Molecular Methods in the Diagnosis and Prognostication of Melanoma: Pros & Cons Ben J. Friedman, MD Senior Staff Physician Department of Dermatology Department of Pathology and Laboratory Medicine Henry Ford Hospital, Detroit, MI, USA
Disclosures I have no conflicts of interest
Question Can adjunctive molecular assays help us make more accurate diagnoses and prognosticate better? 3
Outline Diagnosis 1. Array Comparative Genomic Hybridization (acgh) 2. Fluorescence In-Situ Hybridization (FISH) Multiprobe Assay 3. MyPath [Gene Expression Profiling (qrt-pcr)] Prognosis 4. Decision Dx-Melanoma TM [Gene Expression Profiling (qrt-pcr)] 4
Problem Histopathologically ambiguous lesions common Misdiagnosis has consequences Thickness/ sentinel node limited predictive ability N Engl J Med. 2006 Sep 28;355(13):1307-17.
How often do you request ancillary molecular testing for ambiguous melanocytic lesions? Never < 5 times per 5 -> 20 times > 20 times year per year per year EXPERT PANEL 23% 51% 22% 4% AUDIENCE 0% 14% 57% 29% **Poll from 2018 American Society of Dermatopathology Annual Meeting, Chicago, IL** 6
Gold Standard Limitation for Diagnostic Assays Need substantially more data on long term clinical outcome in cases with ambiguous morphology! J Am Acad Derm. 2016 Oct;75(4):849-850 7
Array Comparative Genomic Hybridization (aka Chromosomal Microarray Analysis, SNP array) 8
Array CGH Detects and maps DNA copy # alterations (CNA) Multiple CNA common in melanoma (>95%) Nevi have no CNA or rarely n= 1 or n=2 Cancer Res. 1998 May 15;58(10):2170-5. Am J Pathol. 2003 Nov;163(5):1765-70. Dermatol Ther. 2006 Jan-Feb;19(1):40-9. 9
JAAD. 2015 Jun;72(6):943-58
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Array CGH: Pros Surveys the whole genome Sensitivity and specificity for CNA > than FISH Degree of agreement with expert morphologists acgh > FISH > GEP Hum Pathol. 2018 Dec 18. pii: S0046-8177(18)30488 Mod Pathol. 2018 Nov;31(11):1733-1743 Mod Pathol. 2016 Aug;29(8):832-43
Array CGH: Cons Not for point mutations/ balanced translocations High tissue requirement (>0.4mm BD) Limited CNA: likelihood of progression? Cost: ~1800$ Turnaround time: ~3-4 weeks J Mol Diagn. 2013 Sep;15(5):581-91. 13
FISH Multiprobe Assay 14
FISH Multiprobe Assay Fluorescent probes-> bind specific DNA segments Detects deleterious gains and losses (acgh data) 6p25, 8q24, 9p21, and 11q13 94% sensitive, 98% specific (n=102) Am J Surg Pathol. 2009;33(8):1146-1156 Am J Surg Pathol. 2012;36(6):808-817 15
8q24 (MYC) Pathology. 2017 Dec;49(7):740-749. 16
FISH Pros Less technical requirements than acgh Detection of malignant subpopulations Insurance more likely to cover Turnaround time ~5 days Am J Surg Pathol. 2013 May;37(5):676-84 17
FISH Cons Heterogeneity of melanoma Tetraploidy pitfall Poor performance in ambiguous lesions? Cost: ~$1350-1685 Am J Surg Pathol. 2013 May;37(5):676-84 Am J Surg Pathol. 2013 Dec;37(12):1783-96 Ann Diagn Pathol. 2017 Jun;28:30-36 18
mypath [GEP (qrt-pcr)] 19
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GEP (mypath ) Validation study n=1400 specimens Triple DP consensus, lack of indeterminate score, and samples >10% tumor volume n=736 specimens Sensitivity: 91.5%, Specificity 92.5% Cancer. 2017 Feb 15;123(4):617-628 21
GEP [mypath ]: Pros Tumor-immune microenvironment Cell differentiation, cell signaling, immune response Lower tissue requirement than acgh Turnaround time ~7 days J Cutan Pathol. 2015 Apr;42(4):244-52 22
GEP [mypath ]: Cons Indeterminate scores: up to 16% Insufficient RNA: up to 8% Not for: recurrent lesions, re-excisions, immunosuppressed Reliability in ambiguous lesions unknown Cost: 1950$ Cancer. 2017 Feb 15;123(4):617-628 23
Molecular Prognostication of Melanoma 24
TNM staging AJCC 7th Edition Cancer Staging- Cutaneous Melanoma 25
Decision DxMelanomaTM [GEP (qrt-pcr)] 26
Prognostic 31-gene signature Clin Cancer Res. 2015 Jan 1;21(1):175-83 27
GEP (Decision Dx) Low risk (class 1) & high risk (class 2) enhanced surveillance of high risk adjuvant/ earlier therapy for high risk reduce anxiety for low risk Clin Cancer Res. 2015 Jan 1;21(1):175-83 28
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n=523; stage 1, 2, and 3 J Am Acad Derm. 2019 Jan;80(1):149-157 30
GEP (Decision DxTM): Pros Strong independent prognostic indicator NPV of Class 1A: >/= ~85% GEP+SNL status: better risk stratification J Am Acad Dermatol. 2015 May;72(5):780-5.e3 BMC Cancer. 2018 Feb 5;18(1):130 31
GEP (Decision DxTM): Cons PPV of Class 2 in AJCC Stage 1= ~10% or less Weak evidence for radiologic screening Cost effective? => $8,000 Dermatol Surg. 2018 Dec;44(12):1494-1500 BMC Cancer. 2018 Feb 5;18(1):130 J Am Acad Derm. 2019 Jan;80(1):149-157 32
Conclusion acgh, FISH, GEP (mypath ) are promising adjuncts to histopathology LTO data in ambiguous tumors limited GEP (mypath ): need independent nonmanufacturer conducted studies 33
Conclusion GEP (Decision Dx TM) = independent prognostic parameter Need prospective studies -> clinical utility Low PPV in stage 1, may limit use to thicker tumors in conjunction with SNL status 34
References 1. Cancer Res. 1998 May 15;58(10):2170-5. 2. Am J Pathol. 2003 Nov;163(5):1765-70. 3. Dermatol Ther. 2006 Jan-Feb;19(1):40-9. 4. Hum Pathol. 2018 Dec 18. pii: S0046-8177(18)30488 5. Mod Pathol. 2018 Nov;31(11):1733-1743 6. Mod Pathol. 2016 Aug;29(8):832-43 7. J Mol Diagn. 2013 Sep;15(5):581-91. 8. Am J Surg Pathol. 2009;33(8):1146-1156 9. Am J Surg Pathol. 2012;36(6):808-817. 10. Am J Surg Pathol. 2013 Dec;37(12):1783-96 11. Ann Diagn Pathol. 2017 Jun;28:30-36 12. J Cutan Pathol. 2015 Apr;42(4):244-52 35
References 13. Cancer. 2017 Feb 15;123(4):617-628 14. Cancer Epidemiol Biomarkers Prev. 2017 Jul;26(7):1107-1113 15. Hum Pathol. 2018 Dec 16. pii: S0046-8177(18)30487-8. doi 16. J Invest Dermatol. 2015 Apr;135(4):1190-1193 17. N Engl J Med. 2006 Sep 28;355(13):1307-17. 18. Dermatol Surg. 2018 Dec;44(12):1494-1500 19. Clin Cancer Res. 2015 Jan 1;21(1):175-83 20. J Am Acad Dermatol. 2015 May;72(5):780-5.e3 21. J Am Acad Derm. 2019 Jan;80(1):149-157 22. Am J Surg Pathol. 2013 May;37(5):676-84 23. Pathology. 2017 Dec;49(7):740-749. 36