| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2001: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
OBJECTIVE : Currently there is no simple test to detect pancreatic cancer (PC). Fasting plasma islet amyloid polypeptide (IAPP) was reported to be increased in patients with PC and a soluble factor from PC cells was reported to stimulate IAPP secretion, suggesting the possibility of an usefulness of IAPP as a marker for early detection of PC. Therefore, sensitivity and specificity of plasma IAPP in combination with CA19-9 for early detection of PC were studied. METHODS : Since IAPP is easily degraded by.proteases present in blood, plasma samples were collected in tubes containing protease inhibitors (2 mg/L antipain dihydrochloride, 25mg/L elastatinal, 0.5mg/L leupeptin and 0.5g/L EDTA). The assay system for plasma IAPP was established I (Am J Pathol 157 : 2101, 2000). RESULTS : In samples from controls, IAPPwas 1.8 - 5.9 pmol/L. Mean plasma IAPP concentration was increased in patients with PC as compared with controls (mean±SE, 7.1±0.9 vs 4.0±0.3 pmol/L). Patients with cancer of islet cell, ampullary, gallbladder and renal cell and with acute and chronic pancreatitis also showed high levels. Sensitivity and specificity of IAPP for detection of PC were 47% and 73%, respectively, when a cutoff of 6 pmol/Lwas used. IAPP was stable by 2h at 4℃ plasma in the presence of the protease inhibitors. By contrast, synthetic IAPP added to plasma containing aprotinin and EDTA, which are routinely used for estimation of other peptides, lost 16% of IAPP activity by 2hat 4℃. A combination of IAPP and CA19-9 showed a sensitivity of 85% with a specificity of 63% when either IAPP or CA19-9 was higher than each cutoff value. CONCLUSIONS : These results suggested that plasma IAPP lacks sensitivity for detection of PC and is not powerful as a tumor marker when used by itself. The difficulty of finding a tumor marker for PC may reflect heterogeneity of PC cells.
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