My former Strength of Materials professor used to tell us:

"Nature is simple. If someone can't explain something to you in simple terms so that you understand it well enough to explain it to someone else, then it's only because they don't understand it themselves."

And, I've always found that to be true. Whenever anything seems complicated, it's only because we don't fully understand it. If we did, we'd see that it's simple.

Before Newton, asking why something fell when you dropped it was considered a stupid question. And, the orbits of the planets around the Sun were considered to be circles. That's because the Heavens are perfect, and a circle is a perfect shape, and so the only "correct" shape for a planetary orbit would be a circle. Then, Isaac Newton discovered the piece of the puzzle called "gravity", and we realized it wasn't a stupid question and why planetary orbits should be elipses instead of circles. That puzzle went from incomprehensible to simple with the discovery of gravity.

The cure for cancer is going to turn out to be simple. It seems complicated now only because we don't have all the pieces of the puzzle, or at least we don't know which pieces we're missing or which one's we're overlooking, and so we don't understand the process. Once we understand cancer better, we're going to have all the pieces and they're going to fall into place in a simple and understandable way, just like we now understand the causes and cures of cholera, leproscy and the Bubonic plague. Everything seems complicated until you understand it, and then it turns out to be simple after all. The greatest clue we have to understanding is that Nature always favours simplicity.