pancreas diseases : Development of a blood test for pancreatic cancer pt2

Final Report
Pancreatic cancer is one of the most lethal of human diseases. It is the fourth leading cause of cancer-related death among men and women in the United States. The average five-year survival rate is less than 5%. In 1999, the expected death rate includes 2,700 California residents and 28,600 individuals in the United States of America.

Numerous scientific studies designed to reveal the causes of pancreatic cancer have consistently identified cigarette smoking as a significant risk factor. In fact, cigarette smoking remains the only well-established risk factor for pancreatic cancer. The risk of pancreatic cancer appears to correlate with the amount of cigarette smoking. These findings have been supported by experiments in the laboratory. When laboratory rats are fed chemicals derived from tobacco, cancers of the lung and pancreas result. Thus cigarette smoking can cause pancreatic cancers.

At this time, the only therapy for pancreatic cancer is surgical removal early in the course of the disease. Unfortunately, pancreatic cancer is usually discovered when symptoms appear and the disease is far advanced. The diagnosis of pancreatic cancer currently requires sophisticated medical technology. A simple blood test that is able to indicate whether pancreatic cancer is present would represent a major step toward the early diagnosis of pancreatic cancer. The early diagnosis of pancreatic cancer followed by surgery is currently the only hope for patient survival.

Studies supported by the TRDRP enabled our laboratory to develop a blood test for a protein, GP2, which is made only in the pancreas and is released into the bloodstream with pancreatic disease. Our previous success with laboratory animal models of pancreatic diseases led to the efforts toward developing a similar blood test for humans with pancreatic cancer. The development of the antibodies for this project required the cloning of the human GP2 gene, which was used to produce the protein in cultured cell lines. The protein was then used to immunize mice, from which the subsequent antibodies were derived. With the availability of the necessary reagents, we were successful in developing a sensitive test for GP2. Normal GP2 blood levels were established using human subjects without a history of pancreatic disease.

Our initial result with 20 patients with pancreatic disease showed that the average GP2 level was significantly elevated in patients with pancreatic cancer and other pancreatic diseases. The sensitivity of the test in our small sample of patients was 60%, which was approximately equivalent to CA19-9, the most commonly used marker for pancreatic disease at this time. The sensitivity is less than the desired 80% level needed to be used as a screening tool. The assay was correct 70% of the time when used to detect any type of pancreatic disease. Whether the GP2 assay will be useful in pancreatic cancer or other pancreatic diseases will be determined as more patients are enrolled in the future.

by Anson Lowe , M.D. -