Association between dietary heterocyclic amine levels, genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 and risk of colorectal cancer: a hospital-based case-control study in Japan.
OBJECTIVE
Although associations between dietary HCA intake and colorectal cancer risk have been investigated, results have been suggestive but inconsistent. The aim of this hospital-based case-control study was to examine the impact of heterocyclic amine (HCA) intake on colorectal cancer risk. A further objective was to investigate the possible effect of genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 on colorectal cancer.


METHODS
HCA exposure data were assessed using a self-administered food frequency questionnaire, and estimated HCA intake was verified by measuring the PhIP value in human hair. A total of 117 cases and 238 controls were included in these analyses. Odds ratios (ORs) were calculated using conditional logistic regression analysis to compare intake levels between the first and third tertiles.


RESULTS
No statistically significant increase in the risk of colorectal cancer with respect to total HCA intake was shown by analysis (OR = 0.99, 95% CI = 0.21-4.81). Furthermore, no association with risk was seen for individual HCAs, including PhIP, MeIQ, and MeIQx. Although variant alleles of CYP1A2 were associated with colorectal cancer (OR = 0.27; 95% CI = 0.07-0.99), genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 did not influence the association of HCA intake with colorectal cancer.


CONCLUSIONS
In the present study in subjects with low HCA exposure and with a limited sample size, no association was found between HCA intake and colorectal cancer, or any evidence of influence by genetic polymorphisms of NAT2, CYP1A1, and CYP1A2.
Kobayashi
Minatsu
M
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan. mnkobaya@otsuma.ac.jp
Otani
Tetsuya
T
Iwasaki
Motoki
M
Natsukawa
Shusuke
S
Shaura
Kozo
K
Koizumi
Yoichi
Y
Kasuga
Yoshio
Y
Sakamoto
Hiromi
H
Yoshida
Teruhiko
T
Tsugane
Shoichiro
S
D000328:Adult; D000368:Aged; D001191:Arylamine N-Acetyltransferase / Q000235:genetics*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000235:genetics*; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics*; D005260:Female; D006571:Heterocyclic Compounds / Q000378:metabolism*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012307:Risk Factors
D006571:Heterocyclic Compounds; C504573:CYP1A2 protein, human; D019363:Cytochrome P-450 CYP1A1; D019388:Cytochrome P-450 CYP1A2; D001191:Arylamine N-Acetyltransferase; C478900:NAT2 protein, human