Ilka Ruschenburg

POINT MUTATIONS AND NUCLEOTIDE INSERTIONS IN THE MDM2 ZINC FINGER STRUCTURE OF HUMAN TUMOURS

This study investigates the human oncoprotein MDM2, which interferes with regulation of cell division and apoptosis. Fifteen mixed–type follicular non‐Hodgkins lymphomas, ten leukaemias, two hepatocellular carcinomas, one osteosarcoma, and ten normal cell lines (fibroblasts, osteoblasts, mesothelium, peripheral lymphocytes) were tested for MDM2 expression and MDM2 gene mutation by reverse transcriptase‐polymerase chain reaction (RT‐PCR), immunocytochemistry, and nucleotide sequence analysis. Two follicular lymphomas, three leukaemias, both hepatocellular carcinomas, and the osteosarcoma sample showed transcription of the activated MDM2 gene. These samples lacked amplified MDM2 genes and carried mis‐sense, non‐sense and frame‐shift mutations in a zinc finger region of MDM2, altering the amino acid sequence or causing premature termination of transcription. The mis‐sense mutations were found in tumour cells that showed significant accumulation of MDM2 and lack of nuclear p53. Non‐sense mutations and frame‐shift mutations were found in tumours lacking MDM2 proteins. The mutations may affect the biological properties of MDM2 proteins.

Decrease in glucokinase and glucose-6-phosphatase and increase in hexokinase in putative preneoplastic lesions of rat liver.

SummaryPreneoplastic liver lesions were produced in female Wistar rats by oral administration of 2-acetyl-aminofluorene for 165 days succeeded by a carcinogen-free standard diet up to 420 days. During the treatment numerous altered hepatic foci (AHF) and hyperplastic nodules (HN) were detected histochemically by a focal decrease or lack of adenosine-5-triphosphatase and glucose-6-phosphatase (G-6-Pase) activities. In addition, the immunohistochemically demosntrable amount of L-type pyruvate kinase was clearly reduced. The histochemically demonstrated decrease of G-6-Pase was substantiated by microbiochemical determination of the enzyme activity in microdissected material. Moreover, during the experimental period a continuous decrease in glucokinase and an increase in hexokinase was detected microbiochemically within AHF and HN. These alterations indicate, a shift in the carbohydrate metabolism from gluconeogenesis to glucose utilization and pentose-phosphate-pathway for biosynthesis of nucleic acids. Beside other oncofetal markers, HK may be used as indicator of the early stages of liver carcinogenesis.

The Value of Anti-Calretinin Antibody in the Differential Diagnosis of Normal and Reactive Mesothelia versus Metastatic Tumors in Effusion Cytology

In effusion cytology the distinction of reactive mesothelia from metastatic carcinoma cells may be a diagnostic challenge. Immunocytochemistry using antibodies suitable to detect epithelial cells must be considered carefully due to limited sensitivity and specificity of these antibodies. Efficient results in histological differential diagnosis of malignant mesothelioma versus lung-adenocarcinoma applying a novel antiserum against the calcium binding protein calretinin inspirated us to investigate the value of anti-calretinin antibody in effusion cytology combined with an epithelial marker. Cytoslides prepared by cytocentrifugation from 42 malignant and 65 reactive effusion specimens were immunostained using antibodies against calretinin and the epithelial marker Ber-EP4. Positive immunoreaction for calretinin in normal and reactive mesothelial cells was noted in 93% of the cases, whereas immunoreaction for calretinin was completely negative in the metastatic cells in 95% of the malignant effusions. Metastatic carcinoma cells were detected with anti-Ber-EP4 in 83% of malignant effusions. Non-specific positive reactions for Ber-EP4 in single mesothelial cells were observed in 16% of all cases and, moreover, frequently with macrophages or neutrophilic granulocytes. Our results demonstrate high sensitivity and specificity of anti-calretinin antibody for mesothelial cells in effusion specimens. They support its application to improve the diagnostic reliability of epithelial markers, especially because anti-calretinin antibody could be helpful in the assessment of false positive and false negative reactions of epithelial markers.

The sentinel lymph node concept

From the contents: General Part: Definition and Basic Principles Main Techniques of Sentinel Lymph Node Labeling Different Aspects on Type and Localization of the Primary Basic Strategies in Sentinel Node Detection and Verification of Cancer Metastasis into the Regional Node PET: Significance for Preoperative N-Staging Detection and Radiological Imaging of SLN Lymphatic Drainage to the SLN.- Special Part: The Sentinel Lymph Node Concept Related to Main Tumor Types and Subtypes, Applicability in Daily Routine Work: Breast Cancer Thyroid Cancer Cancers of the Face, Nose Pharynx, and Oral Cavity Lung Cancer Malignant Melanoma Esophageal and Gastrointestinal Cancer SLN Staging in Carcinoide and Neuroendocrine Tumors The Sentinel Lymph Node Concept in Cancers of the Female Genitalia Cancers of the Male Genitalia Prostate Cancer: an Overview Cancers of the Urinary Tract Closing Remarks Therapy Regimens Used in Adjuvant and Neoadjuvant Treatment of the Tumor Types Discussed.

Downregulation of the Retinoblastoma Gene Expression in the Progression of Malignant Melanoma

The retinoblastoma gene is a cell cycle regulator preventing cells from entering into S-phase. An altered expression of the retinoblastoma gene has been reported in the majority of human malignancies. The main aim of this study was to investigate retinoblastoma gene expression in the full spectrum of melanoma progression from naevus to melanoma metastases by applying immunohistochemistry and RT-PCR. All naevi with and without dysplasia showed high expression of the retinoblastoma gene. In primary melanomas, Rb-positive cells were found in 82 out of 106. Loss of expression correlated with an increase in Clark level and shorter survival rates. An independent prognostic role of the retinoblastoma gene was confirmed by Cox multivariate analyses (p < 0.01). In melanoma metastases, retinoblastoma gene expression (at the RNA level) was found in 18 out of 26 melanoma lymphatic metastases, and in 2 out of 5 liver metastases. Our results indicate a downregulation of the retinoblastoma gene in the progression of melanocytic tumours.

Reverse transcriptase polymerase chain reaction for detecting Ewing's sarcoma in archival fine needle aspiration biopsies

OBJECTIVE Previous studies on pediatric soft tissue sarcomas have demonstrated a chromosomal 11;22 (q24;q12) translocation in Ewings sarcoma (ES) and peripheral primitive neuroectodermal tumors that appears to be a unique oncogenic marker. To investigate the usefulness of reverse transcriptase polymerase chain reaction (RT-PCR) as an ancillary method for cytodiagnosis, we tested archival aspirates derived from ES patients to establish whether any beta-actin RNA expression or tumor-specific EWS/FLI-1 gene translocation had occurred. STUDY DESIGN Sixteen skeletal specimens aspirated 10-15 years earlier from patients with cytologic and histologic diagnoses of ES were prepared for PCR. The amplification products were sequenced. RESULTS Amplifiable RNA was detected in smears from 12 patients by beta-actin RT-PCR. Seven aspirates from beta-actin-positive patients showed ES-specific genomic translocation (58%). Sequence analysis of the resulting PCR fragments revealed EWS/FLI-1 fusion transcriptions of varying length. CONCLUSION When RNA was retrievable, RT-PCR applied to routinely stained aspirate smears was a highly specific method in differential diagnosis of ES.

Borderline Tumors of the Ovary : A Clinico-Pathologic and Immunohistochemical Study of 54 Cases

Objective:To study EGF‐R, HER‐2/neu (p185), p53, Mib‐1 (Ki‐67), Bax, Bcl‐2, ras expression and ploidy in borderline tumors of the ovary by assessing their frequency, and relationship to histologic type, tumor recurrence and survival.

Relation between DNA ploidy status and the expression of the DNA‐mismatch repair genes MLH1 and MSH2 in cytological specimens of melanoma lymph node and liver metastases

DNA‐mismatch repair is essential for preventing genetic instability, and its important protective role has been demonstrated in several tumors. The main aim of this study was to investigate the expression of MLH1 and MSH2 (on the RNA level) in melanoma liver and lymph node metastases, and to define the relation between DNA ploidy status and mismatch repair gene expression.