, CD1a, S100, alpha-actin, factor Vill and UEA were used to analyse the various infiltrating cell types and the cells involved in allograft arteriopathy. In several cases NISH and immunohistochemistry were combined to facilitate the typing of cells. Our study showed that up to several years after transplantation the glomerular, tubular and endothelial cells retained donor origin. The only cells of recipient origin were the inflammatory cells, predominantly macrophages and T lymphocytes.

[Numerical chromosome aberrations in abortion tissue. Comparison of conventional cytogenetics and interphase cytogenetics in paraffin sections and nuclear suspensions]

Chromosomal aberrations are an important cause of spontaneous abortions. In order to detect numerical aberrations, paraffin-embedded tissue from 26 abortions with known conventional cytogenetic findings (CCG; 25 numerical aberrations and one partial trisomy 7p) was analyzed by means of interphase cytogenetics (ICG) using centromer-specific DNA probes for chromosomes #X, #Y, #10, #18, and #13/#21. Limit-values for the diagnosis of aneusomy in tissue sections were established by classifying the distribution of hybridization signals by CCG data (for gain > or = 15% of nuclei with +1 signal; for deletion > 40% of nuclei with -1 signal). Signal distribution in tissue sections and nuclear suspensions from paraffin blocks analyzed in parallel showed statistically a highly significant correlation (P < 0.0001). ICG and CCG diagnoses corresponded in 18 of 20 cases suitable for evaluation (90%; no false-positive result). No correlation between cytogenetic and histologic findings could be found. ICG proved to be a reliable tool for the detection of numerical chromosomal aberrations in paraffin-embedded tissue of abortions (sections and nuclear suspensions). This, data for genetic counselling of the parents can be provided. The limit values for diagnosis of aneusomy could also be important for the application of ICG in tumor cytogenetics.

Interphase cytogenetic analysis of mucinous ovarian neoplasms

Extending our previous efforts to characterize ovarian neoplasms by interphase cytogenetics, we analyzed a series of 32 mucinous tumors by nonisotopic in situ hybridization with seven different centromere-specific probes as well as by flow and image DNA cytometry; we then compared the data with results of p53 and Ki67 immunohistochemistry and MYC DNA-PCR analysis and of the clinical follow-ups. Of the tumors studied, 11 of 14 (78.6%) mucinous carcinomas, 7 of 7 (100%) mucinous tumors of low malignant potential (LMP), and 7 of 11 (63.6%) mucinous cystadenomas demonstrated chromosomal aberrations. The mean number of chromosomal aberrations (+/- SD) was slightly higher in DNA cytometrically nondiploid cases than in diploid cases (2.0 +/- 1.6 versus 1.6 +/- 1.2, not significant) but did not differ significantly among the study groups (carcinomas: 1.7 +/- 1.4; tumors of LMP; 1.9 +/- 0.7; adenomas: 1.4 +/- 1.4). Aberrations affected chromosomes 1 (14 of 27 cases) and 6 (12 of 31) most frequently, followed by chromosomes 17 (7 of 28), 7 (6 of 29), and X (6 of 28). Signal gain for centromere 1, which was the most prevalent finding (13 of 27), was observed in 3 of 10 mucinous cystadenomas, 2 of 4 mucinous tumors of LMP, and 8 of 13 mucinous carcinomas. All six moderately and poorly differentiated carcinomas demonstrated this aberration. Signal gain of centromere 6 (3 of 13) and centromere 7 (4 of 13) were found only in carcinomas (p < 0.05 and p < 0.025, respectively). The interphase cytogenetic results correlated neither with proliferative activity, immunohistochemical p53 accumulation, MYC DNA amplification, nor postoperative outcome. Compared with serous ovarian neoplasms (Lab Invest 1996, 75:473-485), mucinous tumors demonstrated signal gain for chromosome 1 (p < 0.0001) and signal loss for chromosomes 6 (p < 0.001) and X (p < 0.01) significantly more often. Loss of centromere 17 was more characteristic for serous than for mucinous carcinomas (p < 0.05). Our observations show that chromosomal aberrations in mucinous ovarian neoplasms are apparently not random. These results support the notion that the molecular genetic changes in mucinous neoplasms differ from those in serous tumors.

Sex chromosome determination in extragonadal teratomas by interphase cytogenetics: clues to histogenesis

Teratomas are neoplasms that are composed of tissues from all three germinal layers. The exact histogenetic origin of teratomas, however, is still controversial. In order to gain more insight into histogenesis of extragonadal teratomas (EGTs), the gonosomal status in 13 congenital EGTs was studied by means of interphase cytogenetics using nonradioactive in situ hybridization (NISH) with centromere-specific DNA probes. By use of this technique a direct correlation of cytogenetic results with morphology was possible. In all EGTs analyzed the gonosomal status in tissues derived from the different germinal layers was identical to that of the nontumorous fetal and placental tissue. This was true irrespective of localization, age, histological type, and classification of the EGT. Our results strongly suggest that EGTs arise from pluripotent diploid precursor cells, for example, either premeiotic germ cells that have not yet undergone the first meiotic division or pluripotent ectopic embryonal or extraembryonal cells. Our data do not support the theory of parthenogenetic EGT development, at least in males.

DNA ploidy and MYC DNA amplification in ovarian carcinomas. Correlation with p53 and bcl-2 expression, proliferative activity and prognosis

There is increasing evidence that DNA ploidy is a prognostic factor in ovarian carcinomas, but it is uncertain whether MYC DNA amplification is an epiphenomenon of DNA nondiploidy or a distinct biological change with an impact on the clinical course of the disease. To clarify these issues we analysed DNA ploidy by flow and image cytometry and MYC copy number by polymerase chain reaction in archival material from ovarian carcinomas with known follow up. The results were compared with proliferative activity (Ki67 index) and p53 and bcl-2 expression. DNA cytometry revealed nondiploidy in 84 of 144 cases (58.3%). Nondiploidy was statistically significantly correlated with histological tumour type, histological grade, Ki67 index > 10%, FIGO stage, presence of residual tumour after debulking surgery and adverse postoperative outcome. Furthermore, DNA nondiploidy was associated with p53 accumulation. We found that 84.9% of the p53-positive cases were nondiploid. This points to the paramount importance of wild type p53 for the maintenance of genome integrity in this tumour type. MYC DNA amplification was seen in 33.8% (26/77 cases) of ovarian carcinoma. There was no correlation between MYC DNA amplification and histological tumour type, histological grade, FIGO stage, DNA ploidy, proliferative activity or prognosis. However, when p53 and bcl-2 expression was taken into account, a statistically significant correlation between gene alteration or expression patterns and histological tumour type was revealed. The group of mucinous carcinomas demonstrated both MYC DNA amplification and strong bcl-2 expression in 50% and contained the largest fraction of cases without aberration (37.5%). Endometrioid carcinomas were characterized by strong bcl-2 expression in 85%, whereas serous and undifferentiated carcinomas predominantly exhibited p53 alterations, frequently accompanied by bcl-2 overexpression or MYC DNA amplification. Thus, in interaction with other genes MYC DNA amplification may play a role in the determination of the varying differentiation patterns of ovarian carcinomas.

Interphase cytogenetic analysis of serous ovarian tumors of low malignant potential: comparison with serous cystadenomas and invasive serous carcinomas

The cytogenetic and molecular genetic changes in serous tumors of low malignant potential (LMP) of the ovary have not been well characterized so far. Therefore, we analyzed 20 serous tumors of LMP, 10 invasive serous ovarian carcinomas, and 7 benign serous cystadenomas by nonisotopic in situ hybridization (seven different centromere-specific probes) as well as by flow and image DNA cytometry and compared the data with results of p53 and Ki67 immunohistochemistry, MYC DNA PCR analysis and with the clinical follow-up. All but two tumors of LMP were DNA cytometrically diploid; 9 of 10 invasive carcinomas proved to be DNA nondiploid (p < 0.0001). Nonisotopic in situ hybridization revealed a mean number of 1.5 chromosomal aberrations in tumors of LMP, which differed statistically significantly from cystadenomas (mean, 0.4) and from invasive carcinomas (mean, 3.4) (rho < 0.01). The main changes in tumors of LMP were +6 (7 of 18 cases) and +7 (6 of 19) followed by -3 (5 of 20), -1 (4 of 17) and +X (3 of 20). In the group of invasive carcinomas, the number of cases with signal gains for chromosomes 6 (5 of 8), 7 (7 of 10) and X (4 of 10) and signal loss for chromosome 1 (4 of 9) was even larger. In addition, statistically significantly more cases showed gain of 8 (5 of 10) and loss of 17 (5 of 10) (p < 0.05). Proliferative activity (Ki67 index) was positively correlated with the number of chromosomal aberrations (p < 0.05). There was no association between changes in the centromere signal number of chromosomes 8 and 17 and MYC DNA amplification and immunohistochemical p53 accumulation, respectively. Clinical follow-up showed prognostic differences between tumors of LMP and invasive carcinomas as expected (rho < 0.001) but did not reveal differences within the group of tumors of LMP with regard to the number or type of the chromosomal abnormalities detected. In conclusion, the patterns of chromosomal gains and losses in serous tumors of LMP and invasive serous carcinomas of the ovary do not seem random and suggest a close relation between these neoplasms compatible with sequential stages in a multistep model of ovarian carcinogenesis.

Apoptosis and immunohistochemical bcl-2 expression in colorectal adenomas and carcinomas. Aspects of carcinogenesis and prognostic significance

BACKGROUND

The bcl-2 oncoprotein confers a survival advantage to cells by inhibiting programmed cell death (PCD) or apoptosis. Overexpression of bcl-2 probably plays a role in colorectal carcinogenesis. The aims of our study were to determine bcl-2 expression and PCD index in colorectal adenomas and carcinomas in correlation with p53 expression, Ki-67 index, and histopathology, and to test their prognostic significance in patients with colorectal carcinomas.

METHODS

Immunohistologic staining for bcl-2 (MoAb clone 124), the proliferation-associated Ki-67 antigen (MoAb MIB1), and p53 (MoAb DO1) was performed on archival material from 44 colorectal adenomas and 95 adenocarcinomas (TNM classifications pT2 and -3, pN0, and M0). The PCD was visualized by enzymatic detection of DNA fragmentation.

RESULTS

bcl-2 was expressed in 86% of the adenomas and 67% of the carcinomas. Mean PCD and Ki-67 rates were 1.7 +/- 0.14% and 35 +/- 13% in adenomas and 1.9 +/- 0.15% and 28 +/- 14% in carcinomas, respectively. In carcinomas, bcl-2 expression was correlated with a low PCD index (< 1.5%; P = 0.005). Furthermore, a high Ki-67 index (> or = 25%) was associated with a high PCD index (> or = 1.5%; P < 0.0001). p53 accumulation was seen in 16% of adenomas and in 42% of carcinomas, and did not correlate with bcl-2 expression or PCD index. In the univariate analyses, significantly longer disease free survival intervals were observed in three groups: all patients with bcl-2-positive carcinomas (P < 0.05); the subgroup of carcinomas with bcl-2 expression and low PCD index (P = 0.037); and the subgroup of bcl-2-positive and p53-negative carcinomas (P = 0.021). In the multivariate analysis, however, only tumor stage and p53 expression were independent risk factors for prognosis.

CONCLUSIONS

Our data indicate that bcl-2 expression is characteristic of the early phase of colorectal carcinogenesis. Its physiologic function as an inhibitor of PCD is preserved in most colorectal carcinomas, whereas p53 is apparently not involved in the regulation of PCD in colorectal neoplasias. bcl-2 expression in colorectal carcinomas is associated with a better clinical course. This correlation became even more evident in the subgroups of patients with carcinomas that also had low PCD index or lacked p53 immunoreactivity.

Apoptosis and immunohistochemical bcl-2 expression in colorectal adenomas and carcinomas. Aspects of carcinogenesis and prognostic significance

BACKGROUND

The bcl-2 oncoprotein confers a survival advantage to cells by inhibiting programmed cell death (PCD) or apoptosis. Overexpression of bcl-2 probably plays a role in colorectal carcinogenesis. The aims of our study were to determine bcl-2 expression and PCD index in colorectal adenomas and carcinomas in correlation with p53 expression, Ki-67 index, and histopathology, and to test their prognostic significance in patients with colorectal carcinomas.

METHODS

Immunohistologic staining for bcl-2 (MoAb clone 124), the proliferation-associated Ki-67 antigen (MoAb MIB1), and p53 (MoAb DO1) was performed on archival material from 44 colorectal adenomas and 95 adenocarcinomas (TNM classifications pT2 and -3, pN0, and M0). The PCD was visualized by enzymatic detection of DNA fragmentation.

RESULTS

bcl-2 was expressed in 86% of the adenomas and 67% of the carcinomas. Mean PCD and Ki-67 rates were 1.7 +/- 0.14% and 35 +/- 13% in adenomas and 1.9 +/- 0.15% and 28 +/- 14% in carcinomas, respectively. In carcinomas, bcl-2 expression was correlated with a low PCD index (< 1.5%; P = 0.005). Furthermore, a high Ki-67 index (> or = 25%) was associated with a high PCD index (> or = 1.5%; P < 0.0001). p53 accumulation was seen in 16% of adenomas and in 42% of carcinomas, and did not correlate with bcl-2 expression or PCD index. In the univariate analyses, significantly longer disease free survival intervals were observed in three groups: all patients with bcl-2-positive carcinomas (P < 0.05); the subgroup of carcinomas with bcl-2 expression and low PCD index (P = 0.037); and the subgroup of bcl-2-positive and p53-negative carcinomas (P = 0.021). In the multivariate analysis, however, only tumor stage and p53 expression were independent risk factors for prognosis.

CONCLUSIONS

Our data indicate that bcl-2 expression is characteristic of the early phase of colorectal carcinogenesis. Its physiologic function as an inhibitor of PCD is preserved in most colorectal carcinomas, whereas p53 is apparently not involved in the regulation of PCD in colorectal neoplasias. bcl-2 expression in colorectal carcinomas is associated with a better clinical course. This correlation became even more evident in the subgroups of patients with carcinomas that also had low PCD index or lacked p53 immunoreactivity.

Apoptosis and immunohistochemical bcl-2 expression in colorectal adenomas and carcinomas. Aspects of carcinogenesis and prognostic significance

BACKGROUND

The bcl-2 oncoprotein confers a survival advantage to cells by inhibiting programmed cell death (PCD) or apoptosis. Overexpression of bcl-2 probably plays a role in colorectal carcinogenesis. The aims of our study were to determine bcl-2 expression and PCD index in colorectal adenomas and carcinomas in correlation with p53 expression, Ki-67 index, and histopathology, and to test their prognostic significance in patients with colorectal carcinomas.

METHODS

Immunohistologic staining for bcl-2 (MoAb clone 124), the proliferation-associated Ki-67 antigen (MoAb MIB1), and p53 (MoAb DO1) was performed on archival material from 44 colorectal adenomas and 95 adenocarcinomas (TNM classifications pT2 and -3, pN0, and M0). The PCD was visualized by enzymatic detection of DNA fragmentation.

RESULTS

bcl-2 was expressed in 86% of the adenomas and 67% of the carcinomas. Mean PCD and Ki-67 rates were 1.7 +/- 0.14% and 35 +/- 13% in adenomas and 1.9 +/- 0.15% and 28 +/- 14% in carcinomas, respectively. In carcinomas, bcl-2 expression was correlated with a low PCD index (< 1.5%; P = 0.005). Furthermore, a high Ki-67 index (> or = 25%) was associated with a high PCD index (> or = 1.5%; P < 0.0001). p53 accumulation was seen in 16% of adenomas and in 42% of carcinomas, and did not correlate with bcl-2 expression or PCD index. In the univariate analyses, significantly longer disease free survival intervals were observed in three groups: all patients with bcl-2-positive carcinomas (P < 0.05); the subgroup of carcinomas with bcl-2 expression and low PCD index (P = 0.037); and the subgroup of bcl-2-positive and p53-negative carcinomas (P = 0.021). In the multivariate analysis, however, only tumor stage and p53 expression were independent risk factors for prognosis.

CONCLUSIONS

Our data indicate that bcl-2 expression is characteristic of the early phase of colorectal carcinogenesis. Its physiologic function as an inhibitor of PCD is preserved in most colorectal carcinomas, whereas p53 is apparently not involved in the regulation of PCD in colorectal neoplasias. bcl-2 expression in colorectal carcinomas is associated with a better clinical course. This correlation became even more evident in the subgroups of patients with carcinomas that also had low PCD index or lacked p53 immunoreactivity.

Prognostic significance of p53 expression, chromosome 17 copy number, and DNA ploidy in non-metastasized colorectal carcinomas (stages IB and II)

BACKGROUND AND METHODS

Paraffin-embedded tumor tissue from 101 non-metastasized colorectal adenocarcinomas (tumor stages IB and II--that is, pT2 and 3, pN0, M0) was investigated for p53 expression by immunohistology (IH) (moab DO1), chromosome 17 (#17) copy number by interphase cytogenetics using non-radioactive in situ hybridization (NISH) with a centromer-specific DNA probe (D17Z1), and DNA ploidy by flow cytometry (FCM). The aims of the study were 1) to test whether numerical #17 aberrations are involved in functional TP53 loss in locally confined colorectal carcinomas; 2) to search for correlations between aberrant p53 expression and #17 aberrations with DNA ploidy and histopathology; and 3) to test the prognostic significance of these factors.

RESULTS

Sixty cases (59.4%) showed nuclear p53 expression IH (low-grade p53 accumulation (< 50%), n = 16 (15.8%); high-grade (> or = 50%), n = 44 (43.6%)). Nish showed #17 aneusomy in 46% of the carcinomas (34% deletions, 12% gains). In FCM analysis, 43% of the carcinomas were DNA non-diploid. p53 overexpression correlated statistically significantly with FCM non-diploidy (p = 0.013). Furthermore, #17 aneusomy also correlated with FCM non-diploidy (p = 0.001). However, there was no association between #17 status and p53 expression (IH).

CONCLUSIONS

Our data suggest a role for the TP53 gene in the aneuploidization process. Numerical deletions of #17, however, were not associated with p53 immunoreactivity in the analyzed tumors. With regard to prognosis, the most important independent variable in stage IB/II colorectal carcinomas was tumor stage, followed by high-grade p53 expression of tumor cells; #17 aneusomy was an independent risk factor for tumor relapse/progression but not for survival. As alterations of the investigated variables were not found in all carcinomas under study, different pathogenetic pathways seem to exist in colorectal carcinogenesis.

Apoptosis and immunohistochemical bcl-2 expression in colorectal adenomas and carcinomas. Aspects of carcinogenesis and prognostic significance

BACKGROUND

The bcl-2 oncoprotein confers a survival advantage to cells by inhibiting programmed cell death (PCD) or apoptosis. Overexpression of bcl-2 probably plays a role in colorectal carcinogenesis. The aims of our study were to determine bcl-2 expression and PCD index in colorectal adenomas and carcinomas in correlation with p53 expression, Ki-67 index, and histopathology, and to test their prognostic significance in patients with colorectal carcinomas.

METHODS

Immunohistologic staining for bcl-2 (MoAb clone 124), the proliferation-associated Ki-67 antigen (MoAb MIB1), and p53 (MoAb DO1) was performed on archival material from 44 colorectal adenomas and 95 adenocarcinomas (TNM classifications pT2 and -3, pN0, and M0). The PCD was visualized by enzymatic detection of DNA fragmentation.

RESULTS

bcl-2 was expressed in 86% of the adenomas and 67% of the carcinomas. Mean PCD and Ki-67 rates were 1.7 +/- 0.14% and 35 +/- 13% in adenomas and 1.9 +/- 0.15% and 28 +/- 14% in carcinomas, respectively. In carcinomas, bcl-2 expression was correlated with a low PCD index (< 1.5%; P = 0.005). Furthermore, a high Ki-67 index (> or = 25%) was associated with a high PCD index (> or = 1.5%; P < 0.0001). p53 accumulation was seen in 16% of adenomas and in 42% of carcinomas, and did not correlate with bcl-2 expression or PCD index. In the univariate analyses, significantly longer disease free survival intervals were observed in three groups: all patients with bcl-2-positive carcinomas (P < 0.05); the subgroup of carcinomas with bcl-2 expression and low PCD index (P = 0.037); and the subgroup of bcl-2-positive and p53-negative carcinomas (P = 0.021). In the multivariate analysis, however, only tumor stage and p53 expression were independent risk factors for prognosis.

CONCLUSIONS

Our data indicate that bcl-2 expression is characteristic of the early phase of colorectal carcinogenesis. Its physiologic function as an inhibitor of PCD is preserved in most colorectal carcinomas, whereas p53 is apparently not involved in the regulation of PCD in colorectal neoplasias. bcl-2 expression in colorectal carcinomas is associated with a better clinical course. This correlation became even more evident in the subgroups of patients with carcinomas that also had low PCD index or lacked p53 immunoreactivity.