Apolipoprotein E expression in anaplastic thyroid carcinoma

Objectives: Apolipoprotein E ( Apo E) has been known to play a role in cholesterol transport and metabolism. However, recently the relationship between Apo E and carcinoma progression has been investigated. In this study, we investigated Apo E expression in thyroid carcinoma at both the protein and molecular levels. Methods: We investigated Apo E expression at the protein and molecular level in 124 thyroid neoplasms. Results: In RT- PCR and in situ hybridization, the Apo E mRNA expression level was very low in papillary and follicular carcinomas as well as normal thyroid, but was dramatically elevated in anaplastic carcinoma. In an immunohistochemical study, 32 of 33 anaplastic carcinomas ( 97.0%) showed high levels of Apo E expression, but this phenomenon was seen only in 1 of 51 papillary carcinomas ( 2.0%). None of the follicular carcinomas or adenomas showed high levels of Apo E expression. Conclusions: These findings suggest that Apo E is one of the typical biological characteristics of anaplastic thyroid carcinoma. Copyright (C) 2006 S. Karger AG, Basel.