Overexpression of MAC30 in the cytoplasm of oral squamous cell carcinoma predicts nodal metastasis and poor differentiation.

BACKGROUND Expression of the meningioma-associated protein (MAC30) was increased in several types of tumors, including esophageal, gastric and colon tumors, compared to normal tissue. MAC30 expression levels gradually increased from normal colorectal mucosa to primary colorectal cancer and colorectal cancer spreading to the lymph nodes. MAC30 expression was related to survival in patients with colorectal cancer. However, there is no study on MAC30 in oral squamous cell carcinoma (OSCC). METHODS Therefore, MAC30 expression in OSCC was investigated and possible associations of MAC30 expression with clinicopathological variables in OSCC have been analyzed. MAC30 expression was immunohistochemically examined in 20 normal oral mucosa and 43 OSCC specimens. RESULTS Expression levels of MAC30 in the cytoplasm markedly increased from normal oral epithelial cells to primary OSCC. Strong cytoplasmic staining was significantly higher in primary OSCC compared to normal oral mucosa samples (51 vs. 20%, p = 0.019). Furthermore, MAC30 expression levels in primary tumors of patients with lymph node metastasis exceeded levels in those without metastasis (65 vs. 35%, p = 0.048), and MAC30 expression in poorly differentiated tumors was higher than in well-differentiated ones (90 vs. 39%, p = 0.005). CONCLUSION Overexpression of MAC30 in the cytoplasm of OSCC may predict nodal metastasis and poor differentiation.