Testing the theory of immune selection in cancers that break the rules of transplantation

Area of Science:

• Immunology
• Cancer Biology
• Evolutionary Biology

Background:

• Cancer cells often exhibit reduced immunogenicity, including down-regulation of Major Histocompatibility Complex (MHC) molecules.
• This phenomenon is a cornerstone of the immune surveillance theory.
• However, the direct role of immune system selection in driving these modifications is debated, with alternative explanations including metabolic changes or de-differentiation.

Purpose of the Study:

• To evaluate the evidence supporting immune selection as the cause of cancer cell immunogenicity reduction.
• To investigate the validity of the immune surveillance concept.

Main Methods:

• Review of historical and contemporary transplantation experiments designed to test for immune selection.
• Analysis of naturally occurring transmissible tumors in dogs and Tasmanian devils as models for immune surveillance.

Main Results:

• Transplantation experiments provide insights into the selective pressures on cancer cells.
• Naturally evolved transmissible tumors offer unique experimental systems to study immune surveillance in action.

Conclusions:

• The study critically assesses the evidence linking cancer cell modifications to immune selection.
• Findings from transplantation studies and natural tumor models contribute to understanding the dynamics of immune surveillance and cancer evolution.