Zhaoqing, the customized primers and the protocol recommended by the Agena
Bioscience MassArray iPLEX platform were used. A fixed position in the human
albumin gene was used as a positive control. Because the genotyping success rate
strongly correlates with the EBV DNA abundance (
of the validation samples (483 of the cases and 605 of the controls) could be
successfully genotyped for all the three GWAS candidate markers (i.e., SNPs
162215C>A, 162476T>C and 163364C>T). The slightly lower
success rate in the cases is consistent with the fact that the EBV DNA abundance
was lower in the saliva from patients than from controls. For detailed
information, see
Note
Seven previously reported human SNPs in HLA (rs2860580,
rs2894207 and rs28421666), CDKN2A/2B (rs1412829),
TNFRSF19 (rs9510787), TERT (rs31489) and
MECOM (rs6774494) were genotyped using customized primers
and following the protocol recommended by the Agena Bioscience MassArray iPLEX
platform in the 990 cases and 1105 controls from Zhaoqing. A fixed position in
the human albumin gene was used as a positive control. The genotyping completion
rate for all seven human SNPs was > 95%. Associations with NPC were
assessed with logistic regression under an additive model adjusted for sex and
age.