R4.5h: Immune Avoidance

The immune system is hypothesised to provide protection again malignant transformation of cells by detecting and destroying them. Malignant cells that survive to form a tumour mass must therefore have a means of immune avoidance, either by:

  • Preventing detection of their malignant state
  • Preventing destruction by immune cells
  • Neutralising immune cells

This is supported by the increased frequency of malignancies seen in immunosuppressed patients (HIV infected, transplant recipients, and some leukaemias).

The exact mechanisms by which malignant cells avoid immune detection remains a subject of controversy and research.