ABSTRACT
The chromosomal translocation t(12;21) resulting in the ETV6/RUNX1 fusion gene is the most frequent structural cytogenetic abnormality among patients with childhood acute lymphoblastic leukaemia (ALL). We investigated 62 ETV6/RUNX1-positive childhood ALL patients by single nucleotide polymorphism array to explore acquired copy number alterations (CNAs) at diagnosis. The mean number of CNAs was 2·82 (range 0-14). Concordance with available G-band karyotyping and comparative genomic hybridization was 93%. Based on three major protein-protein complexes disrupted by these CNAs, patients could be categorized into four distinct subgroups, defined by different underlying biological mechanisms relevant to the aetiology of childhood ALL. When recurrent CNAs were evaluated by an oncogenetic tree analysis classifying their sequential order, the most common genetic aberrations (deletions of 6q, 9p, 13q and X, and gains of 10 and 21) seemed independent of each other. Finally, we identified the most common regions with recurrent gains and losses, which comprise microRNA clusters with known oncogenic or tumour-suppressive roles. The present study sheds further light on the genetic diversity of ETV6/RUNX1-positive childhood ALL, which may be important for understanding poor responses among this otherwise highly curable subset of ALL and lead to novel targeted treatment strategies.
Subject(s)
Chromosome Aberrations , Oncogene Proteins, Fusion/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Adolescent , Child , Child, Preschool , Chromosome Banding , Comparative Genomic Hybridization , Computational Biology , Core Binding Factor Alpha 2 Subunit , Female , Genome-Wide Association Study , Humans , Infant , Male , Models, Genetic , Polymorphism, Single Nucleotide , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Treatment OutcomeABSTRACT
Children with acute lymphoblastic leukemia (ALL) react very differently to chemotherapy. One explanation for this is inherited genetic variation. The glutathione S-transferase (GST) enzymes inactivate a number of chemotherapeutic drugs administered in childhood ALL therapy. Two multiplexing methods were applied for genotyping the GSTM1 and GSTT1 genes (distinguishing between 0, 1, or 2 gene copies) and the GSTP1 313 A>G polymorphism, simultaneously. A total of 263 childhood ALL patients were genotyped. No gene dose effect on outcome was demonstrated with either GST polymorphisms. Grouping of GSTM1 and GSTT1 into poor (0 or 1 gene copy)-and good metabolizers (at least 2 gene copies)-showed that the poor metabolizers had a trend toward a better outcome (event-free survival =91.8%) compared with the good metabolizers (event-free survival =83.2%). Similarly, in the adjusted analysis the good metabolizers demonstrated a 2.2-fold higher risk trend of experiencing an event (resistant disease or relapse) compared with the poor metabolizers (P=0.066; hazard ratio =2.248; 95% confidence interval, 0.948-5.327). In conclusion, our results suggest that the combined gene dose of GSTM1 and GSTT1 may influence outcome in childhood ALL.
Subject(s)
Gene Dosage , Glutathione S-Transferase pi/genetics , Glutathione Transferase/genetics , Polymorphism, Genetic , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Adolescent , Child , Child, Preschool , Female , Humans , Infant , MaleABSTRACT
We present an Aboriginal Australian genomic sequence obtained from a 100-year-old lock of hair donated by an Aboriginal man from southern Western Australia in the early 20th century. We detect no evidence of European admixture and estimate contamination levels to be below 0.5%. We show that Aboriginal Australians are descendants of an early human dispersal into eastern Asia, possibly 62,000 to 75,000 years ago. This dispersal is separate from the one that gave rise to modern Asians 25,000 to 38,000 years ago. We also find evidence of gene flow between populations of the two dispersal waves prior to the divergence of Native Americans from modern Asian ancestors. Our findings support the hypothesis that present-day Aboriginal Australians descend from the earliest humans to occupy Australia, likely representing one of the oldest continuous populations outside Africa.
Subject(s)
Genome, Human , Native Hawaiian or Other Pacific Islander/genetics , Animals , Asia , Asian People/genetics , Black People , Computer Simulation , DNA, Mitochondrial/genetics , Emigration and Immigration , Ethnicity/genetics , Asia, Eastern , Gene Flow , Gene Frequency , Genetics, Population/methods , Genome, Mitochondrial , Haplotypes , Hominidae/genetics , Humans , Linkage Disequilibrium , Male , Phylogeny , Polymorphism, Single Nucleotide , Sequence Analysis, DNA , Western Australia , White People/geneticsABSTRACT
Protein annotation provides a condensed and systematic view on the function of individual proteins. It has traditionally dealt with sorting proteins into functional categories, which for example has proven to be successful for the comparison of different species. However, if we are to understand the differences between many individuals of the same species-humans in particular - the focus needs be on the functional impact of individual residue variation. To fulfil the promises of personal genomics, we need to start asking not only what is in a genome but also how millions of small differences between individual genomes affect protein function and in turn human health.
