4586

MUC5AC

mucin 5AC, oligomeric mucus/gel-forming;MUC5AC;mucin 5AC, oligomeric mucus/gel-forming

gastric mucin|lewis B blood group antigen|major airway glycoprotein|mucin 5, subtypes A and C, tracheobronchial/gastric|mucin 5AC, oligomeric mucus/gel-forming pseudogene|mucin-5 subtype AC, tracheobronchial|mucin-5AC|tracheobronchial mucin

11p15.5

protein-coding

Molecular changes are vital for the development of prognostic markers and therapeutic modalities of prostate cancer (CaP). There is growing interest in mucins as treatment targets in human malignancies, including CaP. The role of their expression in the progression of CaP is however unclear. We examined the expressions MUC1, MUC2, MUC4, MUC5AC and MUC6 in CaP tissues using tissue microarrays (TMAs) to look for tumor-associated antigens (TAAs) for targeted therapy. In this study, 120 paraffin-embedded specimens were selected from patients who underwent radical retro-pubic prostatectomy (RRP) or trans-urethral-resection of the prostate (TURP) for primary, untreated CaP and 10 matched lymph node metastases. A series of MUC monoclonal antibodies (mAbs) was used on TMAs by standard immunohistochemistry. Our results indicate that the over-expression of MUC1 was detected in 58% of primary CaP tissues and 90% of lymph node metastases but not in normal prostate or benign tissues, while the expression of MUC2, MUC4, MUC5AC and MUC6 was found to be negative in both normal and cancer tissues. Of the MUC1 positive tumors 86% were Gleason grade 7 or higher. Over-expression of MUC1 was found in late stage CaP while MUC2, 4, 5AC and 6 were negative in CaP. MUC1 is a TAA that is highly related to tumor progression in CaP patients. This antigen is ideal for targeted therapy to control micrometastases and hormone refractory disease but additional studies are necessary to assess its usefulness in patient biopsies and CaP bone metastases before clinical trial.

The purpose of this study was to examine the expression pattern of MUC5AC and SOX2 in ampulla of vater adenocarcinoma and evaluate the association between expression of these gastric epithelial markers and the histologic phenotype of ampulla of vater carcinoma. Six surgically resected samples of ampulla of vater adenocarcinoma, including four intestinal type carcinomas and two pancreatobiliary type carcinomas, were studied. We performed immunohistochemistry with a monoclonal antibody against MUC5AC and a polyclonal anti-SOX2 antibody. In two of the four intestinal type carcinomas, MUC5AC and SOX2 were focally expressed in the superficial neoplastic mucosa. However, in the centre of the tumour and in other invasive lesions, including vascular invasive lesions and metastatic lymph nodes, neither MUC5AC nor SOX2 was expressed. In contrast, in both pancreatobiliary type carcinomas, expression of MUC5AC and SOX2 was maintained or increased in invasive lesions. Our immunohistochemistry data suggest that MUC5AC and SOX2 are associated with the pancreatobiliary phenotype of ampulla of vater carcinoma and involved in later events in carcinogenesis, such as invasion and metastasis.