Date of Award

1-1-2012

Document Type

Campus Access Thesis

Department

Biomedical Science

First Advisor

Daping Fan

Abstract

Heart disease is a leading cause of death in the United States and has consequently sparked a great deal of research into factors that might influence the cardiovascular system (Roger et al., 2012). Total serum cholesterol levels (TC) have been found to significantly correlate with cardiovascular diseases (Siegel et al., 2012). This has driven researchers to look at possible effects of lipid metabolism on other illnesses, such as cancer. This analysis looks at whether there is an association between lipid metabolism parameters (TC, HDL-C, LDL-C) and overall cancer risk as well as the risk of particular cancers such as breast cancer, prostate cancer, and liver cancer. There is considerable uncertainty in this arena; however, some findings are supported by a number of studies.

It was well supported that there is an inverse relationship between serum cholesterol levels and overall incidence of some cancers; however, there still remains some debate about whether this same link applies to overall cancer risk (Jafri et al. 2010). There is no consensus on the individual cholesterol components, HDL-C and LDL-C, and their relationship with overall cancer risk, but the influence of these factors varies according to cancer type (Jafri et al. 2010; Fiorenza et al. 2000). It was found that a relationship between cholesterol and breast cancer risk exists; some found an inverse link while others supported a direct link (Llaverias et al., 2011). Evidence was presented showing an inverse association and no association between HDL-C and breast cancer risk (Gaard et al. 1994; Boyd and McGuire 1990) whereas all possibilities of associations- none, inverse, and direct -were supported for LDL-C and breast cancer risk (Gaard et al. 1994; Hoyer and Engholm 1992; Kokoglu et al. 1994). The little research that has been conducted on the effect of menopausal status on breast cancer risk was also presented and came with inconsistencies. However it was noted that the blood lipid profiles of premenopausal and postmenopausal breast cancer patients were drastically different. (Ha et al. 2009).

Although not as extensive as breast cancer, research on prostate cancer risk also provided multiple contradictions aside from one. Even if no association was reported between total serum cholesterol and prostate cancer risk, it was usually found that patients with high TC levels were at a greater risk of getting high-grade prostate cancer (Mondul et al. 2010). A few current articles presented data suggesting that a direct association between TC and prostate cancer risk (Mondul, 2011), and older studies proposed an inverse association (Morris et al., 1983). Little research was done on TC components so multiple ideas were proposed that no association, an inverse association, and a direct association occurs between HDL-C and prostate cancer risk (Magura et al. 2008; Niemi et al. 2000). LDL-C has not been suggested as an isolated factor.

The relation of lipid metabolism and liver cancer has not been well investigated. Researchers found abnormal plasma lipid profiles in liver cancer patients but they were unable to associate this with liver cancer risk since it generally follows cirrhosis (Borena et al. 2011; Uccello et al. 2011). For this reason, most of the research focuses on Lipoprotein-A, which serves as more of a residual liver function indicator. It was generally supported that a lower serum lipoprotein-A level was associated with primary liver cancer (Jiang et al., 2009). In summary, the relationship between lipid metabolism and cancer risk remains elusive and warrants further investigation.

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