Rebecca Jaslow

Reduced Risk of Bone Metastasis for Patients With Breast Cancer Who Use COX-2 Inhibitors

PURPOSE We hypothesize that the use of cyclooxygenase (COX)-2 inhibitors in early disease phases could protect against the development of bony metastases. PATIENTS AND METHODS The medical charts of patients with stage II-III breast cancer diagnosed between 1999 and 2005 were reviewed. Patients were subdivided according to the use of COX-2 inhibitors after the diagnosis and for > or = 6 months. Bivariate analyses were undertaken, and statistically significant variables were included in a multivariate logistic regression model. RESULTS Eleven percent of patients (74 of 644) who did not use COX-2 inhibitors developed bone metastases compared with 2% (1 of 48) of those who did use COX-2 inhibitors (Fisher exact test, P = .05). Significant predictors for bone metastases in a multivariate logistic regression model included: > or = 3 positive nodes (odds ratio [OR], 3.26 [95% CI, 1.79-5.93]; P < .001), stage IIB-IIIC disease (OR, 3.89 [95% CI: 1.74-8.69]; P = .001) and use of COX-2 inhibitors (OR, 0.12 [95% CI, 0.02-0.88]; P = .037). Adjusting for TNM stage, of the 327 patients with stages IIB-IIIC disease, 22% (63 of 293) had bone metastases in the non-COX-2 group versus 3% (1 of 34) in the COX-2 inhibitors consumers (Fisher exact test, P = .006). In this high-risk group of patients, the calculated OR associated with COX-2 inhibitors was 0.10 (95% CI, 0.01-0.78). CONCLUSION The use of COX-2 inhibitors could reduce the risk of bone metastases in stage II-III breast cancer.

Thalidomide in Multiple Myeloma—From the Clinic to the Laboratory

Multiple myeloma (MM) is a malignant clonal proliferation of plasma cells characterized by the excessive production of a single immunoglobulin protein isotype. In the year 2000, approximately 13,800 new cases of MM were diagnosed in the United States. This accounts for approximately 1% of all malignancies and 10% of hematologic malignancies.1 Over the past decades, the incidence of MM has been steadily increasing. It is twice as common in African-Americans as in the white population and it usually occurs in older individuals with a median age of 69 years.2 Although a number of potential risk factors have been suggested for myeloma, including radiation exposure, genetic predisposition, chronic antigenic stimulation such as rheumatoid arthritis and certain bacterial and viral infections, as well as certain occupational exposures, the etiology of this disease remains unknown.3

Clinical-pathological features and treatment modalities associated with recurrence in DCIS and micro-invasive carcinoma: Who to treat more and who to treat less

The primary aim in the management of DCIS is the prevention of recurrence and contralateral tumor. Risk factors for DCIS recurrence and appropriate treatments are still widely debated. Adjuvant therapies after surgical resection reduce recurrences and contralateral disease, but these treatments have significant financial costs, side effects and there is a group of low-risk patients who would not gain additional benefit. The aim of our analysis was to identify clinical-pathological features and treatment modalities associated with recurrence in DCIS and microinvasive carcinoma. In the Thomas Jefferson University Cancer Registry of Philadelphia, we identified 865 patients with DCIS or micro-invasive carcinoma treated between 2003 and 2013. Associations between recurrence and demographic factors (age at diagnosis, ethnicity), biological features (ER, PR and HER2) and treatment modalities (surgery, radiotherapy and endocrine treatment) were assessed. Our single institution register-based study showed that distribution of age at diagnosis and biological features did not significantly differ among ethnic groups. Younger women and micro-invasive carcinoma patients were more likely to undergo mastectomy, while African Americans were more likely to take endocrine therapy and undergo radiotherapy. In our sample only ER/PR negative DCIS were associated with significantly higher recurrence rate. Moreover, we reported a high rate of HER2 positive recurrences, suggesting that expression of this oncogene may represent a potential biomarker for DCIS at high risk of recurrence. To better define the molecular profile of the subgroup at worse prognosis might help to identify biomarkers predictive of recurrence or second tumors, identifying patients candidates for more appropriate treatments.

Abstract P4-13-18: A phase I study of romidepsin in combination with nab-paclitaxel in patients with metastatic HER-2 negative inflammatory breast cancer (IBC)

Inflammatory breast carcinoma (IBC) is the most aggressive form of breast cancer. The hallmark of IBC is regional extension into dermal lymphatics as tumor emboli causing breast edema and erythema. Pathologic characteristics of IBC include high grade, negative hormone receptor status and overexpression of HER2 and E-cadherin. The latter is the most attractive therapeutic target in IBC. In preclinical studies the histone deacetylase inhibitor, romidepsin targeted E-cadherin, affecting tumor emboli and increasing taxane sensitivity. Rationale: In vitro studies show that histone deacetylase inhibitors (HDACi) with taxanes provide synergy to enhance cell death. HDACi alter expression of AIRH1, a regulator of autophagy, typically silenced in breast cancer. In vitro treatment with HDACi induces expression of AIRH1, resulting in enhanced cell death with taxanes. In vitro studies of IBC have demonstrated the utility of HDACi and romidepsin in IBC cell lines. SAHA and romidespin, HDACis, inhibited self-renewal of IBC tumor spheroids from IBC cell lines. This trial combines romidepsin with a taxane proven in metastatic breast cancer to explore whether the combination will be effective in IBC. Design: This is a phase I trial to assess the safety of romidepsin plus nab-paclitaxel in patients with recurrent or metastatic IBC. The maximum tolerated dose (MTD) of romidepsin + weekly nab-paclitaxel was determined to define the dose for the phase II trial. Secondary objectives included describing the adverse event profile and assessing the overall response rate (ORR) and Clinical Benefit Rate (CBR). This study employed a 3+3 design. DLTs included febrile neutropenia or non-hematologic grade 3 or 4 toxicities. Patients were treated with nab-paclitaxel 100 mg/m2 iv with romidepsin, 7 mg/m2 iv (1st cohort) and 10 mg/m2 iv (2nd cohort), on days 1, 8, 15 of a 28 day cycle. Results: Nine patients were treated. The median age was 52. Three patients were treated in the first cohort. Two patients showed progressive disease (PD). One patient has had stable disease (SD) over 10 cycles and continues treatment. DLT was not reached at 7 mg. Toxicities related to romidepsin included neutropenia, anemia and fatigue. Six patients were treated in the 2nd cohort. Grade 3 hypophosphatemia, a DLT, was reached. One patient had complete response (CR). One patient had SD; four patients had PD. Toxicities related to romidepsin were anemia, neutropenia, GI upset, edema, hyperglycemia, fatigue, hypophosphatemia, pruritis, dry mouth, and increased lab values. The overall response rate (ORR) was 33% (3/9). The table below shows results. Conclusions: This phase I trial shows that romidepsin and nab-paclitaxel are well-tolerated in patients with advanced IBC. The MTD and recommended dose of romidepsin is 10 mg/m2 with nab-paclitaxel 100 mg/ m2 days 1, 8, 15 of a 28 day cycle. A phase II trial is planned in recurrent HER negative IBC patients. Citation Format: Avery TP, Jaslow R, Basu-Mallick A, Zibelli A, Fellin F, Cristofanilli M. A phase I study of romidepsin in combination with nab-paclitaxel in patients with metastatic HER-2 negative inflammatory breast cancer (IBC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-13-18.

Abstract P6-05-07: Improving personalized management of primary breast cancer: Mammaprint® risk stratification and blueprint® molecular subtyping

Background: Historically, breast cancer (BC) patients were offered cytotoxic or endocrine therapy based on factors such as tumor size, stage, and immunohistochemistry (IHC) markers for estrogen receptor (ER) and HER2-positivity. In 2010 the College of American Pathologists revised the breast cancer guidelines on endocrine therapy (ET) to include a lower threshold of ER positivity by immunohistochemistry, changing the definition from 10% to 1% [Hammond et al]. As a result, although a larger number of patients are offered ET, not all may benefit from this expanded definition of ER positivity if their disease is not truly estrogen driven. More recently, sensitive gene profiling assays, such as Blueprint®, can determine intrinsic molecular subtype which may be more sensitive in predicting which patients will benefit from ET. Additionally, Mammaprint® provides risk stratification which can aid in determining which patients could benefit from neoadjuvant therapy. Methods This is an observational analysis of 60 patients with stage I-IV BC. Tissue analysis for ER, PR and HER2 status were determined by IHC/FISH. mRNA expression profiles of 80 genes for Blueprint® (Agendia) analysis provided molecular subtyping: luminal, basal or her2. Moreover, Mammaprint® (Agendia) analysis of 70 genes subdivided patients into low risk or high risk providing further stratification for Luminal-type. Results By IHC staining, 48% of patients were ER+/HER2-, 10% were ER+/HER2+, 8.3% were ER-/HER2+, and the remaining patients (20%) were triple negative (TN) BC. By comparison, molecular profiling classified 21% as luminal A, 18% luminal B, 11.6% Her2 and 35% basal subtype. The 35 ER+ patients were heterogeneous by subtype: 13 were classified as molecular luminal A, 16 were luminal B, 4 were reclassified as HER2 and 2 were basal-like (one of whom had 40% ER positivity). Of the ER+ patients whose IHC quantitative staining was known, 29% with low positivity (less than 10%) were reclassified as basal subtype. Of the 5 patients who are ER+/HER2+, 2 were luminal B and 3 were of the HER2-subtype. Two patients who were TN were reclassified as luminal B, and an ER-/HER2+ was classified as a basal subtype. One patient with ER+/HER2- disease had evidence of both HER2 and luminal B subtype. Of the patients who received neo-adjuvant therapy, pCR was obtained in 33% of luminal, 60% of HER2 and 50% of basal-type patients. Conclusions BluePrint® and Mammaprint® Molecular profiling are useful diagnostic tools which further characterize tumors to predict risk of recurrence and response to treatment. About one third of ER+ patients with low positivity (less than 10%) were reclassified as basal subtype, suggesting that there is a proportion of patients who are exposed to the morbidity of hormonal therapy with little therapeutic benefit. Additionally, the test is predictive of pCR, with the highest rates in the basal and Her2 subtypes, thus enabling clinicians to predict and improve clinical outcomes through more personalized treatment decisions. Citation Format: Mikkilineni L, Austin LK, Limentani K, Jaslow RJ, Avery TP, Palazzo J, Cristofanilli M. Improving personalized management of primary breast cancer: Mammaprint® risk stratification and blueprint® molecular subtyping. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-05-07.

Abstract P2-02-14: Detection and characterization of CTCs isolated by ScreenCell®-Filtration in metastatic breast cancer

Background: Circulating Tumor cells (CTCs) detection has prognostic and predictive implications in patients with metastatic breast cancer (MBC). Genomic and phenotypic analysis of CTCs hold enormous promise as blood-based molecular characterization and monitoring disease progression and treatment benefit with a strong potential to be translated into more individualized targeted treatments. FDA-approved CellSearch™ detection allows only enumeration of CTCs expressing EpCAM without molecular characterization. CTCs represent very heterogeneous populations of tumorigenic cancer cells and some subpopulations have undergone epithelial-Mesenchymal transition (EMT), which is associated metastasis process and an unfavourable outcome. EpCAM-based enrichment technique has failed to detect EMT subpopulations due to the decreased expression or loss of epithelial markers. Non-EpCAM-based approaches are needed for identifying EMT CTCs. The ScreenCell® devices are single-use and low-cost innovative devices that use a filter for enrichment-free isolation of CTCs by a two-steps combining size-based separation and staining using different markers. The DEPArray™ system is the ideal downstream isolation system to collect single or pooled CTCs for molecular and genetic analysis. In this study, we evaluated the feasibility of achieving CTCs detection/enumeration using ScreenCell® filtration followed by single cell isolation with the DEPArray™ in MBC patients. Methods: The first part of the study consisted in evaluating CTCs detection/enumeration in 30 patients with stage III and stage IV breast cancer. 3 mL of whole blood in an EDTA or Transfix tubes was collected and processed on the ScreenCell® Cyto device following the instructions of the supplier. CTCs were stained with cytokeratin (CK-8, 18, and 19), leukocyte antigen (CD45), and a nuclear dye (DAPI) and counted under fluorescence microscope. CTCs were identified as positive staining for CK and DAPI and negative staining for CD45 (CK+/DAPI+CD45-). In the second part, After enrichment, CTCs were stained with CK, CD45, and DAPI and sorted with DEPArray™ Platform (Silicon Biosystems, Inc). Single CTCs were collected and the DNA of each single CTCs was amplified with Ampli1™ WGA kit, and the genome integrity index (GII) was assessed by Ampli1™ QC kit (Silicon Biosystems, Inc). Library was constructed and whole exome sequencing (WES) of DNA mutations was conducted. Results: Twenty patient samples had CTCs detected (66.7%), the number of CTCs was 1 to 347 per 3.0 ml of whole blood. CTC-clusters were detected in 7 patient samples (23.3%). Single CTCs were collected on DEPArray™ platform after enrichment with ScreenCell filtration. GII was confirmed with the presence of short, medium, and long DNA fragments (3 to 4 PCR bands) in the WGA library by PCR-based assay. All collected CTCs showed high GII as measured by Ampli1™ QC kit (GII ≥ 3) for WES of DNA mutations. The data analysis of WES results is under processing. Conclusions: ScreenCell® filtration is simple and effective devices to isolate CTCs and identify CTC-clusters. Isolation of single cells for molecular analysis using the combination of ScreenCell® filtration and DEPArray™ Platform is feasible for genetic characterization of CTCs. Citation Format: Mu Z, Benali-Furet N, Uzan G, Ye Z, Austin L, Wang C, Nguyen1 T, Avery T, Jaslow R, Yang H, Cristofanilli M. Detection and characterization of CTCs isolated by ScreenCell®-Filtration in metastatic breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-02-14.

Abstract P2-08-09: Prognostic values of circulating tumor cell (CTC) enumeration and their clusters in advanced breast cancer

Background The enumeration of circulating tumor cells (CTCs) has been proven to have prognostic values in several solid tumors including breast cancer. It has been established that a cut-off of 5 CTCs in 7.5 ml of blood may significantly differentiate breast cancer patients with favorable and unfavorable survival. However, CTC enumeration has not been shown to further predict the prognosis in those patients with more than 5 CTCs in 7.5 ml of blood. There are several recent in vitro and in vivo studies suggesting that clusters of CTC can be identified in blood and those clusters may play an important role in tumor progression and metastasis. Few clinical studies have been reported to enumerate CTC clusters and evaluate their prognostic values. In the current study, we hypothesize that the enumeration of CTC clusters play an important role in the prognostication of advanced breast cancer patients by providing additional predictive performance independent of CTC enumeration. Methods In an ongoing study of blood-based breast cancer biomarkers, we enrolled 114 patients with stages III and IV breast cancer. Among them, 68 patients had inflammatory breast cancer (IBC), an extremely aggressive form of breast cancer with a much lower survival rate than non-IBC breast cancer patients. The number of single CTCs and CTC clusters (two or more CTCs bound together) in 7.5 ml blood sample were counted using the CellSearch™ system (Janssen Diagnostic) at baseline study entry, and their associations with the progression-free survival (PFS) of patients were evaluated using Kaplan Meier curves and Cox proportional hazards modeling. Results Baseline CTCs were detected in 67 (58.77%) patients. Thirty-five (30.70%) and 19 patients (16.67%) had elevated CTCs (≥5 CTCs/7.5 mL) and clusters, respectively. IBC patients had a slightly higher percentage of cluster (17.65%) compared to non-IBC patients (15.22%). Patients with elevated baseline CTC and cluster had worse PFS (log rank P, 0.0009 and 0.0035, respectively). Compared to patients with Conclusion Baseline enumerations of both individual CTCs and CTC clusters predict PFS in advanced stage breast cancer patients. CTC clusters provide further prognostic value in patients with elevated CTC and their molecular characterizations may provide novel insights into the metastasis process. Citation Format: Ye Z, Mu Z, Wang C, Palazzo JP, Biederman L, Li B, Jaslow R, Avery T, Austin L, Yang H, Cristofanilli M. Prognostic values of circulating tumor cell (CTC) enumeration and their clusters in advanced breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-09.

Abstract P6-03-06: Circulating tumor DNA (ctDNA) for detection of molecular residual disease (MoRD) in breast cancer

Background Metastatic breast cancer (BC) is an incurable condition and treated with palliative intent. Standard diagnostic imaging and serum markers have limited sensitivity and are not recommended in clinical practice. Micrometastatic disease in the bone marrow (DTC) and peripheral blood (CTCs) is a recognized prognostic marker but with limited clinical utility. The detection of asymptomatic disease using a sensitive, reproducible and robust blood-based molecular test, or molecular residual disease (MoRD) could potentially represents a tool with the capability to design early therapeutic interventions and improve outcome. Circulating tumor DNA (ctDNA) has the potential to reflect residual tumor burden with higher diagnostic accuracy. We performed a pilot study in patients with high-risk primary BC. Methods This is a prospective study of 30 patients with either locally advanced BC who had completed primary therapy (21 patients) and had no evidence of disease (NED), or were metastatic but treated with curative intent and currently NED or stable (9 patients). Plasma was analyzed for ctDNA either after completing neo-adjuvant therapy (NAT), for recurrence monitoring after surgery, or when there was a clinical suspicion of recurrence. Guardant360™(Guardant Health) is a ctDNA next generation sequencing panel which produces a quantitative measurement of the mutant allele fraction for single nucleotide variants in 54 genes and copy number variants in 3 genes (panel was expanded to 68 genes in Feb 915) using digital sequencing technology. Results Baseline ctDNA analysis was done for 30 patients and 25 (83%) had serial draws for a total of 76 samples. All patients were stage 3-4 except for two stage 2 patients. ctDNA or MoRD was detected in 17 (57%) of patients and in 39 (51%) of the samples. Of the 18 patients treated with NAT, 11 achieved pCR or had minimal residual disease. Of these 11, six had no ctDNA detected after surgery, 3 had mixed results of no ctDNA and low volume ctDNA alterations on different draws, and 2 had persistent mutations on 2 draws. Ten of these 11 patients remain NED with median follow up of 24 months, while the one patient who recurred had persistent low volume missense ctDNA alterations on serial draws, first detected 6 months before clinically evident recurrence. Of the 7 patients with significant residual disease (less than PR) after NAT, 6 had post-surgical ctDNA detected and 5 have recurred at a median of 13 months after surgery. Four of those patients had ctDNA tested prior to recurrence and all had alterations detected in the blood prior to clinical recurrence. Lastly, one HER2+ metastatic patient treated with curative intent with a subsequent negative PET scan and no ctDNA detected after HER2-targeted therapy progressed on CT 2 months later and repeat ctDNA revealed EGFR mutant allele fraction of 51% and ERBB2 amplification. Conclusions The evaluation of ctDNA in high-risk BC patients can identify MoRD and predict for clinical recurrence. Patients with no or low volume ctDNA after primary treatment remained NED longer than those with multiple or high volume alterations. Future studies will validate these early observations and aid in selecting patients for additional systemic therapy with the hope of improving outcome. Citation Format: Austin L, Jaslow R, Fortina P, Nagy R, Zill O, Talasaz A, Cristofanilli M. Circulating tumor DNA (ctDNA) for detection of molecular residual disease (MoRD) in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-03-06.

Abstract 4918: Concordance of circulating tumor DNA (ctDNA) and next-generation sequencing (NGS) as molecular monitoring tools in metastatic breast cancer (MBC)

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Background MBC is an incurable disease with complex molecular features including somatic mutations that evolve in relation to genomic instability and selective treatment pressure. Patients with treatment-refractory MBC may benefit from tissue genomic evaluation using next-genomic sequencing (NGS). Furthermore, circulating DNA fragments with tumor-specific sequence alterations (ctDNA) found in the blood of patients with advanced disease offer the possibility of non-invasive molecular monitoring. ctDNA detects actionable mutations with the advantage of serial evaluation and allowing capture of inter- and intra-tumor heterogeneity. Methods This is a retrospective evaluation of 28 patients with MBC who failed standard therapies and had baseline plasma analyzed for ctDNA and tissue analysis (NGS) before starting new therapy. We were interested in the performance of the ctDNA test and the concordance rate of genomic alterations detected in the two tests. Selection criteria: progression of disease after standard therapies, need to detect novel molecular abnormalities for possible therapeutic targeting, or confirmation of persistence of genomic abnormalities already demonstrated in tissue or blood analysis. Guardant360™(Guardant Health) involves comprehensive sequencing of a panel of 54 gene associated with solid tumors using single-molecule digital sequencing technology. FoundationOne®(Foundation Medicine) performed the NGS on tissue evaluates the entire coding sequence of 315 cancer-related genes. Results All patients had biopsy-proved metastatic disease, and had ctDNA and NGS performed. 93% of patients had ctDNA alterations detected (with 0.1%-27.8% circulating tumor fraction), and 9 patients had serial ctDNA. Overall, for the patients we detected mutations in ctDNA and tissue, 89% of patients had a specific alteration on ctDNA that matched the NGS analysis. Among all mutations detected in tumors which are in overlapped genes, 71% of alterations were common (83% excluding gene amplifications). Interestingly, for patients who had both tests done within 8 weeks, 70% of had additional alterations in the ctDNA that were not found on NGS, such as ERBB2 mutations. Conclusions Genomic analysis using ctDNA and NGS detects genomic abnormalities in all patients with MBC with high concordance. However, each method was able to detect alterations that the other did not, suggesting the two methods can be complementary in detecting actionable mutations and expanding therapeutic options. Intriguingly, this occurred more frequently with the ctDNA, demonstrating its utility as an adjunct to tissue sampling which permits capture of the inter- and intra-tumor heterogeneity of the disease, and warrants further investigation prospectively. Citation Format: Laura K. Austin, Tiffany Avery, Rebecca Jaslow, Paolo Fortina, Dragan Sebisanovic, LaiMun Siew, Aubrey Zapanta, AmirAli Talasaz, Massimo Cristofanilli. Concordance of circulating tumor DNA (ctDNA) and next-generation sequencing (NGS) as molecular monitoring tools in metastatic breast cancer (MBC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4918. doi:10.1158/1538-7445.AM2015-4918

Abstract 2788: Comprehensive high-depth target sequencing in circulating tumor DNAs of patients with inflammatory and non-inflammation breast cancers

Inflammatory breast cancer (IBC) is an extremely aggressive form of locally advanced breast cancer that affects about 5% of breast cancer patients. The prognosis of IBC patients is remarkably poor, with a three-year survival rate of approximately 30% compared to 60% for patients with non-IBC breast cancers. These facts highlight the importance of accurate characterization, early detection, and timely treatment of IBC patients. Thus, it is important to develop novel and clinically applicable non-invasive biomarkers to characterize the unique presentation of IBC. In this study, we searched for somatic mutations in the circulating tumor DNAs (ctDNAs) that could be used to non-invasively characterize IBC patients and inform their clinical management. Using ctDNAs extracted from plasma of 10 pairs of IBC and non-IBC patients that were matched on major demographic and clinical variables, we conducted a high-depth target next-generation sequencing study that interrogated a comprehensive panel of 127 TCGA (The Cancer Genome Atlas)-reported cancer-related genes with >7000 uniquely designed and validated probes. Overall, we obtained >500x coverage in >80% of the interrogated regions, and >100x coverage in >97% of the regions. We found that C>T mutations predominated in well-reported mutated genes such as TP53, PIK3CA, EGFR, and CDH1. Compared to non-IBC patients, IBC patients appeared to have a higher percentage of mutations in PIK3CA but a lower percentage in TP53. Interestingly, about 78% of mutated genes that were only detected in IBC patients encode zinc finger-related proteins, a family of transcriptional factors that have been implicated in IBC development. In comparison, about 43% of genes that were detected only in non-IBC patients encode proteins important to cell division regulation. Furthermore, network-based stratification (NBS) analysis of the mutation profile revealed clusters of IBC relative to non-IBC samples, indicating the potential of mutation profiling in identifying molecularly distinct subtypes of IBC patients. Preliminary longitudinal analysis of ctDNAs from three patients with multiple plasma samples indicated that de novo mutations in important genes including PIK3CA, RB1, and KRAS appeared in patient blood after chemotherapy and/or targeted therapy treatments. Moreover, the emergence of some of these mutations was temporally correlated with the responses of patients to the treatments they received. Overall, this study provides novel evidence that ctDNA mutation status may help to non-invasively characterize IBC tumors, and might also serve as a novel non-invasive marker to monitor treatment efficacy and prognosis of breast cancer patients. Future studies with larger sample sizes are warranted to confirm our findings and identify additional clinically useful markers for the characterization and management of IBC and non-IBC patients. Citation Format: Hushan Yang, Xue Zhong, Qiang Wei, Zhaomei Mu, Zhong Ye, Yinzhi Lai, Huei-Wen Lin, Rebecca Jaslow, Tiffany Avery, Laura Austin, Zhaohui Sun, Shengrong Lin, Grace Zhao, Ling Fang Tang, Ronald E. Myers, Juan P. Palazzo, Laura Biederman, Bingshan Li, Massimo Cristofanilli. Comprehensive high-depth target sequencing in circulating tumor DNAs of patients with inflammatory and non-inflammation breast cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2788. doi:10.1158/1538-7445.AM2015-2788