News Release

Other highlights of the June 4 JNCI

Peer-Reviewed Publication

Journal of the National Cancer Institute

Working the Night Shift May be Associated with an Increased Risk of Colorectal Cancer

Women who have worked rotating night shifts for years may have an increased risk of developing colorectal cancer, according to a study of more than 78,000 women in the Nurses' Health Study.

Eva S. Shernhammer, M.D., of the Brigham and Women's Hospital and Harvard Medical School in Boston, and her colleagues found that women who worked the night shift at least three nights per month for 15 or more years had a 35% greater risk of colorectal cancer than women who had never worked the night shift.

Exposure to light at night suppresses the production of melatonin, a hormone that has antiproliferative effects on intestinal cancers, the authors explain. "Because night-shift work has become very common in developed countries, future studies should assess the relationship of light exposure to the risk of other cancers and consider the risks in men," they conclude.

Contact: Amy Dayton, Brigham and Women's Hospital, 617-534-1603, adayton2@partners.org.

Study Finds No Association Between Personality and Cancer

Personality type does not appear to be associated with risk of cancer, according to a new study. Naoki Nakaya and Yoshitaka Tsubono, M.D., of the Tohoku University Graduate School of Medicine in Japan, and their colleagues examined the incidence of cancer among 30,000 people in Japan who had completed a personality questionnaire regarding four personality subscales: extraversion (i.e., sociability, liveliness, surgency), neuroticism (i.e., emotional instability, anxiousness), psychoticism (i.e., tough-mindedness, aggressiveness, coldness) and lie (i.e., social naivety or conformity).

During 7 years of follow-up, there were 986 cases of cancer. There was no association between any of the personality subscales and risk of total cancer or of stomach, colorectal, lung, or breast cancer. Although higher levels of neuroticism were associated with cancers diagnosed in the first 3 years of follow-up, the authors suggest that neuroticism may be a consequence of cancer rather than a cause.

Melanoma May be Caused by Two Different Pathways

A new study supports the hypothesis that there may be two separate pathways leading to the development of cutaneous melanoma, possibly explaining why some melanomas occur on less sun-exposed parts of the body.

David C. Whiteman, Ph.D., of the Queensland Institute of Medical Research in Australia, and his colleagues found that people with head and neck melanomas and lentigo maligna melanomas (a subtype of melanoma caused by chronic exposure to the sun) had fewer nevi (moles) and more solar keratoses (sunspots, or premalignant skin lesions) than people with melanomas of the less sun-exposed trunk. In contrast, people with trunk melanomas tended to have fewer solar keratoses and more nevi than people with head and neck or lentigo maligna melanomas. These findings suggest that there are at least two different pathways to melanoma, one associated with the proliferation of pigmented cells, or melanocytes, and the other associated with chronic exposure to sunlight.

Contact: Christine Borthwick, the Queensland Institute of Medical Research, 61-07-3362-0291 or 61-0417-603-390, christiB@qimr.edu.au.

Polymorphism May be Associated with Prostate Cancer Risk

People who carry a polymorphism in the 102V allele of the PON1 gene may be at an increased risk of developing prostate cancer, according to a new study. PON1 encodes human serum paraoxonase, an enzyme that eliminates carcinogenic lipid-soluble radicals. Because the expression of PON1 varies widely in humans, researchers believe certain PON1 polymorphisms might be associated with increased risks of cancer.

Marja Marchesani and Jukka T. Salonen, M.D., Ph.D., of the Research Institute of Public Health at the University of Kuopio in Finland, and their colleagues identified a new single-nucleotide mutation, I102V, associated with decreased serum paraoxonase activity and found that men who carried this mutation were 6.3 times more likely to develop prostate cancer than men who did not carry this mutation. In further analysis, the authors found that patients with familial prostate cancer were more likely to be carriers of this mutation than control subjects.

ELAC2 Polymorphism Not Associated with Prostate Cancer

There appears to be no association between two common polymorphisms in the ELAC2 gene and risk of prostate cancer, despite previous studies that have suggested otherwise. Gianluca Severi of the European Institute of Oncology in Milan, Italy, and John L. Hopper, Ph.D, of the University of Melbourne in Australia, and their colleagues examined two ELAC2 polymorphisms, Ser217Leu and Ala541Thr, among 825 men with prostate cancer and 732 healthy individuals.

They found no association between either polymorphism and prostate cancer, even after excluding control subjects with elevated prostate-specific antigen levels. A combined analysis of their results with those of seven previous studies also failed to produce an association between the polymorphisms and prostate cancer risk. The authors conclude that it is premature to refer to ELAC2 as a prostate cancer susceptibility gene.

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Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.


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