Stress and melanoma: increasing the evidence towards a causal basis

Melanoma is a multifactorial disease with a strong genetic component and known risk factors such as excessive ultraviolet exposure, intermittent sunburns and fair skin type. The prognosis is poor if diagnosis is delayed, in spite of recent treatment advances. Evidence is mounting that the incidence of melanoma is higher in the immunosuppressed and individuals with highly stressful occupations. We present a case series of individuals diagnosed with multiple cutaneous melanomas over a few months to 1 year. All had encountered psychological stressors in their lives, and the melanomas were diagnosed briefly after encountering these stressors. No known causes of immunosuppression were detected to explain the sporadic occurrence of melanomas in these individuals. There is evidence in the current literature that stress can lead to immune disregulation, predisposing an individual to various disease states including melanoma. Stress hormones such as norepinephrine have been shown to cause upregulation of cytokines such as Interleukin 6 and 8, which are proangiogenic and support tumour progression. Coupled with genetic and environmental factors, stress appears to play a role in melanoma formation and progression. Large prospective studies are required to study the link between stress and melanoma and gain further insight into the etiology of melanoma.