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author:("Jing, kaiyuan")
1.  Genome-wide association study identifies novel loci predisposing to cutaneous melanoma† 
Human Molecular Genetics  2011;20(24):5012-5023.
We performed a multistage genome-wide association study of melanoma. In a discovery cohort of 1804 melanoma cases and 1026 controls, we identified loci at chromosomes 15q13.1 (HERC2/OCA2 region) and 16q24.3 (MC1R) regions that reached genome-wide significance within this study and also found strong evidence for genetic effects on susceptibility to melanoma from markers on chromosome 9p21.3 in the p16/ARF region and on chromosome 1q21.3 (ARNT/LASS2/ANXA9 region). The most significant single-nucleotide polymorphisms (SNPs) in the 15q13.1 locus (rs1129038 and rs12913832) lie within a genomic region that has profound effects on eye and skin color; notably, 50% of variability in eye color is associated with variation in the SNP rs12913832. Because eye and skin colors vary across European populations, we further evaluated the associations of the significant SNPs after carefully adjusting for European substructure. We also evaluated the top 10 most significant SNPs by using data from three other genome-wide scans. Additional in silico data provided replication of the findings from the most significant region on chromosome 1q21.3 rs7412746 (P = 6 × 10−10). Together, these data identified several candidate genes for additional studies to identify causal variants predisposing to increased risk for developing melanoma.
PMCID: PMC3298855  PMID: 21926416
2.  Combining Censored and Uncensored Data in a U-Statistic: Design and Sample Size Implications for Cell Therapy Research 
The assumptions that anchor large clinical trials are rooted in smaller, Phase II studies. In addition to specifying the target population, intervention delivery, and patient follow-up duration, physician-scientists who design these Phase II studies must select the appropriate response variables (endpoints). However, endpoint measures can be problematic. If the endpoint assesses the change in a continuous measure over time, then the occurrence of an intervening significant clinical event (SCE), such as death, can preclude the follow-up measurement. Finally, the ideal continuous endpoint measurement may be contraindicated in a fraction of the study patients, a change that requires a less precise substitution in this subset of participants.
A score function that is based on the U-statistic can address these issues of 1) intercurrent SCE's and 2) response variable ascertainments that use different measurements of different precision. The scoring statistic is easy to apply, clinically relevant, and provides flexibility for the investigators' prospective design decisions. Sample size and power formulations for this statistic are provided as functions of clinical event rates and effect size estimates that are easy for investigators to identify and discuss. Examples are provided from current cardiovascular cell therapy research.
PMCID: PMC3154087  PMID: 21841940
U-statistic; clinical trials; score function; stem cells
3.  Primary Biliary Cirrhosis Associated with HLA, IL12A, and IL12RB2 Variants 
The New England journal of medicine  2009;360(24):2544-2555.
Primary biliary cirrhosis is a chronic granulomatous cholangitis, characteristically associated with antimitochondrial antibodies. Twin and family aggregation data suggest that there is a significant genetic predisposition to primary biliary cirrhosis, but the susceptibility loci are unknown.
To identify genetic loci conferring a risk for primary biliary cirrhosis, we carried out a genomewide association analysis in which DNA samples from 2072 Canadian and U.S. subjects (536 patients with primary biliary cirrhosis and 1536 controls) were genotyped for more than 300,000 single-nucleotide polymorphisms (SNPs). Sixteen of the SNPs most strongly associated with primary biliary cirrhosis were genotyped in two independent replication sets. We carried out fine-mapping studies across three loci associated with primary biliary cirrhosis.
We found significant associations between primary biliary cirrhosis and 13 loci across the HLA class II region; the HLA-DQB1 locus (encoding the major histocompatibility complex class II, DQ β chain 1) had the strongest association (P = 1.78×10−19; odds ratio for patients vs. controls, 1.75). Primary biliary cirrhosis was also significantly and reproducibly associated with two SNPs at the IL12A locus (encoding interleukin-12α), rs6441286 (P = 2.42×10−14; odds ratio, 1.54) and rs574808 (P = 1.88×10−13; odds ratio, 1.54), and one SNP at the IL12RB2 locus (encoding interleukin-12 receptor β2), rs3790567 (P = 2.76×10−11; odds ratio, 1.51). Fine-mapping analysis showed that a five-allele haplotype in the 3′ flank of IL12A was significantly associated with primary biliary cirrhosis (P = 1.15×10−34). We found a modest genomewide association (P<5.0×10−5) with the risk of disease for SNPs at the STAT4 locus (encoding signal transducer and activator of transcription 4) and the CTLA4 locus (encoding cytotoxic T-lymphocyte–associated protein 4) and 10 other loci.
Our data show significant associations between primary biliary cirrhosis and common genetic variants at the HLA class II, IL12A, and IL12RB2 loci and suggest that the interleukin-12 immunoregulatory signaling axis is relevant to the pathophysiology of primary biliary cirrhosis. ( number, NCT00242125.)
PMCID: PMC2857316  PMID: 19458352

Results 1-3 (3)