Caveolin-1 expression could be determined in 236 of 295 cases of benign breast disease (80.0%); in detail, 148 of 167 cases of fibroadenoma (88.6%), 65 of 93 cases of sclerosing adenosis (69.9%), 21 of 33 cases of ductal hyperplasia (63.6%) and both cases of radial scar (100%) could be evaluated. Here, CAV1 is linked to breast fibrocystic disease.