Alterations of MUC1 and MUC3 expression in gastric carcinoma: relevance to patient clinicopathological features

Aims: Several studies have reported conflicting and inconclusive results concerning the clinical relevance of mucin expression in gastric carcinoma. This study investigated the correlations between aberrant expression of mucins in gastric carcinoma and patient clinicopathological features. Methods: The expression of MUC1, MUC2, MUC3, MUC5AC, and MUC6 was investigated immunohistochemically in gastric carcinoma (n=46) in relation to patient clinicopathological features. Results: All normal gastric mucosa samples expressed MUC1, MUC5AC, and MUC6. MUC1, MUC2, MUC3, MUC5AC, and MUC6 were expressed in 29, 31, 30, 18, and 21 of the 46 cases of gastric. carcinoma, respectively. The number of cases expressing MUC1 was significantly higher (p<0.01) in patients with a small tumour size (>= 5 cm) and in patients in clinical stages I-II, compared with clinical stages III-IV (p<0.05). Expression was significantly lower (p<0.05) in patients exhibiting metastasis. The number of cases expressing MUC3 was significantly higher in patients in clinical stages III-IV (p<0.05), and in those with serosal invasion (p<0.05) or metastasis (p<0.01). No significant relations were found between MUC2, MUC5AC, MUC6, and clinical stage, metastasis, or tumour size. Conclusions: Membrane bound mucins MUC1 and MUC3 appear to be associated with the development of gastric carcinoma. Patients who maintained high immunoreactivity for anti-MUC1 antibody had a better prognosis whereas those with an increase in anti-MUC3 immunoreactivity had a poorer prognosis, as judged by tumour size, serosal invasion, and metastasis. However, no correlation was found between MUC2, MUC5AC, or MUC6 and clinical prognosis.