MTRR and acute lymphoblastic leukemia: Figure 2 shows the complex structural interactional map and the probabilities of the different structural association types of the relevant SNPs with respect to hyperdiploid ALL susceptibility. The SNPs rs1532268 in MTRR, rs1222809 in DHFR, rs11545078 and rs3780127 in GGH were in pure interaction with hyperdiploid ALL through rs1004474 in TYMS. Note, that directed edges represent only probabilistic relationships between the variables which are not necessary causal.