Persistent infection by chlamydia and gonorrhea may increase the risk of cancer via damage to the DNA, according to a report published in the journal Cell Host & Damage. In addition to mutating host cell DNA, the disease also inhibits cellular mechanisms intended to repair the damage.

Researchers at the Max Planck Institute for Infection Biology in Berlin grew human cells in a lab, then infecting them with chlamydia. The group of cells infected were more likely to show damage than their uninfected counterparts.

The researchers also found that the damage done to the cells is similar to the damage done by cancer. Cells that did not simply die when infected went on to reproduce others imprinted with the same DNA damage.

In 2009, the Center For Disease Control reported that 84,000 women were diagnosed with a gynecologic cancer. It's unclear how many may have been linked with a chlamydia infection, but doctors urge women - who can host the disease for long periods of time with no symptoms - to get screened for it.