Swedish researchers have discovered that a substance found in human breast milk has the ability to kill cancer cells, according to a study published in the PLoS One Journal.

The substance known as HAMLET (Human Alpha-lactalbumin Made Lethal to Tumor cells), was discovered years ago, but has just recently been tested on humans.

In the trial conducted at Lund University in Sweden, patients suffering from bladder cancer were treated with HAMLET. After each treatment, the patients excreted dead cancer cells in their urine, healthy cells remaining intact.

Previous laboratory experiments showed that HAMLET has the ability to kill 40 different types of cancer cells, but this was the first test conducted on humans. The next step will be to test the substance on skin cancer and brain tumors.

The trial breakthrough increases the hopes that HAMLET will be developed into a cancer treatment medication in the future.

Click here to read more from PLoS One.