Analysis of genome instability in breast cancer.

Breast cancer is a heterogeneous disease, previously associated with genomic instability. Our aim was to analyze microsatellite markers in order to determine patterns and levels of instability, as well as possible correlations with histopathological parameters. Polymerase chain reaction was used to characterize microsatellite instability (MSI) and loss of heterozygosity (LOH) in 107 breast carcinomas at twelve microsatellite loci. Some of the markers were selected because of their relation to steroid hormone metabolism, which seems to be related to sporadic breast cancer risk. D5S346 and D17S250 markers showed a statistically significant frequency of MSI. LOH in D3S1611, D17S250, AR and ER-ß were associated with some parameters of worse prognosis. Marker group analysis showed that CYP19, AR and ER-ß were related to histological grade III, ER-negative and PR-negative cases. Our results suggest that marker group analysis may be preferred to the single marker strategy, being predictive of worst prognosis when single markers are unable to provide such information. A further evaluation of steroid metabolism genes and their association with low penetrance genes in breast cancer may be useful.

Molecular analysis of spinocerebellar ataxia trinucleotide repeat behavior in normal individuals of a Brazilian population.

There is a current lack of molecular studies analyzing the behavior of trinucleotide repeat expansions causative of Late Onset Spinocerebellar Ataxias in the Brazilian population. Therefore, this manuscript analyses normal families, as well as one hundred normal individuals of the Espirito Santo State to determine the trinucleotide repeat behavior and the allelic frequencies found in this population. The analysis of normal families demonstrated that, instead of being always stably transmitted over generations, expansions can occur between two generations of unaffected individuals, possibly contributing for the appearance of the ataxic phenotype. Allelic frequency studies demonstrated that some alleles are prevalent in the population, namely, allele 32 for the ATXN1 locus (21.5%); allele 21 for the ATXN2 locus (50%); allele 21 and 23 for the ATXN3 locus (14% each); allele 12 for the ATXN6 locus (21%) and allele 10 for the ATXN7 locus (22.5%).

Polymorphism analysis of MTHFR, factor II, and factor V genes in the Pomeranian population of Espirito Santo, Brazil.

Pomeranian populations worldwide immigrated originally from the north of Europe, and because of their preferential marriage, religion, and cultural habits, they show little or no reproductive mixing with local populations. Methylenetetrahydrofolate reductase gene (MTHFR) C677T, Factor V Leiden, and Factor II G20210A polymorphisms are linked to augmented clotting and their frequencies may vary according to population ethnicity. We aimed to assess the frequencies of these thrombophilic alleles in the Pomeranian population residing in Espirito Santo and compare with the general population of the Espirito Santo state, Brazil. A total of 200 individuals were analyzed. The intrapopulation fixation index of the MTHFR C677T polymorphism was 0.03736. The observed heterozygosity was 0.44 and 0.4 for the general and Pomeranian populations, respectively. According to the chi-square test, both populations are in Hardy-Weinberg equilibrium. Four polymorphic alleles were detected for Factor II (2.02%) and 8 for Factor V (4.81%). Our results show that there is gene flow between the general and the Pomeranian population of Espirito Santo, which should no longer be considered an isolated population.