Clinical Significance of Chromogranin-A Expression in Bile Duct Cancer

Kim, Ki Hwan; Kim, Sun Whe; Kim, Woo Ho; Park, Yong Hyun

Abstract

BACKGROUND: Chromogranin A (CgA) is a 49-kDa glycoprotein produced by endocrine cells and is stored and secreted together with the resident hormones of electron-dense core secretory granules. Although the physiologic role of this protein is still unclear, recent data suggest that it may play a critical role in the maturation of secretory granules. This study was performed in order to evaluate the clinical significance of CgA expression in bile duct cancer.
METHODS
The cases of 113 patients who underwent operations for bile duct cancer from 1986 to 1995 were reviewed for clinicopathologic characteristics, and deparaffinized sections of formalin-fixed tumor tissue samples were immunostained for CgA by using ABC method.
RESULTS
Forty cases (35.4%) had tumor cells stained with CgA. Although poorly differentiated tumors (n=8) were not stained by CgA, no differences were noted in the positive rates for other clinico-pathologic characteristics, including age, sex, extent of disease, lymph-node metastasis, gross type, location of the tumor, and AJCC TNM stage. Eighty-three (83) curatively resected patients were analyzed for survival time based on clinico pathologic characteristics and CgA positivity. There was no difference in the overall survival time between the CgA positive (n=28) and negative (n=55) patients. However, in cases (stage III or IV, n=51) with lymph-node metastasis or adjacent organ invasion, patients (n=17) with a CgA- positive tumor had a significantly better prognosis than those (n=34) with a CgA-negative tumor (p=0.0318). The prognoses for the 28 cases with CgA-positive tumors did not correlate with known prognostic factors, including the TNM stage. Therefore, a CgA positive tumor may have a different tumor biology from that of a CgA negative tumor.
CONCLUSIONS
Neuroendocrine differentiation in bile duct cancer is not a rare phenomenon and may be associated with a good prognosis for advanced bile duct cancer patients who have undergone a curative resection.