Squalene is a compound found in Olive Oil and in high amounts in shark oil. It was touted as the reason sharks don't get cancer, until it was found that sharks can get cancer. Squalene however, remains an anti-cancer compound, is fairly healthy, and benefits cholesterol levels.
Squalane is a nutritional compound found mostly in olive oil and shark oil, and to a lesser extent in wheat germ and rice bran. It can be consumed at high levels through the diet alone if consideration is paid, although supplementation can also help.
It helps protect the body against cancer and the effects of aging, and is generally well tolerated and safe.
A typical preventative dose to alleviate cancer risk would be in the range of 300mg a day, to mimic the dosages found in the mediterranean diet.
Dosages above this are well-tolerated.