Kasahara isoenzyme is associated with which cancer?

• A. Gastrointestinal
• B. Lung
• C. Breast
• D. Pancreatic

Answer: (A)

Enzyme isoforms circulating in blood can reflect the tissue origin of a tumor, since cancers often alter which isoforms they express. Kasahara isoenzyme is a pattern that has been linked historically to malignancies of the gastrointestinal tract. Because this isoenzyme tends to be elevated in GI cancers and is not characteristically elevated in lung or breast cancers (and is not specific to pancreatic cancer alone), the best match among the options is gastrointestinal cancer. Remember, such isoenzyme markers are not perfectly specific and are used alongside imaging and other tests to guide diagnosis.