ABSTRACT
The postulated mechanisms by which the food in our diet might influence the development of cancer involve two distinct sequences: first, the process of carcinogenic initiation — conversion of a normal cell to a neoplastic cell, followed by promotion and progression. The induction of a cancer by a dietary constituent is a multistep process occurring over a period of months to years. Most of these substances are not carcinogenic until metabolically activated via a tissue-mediated chemical alteration. Hypotheses linking the presence or absence of an immune response with the occurrence of cancer have existed for decades. A distinction should be made between immunosurveillance against developing malignancy and immune response to existing tumors. Immune function is adversely affected in both animals and humans by protein-energy malnutrition. The presence of protein-energy malnutrition (PEM) in humans influences both cellular and humoral immune function.
