New York, Apr 5 (IANS): Anti-oxidants are likely to be an effective method of treatment for elderly patients suffering from melanoma, finds a new study.

It also identified that the older tumour cells in the worst form of skin cancer behave differently than the younger tumour cells.

The research showed that changes in the microenvironment make these older tumours cells to spread more and makes them more resistant to treatment with targeted therapies.

"It's fascinating to see that the microenvironment can have such a profound effect on both metastasis, and response to a therapy that is specifically targeted to a mutation in a gene," said lead author Ashani Weeraratna, associate professor at The Wistar Institute in US.

However, the findings revealed that antioxidant N-acetylcysteine (NAC) killed melanoma cells in aged dermal fibroblasts - the cells found in the skin.

Cells found in the skin help the skin recovery from injuries, and can contribute to the growth and invasion of melanoma cells.

For the study, published in the journal Nature, the researchers used dermal fibroblasts from healthy donors 25-35 years of age or from donors 55-65 years of age.

They determined that a secreted factor sFRP2 was present in aging cells, which regulates beta-catenin -- a protein that normally blocks the invasion of melanoma cells.

The age-induced loss of beta-catenin renders melanoma cells less capable of dealing with reactive oxygen species (ROS), resulting in a genetically unstable tumour.

The increased activity of ROS and decreased levels of beta-catenin all contribute to the increased resistance of melanoma to treatment with drugs that inhibit a gene, BRAF, mutated in approximately half of all cases of the skin cancer.

"Our findings highlight how vital it is to treat that melanoma in an age-appropriate manner," said one of the researchers Amanpreet Kaur, a graduate student at The Wistar Institute.