Virtually since the dawning of cell phones various reports have emerged suggesting that the device increases the risk of brain cancer, only to be refuted by another study shortly thereafter.

Saturday is no exception to this rule.

This weekend two high-profile studies painted strong contradicting evidence on the matter, raising the question as to whether a definite conclusion would ever be met.

A study carried out for the Institute of Cancer Research found no convincing evidence of a link between the technology and brain tumors.

The review, done by a committee of experts from Britain, the United States and Sweden concluded there was no risk.

It also found a lack of established biological mechanisms by which radio signals from mobile phones might trigger tumors.

Although there remains some uncertainty, the trend in the accumulating evidence is increasingly against the hypothesis that mobile phone use can cause brain tumors in adults, researchers said.

Sounds definitive enough. But another study, carrying its own authority and released on the same day, says cell phones and brain's don't mix.

A Swedish study found large increased incidence of astrocytoma, the most common form of a malignant brain tumor, in those who had been using cells for over 10 years.

Published in the International Journal of Oncology,and carried out by researchers from the University Hospital of Örebro and Umeå University ,the study  found that long-term usage increased the risk of all malignant tumors by 30 per cent, and astrocytomas in particular by 40 per cent.

The studies come just two months after the World Health Organization's (WHO) International Agency for Research on Cancer (IARC) decided cellphone use should be classified as possibly carcinogenic to humans.

As strange as it may sound, the new studies aren't necessarily contradictory ,since the IARC needed to put mobile phones into a pre-defined risk category.

We are trying to say in plain English what we believe the relationship is. They (IARC) were trying to classify the risk according to a pre-set classification system, said Anthony Swerdlow of Britain's Institute of Cancer Research, who led the review first study told Reuters.

Mobile phone use has risen hugely since the early 1980s, with nearly 5 billion handsets in use today.