ERG protein expression and genomic rearrangement status in primary and metastatic prostate cancer--a comparative study of two monoclonal antibodies.

BACKGROUND: Overexpression of the ERG protein is highly prevalent in prostate cancer (PCa) and commonly results from gene fusions involving the ERG gene. Recently, N-terminal epitope-targeted mouse and a C-terminal epitope-targeted rabbit monoclonal anti-ERG antibody (ERG-MAbs) have been introduced for the detection of the ERG protein. Independent studies reported that immunohistochemistry (IHC) with both ERG-MAbs highly correlates with the underlying ERG gene rearrangement status. However, comparative studies of both antibodies are lacking. Here, we are among the first to compare the mouse ERG-MAb with the rabbit ERG-MAb for their concordance on the same PCa cohort. Furthermore, we assessed whether the ERG protein expression is conserved in lymph node and distant PCa metastases. METHODS: We evaluated tissue microarrays of 278 specimens containing 265 localized PCa, 29 lymph node, 30 distant metastases and 13 normal prostatic tissues. We correlated ERG protein expression with ERG rearrangement status using an ERG break-apart fluorescence in-situ hybridization assay and IHC of both ERG-MAbs. RESULTS: ERG expression and ERG rearrangement status were highly concordant regardless of whether the mouse or rabbit ERG-MAb was used (97.8% versus 98.6%, respectively). Of interest, both ERG antibodies reliably detected the ERG expression in lymph node and distant PCa metastases, of which a subset underwent decalcification. Lymphocytes only revealed immunoreactivity using the rabbit ERG-MAb. If ERG protein expression was present in localized PCa, we observed the same pattern in the corresponding lymph node metastases. CONCLUSIONS: By demonstrating a broad applicability of IHC to study ERG protein expression using either antibody, this study adds an important step toward a facilitated routine clinical application. Further, we demonstrate that the clonal nature of the ERG rearrangement is not restricted to the genomic level, but proceeds in the proteome. Together, our results simplify future efforts to further eliucidate the biological role of ERG in PCa.

[Tonsillar lymphangiomatous polyp]. / Lymphangiomatöser Tonsillenpolyp.

Lymphangiomatous polyps are rare benign lesions of the tonsils. We report the case of a female patient presenting with dysphagia of 15 years' standing due to such a lesion. After surgical excision the patient remained free of symptoms and experienced no recurrence (follow-up 17 months). The histology was characterized by epitheliotropism of lymphocytes as well as dilated lymphatic channels, blood vessels and edema. Immunohistochemical staining with D2-40 monoclonal antibody and podoplanin confirmed the diagnosis of lymphangiomatous polyps. We discuss the current literature.

[Prostate cancer research. Biomarkers as promising options for optimized diagnosis and treatment]. / Prostatakarzinomforschung. Biomarker als Hoffnung für optimierte Diagnostik und Therapie.

A better understanding of signal transduction and gene regulation during prostate carcinogenesis will allow the development of novel diagnostic and prognostic biomarkers and a better prediction of the individual course of prostate cancer disease. It will also enhance the design and development of specific small molecular components aiming for specific therapies. The research groups in Bonn succeeded in the competition for an endowed professorship supported by the Rudolf Becker Stiftung (German Science Endowment Fund) settled in the"Centrum für integrierte Onkologie" funded by the German Cancer Aid. This should be the perfect breeding ground for future research in the field of prostate cancer.

The Ets-1 transcription factor is involved in pterygial angiogenesis.

Pterygial pathology is characterized by abnormal corneal epithelial proliferation, stromal modulation, matrix degradation and a strong tendency for otherwise absent corneal vascularization. As the proto-oncogene Ets-1 is known to play a key role in angiogenesis and matrix degradation in other tissues, its involvement in corneal vascularization was investigated. Fifteen pterygia representing two groups were studied. Group 1 consisted of five clinically active pterygia, and group 2 consisted of 10 samples of clinically non-active pterygia. (35)S-labelled ets-1 antisense and sense riboprobes were used for in-situ hybridization of Ets-1 transcription factor in all pterygia. The cytoplasm of blood vessel endothelial cells showed strong expression of ets-1 mRNA in all group 1 pterygia. In contrast, no expression of ets-1 was found in group 2 pterygia. Proto-oncogene ets-1 expression has been shown for the first time in the metaplastic pterygium, an eye tissue of unknown pathogenesis.

[Orbital aneurysmal bone cyst in a 2-year-old child]. / Aneurysmatische Knochenzyste im Bereich der Orbita bei einem 2-jährigen Kind.

An aneurysmal bone cyst is a rare tumor-like lesion which can affect any part of the skeleton. It is a disease of childhood and adolescence. Reports of its occurrence on the skull base in children are rare. A 22-month-old male patient was admitted to our ENT department with a sudden protrusion of the right eyeball. Radiologically, a cystic, well-defined and contrast enhanced mass on the medial-cranial orbital wall with beginning destruction of the frontal skull base was detected. Histological assessment of a biopsy, which was taken by medial orbitotomy, showed giant-cellular and fibrohistiocytic changes. Definitive histological diagnosis after removal showed an aneurysmal bone cyst. If there is evidence for aggressive, expansive growth, an aneurysmal bone cyst should be included into the ENT-differential diagnosis of orbital tumors. It is not possible to confirm diagnosis from clinical or radiological data. Early biopsy is essential for a reliable diagnosis even if histological assessment is challenging.

[Lymph vascularity and lymph node metastases on PET and PET-CT: immunohistological and clinical observations]. / Das Lymphgefässsystem (LGS I und II) aus chirurgischer Sicht. Lymphgefässe und Lymphknotenabsiedlungen, nach PET, PET-CT, immunhistologischen und klinischen Beobachtungen.

Sarcomatous malignancies only rarely develop regional lymph node metastases: about 2.7% of our evaluated cases. In this paper we provide evidence supporting a new hypothesis that two entirely separate lymph vascular systems exist in humans. One system (LGS I) exists in close proximity to the epithelium and drains into regional lymph nodes. Only sarcomas that originate in the epithelium or its immediate proximity are able to form regional lymph node metastases. The vast majority of sarcomatous malignancies (97.4% of cases) do not give rise to lymph node metastases, since they originate in proximity to a second, more deeply localized lymph node system (LGS II) in the mesenchymally derived tissues of the body. This second system has no connection to regional lymph nodes. Supporting evidence is provided by experience in the operative treatment of extremity lymphedema, PET-CT examinations, radionuclear lymphography, and scientific investigations using antibodies specifically directed at the elements of the lymph vascular system.

[Molecular biological and immunohistochemical analysis of tp53 in human ameloblastomas]. / Molekularbiologische und immunhistochemische Untersuchung des tp53-Gens in menschlichen Ameloblastomen.

AIM: Ameloblastoma is the most frequent epithelial tumor of the jaws. The spread is locally invasive and it tends to recur. Malignant transformation and occurrence of metastases has been described. Immunohistochemical analysis shows an enhanced expression of P53 protein in ameloblastomas. Mutation of the tp53 tumor suppressor gene was verified in several human tumors. In this study histological sections were analyzed for the expression of P53 protein and the tp53 gene was examined for mutations. MATERIAL AND METHODS: Tumor DNA from 29 patients with an ameloblastoma was examined for mutations in exons 5 to 8 of the tp53 tumor suppressor gene using PCR, SSCP,- and sequential analysis. Histological sections of the tumors were analyzed immunohistochemically for an overexpression of P53 protein. RESULTS: Two tp53 mutations (6.9%) in ameloblastomas were verified for the first time. In all 58.6% of the tumors showed an immunoreactivity for P53 protein. There was a statistically significant positive correlation (Fisher's exact test p<0.0148) between an increased number of P53-positive tumor cells and the appearance of recurrence. DISCUSSION: In the face of the uncertain postoperative behavior of ameloblastomas, the immunohistochemical verification of more than 10% P53-positive tumor cells may give a prognostic indication for a tendency to recurrence.

[Laser microdissection in the molecular oncology of prostate cancer]. / Lasermikrodissektion in der molekularen Onkologie des Prostatakarzinoms.

Nearly all diseases, including prostate cancer (PCA), occur in mixed tissues with different cell types interconnected by multiple interactions. Laser microdissection permits a separate analysis of specific cell types necessary to understand tumorigenesis. Microdissection can be combined with different molecular methods for analyses at the levels of the genome, the transcriptome or the proteome. With respect to the molecular pathogenesis of PCA, normal glands can be compared to preneoplasias, and these in turn to the carcinoma. Different malignancy grades, as well as intra- and extraprostatic tumor parts, can be specifically analysed and molecular markers of aggressiveness can be identified. The molecular signatures obtained provide the basis for functional studies. New prognostic markers and therapeutic targets can be expected from such approaches in the near future. A far reaching goal is the computer representation of multiple molecular components and their interactions, "E-cell in cyberspace", in which prognostic behaviour and therapeutic responsiveness can be approximately predicted.

The Ets-1 transcription factor is involved in the development and invasion of malignant melanoma.

The Ets-1 transcription factor plays a role in tumor vascularization and invasion by regulating expression of matrix-degrading proteases in endothelial cells and fibroblasts in the tumor stroma. During early embryogenesis, Ets-1 is expressed in migrating neural crest cells from which melanocytes arise. In the present study, we analyzed Ets-1 expression in various melanocytic lesions and investigated its functional importance in malignant melanomas. We found that Ets-1 was upregulated both in vivo and in vitro in malignant melanoma, compared to benign melanocytic lesions and to primary melanocytes. Assessment of DNA-binding and transactivation assays documented a strong Ets activity in melanoma cells. Using an antisense strategy, the expression and activity of Ets-1 were reduced in the melanoma cell line Mel Im. This correlated with a diminished expression of several Ets-1 target genes known to be involved in invasion, such as MMP1, MMP3, uPA and integrin beta3. In line with these findings, the invasive potential of the melanoma cells measured in a Boyden Chamber model was reduced up to 60% after Ets-1 blockade. This can be attributed to the role of Ets-1 in transcriptional regulation of factors involved in invasion of melanoma cells. We conclude that over-expression of Ets-1 during melanoma development contributes to the malignant phenotype.

GSTP1 hypermethylation as a molecular marker in the diagnosis of prostatic cancer: is there a correlation with clinical stage, Gleason grade, PSA value or age?

OBJECTIVES: Epigenetic events such as promoter hypermethylation have been implicated in prostate carcinogenesis. We present a real-time, methylation specific protocol to detect hypermethylation in the promoter region of the GSTP1 gene in benign hyperplasia and adenocarcinoma of the prostate. METHODS: In our preliminary study, 31 prostate cancer and 5 benign prostatic hyperplasia (BPH) tissue samples were analyzed. Genomic DNA was isolated from formalin-fixed and paraffin-embedded specimens and subjected to sodium bisulfite modification, followed by real-time, methylation specific PCR. Patients with prostatic cancer were also subdivided according to their Gleason score, PSA, age and TNM Staging. Prostate cancer cell lines (LNCaP, DU145, PC3) and a BPH cell line (BPH-1) were also tested as controls. RESULTS: GSTP1 promotor hypermethylation was detected in 28 of the 31 prostate cancer cases (90.3%) and none of the five (0%) BPH cases. Statistical analysis did not reveal a significant correlation between GSTP1 hypermethylation and Gleason score, PSA, age or TNM staging. All prostate cancer cell lines were testes positive for GSTP1 promotor hypermethylation, whereas the BPH cell line (BPH-1) was tested negative. CONCLUSION: GSTP1 promotor hypermethylation occurs during carcinogenesis and is considered to be a major event of prostate carcinogenesis. Our data support this thesis and shows that GSTP1 hypermethylation reliably distinguishes between prostate cancer and BPH . Although it is not yet clear at what time during carcinogenesis hypermethylation of the GSTP1 promotor occurs it seems to provide valuable information for prostate cancer screening and diagnosis. Larger studies are underway to determine the potential role for GSTP1 hypermethylation in clinical settings.

A method for the rapid construction of cRNA standard curves in quantitative real-time reverse transcription polymerase chain reaction.

Quantification of nucleic acids, especially of mRNA, is increasingly important in biomedical research. The recently developed quantitative real-time polymerase chain reaction (PCR) - a highly sensitive technology for the rapid, accurate and reproducible quantification of gene expression - offers major advantages over conventional quantitative PCR. Transcript quantification is performed in the exponential phase of the PCR reaction through extrapolation of fluorescence signals from a standard calibration curve which represents the initial copy number for a given fluorescence signal. We have developed a method for gene transcript quantification which is based on a LightCycler - assisted real-time PCR in combination with a simple and rapid approach for the construction of external cRNA standards with identical gene sequences as the target gene. Synthesis of cRNAs was performed by in vitro transcription with T7 RNA polymerase followed by reverse transcription and real-time PCR. We applied this approach for transcript quantification of eukaryotic initiation factor 3 p110 (EIF3S8) mRNA in normal testicular tissue. We also present a rapid and simple strategy for the construction of cRNA standards for use in real-time PCR.

Presence of genetic alterations in microdissected stroma of human colon and breast cancers.

BACKGROUND: Human carcinomas not only consist of neoplastic epithelial cells but also of tumor stroma, which may play an important role in tumor-progression. Whereas the tumor surrounding stroma is generally believed to represent a reactive component induced by tumor cell derived factors, a contribution of neoplastic cells to stroma formation via epithelium-mesenchyme transition during tumor invasion has become a novel concept in recent years. MATERIALS, METHODS AND RESULTS: We here show, by laser-assisted microdissection, that frequent genetic alterations in non-hereditary invasive human colon and breast cancers (loss of heterozygosity and TP53 mutations) occur not only in the neoplastic epithelial cells, but also in the adjacent fibroblastic stroma and that both components can share clonal features. CONCLUSION: Tumor cell-mesenchyme transitions are among the possible explanations for these findings and could actually occur during tumor invasion in vivo.

Implication of the proliferation and apoptosis associated CSE1L/CAS gene for breast cancer development.

The CSEIL/CAS protein (CAS) is a Ran-binding protein with a function as a nuclear transport (export) factor. CSEIL/CAS, similar to Ran and other ran-binding proteins, plays at the same time an important role in the mitotic spindle checkpoint, which assures genomic stability during cell division. This checkpoint is frequently disturbed in neoplasms of various origin, including breast, hepatic and colonic tumors. CAS is located on chromosome 20ql3 and amplified in several cell lines, including breast, colon and bladder cancer. MEKl phosphorylation is known to be a reason for different CAS localization and activity. We evaluated the expression of CAS in 50 benign and malignant tumors of the breast by immunohistochemistry. Benign lesions of the breast (n=13) revealed a weak, predominantly cytoplasmatic CAS positivity. In ductal and lobular in situ carcinomas (n=17), 70-90% of the tumor cells were positive for anti-CAS staining which was predominantly cytoplasmatic. In invasive ductal and lobular carcinomas (n =20), 70-90% of the tumor cells stained positive with anti-CAS in a predominantly nuclear pattern. Different localization of CAS might affect its role not only for chromosome segregation, proliferation and apoptosis, but also its function in nuclear transport of proteins like retinoblastoma-gene-product, p53 and BRCAl. A different regulation in this checkpoint might contribute to the invasive potential in malignant carcinomas of the breast. Alteration of CAS-activity, possibly via MEKl-inhibition, might therefore be a possible option for breast cancer therapy.

Downregulation of clusterin expression in testicular germ cell tumours.

OBJECTIVES: Clusterin is implicated in many biological processes including cell adhesion, apoptosis and transformation. Clusterin expression was demonstrated during sperm maturation and is overexpressed in different malignancies including breast and prostate carcinomas and anaplastic large-cell lymphomas. METHODS: The aim of this study was to determine the expression of clusterin in a series of different germ cell tumours by immunohistochemistry. Twenty-two seminomas, 27 embryonal carcinomas, 22 mature and immature teratomas, 8 yolk sac tumours and 1 chorion carcinoma as well as 30 normal testes were analysed using a monoclonal antibody. RESULTS: In normal testes strong signals were seen in the maturing germ cells and in Leydig cells. In most tumours examined no clusterin expression was detected (84%). Only a focal weak expression was seen in some teratomas (32%), embryonal carcinomas (15%) and yolk sac tumours (25%). CONCLUSIONS: Our results suggest that clusterin is associated with normal germ cell development and that the loss of clusterin expression might play a role in the malignant transformation of germ cells.

Invasive properties of serous human epithelial ovarian tumors are related to Ets-1, MMP-1 and MMP-9 expression.

The invasive potential of serous epithelial ovarian tumors is the main factor determining their biological behaviour. In contrast to invasive serous ovarian carcinomas serous borderline tumors generally present without stromal invasion and without or non-invading peritoneal implants. Little is known about the reasons underlying these differences. In the present study we found that two matrix-degrading metalloproteinases, collagenases 1 and 4 (MMPs 1 and 9), as well as the Ets-1 transcription factor are expressed at very low levels in serous benign cystadenomas, upregulated in the fibroblastic stroma, but not in the epithelium of borderline tumors and most strongly expressed in both stromal and epithelial tumor cells of serous invasive carcinomas. Since expression of Ets-1 and of MMPs 1 and 9 are topographically related, a transcriptional regulation of both proteases by Ets-1 is suggested. Upregulation of MMPs 1 and 9 within fibroblastic stromal cells of borderline tumors might be related to matrix remodelling and additional expression of both enzymes by the neoplastic cells of invasive carcinomas could then allow invasive propagation. The different expression patterns might supports the view, that no transition of serous borderline tumors into invasive carcinomas occurs.