But now, researchers at Johns Hopkins Medicine have found that they may also kill some cancer cells by starving them of nutrients, and uncovered the mechanism for how that can happen.

In experiments in lab cultures of engineered cells, the researchers found that statins were effective against cancer cells that had a mutation in a gene called PTEN. One type of statin in particular, called pitavastatin, managed to kill almost all of the cancerous cells without affecting many of the healthy human cells around them.

The researchers didn't set out to specifically test for statins' effects on cancer – they were working the other way around. The team was running through an FDA database of 2,500 drugs to see which ones might work against cancer, and statins emerged as one of the most effective.

Next, the researchers investigated how the statins were working. One of the known effects of the drugs is that they block production of a molecule called geranylgeranyl pyrophosphate (GGPP) – and, it turns out, this molecule may be vital for cancer cells to survive.