The three main factors that contribute to pancreatic cancer are genetics, exposure to carcinogens and chance. Pancreatic cancer begins when the DNA of a single cell is damaged and the cell begins to function abnormally. The exact cause of this malfunction can never be ascertained for any given patient, but according to Johns Hopkins Medicine, certain factors are known to increase the risk of pancreatic cancer.
Johns Hopkins Medicine notes that some people are genetically predisposed toward pancreatic cancer. Every human carries a complement of genes inherited evenly from a mother and a father, either of which might be defective. If a person has inherited one gene that is likely to become defective, and the second, normal copy is damaged in some way, the damaged cell is left without a backup gene, and cancer may develop.
Random chance plays a role in this process. As each cell divides and multiplies, there exists a chance that the DNA duplication is not executed perfectly. Such imperfect replication can damage the DNA and lead to cancer. The likelihood of damage is, according to Johns Hopkins Medicine, influenced by behavior. Smokers are routinely exposed to multiple carcinogens and over time, the chemicals in tobacco smoke are likely to damage cancer-suppression genes.