This document summarizes genetic alterations involved in the progression of well-differentiated thyroid carcinomas to poorly differentiated and anaplastic carcinomas. It discusses mutations in genes such as BRAF, RAS, RET/PTC, and PAX8-PPARγ that are involved in early-stage well-differentiated and follicular carcinomas. Additional mutations in p53 and β-catenin are thought to direct dedifferentiation and progression to later stages. Studies of mutations and loss of heterozygosity support a model where well-differentiated tumors progress through poorly differentiated to anaplastic carcinomas through the accumulation of these genetic alterations.

1. Yuri E. Nikiforov Department of Pathology University of Cincinnati Genetic Alterations Involved in the Transition from Well Differentiated to Poorly Differentiated and Anaplastic Thyroid Carcinomas Endocrine Pathology Companion Meeting

3. Thyroid follicular cell Papillary Carcinoma AC PDC PAX8-PPAR γ BRAF RET/PTC RAS P53 β-catenin RAS Molecular Alterations in Thyroid Tumors Hurthle Cell Carcinoma Follicular Carcinoma

4. BRAF

5. SOS B-RAF RAS GRB2 SOS Signaling Pathways Activated by BRAF in Thyroid Tumors Y1015 Y1062 Y1096 MEK ERK c-Jun, Fos , c- Myc , Elk-1 PLC γ Enigma SHC FRS2 P P P RET P P P

6. Kinase domain Spectrum of BRAF Point Mutations in Various Tumors Phe Gly Leu Val 594 595 598 601 596 599 Val Glu Leu 585 Gly 465 Gly 465 Gly 463 RBD C Ala The Lys Ser P P

7. Prevalence of BRAF Mutations in Thyroid Tumors Nikiforova et al. 2003 Cohen et al., 2003 Xu et al., 2003 Namba et al., 2003 Fukashima et al., 2003 Trovisco et al., 2004

8. BRAF Mutations Present in Both Well Differentiated and Poorly Differentiated Carcinoma Areas Nikiforova et al. (2003) DNA DNA BRAF + BRAF + PC,WD PDC

9. BRAF Mutations in Poorly Differentiated and Anaplastic Carcinomas Nikiforova et al. (2003)

11. RAS

13. Mechanism of RAS Activation by Point Mutation GAPs SOS GDSs CDC25 C3G Downstream Effectors Mutations codons 12/13 or 61 RAS RAS GTP GDP H 2 O Pi GTP GDP

14. Molecular Pathways Activated by RAS B-RAF BAD Apoptosis Y1062 RAS GRB2 SOS PLC Ral /Cdc42 DAG PKC AKT Rho Rac MEK ERK PI3K JNK P70S6K MEKK1 BCL c-Jun, Fos , c- Myc , Elk-1 SHC FRS2 RET P P P P

15. Prevalence of RAS Mutations in Thyroid Tumors

16. RAS in Progression of Thyroid Tumors: Case report of AC with areas of FC AC RAS codon 61 CAA CGA + + p53 codon 189 GCC GTC - + Asakawa & Kobayashi (2002) Mutations found: FC

19. RET/PTC Rearrangement

20. RET / PTC Rearrangements

21. SOS GRB2 Y1015 Y1062 RET/PTC Molecular Pathways Activated by RET/PTC PLC γ Enigma SHC FRS2 RAF RAS MEK ERK P P P P c-Jun, Fos , c- Myc , Elk-1

22. Prevalence of RET/PTC in Thyroid Tumors

24. Molecular Pathways in Thyroid Papillary Carcinogenesis RET-PTC 15% 40% BRAF RAS 20% PC PC PC N PDC AC

25. PAX8-PPAR γ Rearrangement

26. Structure of PAX8-PPAR  Fusion Protein Kroll et al. (2000)

28. Prevalence of PAX8-PPAR  in Thyroid Tumors

30. Molecular Pathways in Thyroid Follicular Carcinogenesis PAX8-PPAR γ 35% FA RAS 45% FC FC PDC AC N

31. Mutations Directing Progression/ Dedifferentiation of Thyroid Tumors: p53

32. Mutations Directing Progression/ Dedifferentiation of Thyroid Tumors: β-catenin

33. Specific Genetic Events in Thyroid Tumors: Summary

36. Nikiforov Lab Marina Nikiforova Zhaowen Zhu Raffaele Ciampi Christy Caudill Manoj Gandhi Acknowledgements James Fagin University of Cincinnati Todd Kroll Emory University Giovanni Tallini