To investigate the changes of tenascin (TN) expression during the course of canceration through atypical hyperplasia of breast epithelia. The SP immunohistochemical method was used to study TN expresson in 50 different breast tissues. Results: There was no TN expression in normal breast and grade Ⅰ hyperplasia; immunostaining of TN was detected in 2 cases with grade Ⅱ atypical hyperplasia; the expression of TN in grade Ⅲ atypical hyperplasia (80%) and infiltrating ductal breast cancer (90%) was significantly higher than that in grade Ⅱ atypical hyperplasia (20%); and immunostaining of TN was detected in part of the cancer cells. Conclusion: These results suggest that TN expression in the stroma of serious atypical hyperplasia may play a role in limiting the outgrowth of hyperplastic epithelia.
