Failing to adapt – the ageing immune system's role in cancer pathogenesis

A person's risk of developing cancer rises exponentially with age, an increase that is widely considered to result from cumulative exposure to mutagenic agents. However, cancer incidence rates decelerate and plateau beyond 85 years of age and numerous malignant pathologies peak in incidence during early or middle life, indicating an important role for additional factors in controlling the timing and nature of cancer development. Given that immune function is known to decrease with age, malignant neoplastic change may be induced by increased chronic infection and the onset of a pervasive low grade inflammatory environment. This article discusses in detail the ageing immune system's role in cancer pathogenesis and demonstrates that key polymorphisms coding for relatively low pro-inflammatory cytokine production act to protect some populations from age-induced neoplastic transformation.