International researchers have found five gene variants linked to deadly prostate cancer that could lead to better diagnosis and eventually treatment.

The findings of the US-Swedish research team could help doctors identify which patients have a version of the tumor that could potentially kill them next to those who can be easily treated.

Doctors have been puzzled for years over why some tumors turn deadly while others can be closely monitored for years without growing.

"While previous studies have suggested that genetic background influences prostate cancer outcomes, this is the first study to validate genetic markers associated with lethal disease," said lead author Janet Stanford of the Fred Hutchinson Cancer Research Center in Seattle, Agence France Presse reported.

Researchers analyzed DNA in blood samples from 1,309 Seattle-area prostate cancer patients aged 35 to 74 at the time of diagnosis.

The five genetic markers they identified were: PR, RNASEL, IL4, CRY1 and ARVCF -- are single-nucleotide polymorphisms, or SNPs, DNA variations that may be linked to disease.

They focused on studying the SNP's in genes that potentially played key role biological pathways that could contribute to the progression of prostate cancer, such as inflammation, steroid-hormone production and metabolism, DNA repair, circadian rhythm and vitamin D activity.

They found 22 SNPs that were "significantly associated with prostate cancer-specific mortality," according to the study. They found that patients with a higher number of the SNP variants were at a higher risk of dying from the prostate cancer.

"Patients who carried four or all five of these genetic markers had a 50 percent higher risk of dying from their prostate cancer than patients who had two or fewer," said the study.

Prostate cancer is the most commonly diagnosed of all male cancers with 240,890 cases a year according to the National Cancer Institute. It kills about 32,000 men in the United States per year.