OBJECTIVE: To investigate the role of KAI1 gene expression and loss of heterozygosity (LOH) of KAI1 in metastatic potential and prognosis of pancreatic cancer. METHODS: The expression of KAI1 gene was studied by immunohistochemistry for CD82 on paraffin-embedded tumor tissues. The LOH of KAI1 gene was detected by microdissection, polymerase chain reaction (PCR) and denaturing high performance liquid chromatography (DHPLC). RESULTS: The positivity rate of CD82 in primary pancreatic cancer was 76% (47/62). CD82 expression was significantly higher (P < 0.01) in earlier tumor stages (I and II), as compared to the advanced tumor stages ( III and IV) in which nodal or distant metastases were present. The expression rate of CD82 in patients who survived for more than one year was higher than that in patients who survived for less than one year (P < 0.05). The percentage of LOH at D11S1344 and D11S1326 loci was 17%. CONCLUSIONS: The abnormal expression of CD82 which participates in malignant progression of pancreatic cancer is probably associated with LOH of KAI1 gene. Detection of CD82 expression and LOH of KAI1 gene may carry potential clinical significance in evaluating the metastatic potential and prognosis of pancreatic cancer.