I was recently watching a british late night satiracal talk show [presented as i recal by marcus brickstock not quite as posh as his name suggests.] not unlike john stewarts the daily show in america, and on this particular edition they had someone from a pro smokers organisation come on and interestingly the man [i remember he was a man but not his name] admited that he himself did not smoke but more interestingly than that one of the things that he said was that there is no proof that smoking causes cancer and even more interestingly than that i slowly began to think that he may actually be right about that. What we know about smoke be it from a cigar, or a bonfire, or a cars engine is that it causes lung damage by working its way into the capilerys and slowly but surely stopping the lung from working properly, what we know about cancer is that it is caused by a mutation of cells that slowly expands causing other cells to mutate and then becoming a tumor this process is often caused by radiation and often by a persons genetic code it isn't in and of itself caused by the lung damage caused by smoking nor is a tumor to be cosidered lung damage in and of itself.