Expression of vascular endothelial growth factor family messenger RNA in diseased thyroid tissues

Purpose. Four different factors have recently been identified in the vascular endothelial growth factor (VEGF)family, namely, VEGF-A, VEGF-B, VEGF-C, and VEGF-D. We investigated the expression of each VEGF gene in diseased thyroids using the multiplex reverse transcription-polymerase chain reaction (RTPCR) method. Methods. The subjects were 61 patients (11 with Graves' disease, 41 with primary papillary carcinoma, and 9 with recurrent papillary carcinoma). A semiquantitative multiplex RT-PCR was designed to compare the RT-PCR products of each VEGF mRNA with P-actin mRNA products to determine the relative expression. Results. VEGF-A and VEGF-B mRNA were expressed in all patients, VEGF-C mRNA was expressed in 58 (95.1%), and VEGF-D mRNA was expressed in 28 (46.0%). The expression of VEGF-D mRNA was significantly lower than that of the other VEGF mRNAs. The patients with papillary carcinoma and nodal involvement had significantly higher expression of the VEGF-C mRNA than those without nodal involvement. The expression of VEGF-C mRNA did not directly represent nodal involvement; however, the number of metastatic lymph nodes was positively correlated with the expression of VEGF-C mRNA in the primary tumor. Conclusions. To our knowledge, this is the first clinical study on VEGF-B, VEGF-C, and VEGF-D mRNA expression in diseased thyroids. Although VEGF-C mRNA expression was required for nodal involvement, we assume that other factors and mechanisms are also involved.