There are plenty of chemicals that can cause a chemical reaction to happen without being destroyed themselves. These are known as catalysts and include enzymes,

There are plenty of chemicals that can cause a chemical reaction to happen without being destroyed themselves. These are known as catalysts and include enzymes, for example. I don’t know what the mechanism is for these chemicals to be carcinogenic but there’s no reason to assume that just because they don’t break down that means they are safe to ingest.