There is a common gene in lung, breast, colon and prostrate cancer. It is called the BRCA1 gene and it can easily be tested for. The problem with the test is if you find you carry it, you will spend the rest of your life thinking that every little pain or illness is cancer!!! The bigger problem is that if you find you carry the gene, obtaining health insurance can become difficult as you'd have a 'pre existing condition.'
There are many websites that discuss the advantages of testing for this gene.
Hope this information helps.
Stacey