All an eye is is a cluster of specialized, photosensitive cells. Many microorganisms (i.e. bacteria) who rely on light for photosynthesis are able to sense where light is and move towards it. In that way, some bacteria can be considered to have eye-like functions.

There are certain functions a cancer cell needs to perform and thus certain gene types that need to be mutated. It’s by no means an intentional action on the part of the cancer, but if the cancer can’t grow uncontrollably, get blood flow, evade the immune system, and eventually metastasize it’s not a very effective cancer. The most common cancer types are also often in cells exposed to carcinogens in the environment (lung, skin, etc.).