Supplementary Figure 4 shows that SLCO1B1 rs10841753, rs2306283, rs4149056, and SLC19A1 rs3788200, rs1051266, rs1131596 were in LD, respectively. None of the haplotypes was associated with MTX level or MTX-induced oral mucositis (Supplementary Tables 3 and 4). The gene discussed is SLC19A1; the disease is oral mucositis.