Older age is a risk factor for the development of malignant tumors. Incidence rates for cancer in individuals 50 to 64 years of age are 7 to 16 fold greater than in younger persons (1). Incidence rates for cancer continue to increase for even older age groups. Cancer of the colon, which has a median age of occurrence of 72 years, is the second most commonly diagnosed cancer in the United States that afflicts men and women (1,2). Determining whether there are differences in the cancers that afflict elderly hosts compared to cancers of younger hosts is an important area for research. Understanding the effects of normal or usual age-related changes on biological-functions that contribute to carcinogenesis in the elderly can lead to identification of candidate targets for treatment or intervention and may also help in early detection and diagnosis of age-related diseases. The objective of this pilot study is to evaluate potential age-related differences between groups of colon cancer patients diagnosed with similar histological grade, staging and anatomical site of occurrence. By evaluating age-related differences in a well-defined subgrouping of colon cancer patients, we intend to reduce confounding variables that would exist in the comparison of tumors with different clinicopathological characteristics. There are a number of scientific aspects of biological gerontology that are relevant to oncology. These include 1.) regulation of cellular proliferation and expression of oncogenes and tumor suppressor genes; 2.) telomere length and telomerase; 3.) oxidative free-radical damage and induction of apoptosis; and 4.) immune system function and response (3). The pilot study proposed here will evaluate the aspects of free radical damage and induction of apoptosis in colon cancer. In a cohort of colon cancer patients diagnosed with local, regional or distant adenocarcinoma of the sigmoid colon, we propose to determine with respect to age: levels of oxidative DNA damage, apoptotic activity and the expression levels of the pro-apoptotic gene, BAX, and the anti-apoptotic genes, Bcl-xL and galectin-3. To our knowledge, this is the first study that proposes to examine these aspects in archival colon cancer specimens in relationship to age.
