Heredity is more of a factor than anthing else when it comes to these diseases like cancer, diabetes, etc...
But we all know that second hand smoke is the culprit. It must be villified and we must protect you from your own self, flaglady. You're incapable of doing it.
:-)
My dad's primary cancer was in his kidney, but it spread to his lungs and killed him.
My brother had melanoma and goes for routine MRI's because he's been told that "if" it has spread, the most likely place it will show up is in his lungs.
My girlfriend's sister had breast cancer, but lung cancer killed her in the end.