look at this

http://www.guardian.co.uk/news/datablog/2011/jan/14/mortality-statistics-causes-death-england-wales-2009#zoomed-picture

in 2009, of the just under 500,000 people who died, 140,000 died of cancers of various kinds. it's a major cause of death, OF COURSE curing it has to be a major challenge for the human race

so, we've cured cancer. now what? well, would you look at this: people are living longer, but more importantly many fewer people are dying in their 20s, 30s, 40s, 50s, because there's no cancer to kill them. aging population just took a turn for the even more aging. and the population of the world just took a turn for the increasing even more

so, then what? what would be the long-term future of the human race and life on earth if we cured cancer? ok: speculate!