Melanoma research in New Zealand
New Zealand has the highest incidence of melanoma cancer in the world. Although there are no cures for advanced melanomas at this stage, our scientists are trying to see if they can use the body's own immune system to fight the disease.
What is melanoma?
Melanoma is a type of skin cancer that is associated with over-exposure to UV rays in sunlight. It gets its name from the cell it develops in: a type of skin cell called a melanocyte. Melanocytes are pigment-producing cells and give rise to moles. This is why melanoma is usually linked to changes in mole colour and size.
A superficial melanoma can be surgically removed, but if it is left to grow into the tissue below the upper skin layer it can spread throughout the body and become deadly. At this stage it is called a metastatic melanoma. There are very few treatment options available for someone who has been diagnosed with metastatic melanoma. Late stage disease is usually lethal.
Why is melanoma difficult to treat?
One of the reasons that melanoma is so difficult to treat is that the tumour cells for each person have slightly different protein structures on their surfaces, called epitopes. It is difficult to make a drug that can target all of these different epitopes, especially because new types are showing up all the time!
Activating the body’s own defences
In rare cases, an advanced melanoma can shrink on it’s own – the person’s immune system fights the melanoma. This makes melanoma an unusual cancer, because the immune system seems able to respond to it, trying to rid the body of tissue damaged by the disease. But this response is variable and not often successful, especially if the cancer is spreading faster than the immune system can respond.
A group of researchers at New Zealand’s Malaghan Institute of Medical Research are investigating whether they can use the body’s own natural immune response to develop individualised treatments that target the particular type of melanoma a person has. This takes the form of a vaccine that helps increase the immune system’s ability to fight the cancer cells.
There is a big difference between the planned melanoma vaccine and a traditional vaccine. A traditional vaccine protects a person from getting a particular disease (e.g. if they get infected by a particular virus). Thanks to the vaccine, the immune system already has the instructions it needs to build the antibodies needed to disable the infectious agent (e.g. the virus).
The melanoma vaccine doesn’t provide protection prior to exposure, but is expected to work by either strengthening the existing immune response or by sensitising the immune system to the tumour so that an immune response is initiated.
One of the scientists involved in this work is Julie Walton. She has discovered that the skills she has learned as a scientist are transferable, and allow her to be involved in a variety of different projects. In her melanoma work, she particularly enjoys meeting patients involved in the clinical trials, and seeing people have the hope of recovery from what can be a deadly disease.
- 15 November 2007