Couch, Fergus J.

Abstract To evaluate the racial and ethnic differences in prevalence of germline pathogenic variants (PVs) and the effect of race and ethnicity on breast cancer (BC) risk among carriers, results of multigene testing of 77 900 women with BC (non-Hispanic White [NHW] = 57 003; Ashkenazi-Jewish = 4798; Black = 6722; Hispanic = 5194; and Asian = 4183) were analyzed, and the frequency of PVs in each gene were compared between BC patients (cases) and race- and ethnicity-matched gnomAD reference controls. Compared with NHWs, BRCA1 PVs were enriched in Ashkenazi-Jews and Hispanics, whereas CHEK2 PVs were statistically significantly lower in Blacks, Hispanics, and Asians (all 2-sided P < .05). In case-control studies, BARD1 PVs were associated with high risks (odds ratio > 4.00) of BC in Blacks, Hispanics, and Asians; ATM PVs were associated with increased risk of BC among all races and ethnicities except Asians, whereas CHEK2 and BRIP1 PVs were associated with increased risk of BC among NHWs and Hispanics only. These findings suggest a need for personalized management of BC risk in PV carriers based on race and ethnicity.

Abstract Purpose: To compare the clinical characteristics and overall survival (OS) of germline mutation carriers in homologous recombination repair (HRR) genes and noncarriers with pancreatic ductal adenocarcinoma (PDAC). Experimental Design: Germline DNA from 3,078 patients with PDAC enrolled in a prospective registry at Mayo Clinic between 2000 and 2017 was analyzed for mutations in 37 cancer predisposition genes. Characteristics and OS of patients with mutations in eight genes (ATM, BARD1, BRCA1, BRCA2, BRIP1, PALB2, RAD51C, and RAD51D) involved in HRR were compared with patients testing negative for mutations in all 37 genes. Results: The 175 HRR mutation carriers and 2,730 noncarriers in the study had a median duration of follow-up of 9.9 years. HRR mutation carriers were younger (median age at diagnosis: 63 vs. 66 years, P < 0.001) and more likely to have metastatic disease at diagnosis (46% vs. 36%, P = 0.004). In a multivariable model adjusting for sex, age at diagnosis, and tumor staging, patients with germline HRR mutations had a significantly longer OS compared with noncarriers [HR, 0.83; 95% confidence interval (CI), 0.70–0.97; P = 0.02]. Further gene-level analysis demonstrated that germline ATM mutation carriers had longer OS compared with patients without germline mutations in any of the 37 genes (HR, 0.72; 95% CI, 0.55–0.94; P = 0.01). Conclusions: This study demonstrates that germline mutation carrier status in PDAC is associated with longer OS compared with noncarriers. Further research into tumor biology and response to platinum-based chemotherapy in germline mutation carriers with PDAC are needed to better understand the association with longer OS.

PURPOSE Women with breast cancer have a 4%-16% lifetime risk of a second primary cancer. Whether mutations in genes other than BRCA1/2 are enriched in patients with breast and another primary cancer over those with a single breast cancer (S-BC) is unknown. PATIENTS AND METHODS We identified pathogenic germline mutations in 17 cancer susceptibility genes in patients with BRCA1/2-negative breast cancer in 2 different cohorts: cohort 1, high-risk breast cancer program (multiple primary breast cancer [MP-BC], n = 551; S-BC, n = 449) and cohort 2, familial breast cancer research study (MP-BC, n = 340; S-BC, n = 1,464). Mutation rates in these 2 cohorts were compared with a control data set (Exome Aggregation Consortium [ExAC]). RESULTS Overall, pathogenic mutation rates for autosomal, dominantly inherited genes were higher in patients with MP-BC versus S-BC in both cohorts (8.5% v 4.9% [ P = .02] and 7.1% v 4.2% [ P = .03]). There were differences in individual gene mutation rates between cohorts. In both cohorts, younger age at first breast cancer was associated with higher mutation rates; the age of non–breast cancers was unrelated to mutation rate. TP53 and MSH6 mutations were significantly enriched in patients with MP-BC but not S-BC, whereas ATM and PALB2 mutations were significantly enriched in both groups compared with ExAC. CONCLUSION Mutation rates are at least 7% in all patients with BRCA1/2 mutation–negative MP-BC, regardless of age at diagnosis of breast cancer, with mutation rates up to 25% in patients with a first breast cancer diagnosed at age < 30 years. Our results suggest that all patients with breast cancer with a second primary cancer, regardless of age of onset, should undergo multigene panel testing.

Abstract Germline mutations in TP53 cause a rare high penetrance cancer syndrome, Li–Fraumeni syndrome (LFS). Here, we identified a rare TP53 tetramerization domain missense mutation, c.1000G&gt;C;p.G334R, in a family with multiple late-onset LFS-spectrum cancers. Twenty additional c.1000G&gt;C probands and one c.1000G&gt;A proband were identified, and available tumors showed biallelic somatic inactivation of TP53. The majority of families were of Ashkenazi Jewish descent, and the TP53 c.1000G&gt;C allele was found on a commonly inherited chromosome 17p13.1 haplotype. Transient transfection of the p.G334R allele conferred a mild defect in colony suppression assays. Lymphoblastoid cell lines from the index family in comparison with TP53 normal lines showed that although classical p53 target gene activation was maintained, a subset of p53 target genes (including PCLO, PLTP, PLXNB3, and LCN15) showed defective transactivation when treated with Nutlin-3a. Structural analysis demonstrated thermal instability of the G334R-mutant tetramer, and the G334R-mutant protein showed increased preponderance of mutant conformation. Clinical case review in comparison with classic LFS cohorts demonstrated similar rates of pediatric adrenocortical tumors and other LFS component cancers, but the latter at significantly later ages of onset. Our data show that TP53 c.1000G&gt;C;p.G334R is found predominantly in Ashkenazi Jewish individuals, causes a mild defect in p53 function, and leads to low penetrance LFS. Significance: TP53 c.1000C&gt;G;p.G334R is a pathogenic, Ashkenazi Jewish–predominant mutation associated with a familial multiple cancer syndrome in which carriers should undergo screening and preventive measures to reduce cancer risk.

e24103 Background: Many of the 200,000 patients diagnosed with breast cancer (BC) annually in the United States receive anthracycline-based therapy, increasing their risk of future congestive heart failure. N-terminal brain natriuretic peptide (NT-proBNP) has been used as a biomarker of asymptomatic cardiac dysfunction in the general population and is of interest to identify patients who might benefit from echocardiography during survivorship. This study aimed to assess how age, baseline comorbidities, and time since BC diagnosis impact NT-proBNP levels after anthracycline-based chemotherapy. Methods: This retrospective study, using samples collected in our ongoing prospective Mayo Clinic Breast Disease Registry, included 20 survivors of non-metastatic BC patients per year for each of the first 5 years after anthracycline-based chemotherapy (n=100 total). NT-pro-BNP levels were assessed using a Roche immunoassay. Cardiac risk factors were obtained by chart review. Multivariable linear regression models assessed associations between NT-proBNP values and these independent variables: baseline cardiac risk factors (including hypertension, hyperlipidemia, obesity, diabetes mellitus, and smoking), tumor ER status (surrogate for possible endocrine therapy), time between diagnosis and serum collection, T and N status, use of trastuzumab, and age. Results: The mean age at the time of BC diagnosis was 52.2 (SD 9.8). 13% of tumors were human epidermal growth factor receptor (HER2)-positive and 71% were estrogen receptor (ER) positive. NT-proBNP was elevated in 34%. Mean NT-BNP level was higher (p=0.047) for those in years 4-5 (158 pg/mL) compared to those in years 1-3 (106 pg/mL) (See Table.) Models revealed years from diagnosis to serum draw (p=0.026), older age (p=0.006), more cardiac risk factors (p=0.064), and N2-3 (p=0.001) were associated with elevated NT-pro-BNP level. Use of trastuzumab, ER status, and tumor size were not associated with NT-proBNP. Conclusions: NT-proBNP is elevated in 1/3 of survivors who received anthracycline therapy for BC. As expected, cardiac risk factors and advancing age are associated with higher NT-proBNP. NT-proBNP values >300 were only found in patients who were 4-5 years after diagnosis. Additional research will be needed to further define the diagnostic and prognostic merit of NT-proBNP in survivors after receipt of anthracycline therapy. [Table: see text]

e13680 Background: Multiplex genetic testing (MGT) simultaneously analyzes multiple cancer susceptibility genes and can reveal genetic variants of uncertain significance (VUS) that have unclear associations with cancer risks. Little is known about how people are prepared for receiving VUS results from MGT, or whether their emotional reactions differ based on the levels of cancer risk to which they may be susceptible. Methods: We recruited participants from the online Prospective Registry of Multiplex Testing (PROMPT). Those with only a VUS in a cancer predisposition gene completed a survey including measures of their MGT experience, distress (range 0-30; α = .87), uncertainty (0-45; α = .83), and positive experiences (0-20; α = .75). We used generalized linear modeling to examine how demographics, awareness of the possibility of VUS before testing, and level of cancer risks associated with their VUS gene were related to emotional outcomes. Results: Data were available from 661 individuals (40% response rate, 95% female, 90% white, 78% college graduate, 69% cancer history, age 23-93) with VUS in a gene of high risk (47%), moderate/low risk (35%) or limited evidence of risk (18%). Among the sample, 80.8% reported ever receiving cancer genetic counseling, and only 50.8% reported being aware of the possibility of VUS when deciding about testing. Participants reported low current distress ( M± SD= 3.25±5.19), uncertainty (9.18±8.35) and positive experiences (7.83±5.98). Distress was associated with younger age, less family cancer history, and being unaware of the possibility of VUS before testing; distress was also higher among those with VUS in a gene of high risk than those with VUS in a gene of moderate/low risk or limited evidence of risk ( ps≤.023). Uncertainty was associated with younger age, non-white race, less education, and being unaware of the possibility of VUS; uncertainty was also higher among those with VUS in a gene of high risk than those with VUS in a gene with limited evidence of risk ( ps≤.05). Fewer positive experiences were associated with more education and more family cancer history; those with VUS in a gene of high risk had fewer positive experiences than those with VUS in a gene with limited evidence of risk ( ps≤.03). Conclusions: Many individuals undergoing MGT may not fully understand the prospect of receiving VUS. Clinicians should consider patients’ background, preparation, and level of cancer risk to which they are potentially susceptible, as these factors may affect their emotional adaptation.

1508 Background: With the expansion of multigene panel testing for cancer susceptibility, increasing numbers of patients are identified with pathogenic/likely pathogenic variants (P/LP V) in genes which do not have a clearly actionable increased risk of ovarian cancer (OC) (lifetime risk of OC >5%). However, there is concern that patients and/or providers may ascribe OC risk to such genetic findings with the potential for unnecessary oophorectomy (ooph). Methods: The Prospective Registry of Multiplex Testing (PROMPT) is an online registry for individuals with a genetic alteration detected on multiplex panel testing for cancer susceptibility. Participants self-enroll and complete baseline and annual follow-up questionnaires. PROMPT has enrolled 7388 participants (6936; 93.9% women) since September 2014. Results: 1566 women in the PROMPT registry reported ooph, the indications for which were reported as either cancer treatment (n=481, 30.7%) or benign disease (n=432, 27.6%). An additional 186 (12.8%) reported PV in genes associated with lifetime OC risk >5% ( BRCA1, BRCA2, RAD51C, RAD51D, BRIP, or Lynch syndrome genes). The remaining 467 did not have guideline based indications for ooph due to OC risk and are described further here. 92 (19.7%) had a variant of uncertain significance (VUS) in genes associated with OC, 241 (51.6%) had a personal history of breast cancer (BC) and no VUS in OC genes, and 119 (25.5%) had no personal history of BC and no VUS in OC genes. The majority of women had no family history (FH) of OC in first or second degree relatives (Table). Most ooph occurred prior to age 50. Of the 405 women with CHEK2 P/LP, 11.4% reported ooph (59% under age 50 when age known), as did 13.2% (of 228) with CHEK2 VUS, 8.8% (of 261) with ATM P/LP (66.7% under age 50), and 8.3% (of 387) with ATM VUS. In addition, of the 184 women with PALB2 P/LP, 14.1% reported ooph (35.3% under age 50) as did 11.6% (of 198) with PALB2 VUS. Of those who reported provider discussions, 47.2% stated “my provider recommended this” (including >60% in the OC gene VUS group) and an additional 25.2% stated “my provider presented this as an option, but not a requirement”. In those with no FH of OC, 45.8% stated that their provider recommended ooph. Conclusions: 10-15% of women with PV/VUS in genes not associated with a high risk of OC reported ooph without a clear indication. [Table: see text]

1087 Background: OlympiAD (NCT02000622) demonstrated the benefit of olaparib over standard of care in patients (pts) with HER2-negative (HER2-) metastatic breast cancer (MBC) and germline BRCA mutations (gBRCAm). LUCY (NCT03286842) aimed to provide additional data on the real-world effectiveness and safety of olaparib monotherapy in this setting. Methods: This Phase IIIb, open-label, single-arm study of olaparib 300 mg twice-daily, enrolled pts with HER2- gBRCAm MBC who had received a taxane and/or anthracycline in the (neo)adjuvant/metastatic setting, and ≤2 lines of chemotherapy for MBC. Hormone receptor-positive (HR+) pts had progressed on prior endocrine therapy (ET), and further ET was considered unsuitable. Primary endpoint: investigator-defined progression-free survival (PFS). Secondary endpoints: overall survival, time to first subsequent therapy or death (TFST), and investigator-assessed clinical response rate (CRR). The interim analysis was planned after 160 PFS events. Results: From Oct 2018-Sept 2019, 252 pts were enrolled (160 sites, 15 countries; mean age 46.2 [range 22-75] years; 73.4% ECOG PS 0). Median total treatment duration: 7.9 months (mo; range 0.2-20.0). Median PFS: 8.1 mo (95% confidence interval [CI] 6.9, 8.7; 166 events [65.9%]). Clinical trial information: NCT03286842 . Median TFST: 9.7 mo (95% CI 8.7, 11.1). CRR: 48.6% (95% CI 42.2, 55.0). Adverse events (AEs) in >20% of pts (all grades): nausea, anemia, asthenia, vomiting, and fatigue. 24.6% of pts reported a grade ≥3 AE, including anemia (n=33 [13.1%]). 4.4% of pts had an AE leading to treatment discontinuation. Conclusions: Interim results in this real-world population of pts with HER2- gBRCAm MBC were consistent with the OlympiAD study, and support olaparib as a chemotherapy-free alternative treatment for pts with gBRCAm advanced BC. [Table: see text]

510 Background: Several studies have established the critical role of preexisting immune response in triple negative breast cancer (TNBC). Most studies evaluated the tumor infiltrating lymphocytes in stroma. However, limited data are available with regards to the importance of specific subtypes and spatial distribution of these immune infiltrates. Methods: NanoString IO360 gene expression analysis and Digital Spatial Profiling (DSP) were used. DSP was used to quantify 39 immune-related proteins in stromal and tumor-enriched segments from 44 TNBC samples from the FinXX trial (NCT00114816) and 335 samples from the Mayo Clinic (MC) cohort of centrally reviewed TNBC (Leon-Ferre BCRT 2018). In FinXX trial, 22 patients with recurrence and 22 patients without recurrence were included. In MC cohort, 217/335 patients received adjuvant chemotherapy while 118 patients had surgery only without adjuvant chemotherapy. Regions were segmented based on pancytokeratin staining. The general linear model was used for statistical analysis of differential expression with recurrence free survival (RFS) as a categorical variable (recur yes or no). Kaplan-Meier estimates and Cox regression models were also used for analysis. Results: In the FinXX trial, using global gene expression analysis with IO360, there was no signature significantly associated with RFS. However, using DSP, high protein expression of CD56 in the tumor-enriched segments was associated with significant improvement in RFS (HR 0.26, 95%CI 0.09-0.78, p 0.01). Nevertheless, CD56 expression in the stroma (HR 0.66, 95%CI 0.29-1.53, p 0.33) and all segments (HR 0.53, 95%CI 0.23-1.25, p 0.14) was not significantly associated with improved outcome. We further validated these findings in the MC TNBC cohort where intratumoral CD56 expression was associated with a significant improvement in RFS (HR 0.23, p 0.002) but not stromal CD56 (p 0.79). Interestingly, when evaluating the MC TNBC cohort according to receipt of chemotherapy, intratumoral CD56 was associated with improved outcome only in patients who received chemotherapy (p 0.02 vs. 0.07). In both cohorts, higher expressions of intratumoral PD-L1, HLA-DR, and CD8 were associated with improved outcome. Conclusions: Using an in-depth analysis with spatially defined context, we identify that intratumoral CD56-positive NK cells are associated with improved outcome in TNBC. Our study highlights the potential role of NK cells in TNBC and future implications for biomarkers and therapeutic targets.Support: W81XWH-15-1-0292, P50CA116201-9, P50CA015083. Clinical trial information: NCT00114816 .