Prognostic value of the TP53 Arg72Pro single-nucleotide polymorphism and susceptibility to medulloblastoma in a cohort of Brazilian patients.

Medulloblastoma is a highly cellular malignant embryonal neoplasm, being the most common malignant pediatric brain tumor, accounting for 20-25 % of pediatric central nervous system tumors. To investigate the effect of the TP53 Arg72Pro single-nucleotide polymorphism (SNP) on clinicopathological and phenotypic parameters, we performed a case-controlled study of 122 patients and 122 healthy controls from Brazil. No significant associations were found between the TP53 Arg72Pro genotypes and the clinicopathological parameters studied. Compared with Arg/Arg, which is the most common genotype in the study population, both the Arg/Pro and Pro/Pro genotypes did not influence the medulloblastoma development risk [odds ratio (OR) = 1.36 and P = 0.339 for the Arg/Pro genotype; OR = 1.50 and P = 0.389 for the Pro/Pro genotype]. With regard to prognosis, disease-free survival was not significantly different among the TP53 Arg72Pro SNP genotypes (P > 0.05), but the less frequent genotype (Pro/Pro) was associated with shorter overall survival of medulloblastoma patients (P = 0.021). These data suggest that, although there is no association between the TP53 Arg72Pro SNP and medulloblastoma risk, the Pro/Pro genotype is associated with shorter overall survival of patients submitted to adjuvant therapy. Nevertheless, due to the interethnic composition of the Brazilian population, future studies on larger populations from other parts of the world are essential for a definitive conclusion on the function of the TP53 Arg72Pro SNP.

Inhibitory effect of pisosterol on human glioblastoma cell lines with C-MYC amplification.

Despite the remarkable progress in the characterization of the molecular pathogenesis of glioblastoma multiforme (GBM), these tumors remain incurable and, in most cases, refractory to aggressive cytotoxic treatments. We conducted a morphological and cytogenetic study in two GBM cell lines (U343 and AHOL1), before and after treatment with pisosterol (at 0.5, 1.0 and 1.8 µg ml⁻¹), a triterpene isolated from the fungus Pisolithus tinctorius. No significant alteration was observed in the morphology and frequency of chromosomal abnormalities in the cell lines analyzed after treatment with pisosterol. Using fluorescence in situ hybridization analysis with a locus-specific probe for C-MYC showed that 72% of U343 and 65% of AHOL1 cells contained more than two alleles of C-MYC before treatment. After treatment, no effects were detected at lower concentrations of pisosterol (0.5 and 1.0 µg ml⁻¹). However, at 1.8 µg ml⁻¹ of pisosterol, only 33% of U343 cells and 15% of AHOL1 cells presented more than two fluorescent signals, suggesting that pisosterol blocks the cells with gene amplification. Cells that do not show a high degree of C-MYC gene amplification have a less aggressive and invasive behavior and are easy targets for chemotherapy. Therefore, further studies are needed to examine the use of pisosterol in combination with conventional anti-cancer therapy.

The anticancer homeopathic composite "Canova Method" is not genotoxic for human lymphocytes in vitro.

The Canova Method (CM) is a homeopathic medicine indicated for the treatment of patients with cancer and for pathologies that involve a depressed immune system, such as AIDS. This product is composed of homeopathic dilutions of Aconitum napellus, Arsenicum album (arsenic trioxide), Bryonia alba, Lachesis muta venom and Thuya occidentalis. It stimulates the immune system by activating macrophages. Activated macrophages stimulate the lymphocytes so that they increase their cytotoxic action in response to tumoral growth or infection. Given that the CM stimulates and accelerates the activity of macrophages and lymphocytes, we evaluated genotoxic effects induced in human lymphocytes treated with this homeopathic medication in vitro. Structural and numerical chromosomal aberrations were scored for the assessment of induced genotoxic effects, while the variation in mitotic index was considered as a monitor for induced cellular toxicity. The lymphocytes were cultivated for 24, 48 or 72 h in the following final concentrations of the medicinal composite CM: 4, 8 and 12%. Treatments with the CM did not affect mitotic indexes, nor did they provoke chromosomal aberrations, when compared with untreated controls. There was no cytotoxicity or genotoxicity at the chromosomal level.