Although the effect estimates were very imprecise, the associations between the rare alleles of CYP1B1 SNPs rs1056836 and rs2855658 and KIT exon 11 codon 557-8 deletions were even stronger when the analysis was limited to small intestinal tumors (ORrs1056836 = 5.18, 95% CI: 2.07, 12.95 and ORrs2855658 = 5.17, 95% CI: 2.05, 13.03). Here, CYP1B1 is linked to small intestine neoplasm.