Cancer. The mere mention of the word can drudge up discomfort, as most everyone knows it's second only to heart disease when it comes to claiming lives. Unlike heart disease, though, cancer is difficult to prevent and similarly difficult to fight.

The battle against the myriad forms of cancer, however, also is an opportunity for investors - namely, in health care stocks.

Sales of drugs used to fight the disease are expected to exceed $160 billion by 2021. But because there are so many different types of cancer, that revenue has been and will continue to be widely distributed among the pharmaceutical makers of superior cancer-fighting solutions.

Here's a rundown of the market's top cancer-fighting health care stocks. They come in all shapes and sizes. Some are tightly focused - perhaps only making one drug - while some are arguably overly diversified. In all cases, however, a cancer treatment has the potential to be a game-changer - not just for investors, but for cancer patients as well.

Incyte

The past 12 months have been nothing less than miserable for Incyte (INCY, $70.11) shareholders. Shares have fallen roughly 50% from their July 2017 peak, and the stock's suffered a couple of downgrades just recently. RBC Capital Markets analyst Brian Abrahams downgraded Incyte in June, for instance, lamenting the lack of near-term revenue clarity.

Don't let the stock's poor performance or downgrades mislead you. Incyte has a powerful cancer-fighting drug called Jakafi in its