Prognostic Value of Mutations in TP53 and RAS Genes in Breast Cancer

The identification of molecular indicators of higher risk for specific subgroups of cancer patients may allow to develop more aggressive therapeutic strategies aimed at cases with the highest likelihood of response. This would avoid unnecessary toxicity to patients and alleviate the burden of cancer care for healthcare systems. Activated oncogenes and mutated tumor suppressor genes are causal determinants of the appearance and progression of tumors in man. They therefore represent potential indicators of prognosis and/or response to therapy. However, even in cases of well-studied oncogenes and tumor suppressor genes such as TP53 and RAS, their attributed prognostic and predictive value is often based on studies of insufficient statistical power that often lead to conflicting conclusions. Findings in favor or against the use of TP53 and RAS as prognostic and predictive indicators in breast cancer are reviewed and discussed here.

Different antioxidants status, total antioxidant power and free radicals in essential hypertension

Hypertension is a multi-factorial process, prevalent in developed as well as in developing countries. Different antioxidants and free radicals play an important role in cardiovascular system. In present study, total antioxidant power in terms of FRAP (ferric reducing activity of plasma), free radicals and different antioxidants have been studied in essential hypertensives (n = 50) and normal subjects (n = 50). Levels of total cholesterol, low-density lipids-cholesterol, malonialdehyde, very low-density lipids (VLDL), uric acid, plasma homocysteine and low-density lipids (LDL), were significantly higher in hypertensives as compared to normotensive. HDL-cholesterol, SOD, GPx, reduced glutahione, total glutathione, oxidized glutathione, total thiols, protein thiols, non protein thiols, RNI, total antioxidant power, vitamin A, ascorbic acid and glutahione-S-transferase (GST) were decreased significantly in normotensive. We observed significantly low nitric oxide levels in hypertensive patients. No correlation was observed between severity of disease and plasma nitric oxide levels. There was a significant decrease in plasma FRAP value in essential hypertensives as compared to normotensive controls, which showed a negative correlation with diastolic blood pressure. In conclusion, our study revealed that there was a consistent significant difference between essential hypertensives versus controls with respect to most of the parameters. These complex changes are consistent in the view that essential hypertension is associated with an abnormal level of antioxidant status compared to normal response to oxidative stress or both.

Entendendo o Processo Molecular da Tumorigênese

Nos últimos 25 anos, o reconhecimento dos mecanismos genético-moleculares implicados na gênese e na progressão do câncer tem permitido obter novos métodos de diagnóstico e de acompanhamento, redirecionando de forma drástica a terapêutica do paciente com neoplasia. Alguns marcadores moleculares já estão sendo utilizados na rotina e deverão prover testes sensíveis e específicos para o diagnóstico precoce, estadiamento e acompanhamento do paciente com câncer. As características moleculares de cada tumor deverão permitir predição do seu comportamento, ajudando a delinear estratégias terapêuticas mais efetivas. Apresentamos de forma didática os principais mecanismos controladores do ciclo celular e do crescimento, definindo a importância de oncogenes erroneamente ativados e de genes supressores tumorais perdidos ou não-funcionantes, dos genes envolvidos na programação e manutenção da vida celular e de outros genes que atuam no processo de tumorigênese. Os mecanismos de progressão tumoral, invasão e metastatização à distância são revistos enfatizando-se a aplicação prática do conhecimento a respeito de tais mecanismos. Lembramos o papel da instabilidade genética e dos fenômenos epigenéticos na definição fenotípica do câncer, sugerindo as aplicações da genética molecular na terapia gênica do câncer.