Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Breast cancer is the most common malignant tumor among women, comprising an estimated 24% of all cancer cases and 18% of all cancer deaths. At least half of the patients with primary breast cancer will ultimately die by metastatic disease. The tumor characteristics, the natural course of the disease and the response to therapy vary strongly. A number of recently detected cell biological parameters such as oncogenes/suppressor genes, growth factors and secretory proteins are more or less important prognostic factors, because they influence the characteristics and behavior of a tumor with respect to metastatic pattern, extent of cellular differentiation, growth rate and response to treatment. However, there is no clear consensus how best to identify patients at high or low risk. In our experience c-myc amplification and pS2 protein are strong prognosticators for relapse rate, while in advanced disease (apart from a negative estrogen/progesterone receptor/pS2 status) amplification of HER2/neu is a good prognosticator for failure to endocrine therapy. In the diagnosis of breast cancer, in vivo imaging of tumors by labeled hormones or other factors also forms a new development which might have implications for treatment too. With respect to treatment both endocrine and chemotherapy can cure a minority of patients with micrometastases, but in patients with advanced disease only a prolongation of (progression-free) survival can be reached. Response rates decrease with increasing tumor load. In the past decade a number of interesting new endocrine agents has been developed such as new (pure) (anti)steroidal agents, vitamins, aromatase inhibitors, analogs of peptide hormones, prolactin inhibitors and growth factor antagonists. However, less is known on the (potential) interaction between hormones, chemotherapeutic agents, retinoids, cytokins, growth factor antagonists and irradiation. Rapid detection of new powerful combination therapies are needed to improve treatment results during the nineties.
 ...
PMID:Clinical breast cancer, new developments in selection and endocrine treatment of patients. 144 97

We examined 100 breast cancers for retinoblastoma (Rb) and p53 protein expression by immunohistochemistry using the PMG3.245 and PAb 1801 antibodies. We assessed percentages of reactive cells and their intensity, as well as staining patterns. The results were correlated with neu protein reactivity and a panel of variables, including age, tumor size and type, nuclear grade, estrogen receptor/progesterone receptor content, and lymph node status. Retinoblastoma protein negativity, either partial or complete, was noted in 47% of cases. Surprisingly, a relatively stronger Rb reaction was seen in some high nuclear grade tumors. p53 positivity was found in 23% of cases and was a significant predictor of Rb loss. p53 also was correlated with poorly differentiated (nuclear grade III) neoplasms and neu expression but not with negative ER status. Tissue distribution profiles for Rb-negative and p53-positive cells were variable in this series, with both uniform and heterogeneous patterns observed. This suggests that Rb and p53 alterations may represent early or late events in transformation. Our findings further implicate Rb and p53 derangements in mammary oncogenesis.
 ...
PMID:Retinoblastoma and p53 gene product expression in breast carcinoma: immunohistochemical analysis and clinicopathologic correlation. 146 76

Tumoral biological markers of breast cancer expand the predictive value of conventional prognostic factors, such as tumor size, axillary lymph node status, and histoprognostic grade. They include tumor estrogen and progesterone receptor levels, flow cytometric DNA analysis, to convey a prognostic value. Expression of the product of the gene pS2, which reflects the functional integrity of the estradiol receptor, indicates a good prognosis. In contrast, presence of growth factor receptors, such as the EGF receptor, or amplification of the HER2/neu or INT2 oncogene indicate a poor prognosis. Study of protein gp 170 and GST-pi predicts the response of tumors to chemotherapy, while the study of the potential doubling time (Tpot) provides an indication of the renewal capacity of the tumor. Markers of tumor invasiveness and metastatic potential include proteases (activators and inhibitors) produced either by tumor cells or by the cells of the stroma, gene nm 23, and membrane fatty acids. The place of the last markers in patients' treatment is not known yet. The knowledge of the tumor biological parameters along with clinical features should provide an accurate prediction of the aggressiveness of the tumor, allowing the best adjustment of treatment with the expected behavior of the disease.
 ...
PMID:[Intratumoral biological markers in breast cancers]. 148 91

The accumulation of genetic damage in the forms of activated proto-oncogenes and inactivated tumor-suppressor genes is the driving force in the evolution of a normal cell to a malignant cell. For example, both the activation of ras oncogenes and the inactivation of several suppressor genes, including p53, have been observed in the development of human colon and lung tumors. Point mutations in key codons can activate ras proto-oncogenes and inactivate the p53 suppressor gene. Thus, several critical genes for tumorigenesis are potential targets for carcinogens and radiation that can induce point mutations at low doses. The ras proto-oncogenes are targets for many genotoxic carcinogens. Activation of the ras gene is an early event--probably the "initiating" step--in the development of many chemical-induced rodent tumors. ras Oncogenes are observed in more human tumors and at a higher frequency than any other oncogene, and activation of the proto-oncogene may occur at various stages of the carcinogenic process. Numerous proto-oncogenes other than the ras genes have been shown to be activated in human tumors and to a lesser extent in rodent tumors. Mechanisms that induce aberrant expression of proto-oncogenes are gene amplification and chromosomal translocation or gene rearrangement. Amplification of proto-oncogenes and possibly gene overexpression during the absence of gene amplification occur in the development of many human tumors. For a specific tumor type, amplification of any one proto-oncogene may occur at a low frequency, but the frequency of tumors in which at least one proto-oncogene is amplified can be much higher. Proto-oncogene amplification is usually associated with late stages of tumor progression; however, amplified HER2/neu has been observed in early clinical stages of mammary neoplasia. Activation of proto-oncogenes by chromosomal translocation has been detected at a high frequency in several hematopoietic tumors. Non-ras genes have been detected by DNA transfection assays in both human and rodent tumors. For example, ret and trk genes were found to be activated by gene rearrangements in human papillary thyroid carcinomas. Several potentially new types of oncogenes have also been detected by DNA transfection assays. The etiology of the genetic alterations observed in most human tumors is unclear at present. Examples of ras gene activation and those documented for mutations in the p53 gene demonstrate that exogenous conditions can induce oncogenic mutants of normal genes. The genetic alterations observed in most human tumors are probably generated by both spontaneous events and exogenous conditions.
 ...
PMID:Role of proto-oncogene activation in carcinogenesis. 148 40

Amplification and rearrangement of cellular proto-oncogenes are two of the several possible genetic alterations implicated in carcinogenesis and tumor progression. Although morphologically similar tumors may be heterogeneous at the level of the genome, some tumor types have shown relatively frequent and consistent abnormalities of specific oncogenes. In order to determine the frequency of oncogene amplification and rearrangement in several types of human sarcomas and to determine if histologically similar tumors have common genetic alterations, we analyzed 26 primary sarcomas by Southern hybridization. The oncogene probes utilized were N- and H-ras, sis, EGF-R (erb-B-1), neu (erb-B-2), fos, N- and c-myc, mos, and yes. The tumors studied included: five rhabdomyosarcomas (one alveolar, four embryonal), six malignant fibrous histiocytomas, six leiomyosarcomas, four liposarcomas, two Ewing's sarcomas, one osteosarcoma, and two fibrosarcomas. Oncogene abnormalities were identified in three tumors. One rhabdomyosarcoma showed 12-fold amplification and concurrent rearrangement of sis. This particular tumor also revealed rearrangement of H-ras and 15-fold amplification of c-myc. A second rhabdomyosarcoma revealed rearrangement of neu. A liposarcoma had a sis rearrangement. These findings suggest that many sarcomas show no common structural oncogene abnormalities. The presence of differing oncogene alterations within the rhabdomyosarcoma group indicates genetic heterogeneity among histologically similar sarcomas. The finding of a sis rearrangement in both a liposarcoma and a rhabdomyosarcoma, however, may suggest common oncogenesis among different tumor types.
 ...
PMID:Genomic alterations in sarcomas: a histologic correlative study with use of oncogene panels. 149 46

Immunocytochemical assays were performed on cell cultures as well as on a wide range of human tissues using a monoclonal antibody, MAb 83D4, produced by a murine hybridoma generated by immunization with a cell suspension from a paraffin block of human breast carcinoma tissue. Frozen breast tissue samples (n = 49) were compared to fixed and paraffin-embedded samples (n = 62). Paraffin sections (n = 194) from a variety of human tissues were compared to breast immunoreactivity. Immunoprecipitates, resulting from positive reactions between 83D4 and Avidin Biotin Peroxidase, were evaluated by computer-assisted microcytophotometry (SAMBA). In some frozen breast samples (n = 27), 83D4 antigen distribution was correlated with tumor cell DNA index, ploidy balance, growth fraction (Ki67), hormone receptor (ER, PR) antigenic sites, NORsAg and oncoprotein pHER-2/neu cell content. MAb 83D4 reacted with 3 breast cancer cells lines (MCF7, T47D and H466B) but not with normal epithelial breast cells in culture. The immunostaining in frozen paraffin sections from breast were similar. Like most normal tissues, normal breast did not react with 83D4. Cellular MAb 83D4 antigen concentration increases with the degree of malignancy but is independent of DNA nuclear content, ER, PR, growth fraction and pHER-2neu in cancers. These results suggested that routine immunohistochemical procedures using MAb 83D4 could facilitate the grading of breast cancer, in particular by allowing detection of microvascular invasions in the breast as well as at a distance and of blood-born micrometastases, especially in bone marrow.
 ...
PMID:Monoclonal antibody 83D4 immunoreactivity in human tissues: cellular distribution and microcytophotometric analysis of immunoprecipitates on tissue sections. 156 69

Analysis of epidermal growth factor receptor (EGFr) and estrogen receptor (ER) was performed on tumor samples from 231 patients with operable breast cancer followed for up to 6 years after surgery. The median duration of follow-up in patients still alive at the time of analysis was 45 months. Thirty-five percent of patients (82) had tumors greater than 10 fmol/mg of 125I-EGF binding (EGFr+) and 47% (109) had cystolic ER concentration greater than 5 fmol/mg (ER+), with a marked inverse relationship between EGFr and ER (P less than .00001). EGFr was second only to axillary-node status as a prognostic marker for all patients in terms of both relapse-free and overall survival in univariate analysis (P less than .001, log-rank EGFr + v EGFr-). For patients with histologically negative axillary nodes, EGFr was superior to ER in predicting relapse and survival (P less than .01 and P less than .005, respectively, compared to P less than .1 and P less than .1, log-rank). In a multivariate (Cox model) analysis, only EGFr--out of EGFr, ER, size, and grade--was predictive for either relapse-free or overall survival for patients with node-negative disease (P = .052 and P = .026, respectively). One hundred eighty-seven case patients in the series were assessed for neu expression immunochemically, and 31 were positive. There was a highly significant increased risk of relapse and death in the positive group. In patients with otherwise good prognostic markers (ER+, node-negative, well-differentiated tumors), neu expression predicted for significantly worsened overall survival.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Epidermal growth factor receptor and other oncogenes as prognostic markers. 162 26

Normal tissues, primary tumors, and metastases of mammary and salivary glands and oral/laryngeal mucosa have been analyzed with Northern-blots employing 32P-labeled RNA probes for the expression of the neu oncogene. Neu oncogene expression of a mRNA species of 4.6 kilobases was found in all normal salivary (five) and mammary glands (four) as well as in two normal or inflamed samples of tongue mucosa. This expression was regarded as baseline activity of the neu gene for the respective tissues and was used as standard for the evaluation of benign and malignant tumors. None of 14 squamous cell carcinomas of the oral and laryngeal mucosa showed enhanced neu transcription level. Five fibroadenomas, one benign variant of phylloid tumor, one carcinosarcoma, and one of two proliferative fibrocystic diseases of the breast showed lacking or normal baseline expression of the neu oncogene, as did one monomorphous cystadenolymphoma of the parotid gland. In contrast, four parotid pleomorphic adenomas and one salivary gland adenocarcinoma showed enhanced neu expression. For mammary adenocarcinomas, increased neu oncogene expression concerned ten of 34 cases--all being variants of ductal carcinomas--and all metastases analyzed (six) deriving from three primaries. One adenoid cystic carcinoma also showed enhanced neu expression. Neu overexpression may reflect accidents of genomic reconstitutional events occurring regularly within the differentiation pathway of epithelial/myoepithelial cells. This assumption was supported by further immunohistochemical analysis which showed stainings of myoepithelial and myoepithelia-like cell populations in tumors, especially pleomorphic adenomas and adjacent normal-looking tissues.
 ...
PMID:Comparative investigation of c-erbB2/neu expression in head and neck tumors and mammary cancer. 167 62

Four human ovarian and breast tumor lines expressing the HER2/neu oncogene were resistant to the cytotoxic and DNA-degradative activity of TNF. The resistance was not associated with altered TNF receptor function because Scatchard analysis of 125I-rTNF binding to HER2/neu-expressing target cells revealed receptors with normal binding parameters. Furthermore, the TNF receptors on the resistant lines were capable of signal transduction as evidence by the induction of ADP-ribose polymerase activity and MHC expression. TNF resistance was not reversed by coincubation with drugs that interrupted the glutathione redox cycle. In addition, although coincubation of HER2/neu-expressing targets with cycloheximide resulted in significant TNF-induced lysis, when compared to HER2/neu-nonexpressing targets similarly treated with cycloheximide, a significant relative resistance was still present. To investigate the role of ADP-ribosylation in the resistance of these targets, we used nontoxic concentrations of two inhibitors of ADP-ribose polymerase, 3-aminobenzamide, and nicotinamide. Both inhibitors completely reversed the resistance of HER2/neu-expressing targets to TNF-mediated cytotoxicity and DNA injury in a concentration-dependent fashion. These inhibitors of ADP-ribose polymerase did not act by down-regulating expression of HER2/neu oncogenes. In contrast, aminobenzamide and nicotinamide significantly diminished TNF-induced cytotoxicity of L929 targets. These data suggest that the activity of ADP-ribose polymerase may play a pivotal role in determining the fate of the target cell during exposure to TNF.
 ...
PMID:Inhibitors of ADP-ribose polymerase decrease the resistance of HER2/neu-expressing cancer cells to the cytotoxic effects of tumor necrosis factor. 167 41

In order to obtain further information on the biological role of the HER2/neu oncoprotein monoclonal antibodies (MAbs) were produced against the p185 extracellular domain. To immunize the mice and screen the hybridoma supernatants we selected a lung adenocarcinoma cell line (Calu-3), which demonstrated an over-expression of p185HER2 measured as the reactivity with polyclonal rabbit serum to the 14-amino-acid carboxy-terminal-HER2/neu. Two MAbs, designated MGR2 (IgG1) and MGR3 (IgG2), selected for reactivity on Calu-3 and negativity on A43I live cells, the reference target cell for EGF receptor expression, were found to immunoprecipitate a 185-kDa molecule. Immunodepletion experiments with the polyclonal antiserum and cross-competition experiments indicated that the 2 reagents recognized 2 different epitopes located on the p185HER2 molecule. One of the 2 MAbs, MGR3, was found to internalize, induce p185HER2 phosphorylation and inhibit tumor cell growth in vitro. These results indicate that MGR3 is directed against a determinant located in the p185HER2 ligand binding site and may compete with the p185HER2 ligand, but is incapable of inducing a complete mitotic signal.
 ...
PMID:Selection of monoclonal antibodies which induce internalization and phosphorylation of p185HER2 and growth inhibition of cells with HER2/NEU gene amplification. 167 68


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>