Immunosurveillance and cancer: epidemiologic observations

Area of Science:

• Immunology
• Epidemiology
• Oncology

Background:

• The immunologic surveillance theory posits that the immune system protects against cancer development.
• Immune deficiency states provide a unique model to test this theory by examining cancer risk.
• Previous observations link immune dysfunction to increased neoplasia, particularly lymphoproliferative disorders.

Purpose of the Study:

• To evaluate the validity of the immunologic surveillance theory of cancer.
• To analyze epidemiologic data on cancer risk in individuals with immune deficiencies.
• To identify specific cancer types associated with different immune deficiency syndromes.

Main Methods:

• Review of epidemiologic observations concerning cancer risk in immune-deficient populations.
• Analysis of cancer incidence in groups such as renal transplant recipients and patients with primary immunodeficiency syndromes.
• Examination of patterns of lymphoproliferative and non-lymphoid neoplasms in relation to immune status.

Main Results:

• Lymphoproliferative neoplasms were found to predominate in various immune-deficient groups.
• Specific non-lymphoid neoplasms appeared to occur excessively in some immune disorders, though patterns were inconsistent.
• Overall epidemiologic evidence did not support a general role for immunosurveillance in preventing most cancers.

Conclusions:

• The findings challenge the broad applicability of the immunologic surveillance theory in carcinogenesis.
• Immune deficiency is strongly associated with an increased risk of lymphoproliferative neoplasms.
• Specific immunologic processes may predispose to particular types of cancer, warranting further investigation.