Which tumor marker is commonly used to confirm the diagnosis of chronic myeloid leukemia?

The BCR-ABL fusion gene is a key marker used in the diagnosis of chronic myeloid leukemia (CML). This specific genetic alteration results from a translocation between chromosomes 9 and 22, leading to the formation of the Philadelphia chromosome. The presence of the BCR-ABL fusion gene causes the overproduction of abnormal white blood cells, which is characteristic of CML.

Detecting this fusion gene through laboratory tests, such as polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH), is crucial for confirming the diagnosis of CML. The identification of the BCR-ABL fusion gene not only supports the diagnosis but also helps in monitoring the disease and assessing the efficacy of targeted therapies.

The other tumor markers listed serve different functions and are associated with other conditions. Immunoglobulins are involved in various immune responses, CgA is primarily associated with neuroendocrine tumors, and CEA is often linked to colorectal cancer. Hence, they do not play a direct role in confirming a diagnosis of chronic myeloid leukemia.