Erxi Wu, assistant professor of pharmaceutical sciences, has been invited to write a commentary on a clinical case for the journal, Clinical Advances in Hematology and Oncology. The commentary will be published in January.
The clinical case reports a 58-year-old Caucasian male with stage I pancreatic head adenocarcinoma whose fluctuating carbohydrate antigen 19-9 level did not reflect recurrent pancreatic malignancy. The carbohydrate antigen 19-9 level of the patient decreased from 120 U/ml pre-operation to 89 U/ml after resection. Upon receiving chemotherapy, his carbohydrate antigen 19-9 level was fluctuating without significant clinical symptoms.The patient was later diagnosed with melena and anemia associated with elevated carbohydrate antigen 19-9 levels, which were reduced by a proton pump inhibitor treatment.
According to Wu and his associates, the case supports the statement that carbohydrate antigen 19-9 should not be the only indicator used for diagnosing pancreatic cancer. As pancreatic cancer is one of the leading causes of cancer death with a five-year survival rate of only 4-6 percent and the poor prognosis of pancreatic cancer is attributed to the lack of effective therapy, the late stage presentation, early recurrence and the absence of well-grounded clinical harbingers of early disease, revisit of carbohydrate antigen 19-9 value as a marker for pancreatic cancer is worthwhile, Wu said.
According to the authors, carbohydrate antigen 19-9 also is known to be a sialylated Lewisa blood group antigen. Elevated levels, >37 U/ml, of carbohydrate antigen 19-9 have been associated with gastrointestinal carcinomas, particularly in pancreatic cancer, and is considered one of the most favorable biomarkers for the management of pancreatic cancer. It is the only biomarker related to pancreatic cancer for which U.S. Food and Drug Administration-cleared diagnostics exist.
However, carbohydrate antigen 19-9 seems to fail to fit these standard biomarker criteria due to its inadequate sensitivity, false negative results in Lewis blood type negative, Lea-b-, population and high false positive results induced by obstructive jaundice, 10-60 percent. Another limitation of carbohydrate antigen 19-9 is it may be markedly elevated in patients with other malignancies such as colorectal, liver, breast and lung cancers, as well as non-malignant diseases such as obstructive jaundice, pancreatitis, cirrhosis and lung disorders.
It has been reported markedly elevated carbohydrate antigen 19-9 levels also can be associated with heavy tea consumption. We think that it is necessary to do in-depth investigation on CA 19-9 and to make use of its value as marker for pathological conditions, especially for pancreatic cancer. First, simultaneously measurement of the CA 19-9 antigen and its specific carrier may provide improved prognosis compared with the detection of total CA 19-9. Second, a better understanding of CA 19-9 epitope, sialy-Lewisa binding specificity may be able to optimize the CA 19-9 assay to improve cancer detection. It may also be desired to combine other tumor markers for this malignancy to increase the sensitivity and specificity, Wu said.
For more information on Wus background and research, visit www.ndsu.edu/pharmsci/faculty_staff/erxi_wu.
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