Differential expression of glu-tubulin in relation to mammary gland disease

Tubulin is one of the molecular components that regulate cytosketal structure relating to cell differentiation, invasion, and metastasis in cancer. Recently, glu-tubulin, in which the C-terminal tyrosine of alpha-tubulin is removed by tubulin carboxypeptidase, overexpression has been reported in malignant tumors of the mammary gland immunohistochemically. We identified 147 cases accessioned in the Department of Pathology, International University of Health and Welfare Hospital from 2003 to 2009. Of the 78 malignant tumor cases, staining for glu-tubulin was observed in 56 (71.8%), and only 22 cases showed no significant staining. However, in benign disease, glu-tubulin staining was detected in the cytoplasm of fibroblasts and endothelial cells, but was completely absent from epithelial cells in 64 of 69 cases. When the expression of glu-tubulin was compared between malignant tumor, benign tumor, and other benign disease, a significant differentiation was found among expressions of this protein. These results indicate that glu-tubulin represents a strong selective expression for cancer cells and may be useful to identify and quantify human breast cancer.