Let's take a step back and think about this. Cancer happens all the time - it's whether or not your body, or nature, or whatever synthesis happens that leads it to be a health risk or not. Mutation of cells and multiplication of these "sick" cells and interaction with DNA and the whole immune system. This happens all around us all the time, however only some of them actually form into cancerous cells and cause us to have health problems. Some of it is down to genetics unfortunately, some of it is down to the strength of the cancer forming cells or the susceptability of the victim. You cannot categorically state that ham will cause cancer. Most things in excess can have the potential of causing or increasing the risk of cancer. Take UV light, in small doses it's bloody good for you, however in excessive doses it can cause skin cell mutations and lead to cancer cells forming. Ham whether processed or not (though I really really hate processed foods and keep away from them as much as I can) is going to be fine, but the manufacturing process can cause the protein strands and cells within the meat to change slightly - which in turn if you're unlucky and eat the right quantity you could have a chance of developing something - but really, honestly, you shouldn't worry about. Eat a balanced diet, lots of fruit and veg, keep your sat fats low, and exercise and you will minimise your chances - unfortunately with cancer no one is immune.