Increased expression of CD44 variants in differentiated thyroid cancers.

Expression of CD44 variants in thyroid tumors was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) with a fluorescent image analyzer. Increased expression of CD44 variants compared with normal thyroid tissues was observed in most thyroid follicular tumors, especially in follicular carcinomas, poorly differentiated papillary carcinomas and some follicular adenomas. However, variants were hardly detectable in an anaplastic carcinoma. Analysis with restriction enzymes revealed that the major PCR product, consisting of variant bands, was derived from CD44E. Therefore, the expression of CD44E may be associated with the proliferation of differentiated thyroid cells.