Researchers have claimed that body's immune system can be used as an effective weapon against the most serious type of skin cancer. Patients whose immune system was enhanced by drugs lived longer and their malignant melanomas also reduced noticeably.
Two research teams in the U.S. were able to improvise the immune system's attack on cancer cells. Both these studies were presented at a conference on cancer research at Prague.
Nearly 8000 people in Britain are affected by malignant melanoma every year and it claimed 1,777 lives in 2004.
After diagnosis at the most critical stage, the average life expectancy is around 9 months. Treatment involves surgery or high doses of chemotherapy. Though the tumour size can be reduced but recurrence cannot be prevented.
The amount of activated T-cells that attack the foreign bodies is controlled by regulatory T-cells (Tregs).
Jason Chesney, of the University of Louisville, Kentucky carried out a study on his patients. He gave a combination of diphtheria toxin and interleukin-2 to 7 patients who had advanced form of skin cancer. The 2 were used to eliminate Tregs. The tumours either reduced in size or remained stable in 5 of the patients. All 7 of them are still alive after a year of treatment.
In another study, Jeffrey Weber, of the University of Southern California in Los Angeles, succeeded in blocking a protein on Treg. 25 patients were given antibodies to suppress Tregs. Of them 3 are free of cancer and 24 of them are still alive after nearly one and half years.
Dr Chesney told the cancer conference: 'From the results, we conclude that depleting Treg cells in patients with melanoma may allow the immune system to be activated successfully to kill cancer cells.
'These patients have survived longer than the median average life expectancy of a patient with stage four melanoma.' He added: 'We also believe that, in the future, immunotherapies that depend on depleting Treg cells may prove to be useful in all types of cancer.'
Anna Pavlick, director of the melanoma programme at New York University, said, 'The research is a landmark study.'
However, boosting of immune system does increase the risk of diseases like hepatitis, colitis and dermatitis.
Further studies are required to validate the findings of these two studies. If it woks well, the treatment would be extended to other forms of cancer involving Tregs.