Scientists at Lund University in Sweden were doing some research and needed bacteria and human cells, so they used tumor cells (from humans) and human breast milk. That's when they realized that something in the breast milk was not only killing the bacteria, but ALSO the cancer cells in the tumor!
In brief, the substance, nicknamed 'Hamlet', goes after cancer cells while leaving the healthy cells untouched, and that means it would be much more gentle than chemotherapy..
They've done some clinical trials, and are planning more.
They say there's a lot of work to be done, however, this looks promising!