S100A4 expression is an early event of papillary carcinoma of the thyroid

Objectives: S100A4 is a calcium-binding protein related to the metastatic potential of carcinoma. In order to elucidate its contribution to the progression of thyroid carcinoma, we investigated S100A4 expression in various thyroid neoplasms. Methods: We immunohistochemically examined S100A4 expression in 195 cases of thyroid neoplasms. Results: Although S100A4 was absent in normal follicular cells and follicular adenoma, S100A4 was positive in all 115 cases of papillary carcinoma examined, including 58 microcarcinomas. However, a significant relationship could not be established between S100A4 expression and clinicopathological features of papillary carcinoma. In follicular carcinoma, the widely invasive type expressed S100A4 more frequently than the minimally invasive type ( p = 0.0028). In anaplastic carcinoma, S100A4 was expressed in 61.9% of cases, but the incidence was significantly lower ( p < 0.0001) than that in papillary carcinoma. Conclusions: These findings suggest that ( 1) S100A4 plays a constitutive role in papillary carcinoma and ( 2) S100A4 may be a useful marker for early the detection of this carcinoma. Copyright (C) 2004 S. Karger AG, Basel.