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

The prognostic value of tumoural epidermal growth factor receptor (EGFR), p53, thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) was analysed on 82 advanced head and neck cancer patients (71 men, 11 women; mean age 59). Induction treatment was cisplatin-5-FU +/- folinic acid (61 patients, Chem group) or concomitant cisplatin-5-FU-radiotherapy (21 patients, RChem group). EGFR (binding assay), p53 protein (Sangtec immunoluminometric assay), TS and DPD activities (radioenzymatic assays) were measured on biopsies obtained at time of diagnosis. Significant positive correlation was demonstrated between p53 and EGFR. In the RChem group, p53 was higher in non-complete responders (median 1.03 ng mg(-1)) than in complete responders (median 0.08 ng mg(-1)) (P = 0.057). Univariate Cox analyses stratified on treatment group showed that specific survival (33 events) was significantly related to T staging, p53 taken as continuous or categorial (below vs over 0.80 ng mg(-1)) variable, and EGFR (below vs over 220 fmol mg(-1)); survival increased when EGFR and p53 were below thresholds. Multivariate stepwise analysis including T staging, EGFR and p53 revealed that T staging and EGFR were independent predictors of survival; relative risks were 3.68 for T staging and 2.65 for EGFR. Overall, EGFR remained an independent prognostic factor when response to treatment and T staging were considered in the multivariate analysis.
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PMID:A multifactorial approach including tumoural epidermal growth factor receptor, p53, thymidylate synthase and dihydropyrimidine dehydrogenase to predict treatment outcome in head and neck cancer patients receiving 5-fluorouracil. 1020 6

P53 mutations are currently recognized as the most common genetic alteration in human tumors. The purpose of our study was to evaluate the significance and reliability of p53 genotyping in head and neck cancer as a possible marker permitting the prediction of tumor behavior and clinical outcome. P53 genotyping in our study refers to highly sensitive molecular screening in order to detect structural alterations in the nucleic acid sequence of the gene. Exons 2-11 and adjacent intronic regions were screened for mutations by direct genomic sequencing or by bi-directional dideoxyfingerprinting in 66 primary tumors of the larynx, pharynx and oral cavity. Alterations in the <hot spot region> of the p53 gene were detected in 36% (24 of 66) of the analyzed tumors, no mutation was found in our cohort outside exons 5-8. The frequency of p53 mutation had no correlation to the tumor stage or tumor site. The recurrence rate in patients with a p53 alteration was not significantly higher compared to patients without a p53 mutation in their primary tumors. Summarizing the results of our study only limited reliability of p53 genotyping as an effective concept for molecular testing of head and neck cancer was found.
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PMID:P53 genotyping - an effective concept for molecular testing of head and neck cancer? 1042 79

The genetic alterations observed in head and neck cancer are mainly due to oncogene activation (gain of function mutations) and tumor suppressor gene inactivation (loss of function mutations), leading to deregulation of cell proliferation and death. These genetic alterations include gene amplification and overexpression of oncogenes such as myc, erbB-2, EGFR and cyclinD1 and mutations, deletions and hypermethylation leading to p16 and TP53 tumor suppressor gene inactivation. In addition, loss of heterozygosity in several chromosomal regions is frequently observed, suggesting that other tumor suppressor genes not yet identified could be involved in the tumorigenic process of head and neck cancers. The exact temporal sequence of the genetic alterations during head and neck squamous cell carcinoma (HNSCC) development and progression has not yet been defined and their diagnostic or prognostic significance is controversial. Advances in the understanding of the molecular basis of head and neck cancer should help in the identification of new markers that could be used for the diagnosis, prognosis and treatment of the disease.
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PMID:Genetic alterations in head and neck squamous cell carcinomas. 1045 50

Gene therapy has the potential to provide cancer treatments based on novel mechanisms of action with potentially low toxicities. This therapy may provide more effective control of locoregional recurrence in diseases like non-small-cell lung cancer (NSCLC) as well as systemic control of micrometastases. Despite current limitations, retroviral and adenoviral vectors can, in certain circumstances, provide an effective means of delivering therapeutic genes to tumor cells. Although multiple genes are involved in carcinogenesis, mutations of the p53 gene are the most frequent abnormality identified in human tumors. Preclinical studies both in vitro and in vivo have shown that restoring p53 function can induce apoptosis in cancer cells. High levels of p53 expression and DNA-damaging agents like cisplatin (Platinol) and ionizing radiation work synergistically to induce apoptosis in cancer cells. Phase I clinical trials now show that p53 gene replacement therapy using both retroviral and adenoviral vectors is feasible and safe. In addition, p53 gene replacement therapy induces tumor regression in patients with advanced NSCLC and in those with recurrent head and neck cancer. This article describes various gene therapy strategies under investigation, reviews preclinical data that provide a rationale for the gene replacement approach, and discusses the clinical trial data available to date.
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PMID:p53 tumor suppressor gene therapy for cancer. 1055 Aug 40

Cigarette smoking is the major known risk factor for head and neck cancer. Tobacco promotes oxidative stress and enhances tissue levels of 8-hydroxyguanine (8-OH-G) in smokers. The presence of 8-OH-G does not impede replication but leads to an accumulation of G-->T transversions. Recently, the gene for human 8-oxoguanine DNA glycosylase 1 (hOGG1), an enzyme involved in the repair of 8-OH-G in humans, was cloned and mapped to chromosome 3p. In head and neck tumors, the hOGG1 gene locus is often targeted by loss of heterozygosity (LOH), and the spectrum of mutations in the p53 gene shows a bias in favor of G:C-->T:A transversions, as would be expected if HOGG1 repair functions were disabled. To test the involvement of hOGG1 in head and neck carcinogenesis, we had previously screened 56 tumors for LOH at 3p. From these tumors and two others, we selected 33 tumors demonstrating LOH for further mutational analysis of this gene. No somatic inactivating mutation was found in hOGG1. Polymorphisms involving intron 4 and exon 7 were present in 30% of the patients. A new polymorphism was identified in one patient in exon 6 and led to the amino-acid change G308E. Similar repair activities were found for the wild-type and exon 6-variant enzymes. Therefore, the involvement of hOGG1 in head and neck carcinogenesis is not strongly supported by this work.
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PMID:Frequent allelic loss at chromosome 3p distinct from genetic alterations of the 8-oxoguanine DNA glycosylase 1 gene in head and neck cancer. 1056 2

p53 gene mutations appear in numerous human cancers and are associated with anumber of cellular mechanism changes including a lack of apoptosis. Repeated intratumoral injection of the adenoviral p53 vector (Ad5CMV-p53) in patients with non-small cell lung cancer and head and neck cancer is feasible and well tolerated. Treatment results in expression of the p53 transgene and evidence of increased apoptosis. Dose-related antitumor activity has been seen in phase I trials in both lung and head and neck cancer. Transgene expression appears to occur even in patients who mount an immune response to the adenoviral vector. The evidence to date indicates that gene transfer can occur without contamination of health care workers by the vector. There is preliminary clinical evidence suggesting that the in vivo synergy seen between Ad5CMV-p53 and cisplatin may also occur in patients. Phase II trials are justified and have been started.
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PMID:New horizons: gene therapy for cancer. 1063 Mar 68

Neoadjuvant cisplatin-based chemotherapy has been widely used in the last decade for organ preservation or unresectable disease in advanced stage head and neck cancer. We examined the expression of a series of tumor markers that have been associated with chemotherapy resistance in pretreatment biopsies from 68 patients who received cisplatin-based neoadjuvant chemotherapy at either of two institutions. Patients received either cisplatin/5-fluorouracil (n = 49) or cisplatin/paclitaxel (n = 19). Expression of p53, glutathione S-transferase pi (GSTpi), thymidylate synthase (TS), c-erbB2, and multidrug resistance-associated protein was examined by immunohistochemistry. Expression of glutathione synthetase mRNA was measured by in situ hybridization. The overall response rate for cisplatin-based neoadjuvant treatment was 79%. The expression of several of the tumor markers was associated with resistance to neoadjuvant treatment, but none reached statistical significance. Overall survival (OS) was strongly correlated with the absence of p53 expression. The OS at 3 years was 81% in the p53-negative group, whereas it was 30% in the p53-positive group for patients treated with neoadjuvant chemotherapy (P < 0.0001). Expression of GST pi and TS was also significantly correlated with decreased OS after neoadjuvant treatment. At 3 years, the OS rate was 82% in the low GSTpi score group, compared to 46% in the high GSTpi score group (P = 0.0018). In the TS-negative group, the 3-year OS rate was 71% compared with 40% in the TS-positive group (P = 0.0071). We conclude that p53, GSTpi, and TS may be clinically important predictors of survival in patients receiving neoadjuvant chemotherapy for head and neck cancer.
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PMID:Prognostic value of p53, glutathione S-transferase pi, and thymidylate synthase for neoadjuvant cisplatin-based chemotherapy in head and neck cancer. 1063 46

The aim of the study was to determine the incidence of p53 alterations by mutation, deletion or inactivation by mdm2 or human papillomavirus (HPV) infection in recurrent squamous cell cancer of the head and neck (SCCHN) refractory to radiotherapy. Twenty-two tumours were studied. The p53 status of each tumour was analysed by sequencing of exons 4-9 and by immunohistochemistry. Mdm2 expression was assessed by immunohistochemistry and HPV infection was assessed by polymerase chain reaction of tumour DNA for HPV 16, 18 and 33. Fifteen (68%) of the 22 tumours studied had p53 mutations, while seven had wild-type p53 sequence. p53 immunohistochemistry correlated with the type of mutation. HPV DNA was detected in 8 (36%) tumours and all were of serotype HPV 16. Of these, five were in tumours with mutant p53 and three were in tumours with wild-type p53. Mdm2 overexpression was detected in 11 (50%) tumours. Of these, seven were in tumours with mutant p53 and four were in tumours with wild-type p53. Overall, 21 of the 22 tumours had p53 alterations either by mutation, deletion or inactivation by mdm2 or HPV. In this study, the overall incidence of p53 inactivation in recurrent head and neck cancer was very high at 95%. The main mechanism of inactivation was gene mutation or deletion which occurred in 15 of the 22 tumours studied. In addition, six of the seven tumours with wild-type p53 sequence had either HPV 16 DNA, overexpression of mdm2 or both which suggested that these tumours had p53 inactivation by these mechanisms. This high incidence of p53 dysfunction is one factor which could account for the poor response of these tumours to radiotherapy and chemotherapy. Therefore, new therapies for recurrent SCCHN which either act in a p53 independent pathway, or which restore p53 function may be beneficial in this disease.
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PMID:p53 alterations in recurrent squamous cell cancer of the head and neck refractory to radiotherapy. 1064 94

The candidate tumor-suppressor gene ING1 encodes p33(ING1), a nuclear protein which physically interacts with TP53. It has been shown that p33(ING1) acts in the same biochemical pathway as TP53, leading to cell growth inhibition. Interestingly, a rearrangement of the ING1 gene was found in a neuroblastoma cell line, supporting its involvement in tumor development. Because ING1 resides on the long arm of chromosome 13 (13q34) (a region frequently deleted in many tumor types), we sought to characterize its role in head and neck squamous-cell carcinoma (HNSCC). We first analyzed 44 primary tumors for loss of heterozygosity (LOH) at 13q, using four widely spaced microsatellite markers (13q14, 13q14.3-q22, 13q22, and 13q34). Twenty (48%) of the tumor samples showed LOH in all of the informative markers tested, including D13S1315 at 13q34. Two of the tumors displayed partial losses restricted to one marker (D13S118 at 13q14 in tumor 1164, and D13S135 at 13q14.3-q22 in tumor 1398). We then determined the genomic structure of the ING1 gene and sequenced the entire coding region in 20 primary tumors showing 13q LOH and in five head and neck cancer cell lines. A single germline polymorphism was detected in 10 of the tumors analyzed (T to C change) located 110 nucleotides upstream of the starting methionine. No somatic mutations were found in any of the samples, suggesting that ING1 is not a tumor suppressor gene target in head and neck cancer. Genes Chromosomes Cancer 27:319-322, 2000.
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PMID:Molecular analysis of the candidate tumor suppressor gene ING1 in human head and neck tumors with 13q deletions. 1067 22

Patients with head and neck cancer are at high risk of developing additional second primary tumors in the aerodigestive tract as a result of the field cancerization phenomenon. In this context, the appearance of a new neoplasm often poses a problem in differential diagnosis between recurrence and new primary tumor. Twelve patients with nasopharyngeal carcinoma (NPC) who received radiation therapy for the primary tumor and developed a second epithelial malignancy in the nasal cavity or nasopharynx during the follow-up period are presented in this report. The differentiation between the 2 entities based on the spatiotemporal relations, histological features, and the status of Epstein-Barr virus in tumor lesions are also presented. Our study showed that the epithelial malignancy after NPC having late-onset or prolonged interval (range, 5 to 18 years), different histological patterns (keratinizing squamous cell carcinoma, neuroendocrine carcinoma, or small cell carcinoma) distinct from the primary NPC (differentiated or undifferentiated nonkeratinizing carcinoma), and absence of Epstein-Barr virus, indicate a newly developed tumor rather than recurrent NPC. Our observations showed for the first time that second primary epithelial malignancy developed in the nasal cavity or nasopharynx years after curative therapy for NPC with a prevalence of 0.4% (12/2,794). Wild-type p53 protein was expressed more often in the original NPC (9 of 12) than in the second tumors (4 of 10), but the significance was not statistically significant (P = .2048). Genomic analysis for p53 mutation and in situ hybridization for human papillomavirus showed negative results, indicating that both important molecular events in NPC or head and neck cancer play a small role in this particular type of newly developed second malignant tumor. More studies are warranted for further clarification for the development of second epithelial malignancies in treated NPC patients.
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PMID:Second primary epithelial malignancy of nasopharynx and nasal cavity after successful curative radiation therapy of nasopharyngeal carcinoma. 1068 38


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