Why is acute leukemia more common in males? A possible sex-determined risklinked to the ABO blood group genes

Acute leukemia is more common in males at almost every age, and this fact r emains unexplained. A study was carried out in northeast peninsular Malaysi a, where the population is predominantly Malay, to examine whether there wa s a difference in ABO blood group distribution between males and females wi th acute leukemia (AL). The ABO blood groups of 109 male and 79 female pati ents with AL (98 ALL, 90 AML) were compared with those of 1019 controls. In the control population, 39.7% were group O, Among males with AL, 39.4% wer e group O, whereas among females with AL, the proportion was 24.1% (p = 0.0 3), The same trend to a lower proportion of group O among females was seen if the group was divided into adult/pediatric or lymphoblastic/myeloblastic groups, though these differences were not statistically significant. If th ese findings can be confirmed, they suggest the presence of a "sex-responsi ve'' gene near to the ABO gene locus on chromosome 9, which relatively prot ects group O women against AL, at least in our population. The existence of such a gene might also partly explain why acute leukemia, and possibly oth er childhood cancers, are more common in males.