In subsite analyses in the Japanese, the interactions between processed meat and NAT2 was statistically significant for colon cancer (P = 0.04) but not for rectal cancer (P = 0.41), although the ORs for processed meat within NAT2 category in each subsite analysis were similar to those for colorectal cancer (changes <9%). This evidence concerns the gene NAT2 and malignant colon neoplasm.