Citations

These NCCN Guidelines Insights highlight the updated recommendations for use of multigene assays to guide decisions on adjuvant systemic chemotherapy therapy for women with hormone receptor–positive, HER2-negative early-stage invasive breast cancer. This report summarizes these updates and discusses the rationale behind them.

Abstract In lung adenocarcinoma, gene fusion involving the anaplastic lymphoma kinase (ALK) gene leads to overexpression of its tyrosine kinase domain, which serves as the oncogenic driver in lung tumors carrying such a molecular alteration. Similar fusions involving ROS1, RET and NTRK are also found in lung cancer and tumors with oncogenic fusions often respond well to targeted therapy. However, these tumors do develop resistance to the targeting drug and patients eventually relapse while on treatment. Although newer drugs have been developed, it remains a challenge to effectively control cancer recurrence after targeted therapy. In vivo tumor models carrying these fusions, particularly those that have progressed while on targeted treatment, will help to facilitate further drug evaluations prior to their administration to the patient as well as offer an opportunity to better understand the molecular mechanisms driving disease onset, progression, and drug resistance in tumors carrying the fusion of interest. Here, we describe the first patient-derived tumor xenograft (PDX) carrying an STRN-ALK fusion. The patient was diagnosed with stage IV lung adenocarcinoma in 2011. She was initially treated with crizotinib and remained stable until 2015. At the time of disease progression, a biopsy was taken with patient consent under CT guidance from a chest wall mass using an 18-gauge needle and then implanted into two SCID-beige mice subcutaneously and into the fat pad of the kidney. Palpable tumor was observed in both mice at about 28 weeks post implantation and passaged at 36 weeks. They have been passaged two successive times and viably frozen. Pathologic analysis of the PDX showed that both tumors have the same mucinous morphology as observed in the original biopsy sample. RNA-seq and matepair analysis revealed that the tumors carry a rare fusion involving the first three exons of STRN and exon 20 to 3’ end of the ALK gene. The patient has been on ceritinib since January 2016 and remains stable as of last follow up. Several unique features contributed to the success of this study. 1) The metastatic chest wall lesion used for the PDX developed was easily accessible on the chest wall using a relative large 18-gauge needle for CT-guided biopsies. 2) The slow growth of the tumor biopsy mirrors the clinical course of the disease observed in the patient. 3) The patient remains clinically stable and continues to respond to TKi. The availability of a viable PDX tumor model for this rare STRN-ALK fusion offers a unique opportunity to identify the most appropriate drug for the patient at the time of disease progression as well as the opportunity to examine the unique molecular features associated with this rare ALK fusion. This work was supported in part by the National Foundation for Cancer Research Hillsberg Lung Cancer Translational Research Grant and by the Biomarker Discovery Program at the Mayo Clinic Center for Individualized Medicine. Citation Format: HongZheng Res, XiaoNan Hou, Karlyn E. Pierson, Patric Eiken, Asha Nair, PingYang Yang, Joanne Eunhee Yi, Aaron S. Mansfield, Jin Jen. Establishment of a unique patient-derived tumor model positive for STRN-ALK fusion from a patient with stage IV lung adenocarcinoma [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr A17.

606 Background: Between 3-5% of CRC patients have BRCA1/2 pathogenic mutations. This study aims to identify associations between BRCA1 and BRCA2 mutations and clinical characteristics in CRC. Methods: A total of 6396 CRC tumor samples were tested with Next-Generation Sequencing (NGS) on a 592-gene panel, pathogenic or presumed pathogenic variants were counted as mutations (mt). Microsatellite instability (MSI) and tumor mutational burden (TMB) were tested by NGS. Statistical correlations were investigated using ANOVA, Chi-square and t-test. Results: Among tumors sampled, 53% derived from male patients and median age was 60 years. BRCA1 mt were detected in 1.1% (n = 72) of tumors, while BRCA2 in 2.8% (n = 179). BRCA1 mt were more frequent in women (W;65%) than men (M;35%) (p = 0.0019) while no relationship with sex was seen for BRCA2 mt (42% F vs. 58% M). No significant associations with age were noticed. Majority of pathogenic mt in BRCA1 (52%; n = 34) and BRCA2 (62%; n = 103) occurred in MSI-High (MSI-H) cases. MSI-H pts had more frameshift mt in both BRCA1/2 than MSS pts. MSS cases had lower rates of BRCA1 and 2 pathogenic mt (44% and 37%, respectively). Right-sided tumors were significantly associated with BRCA1 (p = 0.0056) and BRCA2 (p < 0.0001) mt in MSI-H cases only. BRCA1/2 mt were associated with higher TMB in all CRCs, including MSI-H and MSS cases (p < 0.001). POLE mt (n = 31) were associated with higher BRCA1/2 mt rates (9.6%, 55% respectively). Among MSS cases with POLE wild-type status, BRCA1 (p = 0.0269) and BRCA2 (p = 0.0151) mt were associated with high TMB and combining both BRCA1/2 mutations led to an even higher TMB (3.6%; p = 0.001). Conclusions: This is the first study to show that BRCA1/2 mutations are more frequent in MSI-H, and independently associated with higher TMB, pathogenic POLE mutations, and right-sided tumors in MSI-H CRCs. Given their relationship with TMB, the presence of BRCA1/2 mutations may be potential predictive biomarkers for checkpoint or PARP inhibitors in CRC, a finding that should be prospectively evaluated.

60 Background: DDR mutations are associated with higher neoantigen load and tumor infiltrating lymphocytes, and are a potential biomarker for immunotherapy. We investigated the association of DDR mutations in gastric (GC), esophageal (EC), and gastroesophageal junction (GEJ) cancers with MSI, PD-L1, and TMB, known predictors for immune checkpoint inhibitors. Methods: 20 DDR mutations were tested by Next-Generation Sequencing (NGS) with a 592-gene panel on a total of 1935 (709 EC; 831 GC; 355 GEJ) cancers. TMB was assessed by NGS, MSI by NGS or fragment analysis, and PD-L1 by IHC (22c3 for CPS or SP142). Results: GC had the highest DDR mutation rate compared to EC and GEJ (27% vs. 20%, p = 0.0005 and 17%, p = 0.0002, respectively). MSI-High (MSI-H) was significantly more common in the DDR mutated cohort (DDR-M) compared to non-mutated cancers (18% vs. 1%; p < 0.0001). TMB-High (≥ 10 mutations/megabase [mt/MB]) was higher in DDR-M (35% vs. 21%; p < 0.0001); in DDR-M cohort, GC had the highest TMB compared to DDR-M EC and GEJ (mean: 13.8 vs. 9.4 vs. 10 mt/MB, respectively; p < 0.0001). DDR mutations were more frequent in the PD-L1 combined positive score (CPS) ≥ 50 group than CPS 0 (42.9% vs. 24%; p = 0.037) and CPS 1-9 (42.9% vs. 20.6%; p = 0.005). ARID1A, ATRX, BRCA2, and PTEN were the most prevalent DDR mutations in MSI-H (87%, 31%, 25%, 24%, respectively); ARID1A, ATRX, BRCA2, and PTEN in TMB-High (47%, 7.7%, 6.7%, 6.8%) and ARID1A, BRCA2, RAD50, and WRN in PD-L1 high (CPS ≥ 10) (48.5% vs. 5.2% vs. 2.5% vs. 3.4%). Conclusions: MSI-H, TMB-high and high PD-L1 expression were significantly more prevalent in the DDR-M cohort compared to non-DDR-mutated cancers, most pronounced in GC. Alterations in ARID1A, ATRX, BRCA2, and PTEN were correlated with MSI-H and TMB-high while ARID1A, BRCA2, RAD50, and WRN were correlated with increased PD-L1 expression. Our findings may help identify patients for tailored immunotherapy approaches in future clinical trials.

505 Background: MSI is a tumor biomarker for immunotherapy efficacy that is closely associated w/deficient MMR, and is also variably associated w/somatic muts of the MMR genes, loss of MMR protein expression by immunohistochemistry (IHC), and high TMB. Germ-line muts (Lynch syndrome/LS) in the 4 MMR genes are recognized to have distinct cancer spectrums/penetrance in LS, yet across all tumors, gene-specific variability in MMR IHC, MMR muts, and TMB is understudied. Methods: Results of TGPs performed by Caris Lifesciences (2015-17) were analyzed in colorectal (CRC), endometrial (EC) and all other cancers/tumors (OT) as: 1) all MSI-H tumors (n = 1057) and 2) all tumors w/ ≥1 mut in an MMR gene (n = 470). A subset of cases had IHC for MMR protein and PD-L1 expression. MSI and TMB were determined by NGS. Results: Characteristics of MSI-H tumors and tumors w/ ≥1 MMR mut are seen in the Table. A single MSH6 mut [F1088fs] in a coding microsatellite represented 31% of all MMR muts detected. F1088fs was found in 58% tumors w/MLH1/PMS2 loss (IHC) but only 25% w/MSH2/MSH6 loss (p < 0.001), was more commonly seen in EC vs CRC/OT (p < 0.001), and was negatively associated w/somatic POLE mut (p = 0.002). Distinct mut signatures in the MMR genes (e.g. GLUàSTOP) were seen in tumors w/POLE muts and DNA repair genes. Conclusions: MSI-H and MMR mutated tumors demonstrate marked gene-specific heterogeneity in IHC patterns, TMBs, and somatic muts that may be relevant to treatment selection, resistance, and response. [Table: see text]

Background: The characterization of sleep in those with neurodegenerative disease (NDD) is essential in understanding the potential neurobiological mechanisms that underlie the connection between sleep disruption and NDD manifestations and progression. Objective: Explore the inter-relationships between NDD and age, sex, diagnosis of obstructive sleep apnea, snoring, and duration of sleep time with the head in the supine and non-supine positions. Methods: A case-control design was used to evaluate differences in sleep position obtained from multi-night, in-home Sleep Profiler recordings in 45 patients with diagnosed NDD (24 with mild cognitive impairment, 15 with Alzheimer’s disease, and 6 with Lewy Body, Parkinson’s, or other dementias) and 120 age-sex matched controls with normal cognition (NC). Results: The frequency of supine sleep >2 h/night was significantly greater in the NDD than in the NC group ( p < 0.001, odds ratio = 3.7), and remained significant after controlling for age, sex, snoring, and obstructive sleep apnea diagnosis ( p = 0.01). There were no group differences in nocturnal mobility i.e., number of head position changes/h. Conclusion: This study demonstrates the utility of in-home measurements of sleep in defining the association of supine sleep position with neurodegenerative disorders. Our findings warrant further investigation, particularly in light of the recent evidence suggesting that sleep may an active role in the brain’s ability to clear CNS neurotoxins and metabolites.

53 Background: The National Academy of Medicine recommends interprofessional collaboration to promote optimal patient- and family-centered care. We sought to understand whether medical and psychosocial professionals who participated in an interprofessional communication intervention perceived it as distinct from usual clinical care. Methods: Our intervention targeted “medical” (physicians, nurse practitioners) and “psychosocial” (social workers, psychologists) professionals. It consisted of an interprofessional family conference, using a structured conversation guide, conducted during the first 6 months of a child’s cancer care. Conferences aimed to enable families to share hopes and worries and ask questions about their child’s care. Clinicians received a 60-minute training focused on communication skills, such as eliciting families’ hopes and worries, and suggested approaches to collaborating during conferences. Clinicians participated in debriefing interviews after each conference (range 1-3). Three of us conducted thematic analysis of interview data. Results: Twenty-two professionals (6 attending MDs, 4 fellow MDs, 8 NPs, and 8 psychosocial clinicians) gave 34 interviews. Medical and psychosocial professionals described interprofessional family conferences as distinct from usual practice patterns, largely due to their interprofessional colleagues’ presence. This co-presence contributed to “being on the same page.” Conferences sometimes bred a new understanding of a family’s needs and consequent care changes. However, both medical and psychosocial professionals noted that psychosocial professionals often were not vocal contributors to the conference. Some psychosocial clinicians reported being unsure of “the rules.” Conclusions: An interprofessional communication intervention promoted shared understanding between interprofessional colleagues. However, medical professionals were described as more vocal, perhaps due to insufficient role clarity or medical dominance.