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Asparaginase is an important component for treatment of childhood acute lymphoblastic leukemia (ALL). The basis for interindividual differences in asparaginase sensitivity remains unclear. To comprehensively identify genetic variants important in the cytotoxicity of asparaginase, we used a genome-wide association approach using the HapMap lymphoblastoid cell lines (87 CEU trio members) and 54 primary ALL leukemic blast samples at diagnosis. Asparaginase sensitivity was assessed as the drug concentration necessary to inhibit 50% of growth (inhibitory concentration (IC)(50)). In CEU lines, we tested 2,390,203 single-nucleotide polymorphism (SNP) genotypes at the individual SNP (P<0.001) and gene level (P<0.05), and identified 329 SNPs representing 94 genes that were associated with asparaginase IC(50). The aspartate metabolism pathway was the most overrepresented among 199 pathways evaluated (P=8.1 × 10(-3)), with primary involvement of adenylosuccinate lyase and aspartyl-tRNA synthetase genes. We validated that SNPs in the aspartate metabolism pathway were also associated with asparaginase sensitivity in primary ALL leukemic blast samples (P=5.5 × 10(-5)). Our genome-wide interrogation of CEU cell lines and primary ALL blasts revealed that inherited genomic interindividual variation in a plausible candidate pathway can contribute to asparaginase sensitivity. [ABSTRACT FROM AUTHOR]

The genetic risk factors for etoposide-induced leukemia with MLL translocations remain largely unknown. To identify genetic risk factors for and novel characteristics of secondary leukemia, we profiled 116 204 single nucleotide polymorphisms (SNPs) in germline and paired leukemic cell DNA from 13 secondary leukemia/myelodysplasia cases and germline DNA from 13 matched and 156 unmatched controls, all with acute lymphoblastic leukemia treated with etoposide. We analyzed global gene expression from a partially overlapping cohort. No single locus was altered in most cases. We discovered 81 regions of loss of heterozygosity (LOH) in leukemic blasts and 309 SNPs whose allele frequencies differed in cases vs controls. Candidate genes were prioritized on the basis of genes whose SNPs or expression differentiated cases from controls or showed LOH or copy number change in germline vs paired blast DNA from the13 cases. Three biological pathways were altered: adhesion, Wnt signaling and regulation of actin. Validation experiments using a genome scan for etoposide-induced leukemogenic MLL chimeric fusions in 15 HapMap cell lines also implicated genes involved in adhesion, a process linked to de novo leukemogenesis. Independent clinical epidemiologic and in vitro genome-wide approaches converged to identify novel pathways that may contribute to therapy-induced leukemia.Leukemia (2007) 21, 2128–2136; doi:10.1038/sj.leu.2404885; published online 2 August 2007 [ABSTRACT FROM AUTHOR]

Essential hypertension (EH), a complex disease, is an important worldwide public-health challenge and is considered to be caused by the interaction of genetic determinants and environmental factors. [ABSTRACT FROM AUTHOR]

Heme oxygenase-1 (HO-1) is a rate-limiting enzyme in heme degradation, producing carbon monoxide (CO), which carries potent antiproliferative and anti-inflammatory effects in the vascular walls. Transcription of the HO-1 gene is regulated by the length polymorphism of dinucleotide guanosine thymine repeat (GT)n in the promoter region, which was measured in this study to determine its association with arteriovenous fistula (AVF) failure in Chinese hemodialysis (HD) patients in Taiwan. L allele means (GT)n30 and S allele means (GT)n<30. Therefore, there are two L alleles for L/L genotype, one L and one S allele for L/S genotype, and two S alleles for S/S genotype. Among the 603 HD patients who were enrolled in this study, 178 patients had history of AVF failure, while 425 patients did not. Significant associations were found between AVF failure and the following factors (hazard ratio): longer HD duration (1.004 month), lower pump flow (0.993 ml/min), higher dynamic venous pressure (1.010 mmHg), location of AVF on the right side (1.587 vs left side) and upper arm (2.242 vs forearm), and L/L and L/S genotypes of HO-1 (2.040 vs S/S genotype). The proportion of AVF failure increased from 20.3% in S/S genotype and 31.0% in L/S genotype to 35.4% in L/L genotype (P=0.011). Relative incidences were 1/87.6 (1 episode per 87.6 patient-months), 1/129, and 1/224.9 for HD patients with L/L, L/S, and S/S genotypes, respectively (P<0.002). The unassisted patency of AVF at 5 years decreased significantly from 83.8% (124/148) to 75.1% (223/297) and 69% (109/158) in S/S, L/S, and L/L genotypes, respectively (P<0.0001). In comparison with HD patients with S/S genotype, those with L/L genotype had a higher prevalence of coronary artery disease (29.1 vs 14.2%; P=0.005). A longer length polymorphism with (GT)n 30 in the HO-1 gene was associated with a higher frequency of access failure and a poorer patency of AVF in HD patients. The longer GT repeat in the HO-1 promoter might inhibit gene transcription, and consequently offset the CO-mediated protective effect against vascular injury.Kidney International (2006) 69, 165–172. doi:10.1038/sj.ki.5000019 [ABSTRACT FROM AUTHOR]

A letter to the editor is presented related to acute lymphoblastic leukemia (ALL) in African American children.

Background: ALK‐tyrosine kinase inhibitors (TKIs) have been proven effective for treating ALK‐positive non‐small cell lung cancer (NSCLC), although patients present with variable responses and disease progression courses. The detailed underlying molecular mechanisms require further investigation to yield a better prognosis. Methods: Targeted next‐generation sequencing (NGS) mutation profiling was performed on samples from 42 NSCLC patients confirmed positive for ALK rearrangements by fluorescence in situ hybridization or immunohistochemistry who experienced disease progression after crizotinib treatment. Results: ALK rearrangements were not confirmed in six patients (14%) with other potential oncogenic drivers identified by NGS, who therefore did not respond to crizotinib and had significantly shorter overall survival (OS) compared to NGS ALK ‐positive patients. Fifteen ALK activating mutations were detected in 8 out of 26 post‐treatment samples (31%), among which ALK L1196M and G1269A were the most common acquired mutations detected in half of the patients with ALK activating mutations. Dynamic monitoring of the genetic evolution in one patient revealed both spatial and temporal heterogeneity of resistant mechanisms during different ALK‐TKI treatment courses. Activation of ALK downstream or bypass pathways was detected in patients without ALK activating mutations, such as genetic alterations in PIK3CA, MET, and KRAS. Interestingly, we identified two patients with acquired mutations in the DNA mismatch repair gene POLE, which resulted in a dramatically increased tumor mutation burden, and might contribute to the poor response to crizotinib. Conclusions: Heterogeneous resistant mechanisms have been identified and correlate to diverse responses to crizotinib. Comprehensive and dynamic mutation profiling is required to better predict clinical outcomes. [ABSTRACT FROM AUTHOR]

Calcineurin is a calcium/calmodulin-dependent protein phosphatase composed of two subunits, a regulatory subunit of calcineurin B (CNB) and a catalytic subunit of calcineurin A (CNA). PPP3CC is the γ isoform of CNA located at the chromosome 8p21.3 region. To evaluate the association between PPP3CC and schizophrenia in the Taiwanese population, 10 single nucleotide polymorphism (SNP) markers across the gene were genotyped by the method of MALDI-TOF in 218 schizophrenia families with at least two affected siblings. One SNP (rs2272080) located around the exon 1 untranslated region was nominally associated with schizophrenia (P=0.024) and significantly associated with the expression of PPP3CC in lymphoblast cell line; the TT and TG genotype had significantly higher relative expression levels than the GG genotype (P=0.0012 and 0.015, respectively). In further endophenotype stratification, the single locus of rs2272080 and the haplotypes of both two-SNP haplotype (rs7833266–rs2272080) and seven-SNP haplotype (rs2461491–rs2469758–rs2461489–rs2469770–rs2449340–rs1482337–rs2252471) showed significant associations with the subgroup of schizophrenia with deficits of the sustained attention as tested by the continuous performance test (CPT, P<0.05) and the executive functioning as tested by the Wisconsin Card Sorting Test (WCST, P<0.05). The results suggest that PPP3CC gene may be a true susceptibility gene for schizophrenia.Molecular Psychiatry (2007) 12, 966–974; doi:10.1038/sj.mp.4001977; published online 6 March 2007 [ABSTRACT FROM AUTHOR]

Evidence for association with schizophrenia has been reported for NOTCH4, although results have been inconsistent. Previous studies have focused on polymorphisms in the 5′ promoter region and first exon of NOTCH4. Our aim was to test the association of the entire genomic region of NOTCH4 in 218 families with at least two siblings affected by schizophrenia in Taiwan. We genotyped seven single nucleotide polymorphisms (SNPs) of this gene, with average intermarker distances of 5.3 kb. Intermarker linkage disequilibrium (LD) was calculated usinggold software, and single-locus and haplotype association analyses were performed usingtransmit software. We found that the T allele of SNP rs2071285 ( P= 0.035) and the G allele of SNP rs204993 ( P= 0.0097) were significantly preferentially transmitted to the affected individuals in the single-locus association analysis. The two SNPs were in high LD (D′ > 0.8). Trend for overtransmission was shown for the T-G haplotype of the two SNPs to affected individuals ( P= 0.053), with the A-A haplotype significantly undertransmitted ( P= 0.034). The associated region distributed across the distal portion of the NOTCH4 gene and overlapped with the genomic region of the G-protein signaling modulator 3 and pre-B-cell leukemia transcription factor 2. In summary, we found modest association evidence between schizophrenia and the distal genomic region of NOTCH4 in this Taiwanese family sample. Further replication for association with the distal genomic region of NOTCH4 is warranted. [ABSTRACT FROM AUTHOR]