Study of Atomic Bomb Survivors Finds Association Between Radiation Exposure and Male Breast Cancer
Exposure to ionizing radiation is associated with an increased risk of male breast cancer, according to a new study.
Male breast cancer is rare, accounting for less than 0.5% of cancers in males and about 1% of all breast cancers. Because of its rarity, the etiology of the disease has not been well described, but many of the risk factors for breast cancer in women--including family history and higher social class--are known to be risk factors for breast cancer in men as well. However, it is not known if ionizing radiation, a well-known risk factor for female breast cancer, is also a risk factor for male breast cancer.
To investigate the role of ionizing radiation in the development of male breast cancer, Elaine Ron, Ph.D., of the National Cancer Institute, and colleagues evaluated male breast cancer incidence among the 45,880 male members of the Life Span Study cohort of Japanese atomic bomb survivors.
There were nine cases of male breast cancer among exposed study members (1.8 cases per 100,000 person years), and three cases among non-exposed study members (0.5 cases per 100,000 person years). The researchers conclude that these results add to the limited information that has shown an association between ionizing radiation and male breast cancer risk.
Contact: National Cancer Institute Press Office, 301-496-6641, NCIPressOfficers@mail.nih.gov
Study Examines Natural History of HPV in HIV–Positive Women
Women with human immunodeficiency virus (HIV)/AIDS have high rates of human papillomavirus (HPV) infection and an elevated risk of developing cervical cancer. However, information is lacking regarding several fundamental aspects of the association between HIV and HPV infections. A new study has found that, in women with HIV, the combination of plasma HIV RNA level and CD4+ T-cell count appears to have a strong interactive association with HPV detection.
To explore the association between the combination of plasma HIV RNA level and of CD4+ T-cell count and the natural history of HPV infection, Howard D. Strickler, M.D., M.P.H., of Albert Einstein College of Medicine in the Bronx, N.Y., and colleagues assessed HIV–positive women and HIV–negative women semi-annually for cervicovaginal HPV by polymerase chain reaction and for squamous intraepithelial lesions (SIL) by Pap smear.
The researchers found a strong statistical interaction between the associations of CD4+ T-cell count and of plasma HIV RNA level with both prevalent and incident detection of HPV. SIL prevalence and incident detection had similar associations. Some of the HPV types incidentally detected may reflect HPV reactivation of a quiescent previous infection, as shown in sexually inactive women. A more moderate association between HIV coinfection and HPV persistence was observed, and could explain, in part, why cervical cancer rates have not reached epidemic proportions in HIV–positive women.
Contact: Abe Habenstreit, Media Relations, Albert Einstein College of Medicine, 718-430-3101, firstname.lastname@example.org
Associations Among Genetic Polymorphisms and Lung Cancer Risk Examined With New Method
A new study has found that two specific gene variants may play roles in the development of lung cancer.
Base excision repair (BER) is one of many ways in which cells can cope with DNA damage. It has been suggested that genetic variations in DNA repair genes may be associated with DNA repair capacity and cancer risk.
Paul Brennan, of the International Agency for Research on Cancer in Lyon, France, and colleagues examined associations between each of four polymorphisms of BER genes (OGG1 Ser326Cys, XRCC1 Arg194Trp, XRCC1 Arg280His, and XRCC1 Arg399Gln) and lung cancer risk among 2,188 lung cancer patients and 2,198 control subjects without lung cancer. Overall, neither the OGG1 genotype nor the XRCC1 polymorphisms were associated with lung cancer risk. However, subjects who carried the OGG1 Cys/Cys genotype had an increased risk of adenocarcinoma compared with subjects who carried the Ser/Ser genotype, and the XRCC1 Arg194Trp and Arg280His polymorphisms were each associated with a reduced risk of lung cancer among heavy smokers.
In a unique step for a study of gene–environment interactions, the researchers performed statistical tests to determine the probability that their results were true. Based on the results of this analysis, the authors conclude that the subgroup result for the XRCC1 Arg280His polymorphism is likely to be a false-positive result, whereas the findings on OGG1 Ser326Cys and XRCC1 Arg194Trp are likely to represent true associations.
In an editorial, Marianne Berwick, M.D., Ph.D., of the University of New Mexico in Albuquerque, and colleagues point out that estimating false-positive reporting probabilities of associations among genetic variants, environmental exposures, and disease can be problematic because the best way to do these calculations remains unclear. The authors describe how well-done meta-analyses or pooled analyses of available studies might be a useful way to obtain the information needed for these calculations.
Birth Order, Immune Dysregulation May Be Related to Non-Hodgkin Lymphoma Risk
Early birth order and a history of atopic conditions--such as hay fever and food allergies--are associated with a reduced risk of non-Hodgkin lymphoma (NHL), according to a new study.
Immune deficiency is a strong risk factor for NHL, which arises from cells of the immune system. Whether atopy--another form of immune system dysregulation that is characterized by certain hypersensitivity reactions, such as hay fever, asthma, eczema, and specific allergies--is associated with NHL has been less clear.
To examine this association, Andrew Edwin Grulich, M.B.B.S., Ph.D., of the University of New South Wales in Sydney, Australia, and colleagues carried out a population-based case–control study of NHL patients without immune deficiency. Because late birth order and childhood crowding are inversely associated with atopy, the authors assessed birth order and history of childhood crowding as well as history of atopic conditions.
The risk of NHL was inversely related to birth order, with only and first-born children having about half the risk of NHL compared with that of fourth- or later-born children. A history of atopic conditions was also associated with a reduced risk of NHL.
Contact: Andrew Grulich, University of New South Wales, 61-2-9385-0956, email@example.com
Hormone Concentrations May Be Associated With Breast Cancer Risk Among Postmenopausal Hormone Users, Study Finds
Although women who use postmenopausal hormones (PMH) have different concentrations of hormones in their blood compared with women who do not use PMH, these concentrations appear to be associated with breast cancer risk in both groups, according to a new study.
Concentrations of sex hormones in blood plasma are associated with breast cancer risk among women not using PMH, but it is unknown if a relationship exists among PMH users. To examine this association, Shelley S. Tworoger, Ph.D., of Brigham and Women's Hospital and Harvard Medical School in Boston, and colleagues conducted a nested case–control study within the Nurses' Health Study.
The authors observed that PMH users had higher levels of estradiol, free estradiol, sex hormone-binding globulin, and testosterone and lower levels of free testosterone than non-users. Estradiol and free estradiol were positively associated with risk among women older than 60 years and those with a body mass index of less than 25 kg/m2. The authors conclude that although PMH users and non-users have different hormonal profiles, plasma sex hormone concentrations are associated with breast cancer risk among PMH users.
Contact: Shelley S. Tworoger, Brigham and Women's Hospital, firstname.lastname@example.org
Also in the April 20 JNCI:
- No Improvement in Overall Survival With Lymph Node Removal in Treatment of Advanced Ovarian Cancer: http://www.eurekalert.org/emb_releases/2005-04/jotn-nii041405.php
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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