Mammary carcinogens identified in charred meats and tobacco

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Mammary carcinogens identified in charred meats and tobacco

JoAnn Guest

Nov 02, 2004 19:17 PST

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ABSTRACT: GSTM1 and GSTT1 polymorphisms

and breast cancer risk

http://www.annieappleseedproject.org/charmeatsmok.html

 

Glutathione S-transferases (GSTs) are a family of important enzymes

involved in the detoxification of a wide variety of known and

suspected carcinogens, including potential mammary carcinogens identified in

charred meats and tobacco smoke.

 

A substantial proportion of the Caucasian population has a

homozygous deletion (null) of the GSTM1 or GSTT1 gene, which results in lack of

production of these isoenzymes.

 

We conducted a case-control study in a cohort of postmenopausal Iowa

women who in 1986 completed a mailed questionnaire on lifestyle

factors including information on cigarette smoking and breast cancer risk

factors. DNA samples and information related to charred meat intake

were obtained, in the case-control study, from breast cancer cases

diagnosed during 1992-1994, and a random sample of cancer-free cohort members.

 

Included in this study were 202 cases and 481 controls who were

genotyped for GSTM1 or GSTT1 gene polymorphisms. Compared to women

who had both GSTM1 and GSTT1 genes, a 60% elevated risk (95% CI = 1.0-

2.5) was observed among those whose GSTM1 or GSTT1 gene was deleted.

 

When stratified by meat eating habits, the risk of breast cancer

associated with null GSTM1 or GSTT1 genotype was observed primarily

among women who ate meats consistently well- or very well-done.

Women

who carried either one of the null genotypes and consumed meat

consistently well- or very well-done had a 3.4-fold elevated risk of

developing breast cancer (95% CI = 1.6-7.1).

 

Cigarette smoking was not a risk factor for breast cancer among

women who had either the GSTM1 or GSTT1 genes. Among those with the null

GSTT1 genotype, however, a significantly elevated risk of breast cancer

was associated with cigarette smoking (OR = 2.5, 95% CI = 1.1-5.4) and

the association was stronger among former (OR = 4.4, 95% CI = 1.5-12.

than current smokers (OR = 1.3, 95% CI = 0.4-4.1).

 

This study suggests that certain null GST genotypes may be

associated with an elevated risk of breast cancer and the association may be

modified by charred meat intake and cigarette smoking.

 

[07/16/2002; Breast Cancer Research and Treatment]

 

 

 

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JoAnn Guest

mrsjo-

DietaryTi-

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