Preparation of thyroid tumor cells in aspiration biopsies for aspiration biopsy nucleic acid diagnosis

Background. The relative expression level of trefoil factor 3 (TFF3) mRNA to galectin-3 (LGALS3) mRNA (T/G ratio) is a useful marker to distinguish thyroid follicular carcinomas from adenomas. However, because of the interference by the simultaneously aspirated peripheral blood cells or infiltrating lymphocytes, the precise measurement of the T/G ratio in aspirates is difficult. Methods. We tested 2 methods of selecting thyroid tumor cells and removing blood cells from the aspirates. One method was selection with magnetic beads coated with Ber-EP4 antibody and the other was filtration through a nylon mesh. Results. After selection with Ber-EP4 antibody, T/G ratios in aspirates showed varied degrees of difference from those in the corresponding tissues. After mesh filtration, differences in T/G ratios between the aspirates and the corresponding tissues were less than 200% in all 8 cases. Conclusion. Mesh filtration of aspirates proved superior results for the measurement of T/G ratio.