Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several mechanisms of resistance to chemotherapy have been identified among the agents that are commonly used in the systemic treatment of patients with esophageal cancer: paclitaxel, platinum, and 5-FU. A recent study from our laboratory evaluated the initial endoscopic biopsy material from patients who subsequently underwent trimodality therapy, including chemotherapy with cisplatin and 5-FU, radiation therapy, and surgery. IHC analysis was performed on seven markers of chemotherapy or radiation therapy resistance: P-gp, GST-pi, MT (platinum inhibitors); EGF-R, TGF-alpha, erb-B2 (activation of cell growth cascade); and p53 (interferes with chemotherapy-induced apoptosis). In this study, elevated expression of GST-pi and P-gp were associated with decreased survival and may be markers of treatment resistance. Expression of erb-B2 was associated with enhanced survival and may be a marker of treatment sensitivity. Assessment of the probability of chemoresistance of a particular tumor using the expression of molecular biologic markers may allow for the selection of a more favorable chemotherapeutic agent. Furthermore, understanding the mechanisms of resistance, including the mechanisms of DNA repair, may provide insight into mechanisms to reverse or to inhibit resistance to chemotherapy. DNA repair mechanisms are used by cells to protect themselves against mutagens and carcinogens. DNA repair inhibitors may increase the mutagenicity associated with DNA damage and may prove to be an ineffective oncologic treatment strategy; however, the possibility exists that DNA repair inhibition may improve the efficacy of anticancer agents, and this should be tested. The value of this strategy may be in allowing treatment doses to be decreased and lessening side effects while maintaining therapeutic efficacy.
 ...
PMID:Molecular biology of esophageal cancer. 1096 50

Pancreatic ductal adenocarcinoma (PDAC) presently has an incidence of approximately 8 to 10 cases per 100,000 citizens in European countries, and the incidence has been increasing throughout the last decades. Approximately 30,000 patients die every year from PDAC in Western Europe and most of the newly diagnosed patients present with an already unresectable tumor stage. Self-sufficiency in growth signals, insensitivity to antigrowth signals, and evasion of apoptosis are hallmarks of malignant growth. In PDAC a variety of growth factors are expressed at increased levels. For example, the concomitant presence of the EGF-receptor and its ligands EGF, TGF-alpha, and/or amphiregulin is associated with enhanced tumor aggressiveness and shorter survival periods following tumor resection. In addition, PDACs often exhibit alterations in growth inhibitory pathways such as Smad4 mutations and Smad6 and Smad7 overexpression, and evade apoptosis through p53 mutations and aberrant expression of apoptosis regulating genes such as members of the Bcl family. Taken together, the abundance of growth promoting factors and the disturbance of growth inhibitory and apoptotic pathways give pancreatic cancer cells a distinct growth advantage which clinically results in rapid tumor progression and poor survival prognosis.
 ...
PMID:Pancreatic cancer--new aspects of molecular biology research. 1107 87

Epidermal growth factor receptor (EGF-R) and its ligand, transforming growth factor-alpha (TGF-alpha), play an important role through the autocrine growth-regulation system in several human cancers, including breast cancer. However, the clinical significance of co-expression of EGF-R and TGF-alpha has not been elucidated. One hundred seventy-three female patients diagnosed as invasive ductal carcinoma who had undergone a mastectomy (159 patients) or breast-conserving surgery (14 patients) were followed up for 81 to 119 months (median 94 months) post-operatively. Immunoreactivity for EGF-R, TGF-alpha, p53 and c-erbB-2 with paraffin-embedded carcinoma tissue was investigated using labeled streptavidin-biotin methods. Positive rates of carcinoma cells were 27%, 33%, 32% and 26% for EGF-R, TGF-alpha, p53 and c-erbB-2, respectively. Expression of EGF-R only was observed in 16% (28/173), of TGF-alpha only in 22% (38/173), of both EGF-R and TGF-alpha in 11% (19/173) and of neither in 51% (88/173). By univariate analysis, significant differences in overall survival and disease-free survival were noted according to the co-expression of EGF-R and TGF-alpha (p< 0.0001, p<0.0001), co-expression of EGF-R and c-erbB-2 (p = 0.0029, p = 0.0028), nodal status (p = 0.0028, p = 0.0001), tumor size (p = 0.0001, p<0.0001) and c-erbB-2 expression (p = 0.0034, p = 0.018), respectively. The status of p53 expression (p = 0.01), estrogen receptor (p = 0.042) and progesterone receptor (p = 0.046) showed significant differences in overall survival. According to Cox's multivariate analysis, co-expression of EGF-R and TGF-alpha had the most significant effect on disease-free survival (p<0.0001) and overall survival (p<0.0001), followed by nodal status. Co-expression of EGF-R and TGF-alpha by immunohistochemical detection is an independent prognostic indicator, and it may be helpful for determining the group of breast-cancer patients with an aggressive phenotype.
 ...
PMID:Co-expression of epidermal growth factor receptor and transforming growth factor-alpha predicts worse prognosis in breast-cancer patients. 1110 91

Pancreatic cancer has an incidence of approximately 8 to 10 cases per 100,000 citizens in Western industrialized countries, and the incidence has been increasing throughout the last decades. Insensitivity to antigrowth and apoptotic signals as well as self-sufficiency in growth signals are hallmarks of malignant growth. Pancreatic cancers often exhibit alterations in growth inhibitory pathways such as Smad4 mutations and Smad6 and Smad7 overexpression, and evade apoptosis through p53 mutations and aberrant expression of apoptosis regulating genes. In addition, in pancreatic cancer a variety of growth factors are expressed at increased levels. For example, the concomitant presence of the EGF-receptor and its ligands EGF, TGF-alpha, and/or amphiregulin is associated with enhanced tumor aggressiveness and shorter survival periods following tumor resection. Furthermore, a number of other growth factors and their receptors, such as fibroblast growth factors, nerve growth factor, platelet-derived growth factors, and insulin-like growth factors and their respective receptors are expressed at increased levels in pancreatic cancer and are thought to contribute to its malignant phenotype. Taken together, the disturbance of growth inhibitory and apoptotic pathways and the abundance of growth promoting factors give pancreatic cancer cells a distinct growth advantage which clinically results in rapid tumor progression and poor survival prognosis.
 ...
PMID:Growth factors and their receptors in pancreatic cancer. 1113 19

The type I family of growth factor receptors is known to play a role in the development of several carcinomas, but its role in hepatic malignancies is not clearly understood. In this study we investigated the expression of this family of EGF-R, c-erbB-2, c-erbB-3 and c-erbB-4 in 38 intrahepatic cholangiocellular carcinomas (CCC) by means of immunohistochemistry. EGF-R expression was related to lymph node metastasis, aberrant p53 expression, proliferating activity, and carcinoma differentiation. c-erbB-2 expression was observed in more than 50% of the cases, but was not related to any clinicopathological features, c-erbB-3 expression was linked to lymph node metastasis, and c-erbB-4 expression was directly related to proliferating activity and lymph node metastasis. These results indicate that: 1) EGF-R contributes greatly to CCC progression, and c-erbB-3 and c-erbB-4 have roles similar to but less than that of EGFR, and 2) c-erbB-2 is expressed in CCC in high incidence, but its clinical role in CCC remains unclear.
 ...
PMID:Expression and clinical significance of the erbB family in intrahepatic cholangiocellular carcinoma. 1126 24

Lung cancer is a leading cause of cancer death worldwide; however, despite major advances in cancer treatment during the past two decades, the prognostic outcome of lung cancer patients has improved only minimally. This is largely due to the inadequacy of the traditional screening approach, which detects only well-established overt cancers and fails to identify precursor lesions in premalignant conditions of the bronchial tree. In recent years this situation has fundamentally changed with the identification of molecular abnormalities characteristic of premalignant changes; these concern tumour suppressor genes, loss of heterozygosity at crucial sites and activation of oncogenes. After considering the morphological modifications that occur in premalignant lesions of the bronchial tree, we analyse the alterations occurring in a series of relevant genes: p53 and its functional regulation by MDM2 and p14ARF, p16INK4, p15INK4b, FHIT, as well as LOH at important sites such as 3p, 8p, 9p and 5q. Activation of oncogenes is considered for K-ras, the cyclin D1, the heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1), and finally the c-myc oncogene. The expression of c-myc is influenced strongly by the presence of growth factors (GFs), among which EGF is of prime importance, as well as its receptor coded for by the c-erbB-2 oncogene. Basic knowledge at the molecular level has extremely important clinical implications with regard to early diagnosis, risk assessment and prevention, and therapeutic targets. The novel techniques for early diagnosis and screening of premalignant lung lesions, such as fluorescence bronchoscopy, endobronchial ultrasound, spiral computed tomography combined with precise spatial localization techniques, should basically change the approach to the problems raised by this disease and allow for an increased discovery rate of incipient lesions. Sequential applications will lead to the identification of individuals/populations at high risk, while the availability of accurate 'intermediate end points' will enable the effects of preventive trials to be monitored. Finally, the same molecular abnormalities may serve as 'starting points' for innovative treatments designed to restore the altered functions to normality. Recent developments in our knowledge and understanding of the molecular genetic abnormalities in premalignant lung lesions open an era of hope.
 ...
PMID:Molecular genetic abnormalities in premalignant lung lesions: biological and clinical implications. 1143 8

Primary erythroid progenitors can be expanded by the synergistic action of erythropoietin (Epo), stem cell factor (SCF) and glucocorticoids. While Epo is required for erythropoiesis in general, glucocorticoids and SCF mainly contribute to stress erythropoiesis in hypoxic mice. This ability of normal erythroid progenitors to undergo expansion under stress conditions is targeted by the avian erythroblastosis virus (AEV), harboring the oncogenes v-ErbB and v-ErbA. We investigated the signaling pathways required for progenitor expansion under stress conditions and in leukemic transformation. Immortal strains of erythroid progenitors, able to undergo normal, terminal differentiation under appropriate conditions, were established from fetal livers of p53-/- mice. Expression and activation of the EGF-receptor (HER-1/c-ErbB) or its mutated oncogenic version (v-ErbB) in these cells abrogated the requirement for Epo and SCF in expansion of these progenitors and blocked terminal differentiation. Upon inhibition of ErbB function, differentiation into erythrocytes occurred. Signal transducing molecules important for renewal induction, i.e. Stat5- and phosphoinositide 3-kinase (PI3K), are utilized by both EpoR/c-Kit and v/c-ErbB. However, while v-ErbB transformed cells and normal progenitors depended on PI3K signaling for renewal, c-ErbB also induces progenitor expansion by PI3K-independent mechanisms.
 ...
PMID:Leukemic transformation of normal murine erythroid progenitors: v- and c-ErbB act through signaling pathways activated by the EpoR and c-Kit in stress erythropoiesis. 1143 28

The human papillomavirus type 16 (HPV16) E5 protein associates with the epidermal growth factor receptor (EGFR) and enhances the activation of the EGFR after stimulation by EGF in human keratinocytes. Phosphatidylinositol 3-kinase (PI3K) and ERK1/2 mitogen-activated protein kinase (ERK1/2 MAPK), two signal molecules downstream of the EGFR, have been recognized as participants in two survival signal pathways in response to stress. The fact that E5 can enhance EGFR activation suggests that E5 might act as a survival factor. To test this hypothesis, the apoptotic response of UV B-irradiated primary keratinocytes infected with either control retrovirus, LXSN, or HPV16 2E5-expressing recombinant retrovirus was quantitated. Under the same conditions, LXSN-infected cells showed extensive apoptosis, while E5-expressing cells demonstrated a significant reduction in UV B-irradiation-induced apoptosis. The E5-mediated protection against apoptosis was blocked by wortmannin and PD98059, specific inhibitors of the PI3K and ERK1/2 MAPK pathways, respectively, suggesting that the PI3K and ERK1/2 MAPK pathways are involved in this process. Western blot analysis showed that Akt (also named protein kinase B), which is a downstream effector of PI3K, and ERK1/2 MAPK were activated by EGF. When cells were stimulated by EGF and irradiated by UV B, the levels of phospho-Akt and phospho-ERK1/2 activated by EGF in E5-expressing cells were about twofold greater than those in LXSN-infected cells. Two other UV-activated stress pathways, p38 and JNK, were activated to the same level during UV B irradiation in both LXSN-infected cells and E5-expressing cells, indicating that E5 protein did not affect these two pathways. After UV B irradiation, p53 was activated in both LXSN-infected cells and E5-expressing cells, and cell cycle analysis showed that nearly all cells in both cell populations were growth arrested. These data suggest that unlike HPV16 E6, which blocks apoptosis by inactivation of p53, HPV16 E5 protects cells from apoptosis by enhancing the PI3K-Akt and ERK1/2 MAPK signal pathways.
 ...
PMID:E5 protein of human papillomavirus type 16 protects human foreskin keratinocytes from UV B-irradiation-induced apoptosis. 1173 87

Clinical responses to the HER1 (EGF receptor) inhibitors and HER2/neu/ErbB2 inhibitors correlate with high levels of receptor expression. However, a significant subset of patients with high receptor levels appear to be refractory to treatment. We have observed similar results in the 60 cell lines of the NCI Anti-Cancer Drug Screen using a panel of 11 selective HER1 inhibitors. As expected, low HER1-expressing cell lines were insensitive to HER1 inhibitors. In cell lines with high HER1 expression, low concentrations of HER1 inhibitors potently inhibit both HER1 phosphorylation and the mitogen-activated protein kinase (MAPK) pathway. However, this inhibition did not always correlate with cellular arrest. High HER1-expressing cell lines can be subdivided into two groups based on their sensitivity to HER1 inhibitors. In the sensitive group, receptor and growth inhibition was concordant and occurred at sub-micromolar concentrations of HER1 inhibitors. In the insensitive group, receptor inhibition occurred at a low concentration (< 1 microM) but concentrations that were ten times or higher were required for growth inhibition. Also, neither induction of p21 and cyclin D1 nor p53 status could explain the difference between sensitive and insensitive cells. Although EGF activated the MAPK pathway in all cell lines, only drug-sensitive cell lines responded to EGF (accelerated entry from G1 to S) and to HER1 inhibitors (G1 arrest) by changes in cell cycling. Furthermore, an EGF-dependent immortalized mammary epithelial cell line was extremely sensitive to a panel of HER1 inhibitors. We infer that independence from mitogen-mediated signaling confers insensitivity to HER1 inhibitors in a large subset of cancer cell lines.
 ...
PMID:Differential sensitivity of cancer cells to inhibitors of the epidermal growth factor receptor family. 1179 Nov 82

Soluble and nuclear estrogen receptor (ER) content was measured by ligand binding assay, and estrogen and progesterone receptors by immunohistochemical assays (ER-ICA and PR-ICA) in 214 patients with breast cancer recruited at the "M. Ascoli" Cancer Hospital Centre in Palermo, Sicily, to assess the discriminant and predictive value of these parameters. On follow-up, data from both ER-ICA and PR-ICA showed a statistically significant difference, PR-positive patients having longer disease-free (DSF) and overall (OS) survival than PR-negative ones. Conversely, ER status did not correlate significantly with both DFS (P = 0.6) and OS (P = 0.2). In particular, PR-positive patients had 59 +/- 18 months DFS and 67 +/- 12 months OS, compared to 51 +/- 22 months DFS and 57 +/- 17 months OS of PR-negative cases. The present evidence implies that a PR-negative status identifies breast cancer patients with early relapse, as also suggested by previous studies. It also agrees with the results of ligand binding assay of ER, where ER status is a good discriminant and predictor of response to endocrine treatment, but is unable to anticipate early relapse in breast cancer patients. Evidence that PR status is a statistically significant prognostic indicator deserves further study to ascertain whether or not PR should be regarded as an ER-dependent parameter or be related to other biological variables such as growth factor (e.g., EGF), oncogene (e.g., Her2/Neu), or tumor suppressor gene (e.g., p53) products.
 ...
PMID:Ligand binding and cytochemical analysis of estrogen and progesterone receptors in relation to follow-up in patients with breast cancer. 1209 34


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