Galectin-3 and CD44v6 as markers for preoperative diagnosis of thyroid cancer by RT-PCR

The aim of the study was to determine the diagnostic value of reverse transcriptase polymerase chain reaction (RT-PCR) analysis of galectin-3 and CD44v6 as markers for preoperative diagnosis of malignancy in lesions of the thyroid. RT-PCR analysis of galectin-3 and CD44v6 expression was performed on RNA isolated from fine-needle aspirates of thyroid lesions from 428 patients. The results were evaluated against the postoperative histopathological diagnosis or definitive cytological diagnosis in cases of nodular goiter and Hashimoto thyroiditis. A total of 57 (13%) samples were inadequate for RT-PCR. Galectin-3 and CD44v6 were positive in 167 (45%) and 158 (43%) out of 371 adequate samples, respectively. Galectin-3 and CD44v6 were positive in 56 (86%) and 54 (83%) out of 65 papillary carcinomas, in 16 (29%) and 18 (32%) out of 56 Hashimoto's thyroiditis, in 61 (34%) and 52 (29%) out of 181 nodular goiters, in 23 (43%) and 23 (43%) out of 53 follicular adenomas, in 3 (100%) and 3 (100%) out of 3 follicular carcinomas, and in 8 (62%) and 8 (62%) out of 13 Hurthle cell adenomas, respectively. Specificity, sensitivity, and positive and negative predictive values in discriminating between malignant and benign thyroid nodules were 64, 87, and 35 and 96% for galectin-3; 67, 84, and 36 and 95% for CD44v6; and 79, 82, and 47 and 95% for the analysis of both markers (considered positive only if both galectin-3 and CD44v6 were positive), respectively. Owing to relatively low specificity, the clinical value of galectin-3 and CD44v6 analysis by RT-PCR as a marker for preoperative diagnosis of malignancy in thyroid lesions is limited.