Despite its former reputation as being immunosuppressive, it has become evident that radiation therapy can enhance antitumor immune responses. This quality can be harnessed by utilizing radiation as an adjuvant to cancer immunotherapies. Most studies combine the standard radiation dose and regimens indicated for the given disease state, with novel cancer immunotherapies. It has become apparent that low-dose radiation, as well as doses within the hypofractionated range, can modulate tumor cells making them better targets for immune cell reactivity. Herein, we describe the range of phenotypic changes induced in tumor cells by radiation, and explore the diverse mechanisms of immunogenic modulation reported at these doses. We also review the impact of these doses on the immune cell function of cytotoxic cells in vivo and in vitro.

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The telomere is a region of repetitive DNA located at the ends of eukaryotic chromosomes, which protect genetic material from degradation during cellular replication. As a consequence of the inability of DNA polymerase to fully replicate the ends of the chromosome, the telomere progressively shortens as an organism ages. Telomere length in individuals is highly variable, and studies have shown that shortened telomeres are associated with poor prognoses in many diseases, including cancers and other diseases that disproportionately affect American-Americans. There is also strong evidence that environmental and behavioral factors can play an epigenetic role in telomere length homeostasis. Chronic stress is associated with shorter telomeres in women, but studies have not been explicitly done to assess the role of chronic stress in men or minorities. Though there is little evidence of a functional relationship between shortened telomeres and heightened disease states, it is clear that telomeres reflect the health of the individual. We hypothesize that telomere length can be used as a diagnostic indicator of health status, and that the average telomere length are shorter in African-American men due in part to higher levels of chronic stress. To test this hypothesis, we examined the telomere length of DNA from the peripheral blood mononuclear leukocytes of more than 40 African-American men and administered a stress survey to assess chronic stress levels. Preliminary analysis of the data indicates a potential negative association between stress and telomere length, though the results are not significant. We also observed a significant negative correlation between telomere length and body mass index. The results indicate that environmental factors can affect telomere length in African-American men, and that telomere length may be a useful health status indicator in this population. Citation Format: Samantha Simon, Wallace Sharif. The association between chronic stress and telomere length in African American men. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr A69.

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