Alcohol Intake & Risk of Estrogen-Receptor Positive Br Ca

Institution: University of Southern California
Investigator(s): Shelley Enger, Ph.D. -
Award Cycle: 1995 (Cycle I) Grant #: 1FB-0341 Award: $73,996
Award Type: Postdoctoral Fellowship
Research Priorities
Etiology and Prevention>Etiology: the role of environment and lifestyle



Initial Award Abstract (1995)
In this study, the association of alcohol intake with risk of breast cancer will be assessed separately for estrogen receptor-positive and estrogen receptor-negative tumors, using data from two large epidemiological studies of risk factors for breast cancer. Estrogen receptors are cellular proteins that bind estrogen, a hormone that stimulates growth of breast tissue. Breast tumor cells with higher levels of estrogen receptors (estrogen receptor-positive tumors) respond better to hormonal therapies than breast tumor cells with low levels of estrogen receptors (estrogen receptor-negative tumors). If alcohol intake is related only to estrogen receptor-positive tumors, this may clarify the role of alcohol in the etiology of breast cancer, and potentially support an estrogen-mediated effect of alcohol on breast cancer. In addition, an association of alcohol with risk of breast cancer that differs for estrogen receptor-positive and estrogen receptor-negative cancers would support the hypothesis that estrogen receptor status defines different types of breast cancer, rather than two stages in the development of one disease.

Subjects are 2,330 women diagnosed for the first time with breast cancer (cases) and 2,330 women without breast cancer (controls) participating in two population-based case-control studies (Studies A and B) of risk factors for breast cancer. All subjects are white (Anglo or Hispanic) female residents of Los Angeles County. Each case subject is individually matched to a control subject on age, parity (Study A only), and neighborhood of residence. Eligible cases in Study A were women in Los Angeles County aged 40 years or younger diagnosed with in situ (localized) or invasive breast cancer from July, 1983, through December, 1988. Eligible cases in Study

B were women in Los Angeles County aged 55-64 years diagnosed with in situ or invasive breast cancer from March, 1987, through December, 1989. Alcohol consumption, demographics, and other information were obtained in interview questionnaires. Estrogen receptor status was determined for all case subjects, but for 80 percent of the subjects the original pathology laboratories must be queried for the results. Appropriate statistical analyses will be used to estimate the association of alcohol intake with risk of estrogen receptor-positive and estrogen receptor-negative breast cancer.

The results of this research may increase understanding of mechanisms through which alcohol might increase the risk of breast cancer, and the postdoctoral fellow will gain valuable experience working in a renowned breast cancer research program, leading to a career in breast cancer research.


Final Report (1997)
The association of alcohol consumption with breast cancer risk was assessed for breast cancer tumors with different estrogen (ER) and progesterone-receptor (PR) levels or "status profiles". Breast tumor cells with higher ER and PR levels (receptor positive, ER+, PR+) are more responsive to certain cancer treatments than are cells with low ER and PR levels (receptor negative, ER-, PR-). Furthermore, they are also associated with better treatment outcomes.

Some studies have suggested that higher levels of alcohol intake are associated with slightly higher breast cancer risks, but it is uncertain whether this association differs for women with different ER/PR status profiles. This issue was examined using data from a large study of breast cancer risk factors conducted in Los Angeles County.

All women in the study are white (Anglo or Hispanic) residents of Los Angeles County. Eligible ‘case’ subjects were all women aged 55-64 years diagnosed for the first time with in situ (localized) or invasive breast cancer from 03/87 through 12/89. Each case subject was individually matched to a ‘control subject’ (that is, a woman without breast cancer but similar in other respects including age and neighborhood of residence). Information such as levels of alcohol consumption, reproductive histories, and other information thought to be important were obtained from each woman through interview questionnaires.

Alcohol consumption was associated with increased risks of ER+/PR+ breast tumors among women who consumed 27 grams of alcohol (approximately 2 drinks) or more per day on average at age 40 and at the reference age. Women whose maximum alcohol consumption was 27 grams or more per day also experienced an increased risk of hormone-receptor positive tumors. We observed essentially no association of alcohol consumption with risk of ER-/PR- tumors.

Our findings confirm our hypothesis that alcohol intake is related only to hormone-receptor positive tumors, supporting an estrogen-mediated effect of alcohol on the development of breast cancer. Although the mechanisms are not known, others have reported that alcohol consumption alters hormone levels of both pre- and postmenopausal women, and hormone levels have been implicated in the development of breast cancer. In addition, our observation that the association of alcohol consumption with breast cancer risk was restricted to hormone-receptor positive cancer also provides evidence that ER/PR positive and ER/PR negative tumors have distinct etiologies and do not represent different stages of disease. Although the issue is not yet resolved, fairly substantial epidemiologic and clinical evidence suggests that hormone-receptor status defines distinct tumor types, and our findings provide further support for this hypothesis.

Brestfeeding history, pregnancy experience and risk of breast cancer
Periodical:British Journal of Cancer
Index Medicus: Br J Cancer
Authors: Enger SM, Ross RK, Henderson BH, and Bernstein L
Yr: 1997 Vol: 76 Nbr: 1 Abs: Pg:118-123