HLA-C and acute myeloid leukemia: To investigate which HLA allele, HLA-B*40:01 or HLA-C*03:04, has the main influence on the protective effect, we compared frequencies of patients with AML and of the control group among B*40:01-negative–C*03:04-positive (B*40:01neg–C*03:04pos) (n = 21 out of 477), B*40:01-positive–C*03:04-positive (B*40:01pos–C*03:04pos) (n = 18 out of 477) in comparison with HLA-B*40:01-positive (B*40:01pos) (n = 19 out of 477) individuals as shown in Figure 4A.