Cancer is the uncontrolled growth and spread of cells. It can affect almost any part of the body. The growths can invade surrounding tissue, adjoining parts of the body or spread to other organs – a process referred to as metastasis. Cancer is the leading cause of death worldwide although some types of cancer are more common in some countries than others and differ among men and among women http://www.who.int/topics/cancer/en/.
Although cancer arises from one single cell, the transformation from a normal cell into a tumor cell is a multistage process involving the interaction between a person's genetic factors, social and environmental factors including diet quality. Knowledge about the causes of cancer, and interventions to prevent and manage the disease is extensive and can be found on health organization Websites such as the World Health Organization (http://www.who.int/mediacentre/factsheets/fs297/en/index.htm l). In addition, countries have their own cancer research programs and centers such as the National Cancer Institute, U.S. National Institutes of Health (http://www.cancer.gov /), Cancer UK (http://www.cancerindex.org/clink44k.htm), the European Association for Cancer Research (http://www.eacr.org/) and Cancer Council Australia (http://www.cancer.org.au/Home.htm).
The field of investigation of the role of nutrition in cancer is extensive. More information can be found in the second expert report of the World Cancer Research Fund and American Institute for Cancer Research “Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective” www.dietandcancerreport.org.
Research suggests that plant based diets high in cereals, grains, fruits and vegetables are protective; and, although not a vegetable, mushrooms often are used as a vegetable in cuisines associated with lower risk of chronic disease in general. Epidemiology, in vitro cell culture studies, animal studies and limited clinical trials suggest mushrooms may lower the risk of breast cancer, particularly in post-menopausal women. Mushrooms’ low energy density can help lower caloric intake and help prevent obesity, a risk factor for breast cancer. Estrogen is a major factor in the development of breast cancer. After menopause, although the ovaries stop producing estrogen, other cells (fat cells and breast cancer cells) continue to do so. A small clinical trial investigating whether white button mushrooms act as aromatase inhibitors in post menopausal breast cancer survivors is currently being conducted
From the Executive Summary
Anti-Cancer Properties: Anti-tumour effects, primarily in human cell lines, have been reported from polysaccharides extracted from a variety of mushrooms. The polysaccharides belong to the betaglucan family of compounds and appear to exert their antitumourigenic effects via enhancement of cellular immunity e.g. via activation of T helper cells and induction of the production of interferon (IFN)-gamma and certain interleukins. Anti-tumour effects of proteoglycan fractions from a variety of mushrooms, including Agaricus bisporus, involve the elevation of natural killer (NK) cell numbers and the stimulation of inducible nitric oxide synthase gene expression, which is then followed by nitric oxide production in macrophages via activation of the transcription factor, NF-kappaB. Activation of NK cells is likely via interferon-gamma and interleukin mediated pathways.