The complex interplay between cholesterol and prostate malignancy

Cancer, inflammation, and insights from ayurveda

A recent, exciting discovery relates to the concept of "shared pathology" between cancer and metabolic syndrome. One major pathway common to cancer and metabolic syndrome is chronic inflammation, which is a major driving force in carcinogenesis. Indeed, chronic inflammation precedes most cancers and is considered a "hallmark" of the neoplastic process. We discuss molecular and biochemical evidence which links diet, obesity, abnormal lipid metabolism, and type 2 diabetes mellitus with chronic inflammation. We also explain how each of these factors is linked with biochemical aberrations of carcinogenesis and the prevalence and risk of cancer. While there are reliable biomarkers for chronic inflammation, there are few markers for a mechanistic link between early inflammation and digestive disorders. Discovery of such a marker could lead to identification of a new subtype of patients with digestive disorders that predispose them to cancer and/or metabolic syndrome. In this context, we discuss the ayurvedic concept of "Ama" which is thought to be a toxic, proinflammatory waste-product of improper digestion. We then develop hypotheses and outline preclinical and clinical experiments designed to prove whether "Ama" can serve as a novel and reliable biomarker that links abnormal digestive status, with the onset of chronic inflammation.

Plasma total, LDL, and HDL cholesterol and risk of aggressive prostate cancer in the Cancer Prevention Study II Nutrition Cohort

PURPOSE

Some recent studies have suggested that higher total cholesterol levels are positively associated with risk of aggressive prostate cancer. However, evidence about this association is limited and few studies examined cholesterol subfractions. We therefore examined associations of total, LDL, and HDL cholesterol concentrations with subsequent risk of aggressive prostate cancer within the Cancer Prevention Study II Nutrition Cohort.

METHODS

A total of 14,241 men with no history of cancer provided a blood sample between 1998 and 2001. During follow-up through 2007, 236 of these men were diagnosed with aggressive prostate cancer (AJCC stage ≥ III or Gleason score ≥ 7 (4 + 3)). Plasma total, LDL, and HDL cholesterol concentrations were measured in these 236 cases and 236 age and race-matched controls. Multivariable-adjusted odds ratios (OR) and 95 % confidence intervals (CI) were estimated using conditional logistic regression, adjusting for use of cholesterol-lowering drugs, history of heart attack, and physical activity.

RESULTS

Neither total, LDL, nor HDL cholesterol concentrations were associated with risk of aggressive prostate cancer. OR's for a 1 standard deviation (SD) difference were 0.93 (95 % CI 0.76-1.14) for total cholesterol (SD = 33.7 mg/dl), 0.94 (95 % CI 0.77-1.15) for LDL cholesterol (SD = 30.3 mg/dl), and 0.97 (95 % CI 0.82-1.16) for HDL cholesterol (SD = 12.5 mg/dl). Results were similar in analyses excluding the first 2 years of follow-up or users of cholesterol-lowering drugs.

CONCLUSIONS

These results do not support an association between total cholesterol or its subfractions and risk of aggressive prostate cancer.

Cholesterol and benign prostate disease

The origins of benign prostatic diseases, such as benign prostatic hyperplasia (BPH) and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), are poorly understood. Patients suffering from benign prostatic symptoms report a substantially reduced quality of life, and the relationship between benign prostate conditions and prostate cancer is uncertain. Epidemiologic data for BPH and CP/CPPS are limited, however an apparent association between BPH symptoms and cardiovascular disease (CVD) has been consistently reported. The prostate synthesizes and stores large amounts of cholesterol and prostate tissues may be particularly sensitive to perturbations in cholesterol metabolism. Hypercholesterolemia, a major risk factor for CVD, is also a risk factor for BPH. Animal model and clinical trial findings suggest that agents that inhibit cholesterol absorption from the intestine, such as the class of compounds known as polyene macrolides, can reduce prostate gland size and improve lower urinary tract symptoms (LUTS). Observational studies indicate that cholesterol-lowering drugs reduce the risk of aggressive prostate cancer, while prostate cancer cell growth and survival pathways depend in part on cholesterol-sensitive biochemical mechanisms. Here we review the evidence that cholesterol metabolism plays a role in the incidence of benign prostate disease and we highlight possible therapeutic approaches based on this concept.