Moles increase the risk of developing melanoma, the most deadliest type of skin cancer, by four times, according to a study by the University of Melbourne, University of Oxford, and the Epworth HealthCare.

Every year, around 2,000 Australians die from skin cancer. Australia has one of the highest skin cancer rates in the world.

For the study, the researchers compared the medical records of two groups of people - 271,656 with moles recorded during a hospital visit and 10,130,417 without any mole. The researchers found that the group with moles were approximately 4.6 times more likely to be diagnosed with melanoma than the other group.

"We found that the increase was greater when the mole was at the same site as the melanoma - people with moles on their trunk were nine times more likely to develop melanoma on the trunk, and 5.6 times more likely to develop melanoma elsewhere on the body," Professor Rodney Sinclair, Professor of Medicine at the University of Melbourne and Director of Dermatology at Epworth HealthCare, said in a statement.

"Our results show patients with a hospital diagnosis of moles, have a high risk of developing melanoma both around the site of the mole and elsewhere on the body."

Sinclair recommends people to regularly check their moles and report any change (size, shape and color) to their doctors. These people might benefit from immediate diagnosis.

"When melanoma develops in a pre-existing mole, there is usually an area of colour change, and it is the distinction in colour from the remainder of the mole that is a clue that it might be harmful. If a new mole develops in an adult, then it is best to see your GP," said Sinclair.

The researchers from the Indiana University, Harvard University and INSERM have discovered a novel predictor of breast cancer - Cutaneous nevi or moles. Women, who have many moles on their skin, face heightened risk of developing breast cancer.

"Additional studies should be carried out to investigate melanocytic nevi and other cutaneous features in association with the risks of breast cancer and other estrogen-related proliferative diseases. It is our hope that this research will provide etiologic insights and test practical uses of nevi and related phenotypes for their potential utility in breast cancer risk assessment," the researchers said in a press release.