Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Recurrent mutation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,693 records · Page 94Linked to original sources
PubMed2005

Clinical relevance of dominant-negative p73 isoforms for responsiveness to chemotherapy and survival in ovarian cancer: evidence for a crucial p53-p73 cross-talk in vivo.

PURPOSE: We aimed to determine the clinical role of the p53 family members p53 and p73 in the responsiveness to platinum-based chemotherapy and survival in ovarian cancer, considering their cross-talk and the p53 polymorphism at codon 72. EXPERIMENTAL DESIGN: A detailed analysis of p53 and p73 in a series of 122 ovarian cancers was done. We used a functional yeast-based assay to determine the p53 mutational status. Red yeast colonies, indicating mutant p53, were subsequently sequenced to determine the specific p53 alteration. p53 mutations were divided into two groups according to their previous characterization in the literature: those that efficiently inhibit transcriptionally active TAp73 function and those that do not. A p53 polymorphism at codon 72 was determined in corresponding normal tissue or blood of ovarian cancer patients. Isoform-specific p73 expression analysis using real-time reverse transcription-PCR has previously been done in the majority of ovarian cancers included in this study. In a retrospective chart review, responsiveness to chemotherapy was assessed, and survival data with long follow-up times were collected. RESULTS: Eighty of 122 (65.6%) of ovarian cancers harbored p53 mutations. p53 mutational status was an important determinant of responsiveness to platinum-based chemotherapy in all patients with a residual tumor of <2 cm in diameter after initial surgery (wild-type versus mutant, P = 0.029). In addition, p53 mutational status was a strong prognosticator for recurrence-free and overall survival (P < 0.0001 and P = 0.003, respectively) in univariate analyses. High expression levels of dominant-negative p73 isoforms (DeltaNp73 and DeltaN'p73) significantly correlated with chemotherapeutic failure (P = 0.048) and with worse recurrence-free and overall survival in patients with p53 mutant cancers (P = 0.048 and P = 0.005, respectively). Eight p53 mutations, present in 19 cases, were found that efficiently inhibit TAp73 (i.e., 175H, 220C, 245S, 245D, 248W, 248Q, 266E, and 273H). Patients with p53 mutations that efficiently inhibit TAp73 function had a significantly shorter overall survival than patients with p53 mutations of unknown effect on TAp73 (P = 0.044). The p53 polymorphism at codon 72 had no influence on responsiveness to chemotherapy or survival. CONCLUSION: We provide the first clinical evidence that dominant-negative p73 isoforms contribute to drug resistance in vivo, underscoring the importance of a p53-p73 cross-talk. NH2-terminally truncated p73 isoforms were of significant clinical effect by providing an additional unfavorable factor for response to platinum-based chemotherapy and survival in p53 mutant ovarian cancers.

Adenocarcinoma, Mucinous↗
PubMed2003

A mutant TP53 gene status is associated with a poor prognosis and anthracycline-resistance in breast cancer patients.

This study evaluates the prognostic and predictive relevance of a mutated p53 in a series of 254 samples from primary breast cancer patients. C-erbB-2 analysis was defined in a limited subpopulation of 79 patients. p53 and c-erbB-2 status was analysed by immunohistochemical staining of the tumour samples. Positive p53 immunostaining was present in 86 cases (34%) and correlated with a high malignant grade, negative progesterone receptor status and ductal histology of tumour. C-erbB-2 positivity was seen in 38 samples (48%). Within an average follow-up time of 74 months, 121 patients developed recurrent or metastatic disease. Patients with mutated p53 showed a statistically significant shorter overall survival and disease-free survival in both univariate and multivariate analyses. The worst clinical outcome was seen in patients who were both p53- and c-erbB-2-positive. The response rate to anthracycline-based chemotherapy in metastatic disease was low in the p53-positive cases. Our results help to clarify the independent prognostic role of a mutated p53 status in breast cancer patients, indicating that this gene might be predictive of anthracycline resistance. Patients with a mutant p53 status and overexpressing c-erbB-2 should be regarded as high-risk cases.

Adult↗
PubMed2005

No hepatitis recurrence using combination prophylaxis in HBV-positive liver transplant recipients with YMDD mutants.

Recurrence of hepatitis B impairs the outcome of liver transplantation (OLT). In serum hepatitis B virus (HBV)-DNA-positive recipients, prophylaxis using lamivudine and immunoglobulins (HBIg) reduces the risk of recurrence, but it is undefined whether this regimen also protects candidates with YMDD mutants. Seventeen OLT viraemic candidates received pre-emptive lamivudine followed by post-OLT prophylaxis with lamivudine and HBIg. Both sera and liver biopsies were prospectively collected and high-sensitive polymerase chain reaction (PCR) assay was applied for HBV-DNA detection. Finally, the presence of YMDD mutants was explored in all PCR-positive samples. All patients remained hepatitis B recurrence-free after a mean follow up of 32 months. By PCR, serum HBV-DNA was detectable in 64.3% of cases at OLT-baseline, in 64.7% under combined prophylaxis and in 58.8% in patients (70.5% of the total) with a minimum follow up of 24 months. At OLT-baseline, YMDD mutants were found in 44.4% of patients. After OLT, mutants were present in 50% of patients but only in 16.6% of cases in the long period. Although 41% of the native livers and 42.8% of the analysed grafts harboured HBV-DNA, YMDD mutants were detected in 57% of the native positive livers. YMDD mutants were largely detected both at OLT-baseline and post-OLT, but their presence decreased over time. Regardless of the presence of YMDD mutants, no hepatitis B recurrence was observed in our OLT recipients using pre-emptive lamivudine followed by continuous prophylaxis with lamivudine and HBIg.

Adult↗
PubMed2006

The RET mutation E768D confers a late-onset familial medullary thyroid carcinoma -- only phenotype with incomplete penetrance: implications for screening and management of carrier status.

OBJECTIVE: We describe a 4-generation family with familial medullary thyroid carcinoma (FMTC) -- a variant of multiple endocrine neoplasia type 2 (MEN 2) without extra-thyroid features. RET mutation analysis confirmed an E768D mutation in exon 13 in 8 family members, 3 affected with medullary thyroid cancer alone while the other 5 were detected to be mutation carriers. This mutation has been described in very few families worldwide and the spectrum of disease and natural history is unclear. RESULTS: Three affected members had medullary thyroid cancer (MTC) confirmed histologically at ages 25, 50 and 56 years, respectively. The E768D mutation appears to have a less aggressive clinical course compared to other high risk RET mutations with no evidence of clinical recurrence up to 11 years after initial therapy. Of five gene carriers identified, two are asymptomatic at the age of 70 and 61, and three had raised calcitonin levels at 46, 39, and 45 years. Following total thyroidectomy, one gene carrier had a histologically normal thyroid at age 46, following a mildly elevated calcitonin, one had C-cell hyperplasia at the age of 39, and one had a frank focus of carcinoma in the left thyroid lobe at the age of 45. No members had evidence of phaeochromocytoma or parathyroid disease on screening. CONCLUSION: The RET E768D mutation is associated with MTC with a later age at presentation, incomplete penetrance and less aggressive course compared with other high risk RET mutations. To date in this family the E768D mutation has not been associated with either phaeochromocytoma or hyperparathyroidism. The appropriate screening strategy for and management of E768D carriers is difficult reflecting the phenotypic heterogeneity.

Adult↗
PubMed2007

Prognostic value of p53 for high risk superficial bladder cancer with long-term followup.

PURPOSE: The risk of muscle invasive disease in a high risk patient with superficial bladder cancer is up to 50%. Identifying patients at risk for progression remains an unsolved problem. A suggested prognosticator is mutations in the p53 tumor suppressor gene. We determined the value of p53 mutation, as demonstrated by mutation analysis, in a clinically selected group of high risk patients with superficial bladder cancer. MATERIALS AND METHODS: p53 Mutation analysis was performed by automated sequencing of bladder wash samples of 105 patients with high risk superficial bladder cancer. The mutation and WT groups were subsequently compared with regard to mortality, progression, disease worsening and the recurrence-free period. RESULTS: A total of 29 patients had a mutation and 76 had WT. Median followup was 58.3 months (range 3 to 161). A total of 13 patients died of bladder cancer, including 6 of 29 with a mutation and 7 of 76 patients in the WT group. p53 Mutation had no significant prognostic value for decreased survival, progression or disease worsening. Recurrence-free survival was significantly lower in the WT group. CONCLUSIONS: We observed a trend toward a worse clinical outcome in high risk patients with a p53 mutation in the bladder wash. However, no significant differences were seen in clinical outcome parameters. Based on these data we conclude that the prognostic value of a p53 mutation is insufficient for individual policy making.

DNA Mutational Analysis↗
PubMed2006

Resistance to gefitinib.

Subsets of patients with non-small cell lung cancer (NSCLC) who carry somatic mutations in the epidermal growth factor receptor (EGFR) have responded remarkably well to a tyrosine kinase inhibitor (TKI), gefitinib. Despite the dramatic response to this inhibitor, most patients nevertheless ultimately have a relapse. We herein report a case of advanced NSCLC in a patient carrying mutated EGFR (delE746-A750) who had a relapse after dramatic improvement by gefitinib treatment. The DNA sequence of the EGFR gene in a tumor biopsy specimen obtained from the relapse site revealed the presence of a second point mutation, resulting in a threonine-to-methionine amino acid substitution at position 790 of EGFR, which could not be detected in the tumor specimen taken before the treatment. Screening subjects with EGFR mutations therefore allows us to identify patients who can be successfully treated with gefitinib. Such observations should also help us in the search for more effective therapies against a specific subset of NSCLC.

Antineoplastic Agents↗
PubMed1976

A matrix method for calculating recurrence risks of unilocal disorders for genetic counselling.

A matrix method to calculate conditional likelihoods in a pedigree and use them to determine recurrence risks for unilocal disorders in genetic risks is presented in this paper. Different matrices are assigned to individual members of the pedigree and combined into matrix expressions. The method is explained for X-linked recessive conditions and autosomal dominant conditions with incomplete penetrance.

Female↗
PubMed2000

A prospective trial of midwest breast cancer patients: a p53 gene mutation is the most important predictor of adverse outcome.

Several retrospective studies have suggested p53 gene mutation as an adverse prognostic indicator in breast cancer patients, based on a selective growth advantage of p53 mutant cancer cells and their presumed resistance to current adjuvant therapy regimens. A cohort of 90 Caucasian midwestern breast cancer patients was analyzed prospectively (60 months of follow-up) with a rigorous mutation detection methodology. The presence of a p53 gene mutation was the single most adverse prognostic indicator for recurrence (p = 0.0032) and death (p = 0.0001), and was associated with poor response to both adjuvant (p = 0.0001) and palliative (p = 0.006) therapy. Analysis of the p53 gene with appropriate mutation detection methodology markedly improves the prediction of early recurrence, treatment failure, and death in breast cancer patients.

Breast Neoplasms↗
PubMed2002

Effects of hormone replacement therapy on coagulation and fibrinolysis in postmenopausal women.

It has been speculated that hormone replacement therapy (HRT) containing relatively low dose of estrogen would be different from oral contraceptive pills in causing thromboembolism because activation of coagulation depends on the amount of estrogen. In contrast to this knowledge, activation of coagulation pathways has been detected in postmenopausal women treated with HRT in the observational and clinical studies. In this regard, recent studies have reported a 2 to approximately 4 fold risk of venous thromboembolism or pulmonary embolism in postmenopausal women receiving HRT than in non-users of estrogen. On the other hands, HRT has shown to enhance systemic fibrinolysis with decreased plasma plasminogen activator inhibitor-1 (PAI-1) levels. In addition, levels of D-dimer exhibited a significant inverse correlation with PAI-1 levels, suggesting enhanced fibrinolysis potential. However, small doses of estrogen/progestogen induce increases in fibrinolytic capacity via a marked reduction of PAI-1. In other words, HRT at conventional dosages may affect fibrinolytic activity to a greater extent than coagulation activity, whereas the converse trend holds at higher estrogen doses. The increase in fibrinolytic potential was independent of any effect on coagulation of CEE at conventional dosages. However, in contrast to healthy postmenopausal women, we recently reported that HRT did not significantly decrease PAI-1 antigen levels and rather, increased tissue factor activity and prothrombin fragment F(1+2) levels from baseline in hypertensive and/or overweight postmenopausal women. Activation of coagulation following HRT may not be balanced by activation of fibrinolysis in some postmenopausal women. Thrombogenic events are considered more likely in patients with certain heritable conditions, such as platelet antigen-2 (PIA-2) polymorphisms. Further, Factor V Leiden mutation increases the risk of primary and recurrent venous thromboembolic events by three to sixfold and the risk of myocardial infarction. Indeed, HRT may decrease or increase atherothrombosis risk depending on the presence of Factor V Leiden mutation. Thus, HRT should not be initiated in women with established coronary artery disease or the coexistence of other risk factors for hypercoagulability-malignancy, immobility, obesity, diabetes, advanced age, or inherited traits. However, HRT at conventional dosages improves fibrinolysis potential in healthy postmenopausal women.

Blood Coagulation↗
PubMed2001

A recurrent deletion in the ubiquitously expressed NEMO (IKK-gamma) gene accounts for the vast majority of incontinentia pigmenti mutations.

Incontinentia pigmenti (IP) is an X-linked dominant disorder characterized by abnormal skin pigmentation, retinal detachment, anodontia, alopecia, nail dystrophy and central nervous system defects. This disorder segregates as a male lethal disorder and causes skewed X-inactivation in female patients. IP is caused by mutations in a gene called NEMO, which encodes a regulatory component of the IkappaB kinase complex required to activate the NF-kappaB pathway. Here we report the identification of 277 mutations in 357 unrelated IP patients. An identical genomic deletion within NEMO accounted for 90% of the identified mutations. The remaining mutations were small duplications, substitutions and deletions. Nearly all NEMO mutations caused frameshift and premature protein truncation, which are predicted to eliminate NEMO function and cause cell lethality. Examination of families transmitting the recurrent deletion revealed that the rearrangement occurred in the paternal germline in most cases, indicating that it arises predominantly by intrachromosomal misalignment during meiosis. Expression analysis of human and mouse NEMO/Nemo showed that the gene becomes active early during embryogenesis and is expressed ubiquitously. These data confirm the involvement of NEMO in IP and will help elucidate the mechanism underlying the manifestation of this disorder and the in vivo function of NEMO. Based on these and other recent findings, we propose a model to explain the pathogenesis of this complex disorder.

Blotting, Northern↗
PubMed2000

Primary cutaneous B-cell lymphoma: a clinical, histological, phenotypic and genotypic study of 21 cases.

The clinical, histological, phenotypic and genotypic features of 21 primary cutaneous B-cell lymphomas (CBCLs) have been investigated. The patients were 13 men and eight women aged 34-91 years (median 67) at diagnosis. Eighteen patients had localized disease, and three had multiple skin lesions at diagnosis. Twelve patients developed cutaneous or extracutaneous recurrences, and five died from malignant lymphoma 7-84 months (median 36) after diagnosis. Histological examination showed features of marginal zone/mucosa-associated lymphoid tissue (MALT)-type lymphoma in 12 cases. Three of these had transformed to diffuse large B-cell lymphoma (DLBCL) in relapse biopsies. The remaining cases were seven primary DLBCLs and two cases tentatively classified as follicle centre cell (FCC) lymphoma. The neoplastic B cells showed similar phenotypes and genotypes in most cases (CD20+, CD79+, CD5-, CD10-, cyclin D1-, bcl-2+, bcl-x-, bax-, t(14;18)-negative). p53 protein was expressed in five cases, and four harboured mis-sense or loss-of-function mutations in the p53 gene. Deletion or promoter region hypermethylation of the p16INK4a gene was detected in two patients with DLBCL. The level of retinoblastoma protein expression and the proliferative fraction were significantly higher in DLBCL (> 50%) than in MALT- or FCC-type lymphomas (< 10%). Features associated with an unfavourable prognosis were the presence of multiple skin lesions at diagnosis, transformation from MALT-type lymphoma to DLBCL, and possibly p16INK4a aberrations. It is concluded that most CBCLs are dissimilar from FCC lymphomas and seem to be more closely related to marginal zone/MALT-type lymphomas. It is also suggested that there are fundamental differences between DLBCL and other histological categories of CBCL, indicating that cutaneous DLBCL is a separate entity with an increased growth potential and genetic features similar to DLBCL originating in other anatomical sites.

Adult↗
PubMed2002

[Intestinal pseudoobstructions and gastric necrosis in mitochondrial myopathy].

HISTORY AND CLINICAL FINDINGS: A 24-year-old female patient suffered for 4 months from recurrent abdominal pain, vomiting and diarrhea. Signs of an acute abdomen were the initial reason for admitting the patient to our hospital. The slim, pale patient had a complete bloated abdomen. Neurological status was normal. INVESTIGATIONS, TREATMENT AND COURSE: Radiographic examination showed a paralytic ileus with a megacolon. The recurrent abdominal symptoms were due to a covered perforation of the stomach. This was shrunken, scarred and had to be resected. Further intestinal pseudoobstructions were accompanied by substantial exsudations in the lungs, intestines and abdomen. At this time mutism like behavior patterns and an ophthalmoplegia appeared. Leukoencephalopathy in brain MRI scans and increased liquor-lactate suggested mitochondrial myopathy. DIAGNOSIS: The diagnosis of a mitochondrial myopathy was confirmed by increased liquor-lactate level, muscle biopsy with ragged-red fibers as well as abnormal mitochondrias and molecular-genetic investigations (mtDNA point mutation A3243G). Associations to MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) and MNGIE (mitochondrial neuro-gastrointestinal encephalomyopathy) syndrome are discussed. CONCLUSIONS: Unclear recurrent gastrointestinal symptoms even in the absence of neurological changes may reflect a mitochondrial disease. This applies especially to young patients with recurrent anorexia, vomiting and pseudoobstruction. In case of additional symptoms like ophthalmopathy, deafness, diabetes mellitus or signs of a MELAS syndrome the search for a mitochondrial system disorder is mandatory.

Adult↗
PubMed2003

Distinct mutations in IRAK-4 confer hyporesponsiveness to lipopolysaccharide and interleukin-1 in a patient with recurrent bacterial infections.

We identified previously a patient with recurrent bacterial infections who failed to respond to gram-negative LPS in vivo, and whose leukocytes were profoundly hyporesponsive to LPS and IL-1 in vitro. We now demonstrate that this patient also exhibits deficient responses in a skin blister model of aseptic inflammation. A lack of IL-18 responsiveness, coupled with diminished LPS and/or IL-1-induced nuclear factor-kappaB and activator protein-1 translocation, p38 phosphorylation, gene expression, and dysregulated IL-1R-associated kinase (IRAK)-1 activity in vitro support the hypothesis that the defect lies within the signaling pathway common to toll-like receptor 4, IL-1R, and IL-18R. This patient expresses a "compound heterozygous" genotype, with a point mutation (C877T in cDNA) and a two-nucleotide, AC deletion (620-621del in cDNA) encoded by distinct alleles of the IRAK-4 gene (GenBank/EMBL/DDBJ accession nos. AF445802 and AY186092). Both mutations encode proteins with an intact death domain, but a truncated kinase domain, thereby precluding expression of full-length IRAK-4 (i.e., a recessive phenotype). When overexpressed in HEK293T cells, neither truncated form augmented endogenous IRAK-1 kinase activity, and both inhibited endogenous IRAK-1 activity modestly. Thus, IRAK-4 is pivotal in the development of a normal inflammatory response initiated by bacterial or nonbacterial insults.

Adult↗
PubMed2006

Prevalence and distribution of MEFV mutations among Arabs from the Maghreb patients suffering from familial Mediterranean fever.

Familial Mediterranean fever (FMF) is an autosomal recessive inherited disease caused by mutations in MEFV. This disease is characterized by recurrent episodes of fever accompanied with topical signs of inflammation. Some patients can develop renal amyloidosis. We prospectively investigated MEFV mutations in a cohort of 209 unrelated Arab patients from Maghreb (85 Algerians, 87 Moroccans, and 37 Tunisians) with a clinical suspicion of FMF. FMF is the main cause of periodic fever syndrome in Maghreb. The most frequent MEFV mutations in this cohort were M694V and M694I. These mutations account for different proportions of the MEFV mutations in Algeria (5%, 80%), Morocco (49%, 37%), and Tunisia (50%, 25%) patients. M694I mutation is specific to the Arab population from Maghreb. Other rare mutations were observed: M680L, M680I, A744S, V726A, and E148Q. We estimated the frequency of MEFV mutation carriers among the Arab Maghrebian population at around 1%, which is significantly lower than in non-Ashkenazi Jews, Armenians or Turks.

Algeria↗
PubMed2006

True carcinosarcoma of the esophagus.

Most esophageal carcinosarcomas are diagnosed as so-called carcinosarcoma, in which individual elements may be derived from a single common ancestor cell, and there have been a few reports describing true carcinosarcoma originating from two individual stem cells. We describe a case of esophageal carcinosarcoma exhibiting neoplastic osteoid formation. Immunoreactivity for vimentin and p53 was limited to only the sarcomatous component and was absent in the carcinomatous component. Furthermore, a point mutation in exon 7 of the p53 gene was observed only in the sarcomatous component. Both sarcoma and carcinoma cells distinctively metastasized to different lymph nodes. These observations led us to diagnose the esophageal tumor as a true carcinosarcoma.

Carcinosarcoma↗
PubMed2006

Mutational analysis of PRDM1 indicates a tumor-suppressor role in diffuse large B-cell lymphomas.

The PR (PRDI-BF1-RIZ) domain zinc finger protein 1 (PRDM1) is a transcription repressor with a pivotal role in plasma-cell differentiation. We identified clonal inactivating mutations in PRDM1 in the diffuse large B-cell lymphoma (DLBCL) cell line OCI-Ly3 and in 8 of 35 de novo clinical DLBCL samples. The mutational spectrum consists predominantly (7 cases) of single-nucleotide mutations affecting consensus splice donor sites, some of which are recurrent, that lead to splicing aberrations and premature translation termination. In 2 of these cases, point mutations appear to be caused by RNA editing with G-to-A and U-to-G conversions. Other mutations include frame-shift deletion and chromosomal inversion. Except for one mutant, which may act as a dominant-negative, all mutations are associated with either deletion or silencing of the paired PRDM1 allele. This study identifies PRDM1 inactivation as a recurrent genetic defect in DLBCL cells and establishes PRDM1 as a potential tumor suppressor gene in DLBCL. Moreover, it implies inhibition of terminal differentiation as a pathogenetic pathway in DLBCL, particularly for the activated B-cell-like DLBCL. It also demonstrates for the first time the potential role of RNA editing in lymphomagenesis.

Amino Acid Sequence↗
PubMed1993

Metachronous multifocal development of urothelial cancers by intraluminal seeding.

To investigate the clonal origin of multifocal urothelial tumours, we analysed the p53 tumour-suppressor gene in 3 cases with bladder tumours developing after treatment for a renal pelvic or ureteral tumour and in 1 case with a ureteral tumour after treatment for a bladder tumour. For each case, identical p53 gene mutations were detected in all primary and recurrent tumours. The results suggest that heterotopic recurrence by intraluminal seeding from the original tumour is common in urothelial cancer. The data also support the view that multifocal urothelial tumours are derived from a single progenitor cell.

Female↗
PubMed2001

Relevance of p53 gene alterations for tumor recurrence in patients with superficial transitional cell carcinoma of the bladder.

PURPOSE: The prognostic relevance of p53 protein accumulation in muscle-invasive bladder carcinoma is well documented, but the prognostic relevance of p53 alterations in superficial bladder tumors remains uncertain. Immunohistochemical data are divergent, possibly because of the use of nonstandardized techniques. We therefore investigated the relevance of p53 gene point mutations and loss of heterozygosity (LOH) for tumor recurrence. The results of this molecular analysis were compared with accumulation of the p53 protein as shown by immunohistochemistry. MATERIAL AND METHODS: Representative tumor tissue was selected and microdissected from 40 patients (pTa, 18 patients; pT1, 22 patients; grade I, 7 patients; grade II, 28 patients; grade III, 5 patients). Polymerase chain reaction (PCR) was carried out with exons 5-8. All PCR products were screened for p53 mutations with temperature-gradient gel electrophoresis (TGGE). When mobility shift was observed, direct nucleotide sequencing was performed. Detection of LOH was performed with nonradioactive microsatellite analysis using three markers (TP 53, D17S513 and D17S786) on chromosome 17p. Immunohistochemistry was performed with the DO 7 antibody. Tumor samples with p53 accumulation of 5% or more positive nuclei were classified as positive. Univariate analysis for disease-free survival was performed using Kaplan-Meier analysis and the log-rank test. RESULTS: TGGE and direct sequencing detected mutations in 10 of 40 patients (2 of 18 pTa and 8 of 22 pT1 patients). LOH was detected in 11 patients. Both a mutation and LOH were detected in 3 patients. p53 immunohistochemistry detected at least 5% positive nuclei in 28 of 40 patients (70%). After a median follow-up of 26 months 14 patients suffered disease recurrence. Whereas disease-free survival did not correlate with a mutation (p = 0.77, log-rank test), LOH (p = 0.2) or a mutation in combination with LOH (p = 0.23), a positive p 53 immunoreaction was significantly associated with short disease-free survival (p = 0.009). CONCLUSION: Despite the relatively high percentage of patients with p53 gene alteration in this population no significant correlation between the detection of molecular alteration and disease recurrence could be found. We conclude that, in contrast to immunohistochemical accumulation, gene alterations play only a minor role in tumor recurrence of p53 in patients with superficial transitional cell carcinoma of the bladder, and that immunohistochemical accumulation of the p53 protein has to be explained by mechanisms other than gene mutations.

Carcinoma, Transitional Cell↗