Biomedical subjects

C Poremba

Publications and source records attributed to C Poremba.

63 records · Page 4Linked to original sources

PubMed1995

Adenocarcinoma of the cardia in a young man: detection of somatic p53 mutation by immunohistochemistry and automated direct sequencing.

We describe the unusual case of early-onset adenocarcinoma of the cardia in a 22-year-old male. The patient died within less than one year after diagnosis was established. By immunohistochemistry, p53 expression was observed in the tumor cells. Automated direct sequencing of polymerase chain reaction (PCR) amplified DNA revealed a homozygous transition in p53 codon 280 (AGA to GGA) as the molecular basis of p53 accumulation. Previous studies suggest that gastric carcinomas with mutations in the p53 tumor-suppressor gene are associated with particularly poor prognosis when compared with tumors without p53 mutations. Since carriers of p53 mutations in the germline have a 50 percent likelihood of developing cancer before the age of 30, we examined tumor-free tissue for the presence of a germline mutation in codon 280, but none was found.

Adenocarcinoma↗

PubMed1995

Translocation of gliadin into HLA-DR antigen containing lysosomes in coeliac disease enterocytes.

Coeliac disease is triggered by ingestion of wheat gliadin and is probably immune mediated. There is evidence by light microscopy that expression of class II major histocompatibility complex (MHC) molecules is increased in the small intestinal epithelium of patients with untreated coeliac disease and that gliadin can be taken up by small intestinal enterocytes. The pathway by which gliadin is transported to class II MHC proteins has not been demonstrated. Using an immunogold technique and thin frozen sections of jejunal biopsy specimens, gliadin, HLA-DR antigens, and IgA were localised at an ultrastructural level in the jejunal epithelium of patients with both untreated and treated coeliac disease and controls. Cathepsin D was used as a marker for late endosomes or lysosomes. The results show that gliadin is translocated into vacuoles positive for HLA-DR antigens as well as cathepsin D in jejunal enterocytes of patients with untreated coeliac disease. Secretory IgA may have a role in this translocation of gliadin, which is a specific event that occurred only in jejunal enterocytes from patients with untreated coeliac disease but not in a patient maintained on a gluten free diet or in controls. These results support a central role for epithelial cells of the human intestinal mucosa in the transport of gliadin to an HLA-DR positive compartment which precedes antigen presentation of gliadin to antigen sensitive T lymphocytes.

Antigen Presentation↗

PubMed1995

Immunohistochemical detection of p53 in melanomas with rare p53 gene mutations is associated with mdm-2 overexpression.

Expression of mutant p53 detected by immunohistochemistry has been described in human malignant melanoma, but there are few reports of molecular analyses. To investigate the genetic basis for p53 expression in malignant melanoma, we examined 58 primary tumors and 5 cutaneous metastases. The entire coding sequence of the p53 gene was screened by single-strand conformation polymorphism analysis and direct genomic sequencing of polymerase chain reaction products. p53 and mdm-2 expression were studied by immunohistochemistry. Two p53 gene mutations could be found in 1/63 samples examined, both having occurred in the same specimen from a patient with a nodular melanoma. p53 and mdm-2 expression were found immunohistochemically to increase with tumor progression both in frequency and in the mean proportion of positive cells, with the same cases staining positively for both antibodies. Our results suggest that a) p53 gene mutations are a rare event in human melanoma; b) accumulation and thus immunohistochemically detectable expression of p53 may result from posttranslational mechanisms affecting the p53 gene product; and c) p53 and mdm-2 are more important in late events in melanoma carcinogenesis.

Base Sequence↗

PubMed1994

Rapid detection of loss of heterozygosity of chromosome 17p by polymerase chain reaction-based variable number of tandem repeat analysis and detection of single-strand conformation polymorphism of intragenic p53 polymorphisms.

Intragenic restriction site polymorphisms in amino acid residue 72 in exon 4 and a Mspl polymorphism in intron 6 of the p53 tumour suppressor gene can both serve as polymorphic markers. Probe YNZ22 (D17S5) is a highly polymorphic, variable number of tandem repeat (VNTR) marker which maps to chromosome 17p13.1 where the p53 gene is located. Locus specific amplification by polymerase chain reaction (PCR) technique and subsequent non-isotopic single-strand conformation polymorphism analysis of the PCR fragments was used for the detection of loss heterozygosity (LOH) of 17p including the p53 gene locus. In combination with a PCR-based method for the analysis of the VNTR locus D17S5 using unique sequences flanking the polymorphic region of YNZ22 we investigated tumour DNA and corresponding constitutional DNA from 69 patients, including 39 patients with gastric cancer, 21 patients with osteosarcomas and 9 patients with Ewing's sarcomas. Using all three methods, 49/69 (71%) patients were informative for LOH, which revealed allelic loss in 5/39 (12.8%) gastric cancers, 1/9 (11.1%) Ewing's sarcoma, and 4/20 (20%) osteosarcomas.

Base Sequence↗

PubMed1994

[Hypervariable regions (HVR) as genetic markers in tumor diagnosis. Methodological principles and their use in pathologic diagnosis].

Variable number tandem repeats (VNTR) are highly polymorphic DNA sequences which can be used as genetic markers in different fields of medicine. In this report, we describe the methodology of VNTR in diagnostic molecular pathology, using a rapid, DNA-based approach involving polymerase chain reaction (PCR) amplification and electrophoresis of highly polymorphic DNA satellite sequences. As concrete examples of the application of this approach, we present two case reports: 1. A B-cell lymphoma of the porta hepatis developed in a 54-year-old man 4.5 months after orthotopic liver transplantation for liver failure due to chronic hepatitis C infection. Using DNA polymorphisms as genetic markers, we showed that the tumor was of donor origin. This finding may be important for the patient's subsequent management. 2. An immature teratoma of the left ovary was found during delivery by cesarean section in a 27-year-old woman. The female newborn survived for 9 weeks and then died from central dysregulation because of an intracranial immature teratoma. Because the synchronous tumors were of similar histology, clonal origin in maternal tissues and metastatic spread were initially suspected. Analysis of highly polymorphic DNA markers clearly indicated that the teratoma carried by the child was of independent genetic origin from the mother's tumor.

Brain↗

PubMed1993

[Androgen receptor gene mutations and p53 gene analysis in advanced prostate cancer].

One of the most interesting but still unsolved issues in prostate cancer is the role of androgens, the androgen receptor (AR) and the p53 tumor suppressor gene in the development and/or progression of prostatic neoplasia. DNA obtained from prostate tissues of 7 normal donors, 5 BPH and 10 adenocarcinomas at different stages was amplified by the polymerase-chain-reaction (PCR). The products were analysed by single strand conformation polymorphism (SSCP), and by direct sequencing of those that displayed altered electrophoretic behavior. The molecular analysis of exons 1 to 8 of the AR gene revealed point mutations in codons 340 (exon 1) and 798 (exon 6) in 2/10 prostate carcinomas. No mutations were found in the p53 gene. Our findings suggest that mutations of the AR gene are relatively frequent in prostate cancer and may have therapeutical significance.

Base Sequence↗

PubMed1993

Immature teratomas of different origin carried by a pregnant mother and her fetus.

We describe the case of a pregnant mother and her fetus who both carried teratomas during the pregnancy. The fetus was diagnosed at 38 weeks' gestation to have an intracranial mass, which was later determined to be an immature teratoma. During a cesarean section delivery, an ovarian tumor was found in the 27-year-old mother that was also diagnosed to be an immature teratoma. Because of the similar histology of the tumors carried by both mother and child, a single clonal origin was suspected. Using polymerase chain reaction (PCR) and electrophoresis of highly polymorphic DNA satellite sequences, we determined that the origin of the intracranial teratoma carried by the child was independent of the mother's tumor. We also examined the p53 tumor suppressor gene in constitutional cells from both mother and child for the possible presence of a cancer-predisposing inherited mutation, but none was found. To our knowledge, this is the first report of the simultaneous occurrence of independent malignant immature teratomas in a mother and child during pregnancy.

Adult↗

PubMedDate not supplied

Traditional and emerging molecular markers in neuroblastoma prognosis: the good, the bad and the ugly.

BACKGROUND: Neuroblastomas (NB) are a heterogeneous group of childhood tumours with a wide range of likelihood for tumour progression. As traditional parameters do not ensure completely accurate prognostic grouping, new molecular markers are needed for assessing the individual patient's prognosis more precisely. PATIENTS AND METHODS: 133 NB of all stages were analysed in blind-trial fashion for telomerase activity (TA), expression of surviving, and MYCN status. These data were correlated with other traditional prognostic indicators and disease outcome. RESULTS AND CONCLUSIONS: TA is a powerful independent prognostic marker for all stages and is capable of differentiating between good and poor outcome in putative "favourable" clinical or biological subgroups of NB patients. High surviving expression is associated with an adverse outcome, but is more difficult to interprete than TA because survivin expression needs to be accurately quantified to be of predictive value. We propose an extended progression model for NB including emerging prognostic markers, with emphasis on telomerase activity.

Biomarkers, Tumor↗

PubMedDate not supplied

Comparison of p53 immunoexpression with allelic loss of p53 in ulcerative colitis-associated dysplasia and carcinoma.

We correlated p53 overexpression with allelic deletion of p53 in ulcerative colitis (UC) with high grade dysplasia (HGD, n=12) and carcinoma (CA, n=8). Sections were immunostained against p53 and epithelium was microdissected on consecutive sections with subsequent amplification for LOH of p53 (17p). Staining with anti-p53 was positive in HGD (9 of 12) and CA (7 of 8). Percent positive cells were less in HGD than in CA. LOH of p53 was present in HGD (5 of 12) and CA (5 of 7). Of cases with <10% of positive cells, including negative cases, 50% also showed LOH. These results suggest that most cases with prominent p53 overexpression but also significant numbers of cases with weak or negative expression have associated allelic p53 deletion. We conclude that i) immunohistochemical stains but not LOH for p53 correlate with progression of dysplasia to carcinoma, ii) p53 immunohistochemistry appears to more accurately predict biologic behavior of dysplasia and carcinoma in UC compared to allelic deletion studies alone. Further microdissection studies are necessary to evaluate the possibility of different carcinoma risk in patients with low percentage of p53 overexpression and associated LOH.

Adenocarcinoma↗