Polymorphic deletions of the GSTT1 and GSTM1 genes and susceptibility to bladder cancer.

UNLABELLED: What's known on the subject? and What does the study add? Bladder cancer susceptibility may be determined by genetic differences in the activity of glutathione S-transferases, enzymes that regulate the conversion of exogenous carcinogens to excretable hydrophilic metabolites by glutathione conjugation. The discrepancy of results regarding the association of common genetic polymorphisms and complex diseases such as cancer has raised scepticism in this area of research. Although the evidence generally supports the implication of GSTM1 and GSTT1 polymorphisms in bladder cancer, there is still some debate, with some studies in favour and some against. This study shows a greater risk of bladder cancer in individuals with GSTM1 null genotype, particularly women. This relationship is less evident with GSTT1 null genotypes. Null genotypes in both genes appear to be synergistic, particularly among smokers, and to increase the predisposition to more aggressive tumours. Nevertheless, the role of GSTM1 and GSTT1 polymorphisms in predisposition to bladder cancer should be viewed with caution, due to the multifactorial genetic origin of this condition and the need for long-term longitudinal studies to confirm these results. OBJECTIVE: To estimate the prevalence and importance of GSTT1 and GSTM1 genotypes (implicated in glutathione S-transferase activity) in bladder cancer, to determine whether smoking and occupational factors influence this relationship, and to identify the value of GSTT1 and GSTM1 genotypes as prognostic factors. PATIENTS AND METHODS: A cross-sectional study was conducted with a group of patients with bladder carcinoma and a control group with benign conditions and no history of tumours. The controls were selected and paired as subjects were recruited. Sociodemographic variables, smoking, professional occupation, histological features and the presence of GSTT1 and GSTM1 polymorphisms by multiplex PCR techniques were assessed. RESULTS: GSTM1 genotypes were investigated in 201 patients and 193 controls and GSTT1 genotypes in 190 patients and 163 controls. In the patients group, GSTT1 null genotype was observed in 22.1% (not significant) and GSTM1 null genotype in 54.2% (P=0.008) (odds ratio, OR, 1.7); when considered together, 15.5% (P<0.05; OR, 3.5) of patients had both null genotypes. In the multivariate analysis, the presence of GSTM1 null genotype remained in the model (OR, 2.1) in addition to smoking and age. Subjects with bladder tumour and GSTM1 null genotype were younger than patients without gene deletion (P=0.049). Women with GSTM1 null genotype presented a higher OR than men (P=0.024). When stratified by smoking habit, smokers with both null genotypes showed an OR of 4.7. The percentage of patients with G3 tumours was higher in patients with GSTT1 null genotype (P=0.013) and in patients with both null genotypes (P=0.002). A higher percentage of infiltrating tumours was also observed in patients with both null genotypes (P=0.035). CONCLUSIONS: The data obtained in the present study suggest a higher risk of bladder cancer in individuals with the GSTM1 null genotype. This risk is twofold higher when GSTM1 and GSTT1 null genotypes are both present and is also higher in smokers. A greater predisposition for more aggressive tumours appears to exist, particularly when both null genotypes are combined. Longer-term longitudinal studies are needed to confirm these results.

Implications of p53 gene mutations on patient survival in transitional cell carcinoma of the bladder: a long-term study.

OBJECTIVE: To determine the prognostic value of p53 gene mutations and P53 overexpression for predicting the incidence of recurrence, progression and long-term survival of patients with transitional cell carcinoma (TCC) of the bladder. METHODS: Prospective cohort study with 94 consecutive patients diagnosed and treated for TCC. DNA was obtained from tumor tissue to perform PCR-SSCP of p53 exons 5-9, with automatic sequencing of any mutated samples. Immunohistochemistry using anti-human P53 monoclonal antibody was also performed. Survival was analyzed and the survival curves compared (Mantel-Haenszel). Lastly, a Cox proportional hazards model was constructed. RESULTS: Mutations were found in 46.8% of samples, with 61.8% in infiltrating tumors. Exon 8 was involved in 42.3%. P53 overexpression (cutoff > or =20%) was found in 52.1%. Mean follow-up was 44.1 months; 43.6% had died by the end of this period. Mean survival was lower in patients with exon 8 mutations (38.4 months), compared with patients without this exon mutated (P = 0.016). There were no differences in patient survival based on positive or negative immunohistochemistry (cutoff > or =20%), although survival was lower in patients with a percentage higher than 50% of antibody-stained cells (P = 0.02). In the Cox analysis, tumor stage, pM stage, and interaction between stage > or =pT2 and mutated p53 gene were independent risk factors, with a 6.13-fold risk of death in these patients (P = 0.019). The number of tumors, nuclear grade, pTa stage, and the interaction between GI degree and nonmutated p53 gene remained in the Cox model for superficial tumors, such that these patients had a lower risk of recurrence or progression (P = 0.008). CONCLUSIONS: Alterations in the p53 gene may be indicative of poorer prognosis and greater recurrence in patients with urothelial bladder tumor, in particular, the presence of mutations in exon 8 and a greater percentage of stained cells in the immunohistochemistry. Nevertheless, the classic prognostic factors (primarily, pTNM stage) should still be considered the most useful factors for follow-up of these patients.

Sensitivity and specificity of p53 protein detection by immunohistochemistry in patients with urothelial bladder carcinoma.

OBJECTIVE: To analyze the correlation between the genotypic and phenotypic patterns of p53 in patients with transitional cell carcinoma (TCC) of the urinary bladder. MATERIALS AND METHODS: Cross-sectional study of 73 patients diagnosed with TCC. DNA was obtained from the tumor tissue to perform polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) of exons 5-9 of the p53 gene, with automatic sequencing done on any mutated samples. Immunohistochemistry (IHC) was also performed using anti-human P53 monoclonal antibody, and the diagnostic performance of this test was analyzed by a ROC curve, using the presence of p53 mutations found by PCR-SSCP as 'gold standard'. RESULTS: The cutoff point for defining immunopositivity was 20%. IHC had a specificity of 62.9%, and a sensitivity of 65.8%. The highest sensitivity values appeared in G3 tumors (75%) and infiltrating tumors (71.4%), and the highest specificity values were observed in G1 (77.7%) and G2 tumors (90%) and superficial tumors (66.6%). Mutations in exon 8 gave a positive result most frequently (73.7%) and were considered most relevant in terms of altering P53 function (60.9%). False negatives were documented in 28.5% of infiltrating tumors, and false positives in 33.4% of superficial tumors. CONCLUSIONS: There is a moderate correlation between p53 mutations and P53 protein overexpression, with this stronger in high-grade, infiltrating tumors, in exon 8 mutations, and when the mutation induces relevant changes in the protein structure. Although IHC is useful in routine clinical practice, the classic prognostic factors should still be considered the most important in the follow-up of these patients.

Isolated testicular polyarteritis nodosa.

Isolated polyarteritis nodosa is a rare condition that may be triggered by local exposure to certain agents capable of provoking local immunostimulation without a systemic immune reaction. Isolated polyarteritis nodosa in the testes presents similar histologic characteristics as those of systemic inflammation, although infarcted areas in the testis are more common in generalized polyarteritis nodosa. Definitive diagnosis requires histologic study. We present the case of a 26-year-old patient with isolated testicular polyarteritis nodosa whose symptoms consisted predominantly of intense testicular pain and slight enlargement of both testes.

Determination of vhl gene mutations in sporadic renal cell carcinoma.

OBJECTIVE: Characterization of the molecular status of the vhl gene and its relationship to the usual prognostic factors could help establish new diagnostic and therapeutic strategies. This study determines the presence of vhl gene mutations in tumor tissue from patients with sporadic renal cell carcinoma, the relationship between the mutations and classic prognostic factors, and the possible impact on protein function. MATERIALS AND METHOD: Cross-sectional analytical study investigating vhl gene mutations in tumor tissue by PCR testing of the gene exons and automatic sequencing in 96 patients with sporadic renal cell carcinoma. The characteristics of the mutations detected, as well as their relationship with various clinical and pathological parameters and the possible impact on protein function, were analyzed. RESULTS: Twenty-two mutations were found in 21 patients (21.9%); 68.2% were point mutations. The mutations were associated only with tumor histotype and were located in protein functional domains. Three mutations were detected in the intron position; 73.7% were considered relevant to protein function. CONCLUSION: The percentage of vhl gene mutations in sporadic renal cell carcinoma was relatively low, mutations were seen more often in clear cell carcinoma and were not related to the classic clinical prognostic factors. Mutations of the vhl gene produce important changes in the protein, causing it to lose its tumor suppressor function.

Calcificación bilateral de conductos deferentes / Bilateral calcification of deferent ducts

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