OBJECTIVE.
Mucin 4 (MUC4) is a transmembrane
glycoprotein that is expressed in pancreatic ductal
adenocarcinoma (PDAC), but not in normal pancreatic tissue. MUC4 has a proposed role in pancreatic
tumor progression and
metastasis. The purpose of this pilot study was to investigate MUC4 expression during PDAC
metastasis by comparing the expression in the primary
tumor and paired
lymph node metastases from the same patient. MATERIAL AND METHODS. Surgical specimens from 17 cases of primary PDAC and paired
lymph node metastases were immunohistochemically analyzed for MUC4 expression. The modified histochemical score (H-score) was used for staining assessment. RESULTS. Positive staining for MUC4 was detected in most primary and metastatic PDAC
tumors (15/17 vs. 14/17). The concordance for MUC4 expression in primary
tumors and corresponding
lymph node metastases was 82%. In two cases, the primary
tumor was MUC4-positive and the
lymph node metastases were negative, while in one patient with a MUC4-negative primary
tumor, the
lymph node metastasis was positive. The distribution of H-score for expression of MUC4 significantly correlated (r = 0.615; p = 0.009) between primary
tumors and paired metastatic lesions.
CONCLUSIONS: MUC4 was observed in both primary and matched metastatic
tumors with a high level of concordance, suggesting that MUC4 expression is retained following PDAC
metastasis.