Abstract: Abstract: Objective To establishing an immortal cell line of familial papillary thyroid carcinoma (FPTC), and explore a new approach for studying familial non-medullary thyroid carcinoma (FNMTC). Methods The specimen from a patient with FPTC was selected, separated, and the primary cells were cultured using DMEM/F12 medium (with TSH, T3,EGF and hydrocortisone). To inducing cell immortalization, the exogenous genes SV40T/TERT were transfected into cells by two ways. RT-PCR was used to detect the expressions of thyroid peroxidase (TPO), thyroid globulin (TG), thyroid stimulating hormone receptor (TSHR) and sodium/iodide co- transporter (NIS). Immunofluorescence method was used to detect the expressions of TPO and GPC3. In order to detect the genomic mutations, the peripheral blood DNA of the patient wasextracted. The cell genome was detected. Results The FPTC cells adhered to the plate and showed an irregular polygon shape. The cells can stably grow for six months, FPTC-S (with SV40T transfected) passaged to p26, FPTC cells passaged to p23 and FPTC-ST (with SV40T/TERT transfected) passaged to p19. Both FPTC-S and FPTC-ST can stably express TPO,TG and TSHR in mRNA level. MLH1 R217C mutation existed in the peripheral blood of the patient, and BRAF V600E mutation existed in the primary cultured cells. Either the primary or the immortal cells showed MLH1 R217C mutation.Conclusion This study preliminarily established an immortal cell line of familial papillary thyroid carcinoma with MLH1 R217C and BRAF V600E mutations. This cell line provides a research model for studying these mutations in FPTC.

Key words: thyroid neoplasms, cell line, tumor, cell culture techniques, familial papillary thyroid carcinoma, immortal cell line, primary culture, MLH1, BRAF