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.

A positive attitude does not cure cancer, any more than a negative one causes it.

It remains an astonishing, disturbing fact that in America - a nation where nearly every new drug is subjected to rigorous scrutiny as a potential carcinogen, and even the bare hint of a substance's link to cancer ignites a firestorm of public hysteria and media anxiety - one of the most potent and common carcinogens known to humans can be freely bought and sold at every corner store for a few dollars.

Pharmacology is benefited by the prepared mind. You need to know what you are looking for.

Cancer's life is a recapitulation of the body's life, its existence a pathological mirror of our own. Susan Sontag warned against overburdening an illness with metaphors. But this is not a metaphor. Down to their innate molecular core, cancer cells are hyperactive, survival-endowed, scrappy, fecund, inventive copies of ourselves.

Most discoveries even today are a combination of serendipity and of searching.

I left Delhi in 1989 and remember very little of how life used to be then. Increasingly, in my recent visits to Delhi, I've started to realize that the city has become intellectually very lively. It makes me want to discover the city over and over again.