Nov 22, 2010 Veronica Mitchell
For some time, medical researchers have been investigating the possibility of producing a vaccine to protect against the development of cancer or to slow down the course of the disease by directing the body’s immune system to attack and destroy cancerous cells.
Vaccination against HPV
Some forms of cancer are known to be caused by viruses, an important example being human papillomavirus (HPV), a sexually transmitted infection which can cause cervical cancer. Vaccines protecting against infection by viruses are known to be effective, and have been administered as part of programmes to eradicate or control infectious diseases for many years.
A vaccine protecting against HPV was licensed for use on school girls in the UK in 2008 and is now part of the standard vaccination programme offered to all children. Other viruses causing cancer include hepatitis B and C (liver cancer), Human Immunodeficiency Virus (HIV) and Epstein Barr Virus (lymphomas).
Malignant cells produce tumour antigens
Antigens are proteins which may be expressed on the surface of a cell, or released into the bloodstream. They are recognised by the body’s immune system, and if an antigen is foreign the immune system will develop antibodies specifically targeted at the antigen. The antibodies will direct T-cells to attack and destroy the foreign cell.
Malignant cells are known to express different antigens to healthy cells. There are two classes of tumour antigens: tumour-associated antigens (TAA) which are found mostly on tumour cells, but may be found on other cells, and tumour-specific antigens (TSA) which are found exclusively on tumour cells. TAA and TSA have been identified for most human cancers including melanoma and breast and prostate cancer.