Researchers have found a similarity between placentas and tumors that allowed armed malaria proteins to kill cancer cells, UPI reports.

The researchers were working on a vaccine for pregnant women who contract malaria. The treatment killed several different types of cancer in the lab.

The method of attacking cancer was effective on mice in the treatment of several different types of cancer.

However, researchers said they are not sure if the treatment would be effective on humans.

"For decades, scientists have been searching for similarities between the growth of a placenta and a tumor," said Ali Salanti, a professor in the department of immunology and microbiology at the University of Copenhagen, in a press release. 

"The placenta is an organ, which within a few months grows from only few cells into an organ weighing approx. two pounds, and it provides the embryo with oxygen and nourishment in a relatively foreign environment. In a manner of speaking, tumors do much the same, they grow aggressively in a relatively foreign environment."

Researchers found that the carbohydrate that the malaria cells attach to on a placenta is identical in cancer cells. The researchers then created the protein and added a toxin to it. The protein and toxin then target the cancer cells in the body, are absorbed, release the toxin and the cancer cells die.

Based on the mice, the researchers report the malaria protein appears not to target cells other than cancer.

The study is published in cancer cell.