Search results for "Proto-oncogene"
showing 10 items of 770 documents
Expression of Bax, a pro-apoptotic member of the Bcl-2 family, in esophageal squamous cell carcinoma
1997
Samples of normal esophageal squamous epithelium (n = 10), severe squamous cell dyplasia (n = 22), carcinoma in situ (n = 15), invasive squamous cell carcinoma (n = 172), lymph-node metastasis (n = 21) and 2 permanent esophageal squamous cell carcinoma cell lines were analyzed immunohistochemically for Bax expression using a polyclonal anti-Bax antibody. Immunostaining was evaluated according to a score system (0–8 points) based on the percentage of positive tumor cells and the relative immunostaining intensity. Cytoplasmatic staining for Bax protein was found uniformly in all cell layers of the normal esophageal squamous epithelium. In contrast, a gradual loss of immunoreactivity for Bax w…
Soft tissue Ewing's sarcoma. Characterization in established cultures and xenografts with evidence of a neuroectodermic phenotype.
1990
This study characterizes the histogenesis of soft tissue Ewing’s sarcoma (StEs) based upon an analysis of three tumors. Long-term cultured cell lines and nude mice xenografts were established from original neoplasms or from their metastases. Histologically they revealed a small round cell pattern without signs of differentiation. Several ultrastructural features of neural type were found; the same were also seen on culture cell lines. Moreover, immunohistochemical study for neural markers revealed the presence of HNK-1, NSE, LIRC-LON 36, S-100 protein, glial fibrillary acidic protein, neurofilaments (70 kilodaltons), and chromogranin; some of these markers were present only in the transplan…
Poorly differentiated synovial sarcoma: A case report
2001
Poorly differentiated synovial sarcoma is a rare soft tissue tumor. We studied a case arising in the pleural cavity of a young subject, characterised by the presence of spindle cell, small cell, and large epithelioid cell areas. We performed stains for mucosubstances and analysed the expression of cytokeratins 5/6, 7, 8, 18, 19, CEA, CD34, Ber-Ep4 and calretinin to characterize the phenotype of this neoplasm. We furthermore assessed immunohistochemically the presence of p53, Bcl-2, Bax and caspase 3, four apoptotic markers, to evaluate a relationship between apoptotic activity and the behaviour of this tumor. Our findings showed a strong presence of calretinin, p53 and Bcl-2 in all three ar…
BCL6: somatic mutations and expression in early-stage chronic lymphocytic leukemia
2009
BCL6 somatic mutations affect normal and tumoral post germinal center B-lymphocytes. Our objective was to analyse expression, mutations and polymorphisms in the BCL6 gene and to correlate those variables with the clinical outcome in early-stage chronic lymphocytic leukemia (CLL). CLL samples were used for characterisation of the mutational status of BCL6/ immunoglobulin variable heavy chain (IGHV) genes, and expression of BCL6 was determined by real time PCR and immunoblot. Out of 68 cases, 29% show somatic mutations on BCL6 which occur exclusively in IGHV mutated cases. They are single nucleotide substitutions located mainly in two short mutational hot spots. CLL cells express different le…
Bcl-2 as prognostic factor in head and neck squamous cell carcinoma
2005
A series of 66 cases of oral squamous cell carcinoma (OSCC) was retrospectively analyzed by immunohisto-chemistry for bcl-2 expression to verify its predictive value for clinical outcome in patients with OSCC. After grouping for bcl-2 expression, OSCCs were statistically analyzed for the variables age, gender, histological grading (G), TNM, staging, recurrence, and overall survival rate. Univariate and multivariate (Cox regression) analyses were performed. Thirty-six OSCC (54.5%) showed expression for bcl-2, whereas 30 (44.5%) were negative. No statistical association was found between bcl-2 expression and any variables considered at baseline. Overall disease-specific survival rate at 72 mo…
Germline and somatic mutations in the tyrosine kinase domain of the MET proto-oncogene in papillary renal carcinomas.
1998
Hereditary papillary renal carcinoma (HPRC) is a recently recognized form of inherited kidney cancer characterized by a predisposition to develop multiple, bilateral papillary renal tumours. The pattern of inheritance of HPRC is consistent with autosomal dominant transmission with reduced penetrance. HPRC is histologically and genetically distinct from two other causes of inherited renal carcinoma, von Hippel-Lindau disease (VHL) and the chromosome translocation (3;8). Malignant papillary renal carcinomas are characterized by trisomy of chromosomes 7, 16 and 17, and in men, by loss of the Y chromosome. Inherited and sporadic clear cell renal carcinomas are characterized by inactivation of b…
Alternative lengthening of telomeres--an enhanced chromosomal instability in aggressive non-MYCN amplified and telomere elongated neuroblastomas
2010
Telomere length alterations are known to cause genomic instability and influence clinical course in several tumor types, but have been little investigated in neuroblastoma (NB), one of the most common childhood tumors. In the present study, telomere-dependent chromosomal instability and telomere length were determined in six NB cell lines and fifty tumor biopsies. The alternative lengthening of telomeres (ALT) pathway was assayed by scoring ALT-associated promyelocytic leukemia (PML) bodies (APBs). We found a reduced probability of overall survival for tumors with increased telomere length compared to cases with reduced or unchanged telomere length. In non-MYCN amplified tumors, a reduced o…
Bcl-6 mutation status provides clinically valuable information in early-stage B-cell chronic lymphocytic leukemia
2004
In B-cell chronic lymphocytic leukemia (B-CLL), somatic mutation of IgVH genes defines a subgroup with favorable prognosis, whereas the absence of IgVH mutations is correlated with a worse outcome. Mutations of the BCL-6 gene are also observed in a subset of B-CLL, but the clinical significance of this molecular alteration remains uncertain. We examined the distribution of IgVH and BCL-6 gene mutations in 95 well-characterized patients with Binet stage A B-CLL, and correlated them with clinical, laboratory, cytogenetic findings and disease progression. Mutations of the BCL-6 gene were observed only in cases harboring mutated IgVH. Unexpectedly, coexistence of IgVH and BCL-6 mutations was co…
High concordance of KRAS status between primary colorectal tumors and related metastatic sites: implications for clinical practice.
2008
Abstract Purpose. Several studies have suggested that KRAS somatic mutations may predict resistance to cetuximab- and panitumumab-based treatments in metastatic colorectal cancer (CRC) patients. Nevertheless, most experiences were conducted on samples from primaries. The aim of this study was to evaluate the grade of concordance in terms of KRAS status between primaries and related metastases. Patients and Methods. We analyzed KRAS codon 12 and 13 mutations from formalin-fixed sections of 107 CRC primaries and related metastases. Eight pairs were excluded from the analysis because of the low amount of tumor tissue in the available samples. The main characteristics were: 50 men, 49 women; me…
Efficacy and safety of imatinib in adult patients with c-kit–positive acute myeloid leukemia
2004
Abstract This phase 2 pilot study was conducted to determine the efficacy and safety of imatinib mesylate in patients with c-kit–positive acute myeloid leukemia (AML) refractory to or not eligible for chemotherapy. Twenty-one patients were enrolled and received imatinib 600 mg orally once daily. Five responses were seen primarily in patients, starting with relatively low blast counts in bone marrow (BM) and peripheral blood (PB): 2 patients who were considered refractory on chemotherapy on the basis of persistence of blasts in PB and BM met the criteria for complete hematologic remission, 1 patient had no evidence of leukemia, and 2 patients achieved a minor response. Treatment with imatini…