Methodology, criteria and characterization of patient-matched thyroid cell lines and patient-derived tumor xenografts.

Objective: To investigate the molecular underpinnings of thyroid cancer, preclinical cell line models are crucial; however, similar to 40% of these have been proven to be either duplicates of existing thyroid lines or even nonthyroid-derived lines or are not derived from humans at all. Therefore, we set out to establish procedures and guidelines that should proactively avoid these problems, which facilitated the creation of criteria to make valid preclinical models for thyroid cancer research. Design: Based on our recommendations, we systematically characterized all new cell lines that we generated by a standardized approach that included (1) determination of human origin, (2) exclusion of lymphoma, (3) DNA fingerprinting and histological comparisons to establish linkage to presumed tissue of origin, (4) examining thyroid differentiation by screening two to three thyroid markers, (5) examination of biological behavior (growth rate, tumorigenicity), and (6) presence of common thyroid cancer genetic changes (TP53, BRAF, PTEN, PIK3CA, RAS, TERT promoter, RET/PTC, PAX8IPPAR gamma, NF1, and EIF1AX). Results: We established seven new thyroid cell lines (LAM136, EAM306, SDAR1, SDAR2, JEM493, THJ529, and THJ560) out of 294 primary culture attempts, and 10 patient-derived tumor xenografts (PDTXs; MC-Th-95, MC-Th-374, MC-Th-467, MC-Th-491, MC-Th-493, MC-Th-504, MC-Th-524, MC-Th529, MC-Th-560, and MC-Th-562) out of 67 attempts. All were successfully validated by our protocols. Conclusions: This standardized approach for cell line and PDTX characterization should prevent (or detect) future cross-contamination and ensure that only valid preclinical models are used for thyroid cancer research.