Citations

Abstract The introduction of novel immunomodulatory drugs (IMiDs), such as lenalidomide, has drastically improved the survival of patients with multiple myeloma (MM). While it has been shown that patients with specific cytogenetic subtypes, namely t(4;14), have the best outcomes when treated with bortezomib-based regimens, the relationship between cytogenetic subtypes and response to IMiDs remains unclear. Using DNA synthesis and apoptosis assays, we investigated the relationship between cytogenetic subtype and lenalidomide response in a representative panel of human myeloma cell lines (HMCLs). Additionally, we examined HMCL protein expression levels of the lenalidomide target cereblon (CRBN) and its putative downstream target interferon regulatory factor 4 (IRF4), both of which have previously been shown to be predictive of lenalidomide response in HMCLs. Our results reveal that response to lenalidomide did not correlate with specific cytogenetic translocations. There were, however, distinct groups of lenalidomide-responsive and non-responsive HMCLs, as defined by inhibition of cellular proliferation; notably, all of the hyperdiploid HMCLs fell into the latter category. Repeated dosing of lenalidomide significantly lowered the IC50 of the responsive HMCL ALMC-1 (IC50 = 2.6 μM versus 0.005 μM, p=0.004), but did not have an effect on the IC50 of the non-responsive HMCL DP-6 (p>0.05). Moreover, no association was found between lenalidomide responsiveness and CRBN or IRF4 expression levels. In summary, our data indicate that lenalidomide sensitivity is independent of cytogenetic subtype in HMCLs. Additionally, while CRBN and IRF-4 have been shown to be associated with response to lenalidomide in patients, these findings do not translate back to HMCLs, which could be attributable to factors present in the bone marrow microenvironment. These results suggest that the development of a new treatment paradigm based on cytogenetic subtype of MM alone may be insufficient, and that additional markers may need to be incorporated. Furthermore, the disconnect between our findings of expression of CRBN and IRF-4 in lenalidomide-treated HMCLs and patient data highlights the need for further investigation into the role of the bone marrow microenvironment on the regulation of these previously demonstrated markers of lenalidomide response. Disclosures: No relevant conflicts of interest to declare.

Abstract Alopecia areata (AA), a complex autoimmune hair loss condition, affects approximately 2.1% of the population. Individuals with AA have increased susceptibility to diseases such as atopy and autoimmune disorders, but little is known about first‐degree relatives' risk to develop AA and associated conditions. Genetic counseling for multifactorial conditions, including autoimmune disease is complex, but potentially valuable. Anecdotally we know patients with AA ask medical providers about recurrence risk for family members as well as question whether they and their relatives are at risk for other conditions. Data on AA recurrence risks and comorbid conditions among relatives of affected individuals comprise valuable information that may guide clinical management by genetic counselors. This study investigated the recurrence risk of AA and compared the prevalence of associated conditions among first‐degree relatives to the general population. The study also assessed the validity of self‐reported conditions for a subset of participants. Relatives of individuals with AA ( N = 155), recruited from the National Alopecia Areata Foundation Registry, completed telephone surveys about their personal medical history for 70 medical conditions associated with AA. Medical records for 60 participants were compared to self‐reported responses. One‐sided proportional tests, in which it is assumed the disease prevalence in first‐degree relatives is higher than for those in the general population, yielded a 7.8% estimated risk of AA versus the general population prevalence of 2.1%. Furthermore, there are increased risks of 33 associated conditions, including atopy and other autoimmune conditions. Comparison of medical reports to self‐reported conditions indicated only 12% was incongruent. The findings may help genetic counselors better serve patients and their families by informing them of lifetime risk estimates of developing AA and comorbid conditions, resulting in early diagnosis of autoimmune diseases in AA families. Findings also provide evidence supporting the validity of self‐report data in AA families.

Abstract Abstract 470 Multiple myeloma (MM) is an incurable and fatal neoplasm characterized by the accumulation of clonal plasma cells (PC) that results in significant end organ and tissue damage. MM is preceded by either of two premalignant asymptomatic stages, monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma (SMM), both of which are identified by the presence of clonally expanded abnormal PC populations. While MGUS and SMM patients' abnormal PC populations may remain stable for years, both have a life-long significantly increased risk of progressing to MM (1% and 10% per year, respectively). For this reason, a better understanding of the molecular events prompting malignant progression and increased accuracy in identifying those patients that have begun to transition to MM is urgently needed. In this study, we identified a novel MM marker, CD147 (also known as extracellular matrix metalloproteinase inducer (MMP), or EMMPRIN), that is not only over-expressed on MM PCs as compared to its premalignant counterparts, but whose increased expression correlates with the level of abnormal PC proliferation. To our knowledge, we are the first to demonstrate a role for CD147 in MM. CD147 has been shown by others to display a variety of activities and those with potential relevance to MM include stimulation of increased MMP production and angiogenesis, and playing a critical role in glycolysis via facilitation of excess cellular lactate transport. Our initial experiments revealed that MM PCs overexpress CD147 mRNA relative to MGUS PCs. Flow cytometric analysis corroborated these data and demonstrated variable expression of CD147 across the disease continuum ranging from no expression to bimodal or uniform expression. Indeed, there was a significant difference between CD147 expression on MGUS and SMM PCs compared to that on MM PCs (p=0.02 and 0.005, respectively). We next determined whether CD147 had a signaling role in these cells. Using the natural CD147 ligand, cyclophilin B (CypB), we showed that addition of CypB to either human MM cell lines (HMCLs) or CD138+ patient PCs resulted in increased PC proliferation as measured by [3H]-thymidine incorporation. In a complementary manner, addition of CD147 antibodies significantly inhibited proliferation without an effect on cell viability. By western blot analysis we further demonstrated that CypB-mediated CD147 activation leads to MAPK phosphorylation. Next, we isolated CD147+ and CD147- MM cells from patients whose tumor cells bimodally expressed this marker and assessed the response of each subset to IL-6 and CypB. The CD147+ subset was almost solely responsible for the proliferative response in all cases examined. In addition, we cultured bone marrow mononuclear cells from CD147 bimodally expressing MM patients overnight with bromodeoxyuridine before performing cell cycle analysis on the CD147+ and CD147- MM PC populations. Remarkably, the CD147+ PCs were greatly enriched for cells in the S and G2/M phases of the cell cycle, whereas the CD147- PCs resided almost entirely in the G0/G1 phase. In the final set of experiments, we employed siRNA knockdown strategies using HMCLs to definitively test the role of CD147 in MM cell proliferation. Indeed, IL-6 induced proliferation was significantly compromised following CD147 down regulation, which was not attributed to increased apoptosis. However, IL-6 mediated phosphorylation of MAPK remained robust suggesting that the IL-6 signaling pathway overall was not compromised in these cells. Finally, cell cycle analysis demonstrated that CD147 down regulation resulted in a significant increase in the number of cells in the G0/G1 phase of the cell cycle and a decrease in the number of cells in the G2/M phase of the cell cycle, as compared to cells transfected with control siRNA. In conclusion, our data suggest that the CD147 molecule plays a critical role in the biology of malignant MM PCs, particularly as it concerns MM cell proliferation, and may thus serve as a useful and attractive target for reducing the proliferative compartment of this disease. Ongoing studies are investigating additional roles for MM cell CD147 expression, e.g., its role in MMP induction in the tumor microenviroment. Disclosures: No relevant conflicts of interest to declare.

Abstract Immunoglobulin (Ig) light chain (LC)-associated amyloidosis (AL) is a fatal plasma cell (PC) disorder characterized by the overproduction of Ig light chains that deposit in an abnormal conformation as amyloid throughout the body. Lambda LC are involved in amyloid deposition 2–3 times more often than kappa LC, and certain LC Ig variable genes are more frequently involved than others and influence clinical presentation and outcome. AL is a potential complication of any immunoglobulin clonal process, but is most often pathologically associated with minimal clonal expansion of PC, as seen in monoclonal gammopathy of undetermined significance. It is much less commonly observed in patients with multiple myeloma (MM). Because of this, and to our knowledge, there are no cell lines that have been established from AL patients, an experimental tool that would be of great value in studying amyloid formation and the biology of amyloid producing PC. In this study, we have established two cell lines from a 50 yr old female initially diagnosed with AL. Upon initial diagnosis, the BM aspirate consisted of 27% IgG λPC with a PC labeling index (PCLI) of 1.9% and a κ to λratio of <0.1. Amyloid was present in periosteal vessel walls and in the fat aspirate. The first cell line, ALMC-1, was established from BM mononuclear cells isolated from the diagnostic aspirate. The patient received a peripheral blood stem cell transplant (PBSCT) 2 months later, but relapsed within 100 days post-PBSCT with symptomatic myeloma. At relapse, the patient’s BM aspirate consisted of 70% λ+ PC and a PCLI of 20%; the second cell line, ALMC-2 was established from this aspirate. IgVL and IgVH analysis revealed that both cell lines expressed identical sequences and used IgVλ 6–57*01, IgλJ3*02, and IgλC3*03: both used the IgVH VH3–21 gene and the extent of somatic mutation was approximately 4%. Both cell lines produce significant FLC, and studies are currently underway to characterize in vitro amyloid production. We next used fluorescence in situ hybridization (FISH) to identify the genetic defects in this patient’s tumor population before and after transition to symptomatic MM. The initial BM aspirate at time of diagnosis of AL revealed approximately 30% of the PC had clear evidence of c-MYC gene amplification. In the subsequent draws as well as in both cell lines, 100% c-MYC amplification was identified, consistent with clonal selection. FISH analysis also revealed that 40% of cells had p53 deletion upon initial diagnosis, whereas the subsequent samples and cell lines were 100% for p53 deletion. All cells also had an IgH translocation that did not involve any commonly observed chromosome partners. Lastly, we have characterized the cytokine responsiveness of both cell lines. Although some differences are observed between ALMC-1 and ALMC-2, IL-6 and IGF-1 stimulated growth in both cell lines to varying degrees and both lines expressed autocrine IGF-I. In summary, our initial characterization of ALMC-1 and ALMC-2 predicts that these unique cell lines will prove to be an invaluable tool to better understand AL, from the combined perspectives of amyloidogenic protein structure and amyloid formation, genetics, and cell biology. Insight gained from this model system may eventually have an impact in the clinical arena by providing a better understanding of this incurable disease.

Abstract Objective To assess the negative predictive value (NPV) of breast MRI in detecting residual disease after neoadjuvant chemotherapy (NAC) in women with invasive breast cancer, overall and by tumor subtype. Methods An institutional review board approved retrospective study from January 2010 through December 2016 identified patients with invasive breast cancer who achieved complete MRI response to NAC, defined as the absence of residual enhancement in the tumor bed above background parenchymal enhancement. During the study period, it was our routine practice to assign a BI-RADS 1 or 2 assessment to these cases. The NPV was defined as the ability of a complete MRI response to predict pathologic complete response (pCR) at final surgical pathology. Statistical analyses were performed using a Fisher exact test. Results Among 244 patients who underwent MRI to assess NAC response, 38 (16%) were determined to have complete MRI response by the interpreting radiologist. Of these, 20/38 (53%) had pCR. Complete MRI response did not significantly predict pCR for the total group (P &lt; 0.9). However, NPVs significantly varied by molecular subtype (P &lt; 0.004). True negative MRIs by tumor subtype were 2/10 (20%) for hormone receptor (HR)+/HER2–, 3/10 (30%) for HR+/HER2+, 6/8 (75%) for HR–/HER+, and 9/10 (90%) for triple negative (TN) subtypes. Complete MRI response significantly predicted pCR for only the TN subtype (NPV 90%; P &lt; 0.02). Conclusions In patients with complete MRI response, 53% had pCR. While MRI lacks sufficient NPV to obviate the need for surgical excision, it may add prognostic value for certain molecular subtypes. The TN subtype demonstrated the highest NPV.

OBJECTIVES: Pancreatic cystic lesions (PCLs) may be precancerous. Those likely to harbor high-grade dysplasia (HGD) or pancreatic cancer (PC) are targets for surgical resection. Current algorithms to predict advanced neoplasia (HGD/PC) in PCLs lack diagnostic accuracy. In pancreatic tissue and cyst fluid (CF) from PCLs, we sought to identify and validate novel methylated DNA markers (MDMs) that discriminate HGD/PC from low-grade dysplasia (LGD) or no dysplasia (ND). METHODS: From an unbiased whole-methylome discovery approach using predefined selection criteria followed by multistep validation on case (HGD or PC) and control (ND or LGD) tissues, we identified discriminant MDMs. Top candidate MDMs were then assayed by quantitative methylation-specific polymerase chain reaction on archival CF from surgically resected PCLs. RESULTS: Of 25 discriminant MDMs identified in tissue, 13 were selected for validation in 134 CF samples (21 cases [8 HGD, 13 PC], 113 controls [45 ND, 68 LGD]). A tree-based algorithm using 2 CF-MDMs ( TBX15 , BMP3 ) achieved sensitivity and specificity above 90%. Discrimination was significantly better by this CF-MDM panel than by mutant KRAS or carcinoembryonic antigen, with areas under the receiver operating characteristic curve of 0.93 (95% confidence interval: 0.86–0.99), 0.71 (0.57–0.85), and 0.72 (0.60–0.84), respectively. Cutoffs for the MDM panel applied to an independent CF validation set (31 cases, 56 controls) yielded similarly high discrimination, areas under the receiver operating characteristic curve = 0.86 (95% confidence interval: 0.77–0.94, P = 0.2). DISCUSSION: Novel MDMs discovered and validated in tissue accurately identify PCLs harboring HGD/PC. A panel of 2 MDMs assayed in CF yielded results with potential to enhance current risk prediction algorithms. Prospective studies are indicated to optimize and further evaluate CF-MDMs for clinical use.

e15688 Background: PNETs are marked by histological heterogeneity and variable clinical outcomes. Other than Ki67 index, reliable circulating or tissue biomarkers for prognosis do not exist. Methods: PubMed was searched through 01/31/2017. Inclusion criteria were: 1) prospective/retrospective cohort with defined source population, boundary dates, and justifications for exclusions; 2) assay of primary tumors; 3) clear descriptions of methods including techniques and controls; 4) use of multivariate proportional hazards modeling adjusted for prognostic factors including but not limited to stage or grade; and 5) reporting adjusted hazard ratios (HR) with 95 % confidence intervals and P values. Studies with < 50 % PNETs were excluded. PNET-specific data was summarized in the table. Results: A total of 2958 manuscripts were identified and 462 manuscripts were reviewed. Only 23 multivariate studies met all inclusion criteria. These altogether analyzed 24 unique targets and 14 were associated with survival. Conclusions: This meta-analysis identified 14 markers associated with survival of PNET patients. Future studies should adhere to the REMARK criteria and incorporate the 2017 WHO grading system for multivariate analysis. 1. I-immunohistochemistry, F-fluorescence in situ hybridization, E-enzyme linked immunosorbent assay, M- methylation specific PCR, P-polymerase chain reaction; 2. O-overall survival, F-disease free survival, S-disease specific survival, P- progression free survival.[Table: see text]

Abstract Background: Patients achieving a pathologic complete response (pCR) following neoadjuvant therapy have significantly improved event-free survival relative to those who do not; and pCR is an FDA-accepted endpoint to support accelerated approval of novel agents/combinations in the neoadjuvant treatment of high risk early stage breast cancer. Previous studies have shown that recurrence risk increased with increasing burden of residual disease (as assessed by the RCB index). As well, these studies suggest that patients with minimum residual disease (RCB-I class) also have favorable outcomes (comparable to those achieving a pCR) within high risk tumor subtypes. In this study, we assess whether integrating RCB with MRI functional tumor volume (FTV), which in itself is prognostic, can improve prediction of distant recurrence free survival (DRFS); and identify a subset of patients with minimal residual disease with comparable DRFS as those who achieved a pCR. Imaging tools can then be used to identify the subset that will do well early and guide the timing of surgical therapy. Method: We performed a pooled analysis of 596 patients from the I-SPY2 TRIAL with RCB, pre-surgical MRI FTV data and known follow-up (median 2.5 years). We first assessed whether FTV predicts residual disease (pCR or pCR/RCB-I) using ROC analysis. We applied a power transformation to normalize the pre-surgical FTV distribution; and assessed its association with DRFS using a bi-variate Cox proportional hazard model adjusting for HR/HER2 subtype. We also fitted a bivariate Cox model of RCB index adjusting for subtype; and assessed whether adding pre-surgical FTV to this model further improves association with DRFS using a likelihood ratio (LR) test. For the Cox modeling, penalized splines approximation of the transformed FTV and RCB index with 2 degrees of freedom was used to allow for non-linear effects of FTV and RCB on DRFS. Result: Pre-surgical MRI FTV is significantly associated with DRFS (Wald p&lt;0.00001), and more effective at predicting pCR/RCB-I than predicting pCR alone (AUC: 0.72 vs. 0.65). Larger pre-surgical FTV remains associated with worse DRFS adjusting for subtype (Wald p &lt;0.00001). The RCB index is also significantly associated with DRFS adjusting for subtype (Wald p&lt;0.00001). Adding FTV to a model containing RCB and subtype further improves association with DRFS (LR p=0.0007). RCB-I patients have excellent DRFS (94% at 3 years compared to 95% in the pCR group). Efforts are underway to identify an optimal threshold for dichotomizing pre-surgical FTV and FTV change measures for use in combination with pCR/RCB-I class to generate integrated RCB (iRCB) groups as a composite predictor of DRFS. Conclusion: Pre-surgical MRI FTV is effective at predicting minimal residual disease (RCB0/I) in the I-SPY 2 TRIAL. Despite the association between FTV and RCB, FTV appears to provide independent added prognostic value (to RCB and subtype), suggesting that integrating MRI volume measures and RCB into a composite predictor may improve DRFS prediction. Citation Format: Hylton NM, Symmans WF, Yau C, Li W, Hatzis C, Isaacs C, Albain KS, Chen Y-Y, Krings G, Wei S, Harada S, Datnow B, Fadare O, Klein M, Pambuccian S, Chen B, Adamson K, Sams S, Mhawech-Fauceglia P, Magliocco A, Feldman M, Rendi M, Sattar H, Zeck J, Ocal I, Tawfik O, Grasso LeBeau L, Sahoo S, Vinh T, Yang S, Adams A, Chien AJ, Ferero-Torres A, Stringer-Reasor E, Wallace A, Boughey JC, Ellis ED, Elias AD, Lang JE, Lu J, Han HS, Clark AS, Korde L, Nanda R, Northfelt DW, Khan QJ, Viscusi RK, Euhus DM, Edmiston KK, Chui SY, Kemmer K, Wood WC, Park JW, Liu MC, Olopade O, Tripathy D, Moulder SL, Rugo HS, Schwab R, Lo S, Helsten T, Beckwith H, Haugen PK, van't Veer LJ, Perlmutter J, Melisko ME, Wilson A, Peterson G, Asare AL, Buxton MB, Paoloni M, Clennell JL, Hirst GL, Singhrao R, Steeg K, Matthews JB, Sanil A, Berry SM, Abe H, Wolverton D, Crane EP, Ward KA, Nelson M, Niell BL, Oh K, Brandt KR, Bang DH, Ojeda-Fournier H, Eghtedari M, Sheth PA, Bernreuter WK, Umphrey H, Rosen MA, Dogan B, Yang W, Joe B, I-SPY 2 TRIAL Consortium, Yee D, Pusztai L, DeMichele A, Asare SM, Berry DA, Esserman LJ. Refining neoadjuvant predictors of three year distant metastasis free survival: Integrating volume change as measured by MRI with residual cancer burden [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-07-03.