American Association for Cancer Research

May 2007 CEBP Highlights

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Selected Articles from the May 2007 Issue

The articles referenced in this Highlights section will be available online in HTML and PDF formats to all interested users at no charge until the next issue of Cancer Epidemiology, Biomarkers & Prevention is published. Click on the article title to view the complete article.

View the Table of Contents for the May 2007 issue of Cancer Epidemiology, Biomarkers & Prevention.


High Activity May Lower Endogenous Hormones

Chan et al.

Page 900

Short-term trials indicate that intensive physical activity may influence endogenous sex hormone concentrations. However, the relationship between usual daily physical activity and endogenous hormones in postmenopausal women in the general population is still uncertain. Chan et al. studied over 2,000 postmenopausal women not currently using hormone replacement therapy and found that higher usual physical activity levels among postmenopausal women were related to lower endogenous testosterone and estradiol concentrations. This may be one mechanism that could explain the reported inverse relationship between physical activity and breast cancer.
 

Vitamin D for Lower Breast Density

Brisson et al.

Page 929

Dietary vitamin D has been associated with lower mammographic breast density, a strong biomarker for breast cancer risk. Blood 25-hydroxyvitamin D (25(OH)D) is an integrated measure of vitamin D status (from food, supplements and sun exposure) and varies with season. Brisson et al. assessed seasonal variations of breast density and compared such variations with that of 25(OH)D. In premenopausal women, changes in blood vitamin D appeared to be inversely related to changes in breast density with a lag time of about 4 months. This finding encourages further investigation of the possibility that vitamin D could reduce breast density and breast cancer risk.


Lactase Gene Carries No Prostate Cancer Risk

Torniainen et al.

Page 956

Dairy products containing lactose have been suggested to be risk factors for prostate cancer. A single nucleotide polymorphism C to T residing 13910 base pairs upstream of the lactase gene has been shown to associate with the developmental downregulation of lactase activity underlying the persistence/nonpersistence trait. Torniainen et al. genotyped patients and controls using solid phase minisequencing and analyzed the milk consumption using a questionnaire. The authors concluded that lactase persistence/nonpersistence carried no risk for prostate cancer. Analysis of different milk products showed some evidence for low fat milk as a potential risk factor for prostate cancer.


Lycopene Unrelated to Prostate Cancer

Peters et al.

Page 962

Reports from several studies have suggested that carotenoids, and in particular lycopene, could be prostate cancer preventive agents. This has stimulated extensive laboratory and clinical research, as well as much commercial and public enthusiasm. However, the epidemiological evidence remains inconclusive. Peters et al. investigated the association between pre-diagnostic serum carotenoids and risk of prostate cancer, in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. In this large prospective study, high serum β-carotene concentrations were associated with increased risk for aggressive, clinically relevant prostate cancer. Lycopene and other carotenoids were unrelated to prostate cancer. Consistent with other recent publications, these results suggest that lycopene or tomato-based regimens will not be effective for prostate cancer prevention.


Fatalistic Beliefs Thwart Prevention Behavior

Niederdeppe et al.

Page 998

Fatalistic beliefs about cancer prevention are prevalent in the US adult population. Niederdeppe et al. examined socio-demographic correlates of these beliefs and their associations with regular exercise, smoking, and fruit and vegetable consumption with a national sample of over 6,000 American adults. The authors found that fatalistic beliefs were stronger among less-educated Americans but, when controlling for socioeconomic status (and with one exception), were either weaker or equivalent among African-Americans and Hispanics compared to Whites. Americans who hold fatalistic beliefs about cancer prevention may be at greater risk of cancer because they are less likely to engage in various prevention behaviors including regular exercise, not smoking, and fruit and vegetable consumption. These results should impact future cancer communication and education efforts.