Which tumor marker is associated with pancreatic cancer?

CA 19-9 is the tumor marker that is most closely associated with pancreatic cancer. This carbohydrate antigen is a sialylated Lewis blood group antigen that is elevated in many patients with pancreatic adenocarcinoma. Its levels can also be high in other gastrointestinal malignancies and conditions such as cholangitis, but its strong association with pancreatic cancer makes it particularly useful as a marker in this context. Monitoring CA 19-9 can provide insight into the disease's progression and treatment response, although it is not used for screening or definitive diagnosis because elevated levels can occur in various other conditions.

On the other hand, beta-2 microglobulin, lactate dehydrogenase (LDH), and alpha-fetoprotein (AFP) are more commonly associated with other types of cancers or conditions. For instance, beta-2 microglobulin is often linked with multiple myeloma and certain lymphoproliferative disorders, LDH is a nonspecific marker that can be elevated in many different malignancies or tissue damage, and AFP is primarily associated with hepatocellular carcinoma and germ cell tumors. Therefore, CA 19-9 is the most relevant marker in the context of pancreatic cancer.