M López-Martínez | PubMed Health

PubMed2004

Patterns of methylation profiles as diagnostic markers for multiple hepatocellular carcinomas.

BACKGROUND: Hepatocellular carcinoma often displays multiple tumor nodules, thus posing a problem for differential diagnosis between cancers of both multifocal and metastatic origin. Conventionally, pathological criteria have been used for this purpose, but these are largely subjective. In order to facilitate a more objective differential diagnosis of multiple HCCs, we used the patterns of methylation of p16INK4a, p14ARF, and GSTP1 genes as markers for each tumor nodule. METHODS: Sixty-seven nodules from 30 cases of multiple or recurrent HCCs were examined using methylation-specific PCR (MSP) analysis for the detection of methylation profiles. RESULTS: Hypermethylation was detected in 56.7%, 43.3% and 17.9% of the cases for p16INK4a, p14ARF, and GSTP1 genes, respectively. At the genetic level the inter-nodule methylation profiles were heterogeneous in 23 of the cases and homogeneous in another 7, enabling a multifocal origin to be diagnosed in the former and metastatic origin in the latter. CONCLUSIONS: Methylation profiling seems to be useful in differentiating the clonal origins of multiple cancers, as the information yielded by this method is essentially objective.

Acyltransferases↗

PubMed2001

The Basques according to polymorphic Alu insertions.

Polymorphic Alu insertions provide a set of DNA markers of interest in human population genetics. Approximately 1000-2000 of these insertions have not reached fixation within the human genome. Each one of these polymorphic loci most probably resulted from a unique insertional event, and therefore all individuals possessing the insertion are related by descent not just state. In addition, the direction of mutational change is toward the gain of the Alu element at a particular locus. Therefore, the improved knowledge of both the ancestral state and the direction of mutational change greatly facilitates the analysis of population relationships. As a result, Alu insertion polymorphisms represent a significant tool for population genetic studies. In this study, polymorphic Alu insertions have been employed to ascertain phylogenetic relationships among Basque groups and worldwide populations. The Basques are considered to be a geographic isolate with a unique language and customs. They may be direct descendants of Cro-Magnon enclaves from the upper Paleolithic (38,000 to 10,000 years). The Basques are distributed among narrow valleys in northeastern Spain with little migration between them until recently. This characteristic may have had an effect on allelic frequency distributions. With the aim of studying this possible effect, we have analyzed six autosomal polymorphic Alu loci from four different sites within the Spanish Basque region in order to ascertain any genetic heterogeneity among the Basques. The results are consistent with a lack of homogeneity among these four autochthonous Basque groups.

Alu Elements↗