Blood groups A and AB are associated with increased gastric cancer risk: evidence from a large genetic study and systematic review

Table 1 Distribution of ABO blood group genotypes in gastric cancer cases and controls

rs8176746 × rs687289	No. of cases	Genotype frequency in cases, %	No. of controls	Genotype frequency in controls, %	Phenotype A alleles	Phenotype B alleles	Phenotype AB alleles	Phenotype O alleles
AA×AA	224	4.54	315	5.12		BB
AA×AG	8	0.16	3	0.05		BO ^a
AA×GG	1	0.02	0	0.00		BO ^b
AC×AA	496	10.06	547	8.88			AB
AC×AG	1146	23.24	1563	25.38		BO
AC×GG	14	0.28	3	0.05		BO ^b
CC×AA	255	5.17	313	5.08	AA
CC×AG	1308	26.52	1508	24.49	AO
CC×GG	1480	30.01	1906	30.95				OO

^aThe AG haplotype corresponds to the rare O24, O40 or O41 alleles
^bThe AC× AG genotype denotes either haplotypes AA and CG (the common BO alleles, respectively) or AG and CA, which haplotype is rare in the Han Chinese population. The compound heterozygous genotypes require haplotype phase determination to distinguish B and O alleles from the more rare A and O-variant alleles. Since A and O-variant alleles together represent a minority in Chinese populations, we assumed that these individuals were of the BO blood group for these analyses

ISSN: 1471-2407