Immunization therapy may help some forms of cancer, experts report

Hamburg, Germany  - A revolutionary protein immunization therapy regimen may be effective against at least 10 per cent of certain cancer tumours, according to a team of German scientists.

The team, led by Professor Dr. Magnus von Knebel Doeberitz, Medical Director of the Department of Applied Tumour Biology at the Heidelberg University Hospital, found that immune cells react strongly to the modified proteins in tumour cells in which a DNA repair defect has occurred.

Immunization against "false" proteins could sensitize the immune system from tumour cells in 10 to 15 per cent of cases, they found.

The Heidelberg researchers studied the most frequent form of hereditary colon cancer, the HNPCC syndrome (Hereditary Non-Polyposis Colorectal Cancer Syndrome).

Colon cancer is the third most common form of cancer in Western nations, after lung cancer and skin cancer.

In about 15 per cent of these tumours, there is a defect in certain repair mechanisms of the DNA that leads mainly to changes in the so-called microsatellites.

As the researchers in Heidelberg have now discovered, these changes in micro-satellites cause the tumour cells to begin forming foreign proteins, which can be recognized and attacked by the immune system.

"There are two reasons for this," Professor von Knebel Doeberitz was quoted as saying in Science Daily. "The immune system often reacts too slowly - and some tumour cells are able to hide because they lose the ability to express the foreign proteins on their surface,"

If the scientists can activate the immune system against the foreign proteins soon enough, they feel the growth of the tumours can be inhibited.

Funded with a 380,000-euro (596,000 dollars) grant by the Deutsche Krebshilfe (German Cancer Aid), the research was conducted in co- operation with the German Cancer Research Centre and the European Molecular Biology Laboratory (EMBL). (dpa)