All cancers are alike but they are alike in a unique way.

In the laboratory, we call this the six-degrees-of-separation-from-cancer rule: you can ask any biological question, no matter how seemingly distant-what makes the heart fail, or why worms age, or even how birds learn songs-and you will end up, in fewer than six genetic steps, connecting with a proto-oncogene or tumor suppressor.

Cancer has enormous diversity and behaves differently: it's highly mutable, the evolutionary principles are very complicated and often its capacity to be constantly mystifying comes as a big challenge.

One swallow is a coincidence, but two swallows make summer.

In 2005, a man diagnosed with multiple myeloma asked me if he would be alive to watch his daughter graduate from high school in a few months. In 2009, bound to a wheelchair, he watched his daughter graduate from college. The wheelchair had nothing to do with his cancer. The man had fallen down while coaching his youngest son's baseball team.

There is a very moving and ancient connection between cancer and depression.

Probably the most important reason we are seeing more cancers than before is because the population is ageing overall. And cancer is an age-related disease.