1. Molecular Markers in Thyroid Disease Yeah or Meh?
Walter E. Pofahl, MD, FACS
Professor and Vice Chair
East Carolina University Department of Surgery
Resident Class 1994

2. Faculty Disclosure
No disclosures

3. Case 65 year old female Incidentally noted thyroid nodule
No risk factors for malignancy
No suspicious US characteristics
Right thyroid nodule (1.9 cm)
FNAB benign
Left thyroid nodule (0.9 cm
Atypia of undetermined significance (Bethesda III)
Gene expression classifier testing suspicious

4. Educational Need/Practice Gap
Inappropriate use of molecular markers in thyroid disease
Educational Need
Due to lack of understanding of role of markers in clinical context

5. Objectives
Upon completion of this educational activity, you will be able to:
Discuss the different commercially available molecular marker products
Describe clinical situations where use of molecular markers are helpful
Outline treatment based on results of molecular testing

6. Expected Outcome
Appropriate utilization of molecular markers in the management of thyroid disease

7. Rationale Bethesda Classification Thyroid Cytopathology Category
Malignancy Risk I
Non-diagnostic II
Benign
0-3%
III
Atypia/follicular lesion of undetermined significance
5-15% IV
Follicular neoplasm/suspicious for follicular neoplasm
15-30% V
Suspicious for malignancy
60-75% VI
Malignant
97-99%
15-30% thyroid FNAs indeterminate
15-50% subsequently found to be malignant

8. Progression of Thyroid Tumorigenesis
From Xing M; Nature 2013;13:

9. Molecular Biology Gene mutations Gene amplifications
T1799A point mutation in BRAF
Expression of BRAF-V600E mutant protein
Gene amplifications
Genes encoding PI3K-AKT pathway members
More prevalent in anaplastic cancers
Gene translocations
RET-PTC
Aberrant gene methylation
Hypermethylation driven by BRAF-V600E

10. Gene Mutations in Thyroid Tumors
From Xing M; Nature 2013;13:

11. ATA Guidelines Recommendation 13 Recommendation 14
If molecular testing is being considered, patients should be counseled regarding the potential benefits and limitations of testing and about the possible uncertainties in the therapeutic and long-term clinical implications of results
Recommendation 14
If intended for clinical use, molecular testing should be performed in Clinical Laboratory Improvement Amendments/College of American Pathologists (CLIA/CAP)-certified molecular laboratories, or the international equivalent, because reported quality assurance practices may be superior compared to other settings
Haugen BR, et al. Thyroid 2016

12. ATA Guidelines Recommendation 15 Recommendation 16
For nodules with AUS/FLUS cytology, after consideration of worrisome clinical and sonographic features, investigations such as repeat FNA or molecular testing may be used to supplement malignancy risk assessment in lieu of proceeding directly with a strategy of either surveillance or diagnostic surgery. Informed patient preference and feasibility should be considered in clinical decision-making
If repeat FNA cytology, molecular testing, or both are not performed or inconclusive, either surveillance or diagnostic surgical excision may be performed for and AUS/FLUS thyroid nodule, depending on clinical risk factors, sonographic pattern, and patient preference
Recommendation 16
Diagnostic surgical excision is the long-established standard of care for the management of FN/SFN cytology nodules. However, after consideration of clinical and sonographic features, molecular testing may be used to supplement malignancy risk assessment in lieu of proceeding directly with surgery. Informed patient preference and feasibility should be considered in clinical decision-making
If molecular testing is either not performed or inconclusive, surgical excision may be considered for removal and definitive diagnosis of an FN/SFN thyroid nodule
Haugen BR, et al. Thyroid 2016

13. ATA Guidelines Recommendation 17
If the cytology is reported as suspicious for papillary carcinoma (SUSP), surgical management should be similar to that of malignant cytology, depending on clinical risk factors, sonographic features, patient preference, and possibly results of mutational testing (if performed)
After consideration of clinical and sonographic features, mutational testing for BRAF or the seven-gene mutation marker panel (BRAF, RAS, RET/PTC, PAX8/PPAR𝛾) may be considered in nodules with SUSP cytology if such data would be expected to alter surgical decision-making
Haugen BR, et al. Thyroid 2016

14. Commercially available products
Affirma GEC
Veracyte
ThyGen X and ThyraMIR
Interpace Diagnostics
ThyroSeq
CBL Path

15. Gene Expression Classifier Testing
Affirma (Veracyte)
mRNA expression profile
Micro-array technology
142 genes
Proprietary algorithm
Reported as benign or suspicious
Rule-out test

16. Gene Expression Classifier Testing

17. ThyGenX and ThyraMIR Interpace Diagnostics ThygenX ThyraMIR
Mutation panel
Rule-in test
ThyraMIR
miRNA gene expression
10 genes
Rule-out test

18. ThyroSeq CBL Path Next-generation sequencing
Simulataneous sequencing and detection
>1000 hotspots of 14 thyroid cancer-related genes
42 types of gene fusions
Comprehensive rule-in and rule-out test

19. Comparisons NPV Sensitivity PPV Specificity GEC 75-100% 90-100% 14-57%
7-52%
ThygenX
85%
69%
71%
86%
ThyGenx + ThyraMIR
94%
89%
74%
Thyroseq
96%
90%
83%
93%

20. Zhang M, Lin O. Arch Pathol Lab Med doi: 10.5858/arpa.2016-0100-RA

21. Nishino M. Cancer Cytopathol 2016

22. Nishino M. Cancer Cytopathol 2016

23. Nishino M. Cancer Cytopathol 2016

24. Clinical Scenarios Where Helpful Where Not Helpful Avoiding operation
Determining extent of resection
Where Not Helpful
Total thyroidectomy planned regardless
Patient unwilling to proceed based on results

25. Summary

26. Future Treatment Algorithm