Genetic testing for breast cancer Susan M. Domchek, MD Basser Professor of Oncology University of Pennsylvania

Sex Age Family history – Depends on specific of family history – Depends on whether there is a known genetic susceptibility Reproductive history – Early first period – Late last period – Postmenopausal estrogen use – Late first child – No breast feeding ETOH Obesity Lack of exercise Risk Factors for Breast Cancer

Germline – the genes you are born with – Can be passed on to relatives – Does not mean that disease will happen – Increased risk of disease – There is no one “breast cancer gene” Somatic – changes in tumors that are acquired over time – Can not pass on to relatives – Can be tested as part of decision making for therapy for cancer Germline vs Somatic Genetics

Allele Frequency Relative Risk 125≥10 Common Variants Rare variants (moderate) Rare variants (high) Genetics :Cancer Risk Variants Single nucleotide polymorphisms CHEK2, ATM, NBNBRCA1, BRCA2, TP53

Adapted from Couch, Nathanson, & Offit, Science 2014 Hereditary breast cancer

Risk Assessment Disease Prevention Therapeutics Germline genetic testing as a paradigm for individualized care BRCA1/2 as the prototype

Increased risk of other cancers: Male breast cancer BRCA2>BRCA1 Pancreatic cancer BRCA2 Prostate cancer BRCA2 Melanoma BRCA2 Breast cancer: 50%-70% Second primary breast cancer: 40%-50% Ovarian cancer: 15-55% BRCA1>BRCA2 BRCA1/2-associated cancers: lifetime risk

Breast cancer <45 Ovarian cancer cases (particularly high grade serous) Male Breast Cancer Breast and ovarian cancer in a single lineage 2 or more women with breast cancer <50 Ashkenazi Jewish with breast or ovarian cancer Breast cancer < 60 and triple negative Bilateral breast cancer <60 Pay attention to pancreatic cancer and high grade prostate cancer Ashkenazi Jewish individuals? All women at age 30? Many issues related to population screening Who should be considered for testing?

Estimates of breast cancer risk in BRCA1 carriers: Significant variability in penetrance

Kuchenbaecker et al in press 2016 Genetic modifiers: CIMBA BRCA1 carriers Polygenic risk scores (PRS) using BC susceptibility SNPs identified through population-based GWAS 15,252 BRCA1 8,211 BRCA2

No Prior Breast Cancer TotalBRCA1BRCA2 Total Participants 1, HR (95% CI) 0.54 ( )0.63 ( )0.36 ( ) Domchek et al, JAMA 2010 Breast cancer prior TotalBRCA1BRCA2 Total Participants HR (95% CI) 0.14 ( )0.15 ( )No cancer events Risk Reducing Salpingo-Oophorectomy and the risk of breast cancer RRSO and the risk of ovarian cancer PROSE Consortium

All eligible women AllBRCA1BRCA2 Total Participants2, HR (95% CI)0.40 ( )0.38 ( )0.52 ( ) Domchek et al, JAMA 2010 RRSO and all-cause mortality

Olaparib Veliparib Rucaparib Niraparib BMN-673 Tutt et al, Lancet 2010 Audeh et al, Lancet 2010 Gelmon et al, Lancet Oncology 2011 Treatment of BRCA1/2-associated cancers: Platinum and PARP inhibitors Poly ADP ribose polymerase (PARP) plays a role in the repair of single strand breaks through base excision repair Significant responses observed in patients with germline BRCA1/2- associated breast and ovarian cancer

Tutt et al, Lancet 2010 Tumor shrinkage

Approval is for germline BRCA1 and BRCA2 associated ovarian cancer after treatment with >3 lines of therapy The FDA did not approve maintenance therapy EMA did approve maintenance

Multiple tumor types Cisplatin-resistant ovarian cancer Breast cancer with >3 lines of therapy in metastatic setting Pancreatic and prostate cancer Kaufman et al, JCO 2015 Domchek et al, Gyn Onc 2016

Ovarian (n=193) Breast (n=62) Pancreas (n=23) Prostate (n=8) Other (n=12) All (n=298) BRCA status, n (%) BRCA1 mutation BRCA2 mutation Both 148 (76.7) 44 (22.8) 1 (0.5) 37 (59.7) 25 (40.3) 0 5 (21.7) 17 (73.9) 1 (4.3) 1 (12.5) 7 (87.5) 0 7 (58.3) 5 (41.7) (66.4) 98 (32.9) 2 (0.7) Median (SD) prior regimens for advanced disease 4.3 (2.2)4.6 (2.0)2.0 (1.6)2.0 (1.0)2.2 (1.3)4.0 (2.2) Tumor response rate60 (31.1)8 (12.9)5 (21.7)4 (50)1 (8.3)78 (26.2) Complete response6 (3.1)01 (4.3)007 (2.3) Partial response54 (28)8 (12.9)4 (17)4 (50)1 (8.3)71 (23.8) Stable (>8wks) Stable disease Unconfirmed PR 78 (40) 64 (33) 12 (6) 29 (47) 22 (36) 7 (11) 8 (35) 5 (22) 3 (13) 2 (25) 0 7 (58) 6 (50) 1 (8.3) 124 (42) 99 (33) 25 (9) Kaufman et al JCO, 2015

Data from the gyn onc paper Platinum resistance and PARP treatment Platinum sensitivity status (N= with measurable disease) Confirmed responders n ORR, % (95% CI) Median DoR, months (95% CI) Total (N = 137) (26–42)7.9 (5.6–9.6) Platinum sensitive (N = 39) 1846 (30–63)8.2 (5.6–13.5) Platinum resistant (N = 81) 2430 (20–41)8.0 (4.8–14.8) Platinum refractory (N = 14) 214 (2–43)6.4 (5.4–7.4) Platinum status unknown (N = 3)267 (9–99)6.3 (4.7–7.9) Domchek et al, Gyn Onc 2016

Genetic testing has become complicated…. Single nucleotide polymorphism panels

Not comprehensive sequencing of genes – such as BRCA1/2 Not a stand alone for those with a strong family history Some change in reclassification (change in how you consider someone from a risk perspective) Calibration: How closely the predicted probabilities agree with the actual outcome Clinical utility (or actionability?) – Will more women take tamoxifen? – How should this impact screening in the era of changing screening recommendations? Ongoing studies Key Points

In the US - this has become very complicated….

Gene Myriad MyRisk Ambry Cancer Next InvitaeGeneDx Uwash BROCA Fulgent * # of genes APCxxxxxx ATMxxxxxx BMPR1Axxxxxx BRCA1xxxxxx BRCA2xxxxxx BRIP1xxxxxx CDH1xxxxxx CDK4xxxxxx CDKN2Axxxxxx CHEK2xxxxxx EPCAMxxxxxx MLH1xxxxxx MSH2xxxxxx MSH6xxxxxx MUTYHxxxxxx NBNxxxxxx PALB2xxxxxx PMS2xxxxxx PTENxxxxxx RAD51Cxxxxxx SMAD4xxxxxx STK11xxxxxx TP53xxxxxx Gene Myriad MyRisk Ambry Cancer Next InvitaeGeneDx Uwash BROCA Fulgent * BARD1xxxxx RAD51Dxxxxx MRE11Axxx RAD50xxx NF1xx VHL Renal/PGL xxxx MEN1xxx RET PGL xxx PTCH1xx PALLDx XRCC2xxx CHEK1xx AXIN2xx FANCCxx ATRxx BAP1xx GALNT12xx HOXB13xx POLD1xx PRSS1xx RAD51Axx SDHB Renal/PGL xx SDHC Renal/PGL xx SDHD Renal/PGL xx AKT1x CTNNA1x FAM175Ax GEN1x GREM1x PIK3CAx POLEx PPM1Dx TP53BP1x *Rest of genes on Fulgent: BLM, BUB1B, CTNNB1, CYLD, DDB2, DICER1, EGFR, EGLN1, ERCC2, ERCC3, ERCC4, ERCC5, EXO1, EXT1, EXT2, FANCA, FANCB, FANCD2, FANCE, FANCF, FANCG, FANCI, FANCL, FANCM, GPC3, HRAS, KIF1B, KIT, MC1R, MPL, MSH3, NF2, PDGFRA, PICALM, PMS1, PRKAR1A, PRKDC, PTPN11, RB1, RBBP8, RBM15, RECQL4, ROBO2, SBDS, SLX4, SMARCB1, SUFU, TERT, TSHR, TYR, WRN,WT1, XPA, XPC, XRCC3 Gene Ambry Renal or PGL Fulgent * FHxx FLCNxx MAXxx METxx MITFxx SDHAxx SDHAF2xx TMEM127xx TSC1xx TSC2xx

Assess patient Test for most likely gene(s) Disclose result and reassess Test for most likely gene(s ) Revolution of genetic testing

Assess patient Send multigene panel Disclose result and reassess New approach?

More cost effective (for the testing) to do multigene rather than serial testing Patients (and providers!) can get testing fatigue The same cancer can be seen with different genes mutations –Ovarian cancer in both BRCA1/2 and Lynch –Uterine cancer in Lynch and Cowden –Breast in Li-Fraumeni and BRCA1/2 Isn’t more better? Why do this?

High penetrance and moderate penetrance genes are on one panel –Implications for counseling –Keeping track of it all –Don’t we recognize clinical syndromes? (And if we don’t – what does it mean?) Variants of uncertain significance Clinical utility: order tests you will act on –At least actionability Domchek et al, JCO 2013 Potential Issues

Maxwell et al GIM, 2014 BRCA1/2 negative patients with BC <40 N=278 Patients with Class 4 VUS & Class 5 Mutations N=31 (11%) Class 3 VUS(s) only N=49 (18%) MUTYH Heterozygotes N=6 (2.2%) * Bin A Genes TP53, PTEN, STK11, CDH1, CDKN2A, MLH1, MSH2, MSH6, PMS2, MUTYH (AR) Risk established for breast or other cancers Guidelines available *Clinically actionable* N=7 (2.5%) Bin B Genes ATM, BARD1, BRIP1, CHEK2, FAM175A, MRE11A, NBN, PALB2, RAD50, RAD51C Risk established for breast and some other cancers Less clear actionability N=24 (8.6%) No Class 3-5 Variants N=192 (69%) TP53 N=4 MSH2 N=1 CDKN2A N=1 ATM & CHEK2 N=18 Other genes N=6 White Non-white 6% 31% 63% 13% 74% Class 4/5 Mutation Class 3 VUS No Class 3-5 Variants MUTYH N=1 What will we find?

What do we do? ACCE Framework ParameterDefinition Analytic validity How well test measures property or characteristic it is intended to measure Clinical validity Accuracy of the test in diagnosing or predicting risk for the health condition (sensitivity, specificity, PPV, NPV) Clinical Utility Evidence of improved measurable clinical outcomes Usefulness and added value to patient management ELSI Ethical, legal and social implications

What is actionable? Something that potentially could be acted upon It does not mean that it is acted upon It does not mean that such action benefits a patient Actionability = clinical utility Critically important that all this be studied

Summary of Clinical Validity Easton et al, NEJM 2015

Risk assessment –Value of the true negative –Risk of breast and as well as risk of second primary cancer –Risk of other cancers (Ovarian cancer risk for BRCA1/2 was a major reason for rapid uptake of testing) Clinical utility

Screening and prevention –Need to understand risks and benefits –What age to start screening? –What screening? –What age to have preventative surgery? –What to do with “unexpected” high penetrance mutation When we find things we don’t expect, what should we do? Clinical utility

Therapeutics –Prognosis: may impact administration of adjuvant therapy –Drug development/selection –Will tumors with mutations in these other genes be sensitive to specific types of drugs? Clinical utility

Genetic testing can be very useful to patients and their family members –Both the prevent and to treat cancer Genetic testing is continuously evolving BRCA1 and BRCA2 mutations are the most commonly found and we have reasonable data on how to manage New genetics tests are often less clear in terms of how to change patients care – and improve patient outcome Variants of unknown significance should NOT be managed as mutations In the face of rising prophylactic mastectomies, we need to emphasize to patients how mutations in these genes are different from those in BRCA1/2 Conclusions