I'm always sceptical when a big scientific discovery is in the news, especially when it's to do with something that affects lots of people, such as cancer.
But experts say a new study is a huge step towards finding treatments for breast cancer. They think they've found all 93 genes that, if they mutate, can cause breast cancer. The scientists could use this knowledge to help create new drugs that accurately target a patient's specific form of cancer.
I don't want to celebrate just yet, but this looks like great news in the search for new cancer treatments.