Cancer-associated fibroblast-derived acetate promotes pancreatic cancer development by altering polyamine metabolism via the ACSS2-SP1-SAT1 axis

The ability of tumour cells to thrive in harsh microenvironments depends on the utilization of nutrients available in the milieu. Here we show that pancreatic cancer-associated fibroblasts (CAFs) regulate tumour cell metabolism through the secretion of acetate, which can be blocked by silencing ATP citrate lyase (ACLY) in CAFs. We further show that acetyl-CoA synthetase short-chain family member 2 (ACSS2) channels the exogenous acetate to regulate the dynamic cancer epigenome and transcriptome, thereby facilitating cancer cell survival in an acidic microenvironment. Comparative H3K27ac ChIP-seq and RNA-seq analyses revealed alterations in polyamine homeostasis through regulation of SAT1 gene expression and enrichment of the SP1-responsive signature. We identified acetate/ACSS2-mediated acetylation of SP1 at the lysine 19 residue that increased SP1 protein stability and transcriptional activity. Genetic or pharmacologic inhibition of the ACSS2-SP1-SAT1 axis diminished the tumour burden in mouse models. These results reveal that the metabolic flexibility imparted by the stroma-derived acetate enabled cancer cell survival under acidosis via the ACSS2-SP1-SAT1 axis.

Premastectomy Radiotherapy and Immediate Breast Reconstruction: A Randomized Clinical Trial

Importance

Premastectomy radiotherapy (PreMRT) is a new treatment sequence to avoid the adverse effects of radiotherapy on the final breast reconstruction while achieving the benefits of immediate breast reconstruction (IMBR).

Objective

To evaluate outcomes among patients who received PreMRT and regional nodal irradiation (RNI) followed by mastectomy and IMBR.

Design, Setting, and Participants

This was a phase 2 single-center randomized clinical trial conducted between August 3, 2018, and August 2, 2022, evaluating the feasibility and safety of PreMRT and RNI (including internal mammary lymph nodes). Patients with cT0-T3, N0-N3b breast cancer and a recommendation for radiotherapy were eligible.

Intervention

This trial evaluated outcomes after PreMRT followed by mastectomy and IMBR. Patients were randomized to receive either hypofractionated (40.05 Gy/15 fractions) or conventionally fractionated (50 Gy/25 fractions) RNI.

Main Outcome and Measures

The primary outcome was reconstructive failure, defined as complete autologous flap loss. Demographic, treatment, and outcomes data were collected, and associations between multiple variables and outcomes were evaluated. Analysis was performed on an intent-to-treat basis.

Results

Fifty patients were enrolled. Among 49 evaluable patients, the median age was 48 years (range, 31-72 years), and 46 patients (94%) received neoadjuvant systemic therapy. Twenty-five patients received 50 Gy in 25 fractions to the breast and 45 Gy in 25 fractions to regional nodes, and 24 patients received 40.05 Gy in 15 fractions to the breast and 37.5 Gy in 15 fractions to regional nodes, including internal mammary lymph nodes. Forty-eight patients underwent mastectomy with IMBR, at a median of 23 days (IQR, 20-28.5 days) after radiotherapy. Forty-one patients had microvascular autologous flap reconstruction, 5 underwent latissimus dorsi pedicled flap reconstruction, and 2 had tissue expander placement. There were no complete autologous flap losses, and 1 patient underwent tissue expander explantation. Eight of 48 patients (17%) had mastectomy skin flap necrosis of the treated breast, of whom 1 underwent reoperation. During follow-up (median, 29.7 months [range, 10.1-65.2 months]), there were no locoregional recurrences or distant metastasis.

Conclusions and Relevance

This randomized clinical trial found PreMRT and RNI followed by mastectomy and microvascular autologous flap IMBR to be feasible and safe. Based on these results, a larger randomized clinical trial of hypofractionated vs conventionally fractionated PreMRT has been started (NCT05774678).

Trial Registration

ClinicalTrials.gov Identifier: NCT02912312.

To Dissect or Not to Dissect: Can We Predict the Presence of Four or More Axillary Lymph Node Metastases in Postmenopausal Women with Clinically Node-Negative Breast Cancer?

BACKGROUND

Axillary lymph node (ALN) involvement is important for prognosis and guidance of multidisciplinary treatment of breast cancer patients. This study sought to identify preoperative clinicopathologic factors predictive of four or more pathologically positive ALNs in patients with cN0 disease and to develop a predictive nomogram to inform therapy recommendations.

METHODS

Using an institutional prospective database, the study identified postmenopausal women with cN0 invasive breast cancer undergoing upfront sentinel lymph node biopsy (SLNB) with or without completion ALND (cALND) between 1993 and 2007. Logistic regression analyses identified factors predictive of four or more positive nodes in the cN0 population and patients with one, two, or more SLNs.

RESULTS

The study identified 2532 postmenopausal women, 615 (24.3%) of whom underwent cALND. In the univariate analysis, tumor size, lymphovascular (LVI), histology, estrogen receptor (ER)-positive status, and multifocality/multicentricity were predictive of four or more positive nodes (n = 63; p < 0.05), and all except ER status were significant in the multivariate analysis. Of the 2532 patients, 1263 (49.2%) had hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative disease, and 30 (2.4%) were found to have four or more positive nodes. Of the 130 patients with exactly one positive SLN who underwent cALND (n = 130, 5.4%), 7 had four or more positive nodes, with grade as the only predictive factor (p = 0.01). Of the 33 patients with two or more positive SLNs who underwent cALND, 9 (27.3%) had four or more positive nodes after cALND, but no factors were predictive in this subset.

CONCLUSION

Postmenopausal women with early-stage cN0 HR-positive, HER2-negative breast cancer with a single positive SLN had a very low risk (5%) of having four or more positive nodes on final pathology. With such a low risk of N2 disease, limited staging with SLNB may be sufficient to guide therapy decisions for this subset of patients.

A WNT4- and DKK3-driven canonical to noncanonical Wnt signaling switch controls multiciliogenesis

Multiciliated cells contain hundreds of cilia whose directional movement powers the mucociliary clearance of the airways, a vital host defense mechanism. Multiciliated cell specification requires canonical Wnt signaling, which then must be turned off. Next, ciliogenesis and polarized ciliary orientation are regulated by noncanonical Wnt/planar cell polarity (Wnt/PCP) signaling. The mechanistic relationship between the Wnt pathways is unknown. We show that DKK3, a secreted canonical Wnt regulator and WNT4, a noncanonical Wnt ligand act together to facilitate a canonical to noncanonical Wnt signaling switch during multiciliated cell formation. In primary human airway epithelial cells, DKK3 and WNT4 CRISPR knockout blocks, whereas ectopic expression promotes, multiciliated cell formation by inhibiting canonical Wnt signaling. Wnt4 and Dkk3 single-knockout mice also display defective ciliated cells. DKK3 and WNT4 are co-secreted from basal stem cells and act directly on multiciliated cells via KREMEN1 and FZD6, respectively. We provide a novel mechanism that links specification to cilium biogenesis and polarization for proper multiciliated cell formation.

Robotic-Assisted Nipple Sparing Mastectomy

Minimally invasive approaches to breast surgery have evolved from endoscopic techniques to recent developments in robotic-assisted mastectomies. Initial studies on robotic-assisted nipple-sparing mastectomy (RNSM) have shown improved patient satisfaction and aesthetic outcomes with similar complication rates and oncological outcomes in selected patients. This chapter reviews techniques used and available data on complications and clinical outcomes for RNSM. Currently, RNSM is an investigational technique in the United States and should be performed in clinical trials with U.S. Food & Drug Administration approval to rigorously evaluate the safety and effectiveness of this approach.

Targeting BET Proteins Decreases Hyaluronidase-1 in Pancreatic Cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is characterized by the presence of dense stroma that is enriched in hyaluronan (HA), with increased HA levels associated with more aggressive disease. Increased levels of the HA-degrading enzymes hyaluronidases (HYALs) are also associated with tumor progression. In this study, we evaluate the regulation of HYALs in PDAC.

METHODS

Using siRNA and small molecule inhibitors, we evaluated the regulation of HYALs using quantitative real-time PCR (qRT-PCR), Western blot analysis, and ELISA. The binding of BRD2 protein on the HYAL1 promoter was evaluated by chromatin immunoprecipitation (ChIP) assay. Proliferation was evaluated by WST-1 assay. Mice with xenograft tumors were treated with BET inhibitors. The expression of HYALs in tumors was analyzed by immunohistochemistry and by qRT-PCR.

RESULTS

We show that HYAL1, HYAL2, and HYAL3 are expressed in PDAC tumors and in PDAC and pancreatic stellate cell lines. We demonstrate that inhibitors targeting bromodomain and extra-terminal domain (BET) proteins, which are readers of histone acetylation marks, primarily decrease HYAL1 expression. We show that the BET family protein BRD2 regulates HYAL1 expression by binding to its promoter region and that HYAL1 downregulation decreases proliferation and enhances apoptosis of PDAC and stellate cell lines. Notably, BET inhibitors decrease the levels of HYAL1 expression in vivo without affecting the levels of HYAL2 or HYAL3.

CONCLUSIONS

Our results demonstrate the pro-tumorigenic role of HYAL1 and identify the role of BRD2 in the regulation of HYAL1 in PDAC. Overall, these data enhance our understanding of the role and regulation of HYAL1 and provide the rationale for targeting HYAL1 in PDAC.

Adaptive stimulation of macropinocytosis overcomes aspartate limitation in cancer cells under hypoxia

Stress-adaptive mechanisms enable tumour cells to overcome metabolic constraints under nutrient and oxygen shortage. Aspartate is an endogenous metabolic limitation under hypoxic conditions, but the nature of the adaptive mechanisms that contribute to aspartate availability and hypoxic tumour growth are poorly understood. Here we identify GOT2-catalysed mitochondrial aspartate synthesis as an essential metabolic dependency for the proliferation of pancreatic tumour cells under hypoxic culture conditions. In contrast, GOT2-catalysed aspartate synthesis is dispensable for pancreatic tumour formation in vivo. The dependence of pancreatic tumour cells on aspartate synthesis is bypassed in part by a hypoxia-induced potentiation of extracellular protein scavenging via macropinocytosis. This effect is mutant KRAS dependent, and is mediated by hypoxia-inducible factor 1 (HIF1A) and its canonical target carbonic anhydrase-9 (CA9). Our findings reveal high plasticity of aspartate metabolism and define an adaptive regulatory role for macropinocytosis by which mutant KRAS tumours can overcome nutrient deprivation under hypoxic conditions.

Relationship Between Financial Toxicity and Surgical Treatment for Early-Stage Breast Cancer: A Propensity Score-Matched Comparison of Breast-Conserving Therapy and Mastectomy

BACKGROUND

Financial toxicity (FT) can lead to decreased quality of life and poor treatment outcomes. However, there is limited published data on the extent to which the various surgical treatment approaches for early-stage breast cancer are determinants for FT.

STUDY DESIGN

We performed a single-institution cross-sectional survey of adult female patients with stage 0 to II breast cancer undergoing unilateral breast-conserving therapy or unilateral mastectomy. FT was measured using the Comprehensive Score for Financial Toxicity (COST) survey. Propensity matching was performed to optimize comparability of study groups. A multivariate regression model was used to identify factors associated with worsening FT as a robustness check. Our secondary end point was prevalence of coping strategies associated with cost of cancer care.

RESULTS

Among 294 patients who met inclusion criteria, 203 underwent breast-conserving therapy and 91 received mastectomy. We generated 72 total matched pairs and noted no differences in demographic and socioeconomic characteristics. Of these, 55 pairs had complete COST information, which was comparable on adjusted analysis (26.6 vs 24.7; p = 0.481). High annual income (β = 4.83; p < 0.001) and supplemental insurance (β = 5.37; p < 0.001) were significantly associated with higher COST scores, while change in employment status (β = -4.81; p < 0.001) correlated significantly with lower COST scores. No significant differences were observed in coping strategies.

CONCLUSIONS

Choice of BCT or mastectomy was not associated with a differential risk for FT in early-stage cancer. Decisions on ablative approach should be made based on patient preferences and disease-specific criteria. Transparent counseling on FT for high-risk populations promotes patient-centricity.

Quantitative proteomics identifies the core proteome of exosomes with syntenin-1 as the highest abundant protein and a putative universal biomarker

Exosomes are extracellular vesicles derived from the endosomal compartment that are potentially involved in intercellular communication. Here, we found that frequently used biomarkers of exosomes are heterogeneous, and do not exhibit universal utility across different cell types. To uncover ubiquitous and abundant proteins, we used an unbiased and quantitative proteomic approach based on super-stable isotope labeling with amino acids in cell culture (super-SILAC), coupled to high-resolution mass spectrometry. In total, 1,212 proteins were quantified in the proteome of exosomes, irrespective of the cellular source or isolation method. A cohort of 22 proteins was universally enriched. Fifteen proteins were consistently depleted in the proteome of exosomes compared to cells. Among the enriched proteins, we identified biogenesis-related proteins, GTPases and membrane proteins, such as CD47 and ITGB1. The cohort of depleted proteins in exosomes was predominantly composed of nuclear proteins. We identified syntenin-1 as a consistently abundant protein in exosomes from different cellular origins. Syntenin-1 is also present in exosomes across different species and biofluids, highlighting its potential use as a putative universal biomarker of exosomes. Our study provides a comprehensive quantitative atlas of core proteins ubiquitous to exosomes that can serve as a resource for the scientific community.

Autologous fat grafting in breast reconstruction: implications for follow-up and surveillance

The procedural volume of autologous fat grafting (AFG) has risen over the past several years, specifically in the setting of breast reconstruction, despite controversy surrounding its oncologic safety. While some in vitro and animal models have cast doubt on the oncologic safety of AFG, there is no clinical evidence that AFG in breast reconstruction is associated with an increased risk of cancer development or recurrence or an inability to adequately assess changes in the breast. That being said, recommendations regarding surveillance and follow-up after AFG in breast reconstruction are largely surgeon directed and differ across practices. The purpose of this review is to summarize the current literature and provide evidence-based recommendations.

Oncoplastic partial breast reconstruction: concepts and techniques

Immediate oncoplastic breast reconstruction performed at the time of breast conserving surgery for the treatment of breast cancer merges the therapeutic goals of complete oncologic extirpation with preservation of breast form and function. A constellation of surgical techniques that employs breast volume displacement and/or replacement methods of varying complexity levels have emerged, thus broadening the potential applications for breast conservation therapy to include cases with increased tumor-to-native breast-volume ratios, multicentric or multifocal disease, and/or previous margin-positive resections. This review describes the various reconstructive methods, including the use of local tissue rearrangement, oncoplastic reduction-mastopexy, and locoregional flaps. Classification of the surgical options into levels I and II volume-displacement and volume-replacing techniques is made. Additionally, we explore the oncologic safety and effectiveness of this treatment paradigm by summarizing existing supportive evidence regarding associated risk of surgical complications, rate of margin-positive resection, implications for radiographic surveillance, local recurrence rates, and patient-reported outcomes. In conclusion, surgeons may use a wide variety of oncoplastic techniques for partial breast reconstruction at the time of segmental mastectomy to deliver effective breast conserving treatment for women with breast cancer. A growing body of literature affirms the oncologic safety of this approach. Future directions for research include long-term follow-up data with emphasis on outcomes from patient perspectives.

Effectiveness and Safety of Magseed-localization for Excision of Breast Lesions: A Prospective, Phase IV Trial

OBJECTIVE

A prospective, phase IV study was conducted to assess the effectiveness of Magseed to localize breast lesions requiring surgical excision.

BACKGROUND

Since FDA approval in 2016, Magseed has been increasingly used to localize non-palpable lesions due to advantages over wires or radioactive seeds. This is the first prospective, post marketing trial of Magseed.

METHODS

From 1/2017-2/2018, 107 women with lesions requiring localization were enrolled at a single institution. Primary endpoint was Magseed retrieval rate. Secondary endpoints were adverse events, accuracy of placement, surgery duration and positive margin rate. Clinicians were surveyed for ease of use using a Likert scale. Descriptive statistics and Fisher's exact test were performed to assess univariable associations with positive margins.

RESULTS

There were 124 Magseeds placed including one marker in 93 subjects, 2 markers in 11 and 3 markers in 3. The majority of lesions were masses (63%) followed by calcifications (24%). All 124 Magseeds were placed within 10mm of the target lesion and surgically retrieved with median operative time of 15min (range 4-47). No device-related adverse events occurred. Of the 98 malignant lesions, 9 had positive margins and 7 of them underwent a second surgery for additional margins. On univariable analysis, age ≤ 50 (25.0% vs 6.4%, p=0.04), lesion histology (p = 0.03), and pathologic T-stage (p = 0.04) were significantly associated with positive margins. Clinicians rated the Magseed very or fairly easy to use in most cases.

CONCLUSIONS

The Magseed system for localization of non-palpable lesions was effective and safe; all markers were successfully retrieved with margin-negative resections in 91%. This study supports use of Magseed for localization of breast lesions.

Correlation of circulating or disseminated tumor cells with the Oncotype DX Recurrence Score

PURPOSE

New biomarkers are emerging to predict recurrence risk in women with early-stage breast cancer. High Oncotype DX Recurrence Score® (RS) is associated with worse disease-free and overall survival. Similarly, circulating tumor cells (CTCs, blood) and disseminated tumor cells (DTCs, bone marrow) have prognostic value in breast cancer. We investigated the association between high RS and CTCs or DTCs.

METHODS

Using a prospective database, we evaluated patients with hormone receptor-positive/HER2-negative, node-negative invasive breast cancer from 1/2005 to 1/2017. RS was classified using TAILORx study cutoff points: low (< 11), intermediate (11-25), and high (> 25). CTCs were assessed using CellSearch® and DTCs using cytospin specimens of bone marrow aspirates. Positive result was defined as one or more CTCs or DTCs identified. Chi-square analyses were utilized to evaluate the relationship between RS and CTCs or DTCs.

RESULTS

233 patients were identified from a prospective database, of which 96 had RS results. Of these patients, 88 had CTC results and 58 had DTC results. CTCs were detected in 17/88 (19%) patients, while DTCs were detected in 20/58 (34%). Patients with high RS were not more likely to have CTCs (18%) compared to patients with low/intermediate RS (20%; p = 0.919). Similarly, high RS was not associated with DTC detection, with DTCs present in 40% of patients with high RS versus 33% with low/intermediate RS (p = 0.687). In the subgroup of patients ≤ 50 years, no associations were found between high RS and CTCs (p = 0.383) or DTCs (p = 0.234).

CONCLUSIONS

High Oncotype DX RS did not correlate with CTCs in blood or DTCs in bone marrow in our study.

Abstract 955: Long-term gemcitabine treatment reshapes the pancreatic tumor microenvironment and sensitizes murine carcinoma to combination immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death with a median survival time of 6-12 months. As most patients present with disseminated disease, the majority are offered palliative chemotherapy. With no approved treatment modalities for patients who progress on chemotherapy, we explored the effects of long-term Gemcitabine on the tumor microenvironment in order to identify potential therapeutic options in chemo-refractory PDAC. Using a combination of mouse models, patient-derived xenografts, primary and established cell lines, we first evaluated chemotherapy-induced alterations in the tumor secretome and immune surface proteins by high throughput proteomic arrays. In addition to enhancing antigen presentation and immune checkpoint expression, Gemcitabine consistently increased the synthesis of CCL/CXCL chemokines and TGFβ-associated signals. These secreted factors altered the composition of the tumor stroma, conferring Gemcitabine-resistance to cancer-associated fibroblasts in vitroand further enhancingTGFβ1 biosynthesis. We therefore combined Gemcitabine with anti-PD-1 in transgenic models of murine PDAC, which failed to alter disease course unless mice also underwent genetic or pharmacologic ablation of TGFβ signaling. In the setting of TGFβ signal deficiency, Gemcitabine and anti-PD-1 led to a robust CD8+ T-cell response and decrease in tumor burden, markedly enhancing overall survival. These results suggest that Gemcitabine may prime PDAC tumors for immune checkpoint inhibition by enhancing antigen presentation, but requires the inhibition of an immunosuppressive cytokine barrier. Given the current lack of third line treatment options, this approach warrants consideration in the clinical management of Gemcitabine-refractory PDAC.

Citation Format: Daniel R. Principe, Matthew Narbutis, Sandeep Kumar, Alex Park, Navin Viswakarma, Matthew J. Dorman, Suneel D. Kamath, Paul Grippo, Melissa L. Fishel, Rosa F. Hwang, Dinesh Thummuri, Patrick W. Underwood, Hidayatullah G. Munshi, Jose G. Trevino, Ajay Rana. Long-term gemcitabine treatment reshapes the pancreatic tumor microenvironment and sensitizes murine carcinoma to combination immunotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 955.

Long-Term Gemcitabine Treatment Reshapes the Pancreatic Tumor Microenvironment and Sensitizes Murine Carcinoma to Combination Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death with a median survival time of 6-12 months. Most patients present with disseminated disease and the majority are offered palliative chemotherapy. With no approved treatment modalities for patients who progress on chemotherapy, we explored the effects of long-term gemcitabine administration on the tumor microenvironment to identify potential therapeutic options for chemorefractory PDAC. Using a combination of mouse models, primary cell line-derived xenografts, and established tumor cell lines, we first evaluated chemotherapy-induced alterations in the tumor secretome and immune surface proteins by high throughput proteomic arrays. In addition to enhancing antigen presentation and immune checkpoint expression, gemcitabine consistently increased the synthesis of CCL/CXCL chemokines and TGFβ-associated signals. These secreted factors altered the composition of the tumor stroma, conferring gemcitabine resistance to cancer-associated fibroblasts in vitro and further enhancing TGFβ1 biosynthesis. Combined gemcitabine and anti-PD-1 treatment in transgenic models of murine PDAC failed to alter disease course unless mice also underwent genetic or pharmacologic ablation of TGFβ signaling. In the setting of TGFβ signaling deficiency, gemcitabine and anti-PD-1 led to a robust CD8⁺ T-cell response and decrease in tumor burden, markedly enhancing overall survival. These results suggest that gemcitabine successfully primes PDAC tumors for immune checkpoint inhibition by enhancing antigen presentation only following disruption of the immunosuppressive cytokine barrier. Given the current lack of third-line treatment options, this approach warrants consideration in the clinical management of gemcitabine-refractory PDAC. SIGNIFICANCE: These data suggest that long-term treatment with gemcitabine leads to extensive reprogramming of the pancreatic tumor microenvironment and that patients who progress on gemcitabine-based regimens may benefit from multidrug immunotherapy.See related commentary by Carpenter et al., p. 3070 GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/15/3101/F1.large.jpg.

Oncologic Safety and Surveillance of Autologous Fat Grafting following Breast Conservation Therapy

BACKGROUND

Autologous fat grafting is a useful adjunct following breast reconstruction. The impact of autologous fat grafting on oncologic safety and surveillance remains questionable, particularly following breast conservation therapy.

METHODS

The authors performed a retrospective review of patients who underwent delayed fat grafting following breast conservation therapy between 2006 and 2016. A control group of conservatively managed patients without grafting was matched for cancer stage, age, body mass index, and follow-up. Outcomes included locoregional recurrence and oncologic surveillance.

RESULTS

Seventy-two patients were identified per cohort. There were no differences in median age (50 years versus 51 years; p = 0.87), body mass index (28.2 kg/m versus 27.2 kg/m; p = 0.38), or length of follow-up (61.9 months versus 66.8 months; p = 0.144) between controls and grafted patients, respectively. Overall, four patients in each cohort experienced recurrence (5.6 percent; p = 1.00) with similar cumulative incidence estimates observed (log-rank test, p = 0.534). There were no significant differences in palpable mass (9.7 percent versus 19.4 percent; p = 0.1), fat necrosis (34.7 percent versus 33.3 percent; p = 0.86), calcifications (37.5 percent versus 34.7 percent; p = 0.73), or indication for breast biopsy (15.3 percent versus 22.2 percent; p = 0.23) between breast conservation and breast conservation therapy plus autologous fat grafting cohorts, respectively.

CONCLUSIONS

Overall, the authors found no difference in recurrence rates after breast conservation with or without delayed fat grafting. Furthermore, there were no differences in the rates of fat necrosis, palpable mass, and abnormal radiographic findings. This study represents the longest follow-up to date in in a large matched study of autologous fat grafting with breast conservation therapy demonstrating oncologic safety and no interference with follow-up surveillance.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Patient Selection for Clinical Trials Eliminating Surgery for HER2-Positive Breast Cancer Treated with Neoadjuvant Systemic Therapy

BACKGROUND

Patients with epidermal growth factor receptor 2-positive (HER2+) breast cancer and pathologic complete response (pCR) after neoadjuvant systemic therapy (NST) may be candidates for nonoperative clinical trials if residual invasive and in situ disease are eradicated.

METHODS

This study analyzed 280 patients with clinical T1-2N0-1 HER2+ breast cancer who underwent NST followed by surgical resection to determine key characteristics of patients with pCR in the breast and lymph nodes compared with those with residual disease.

RESULTS

Of the 280 patients, 102 (36.4%) had pCR in the breast and lymph nodes after NST, and 50 patients (17.9%) had residual ductal carcinoma in situ (DCIS) in the breast only. For 129 patients (46.1%), DCIS was present on the pretreatment biopsy, and NST failed to eradicate the DCIS component in 64.3%. Patients with residual disease were more likely to have hormone receptor-positive (HR+) tumors than those with negative tumors (73.4% vs. 50.8%; p < 0.0001). Radiologic response (odds ratio [OR], 5.62; p = 0.002) and HR+ status (OR, 2.56; p < 0.0001) were predictive of residual disease. Combined imaging methods after NST had a sensitivity of 97.1% and a negative predictive value of 70.6% for detection of residual disease. Patients with invasive disease and DCIS shown on the pretreatment core biopsy were less likely than those without DCIS to achieve pCR in the breast (31% vs. 43%; p  = 0.038).

CONCLUSION

The study results delineate and identify unique characteristics associated with HER2+ breast cancers that are important in selecting patients for inclusion in clinical trials assessing nonoperative management after NST, and the low negative predictive value of imaging mandates image-guided biopsy for selection.

A Stromal Lysolipid-Autotaxin Signaling Axis Promotes Pancreatic Tumor Progression

Pancreatic ductal adenocarcinoma (PDAC) develops a pronounced stromal response reflecting an aberrant wound-healing process. This stromal reaction features transdifferentiation of tissue-resident pancreatic stellate cells (PSC) into activated cancer-associated fibroblasts, a process induced by PDAC cells but of unclear significance for PDAC progression. Here, we show that PSCs undergo a dramatic lipid metabolic shift during differentiation in the context of pancreatic tumorigenesis, including remodeling of the intracellular lipidome and secretion of abundant lipids in the activated, fibroblastic state. Specifically, stroma-derived lysophosphatidylcholines support PDAC cell synthesis of phosphatidylcholines, key components of cell membranes, and also facilitate production of the potent wound-healing mediator lysophosphatidic acid (LPA) by the extracellular enzyme autotaxin, which is overexpressed in PDAC. The autotaxin-LPA axis promotes PDAC cell proliferation, migration, and AKT activation, and genetic or pharmacologic autotaxin inhibition suppresses PDAC growth in vivo. Our work demonstrates how PDAC cells exploit the local production of wound-healing mediators to stimulate their own growth and migration. SIGNIFICANCE: Our work highlights an unanticipated role for PSCs in producing the oncogenic LPA signaling lipid and demonstrates how PDAC tumor cells co-opt the release of wound-healing mediators by neighboring PSCs to promote their own proliferation and migration.See related commentary by Biffi and Tuveson, p. 578.This article is highlighted in the In This Issue feature, p. 565.

Palmatine suppresses glutamine-mediated interaction between pancreatic cancer and stellate cells through simultaneous inhibition of survivin and COL1A1

Reciprocal interaction between pancreatic stellate cells (PSCs) and cancer cells (PCCs) in the tumor microenvironment (TME) promotes tumor cell survival and progression to lethal, therapeutically resistant pancreatic cancer. The goal of this study was to test the ability of Palmatine (PMT) to disrupt this reciprocal interaction in vitro and examine the underlying mechanism of interaction. We show that PSCs secrete glutamine into the extracellular environment under nutrient deprivation. PMT suppresses glutamine-mediated changes in GLI signaling in PCCs resulting in the inhibition of growth and migration while inducing apoptosis by inhibition of survivin. PMT-mediated inhibition of (glioma-associated oncogene 1) GLI activity in stellate cells leads to suppression (collagen type 1 alpha 1) COL1A1 activation. Remarkably, PMT potentiated gemcitabine’s growth inhibitory activity in PSCs, PCCs and inherently gemcitabine-resistant pancreatic cancer cells. This is the first study that shows the ability of PMT to inhibit growth of PSCs and PCCs either alone or in combination with gemcitabine. These studies warrant additional investigations using preclinical models to develop PMT as an agent for clinical management of pancreatic cancer.

OncotypeDX Recurrence Score Does Not Predict Nodal Burden in Clinically Node Negative Breast Cancer Patients

BACKGROUND

OncotypeDX recurrence score (RS)^® has been found to predict recurrence and disease-free survival in patients with node negative breast cancer. Whether RS is useful in guiding locoregional therapy decisions is unclear. We sought to evaluate the relationship between RS and lymph node burden.

METHODS

Patients with invasive breast cancer who underwent sentinel lymph node dissection from 2010 to 2015 were identified from a prospectively maintained database. Patients were excluded if they were clinically node positive or if they received neoadjuvant chemotherapy. RS was classified as low (< 18), intermediate (18-30), or high (> 30). The association between RS, lymph node burden, and disease recurrence was evaluated. Statistical analyses were performed in R version 3.4.0; p < 0.05 was considered significant.

RESULTS

A positive SLN was found in 168 (15%) of 1121 patients. Completion axillary lymph node dissection was performed in 84 (50%) of SLN-positive patients. The remaining 84 (50%) patients had one to two positive SLNs and did not undergo further axillary surgery. RS was low in 58.5%, intermediate in 32.6%, and high in 8.9%. RS was not associated with a positive SLN, number of positive nodes, maximum node metastasis size, or extranodal extension. The median follow-up was 23 months. High RS was not associated with locoregional recurrence (p = 0.07) but was significantly associated with distant recurrence (p = 0.0015).

CONCLUSIONS

OncotypeDX RS is not associated with nodal burden in women with clinically node-negative breast cancer, suggesting that RS is not useful to guide decisions regarding extent of axillary surgery for these patients.

Enhanced Pharmacological Ascorbate Oxidation Radiosensitizes Pancreatic Cancer

Pharmacologic ascorbate (P-AscH^-) is emerging as a promising adjuvant for advanced pancreatic cancer. P-AscH^- generates hydrogen peroxide (H₂O₂), leading to selective cancer cell cytotoxicity. Catalytic manganoporphyrins, such as MnT4MPyP, can increase the rate of oxidation of P-AscH^-, thereby increasing the flux of H₂O₂, resulting in increased cytotoxicity. We hypothesized that a multimodal treatment approach, utilizing a combination of P-AscH^-, ionizing radiation and MnT4MPyP, would result in significant flux of H₂O₂ and pancreatic cancer cytotoxicity. P-AscH^- with MnT4MPyP increased the rate of oxidation of P-AscH^- and produced radiosensitization in all pancreatic cancer cell lines tested. Three-dimensional (3D) cell cultures demonstrated resistance to P-AscH^-, radiation or MnT4MPyP treatments alone; however, combined treatment with P-AscH^- and MnT4MPyP resulted in the inhibition of tumor growth, particularly when also combined with radiation. In vivo experiments using a murine model demonstrated an increased rate of ascorbate oxidation when combinations of P-AscH^- with MnT4MPyP were given, thus acting as a radiosensitizer. The translational potential was demonstrated by measuring increased ascorbate oxidation ex vivo, whereby MnT4MPyP was added exogenously to plasma samples from patients treated with P-AscH^- and radiation. Combination treatment utilizing P-AscH^-, manganoporphyrin and radiation results in significant cytotoxicity secondary to enhanced ascorbate oxidation and an increased flux of H₂O₂. This multimodal approach has the potential to be an effective treatment for pancreatic ductal adenocarcinoma.

Suppression of stromal-derived Dickkopf-3 (DKK3) inhibits tumor progression and prolongs survival in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis, and it is unclear whether its stromal infiltrate contributes to its aggressiveness. Here, we demonstrate that Dickkopf-3 (DKK3) is produced by pancreatic stellate cells and is present in most human PDAC. DKK3 stimulates PDAC growth, metastasis, and resistance to chemotherapy with both paracrine and autocrine mechanisms through NF-κB activation. Genetic ablation of DKK3 in an autochthonous model of PDAC inhibited tumor growth, induced a peritumoral infiltration of CD8+ T cells, and more than doubled survival. Treatment with a DKK3-blocking monoclonal antibody inhibited PDAC progression and chemoresistance and prolonged survival. The combination of DKK3 inhibition with immune checkpoint inhibition was more effective in reducing tumor growth than either treatment alone and resulted in a durable improvement in survival, suggesting that DKK3 neutralization may be effective as a single targeted agent or in combination with chemotherapy or immunotherapy for PDAC.

Interplay between interferon regulatory factor 1 and BRD4 in the regulation of PD-L1 in pancreatic stellate cells

The fibrotic reaction is a characteristic feature of human pancreatic ductal adenocarcinoma (PDAC) tumors. It is associated with activation and proliferation of pancreatic stellate cells (PSCs), which are key regulators of fibrosis in vivo. While there is increasing interest in the regulation of PD-L1 expression in cancer and immune cells, the expression and regulation of PD-L1 in other stromal cells, such as PSCs, has not been fully evaluated. Here we show that PSCs in vitro express higher PD-L1 mRNA and protein levels compared to the levels present in PDAC cells. We show that inhibitors targeting bromodomain and extra-terminal (BET) proteins and BRD4 knockdown decrease interferon-γ (IFN-γ)-induced PD-L1 expression in PSCs. We also show that c-MYC, one of the well-established targets of BET inhibitors, does not mediate IFN-γ-regulated PD-L1 expression in PSCs. Instead we show that interferon regulatory factor 1 (IRF1) mediates IFN-γ-induced PD-L1 expression in PSCs. Finally, while we show that BET inhibitors do not regulate IFN-γ-induced IRF1 expression in PSCs, BET inhibitors decrease binding of IRF1 and BRD4 to the PD-L1 promoter. Together, these results demonstrate the interplay between IRF1 and BRD4 in the regulation of PD-L1 in PSCs.

Expanding Implementation of ACOSOG Z0011 in Surgeon Practice

BACKGROUND

After publication of American College of Surgeons Oncology Group (ACOSOG) Z0011, surgeons at our institution limited axillary surgery to sentinel lymph node dissection (SLND) in 76% of patients meeting trial eligibility criteria. Our study objective was to assess incorporation of the trial data into practice 5 years later.

PATIENTS AND METHODS

Patients with clinical T1-2, N0 invasive breast cancer undergoing breast conserving surgery were included. Comparisons were made between patients who underwent axillary lymph node dissection (ALND) and those that had no further surgery.

RESULTS

A total of 396 patients were included. Twelve percent (48/396) had positive SLNs; ALND was performed in 8% (4/48). Patients who underwent ALND were more likely to have 2 positive SLNs (50%, 2/4 vs. 2%, 1/44; P = .02) and microscopic extranodal extension (75%, 3/4 vs. 18%, 8/44; P = .03) than those that did not undergo ALND. Patients who underwent ALND also had a higher nomogram-predicted probability of having additional positive non-SLNs (53%) than those who had SLND alone (22%) (P = .0002). No patients had intraoperative assessment of SLNs performed.

CONCLUSIONS

The practice of omitting ALND in ACOSOG Z0011-eligible patients has expanded over 5 years. Clinicopathologic features continue to impact this decision. Intraoperative SLN assessment is no longer performed.

Identification of Patients With Documented Pathologic Complete Response in the Breast After Neoadjuvant Chemotherapy for Omission of Axillary Surgery

Importance

A pathologic complete response (pCR; no invasive or in situ cancer) occurs in 40% to 50% of patients with HER2-positive (HER2+) and triple-negative (TN) breast cancer. The need for surgery if percutaneous biopsy of the breast after neoadjuvant chemotherapy (NCT) indicates pCR in the breast (hereinafter referred to as breast pCR) has been questioned, and appropriate management of the axilla in such patients is unknown.

Objective

To identify patients among exceptional responders to NCT with a low risk for axillary metastases when breast pCR is documented who may be eligible for an omission of surgery clinical trial design.

Design, Setting, and Participants

This prospective cohort study at a single-institution academic national comprehensive cancer center included 527 consecutive patients with HER2+/TN (T1/T2 and N0/N1) cancer treated with NCT followed by standard breast and nodal surgery from January 1, 2010, through December 31, 2014.

Main Outcomes and Measures

Patients who achieved a breast pCR were compared with patients who did not based on subtype, initial ultrasonographic findings, and documented pathologic nodal status. Incidence of positive findings for nodal disease on final pathologic review was calculated for patients with and without pCR and compared using relative risk ratios with 95% CIs.

Results

The analysis included 527 patients (median age, 51 [range, 23-84] years). Among 290 patients with initial nodal ultrasonography showing N0 disease, 116 (40.4%) had a breast pCR and 100% had no evidence of axillary lymph node metastases after NCT. Among 237 patients with initial biopsy-proved N1 disease, 69 of 77 (89.6%) with and 68 of 160 (42.5%) without a breast pCR had no evidence of residual nodal disease (P < .01). Patients without a breast pCR had a relative risk for positive nodal metastases of 7.4 (95% CI, 3.7-14.8; P < .001) compared with those with a breast pCR.

Conclusions and Relevance

Breast pCR is highly correlated with nodal status after NCT, and the risk for missing nodal metastases without axillary surgery in this cohort is extremely low. These data provide the fundamental basis and rationale for management of the axilla in clinical trials of omission of cancer surgery when image-guided biopsy indicates a breast pCR.

Abstract 2961: Targeting stromal-derived Dickkopf-3 (DKK3) for the treatment of pancreatic ductal adenocarcinoma (PDAC)

Introduction: We and others have shown that pancreatic stellate cells (PSCs) in the tumor-associated stroma of PDAC promote tumor progression and resistance to therapy but the precise mechanisms are unclear. We investigated the role of PSC-derived DKK3, a member of the Dickkopf family of glycoproteins, in PDAC progression, metastasis and response to chemotherapy.

Methods: We evaluated expression of DKK3 in human PDAC tissue and cell lines, human PSCs and in a genetically engineered mouse model (GEMM) of PDAC. The paracrine and autocrine effects of DKK3 on PDAC and PSCs were examined by treatment with exogenous DKK3 and gain- and loss of function assays for proliferation, migration, invasion, and gemcitabine-induced apoptosis. The effects of DKK3 on PDAC progression and metastasis were determined by shRNA neutralization and genetic ablation in orthotopic xenograft models and the KPC autochthonous model of PDAC. We developed novel monoclonal antibodies (mAbs) against DKK3 and tested their ability to neutralize DKK3 and prolong survival in mouse models of PDAC.

Results: DKK3 was expressed at 4.5 times higher levels in human PDAC by Affymetrix profiling compared to normal pancreas and was present in 99% (118/119) of samples on a tissue microarray with moderate to high expression in 59%. In a GEMM of PDAC, DKK3 appeared early with preneoplastic PanIN lesions with increased expression in invasive carcinoma. DKK3 was strongly expressed by PSCs with minimal to no expression in PDAC cells and knockdown by shRNA reduced PSC proliferation and migration by 60% and 84% compared to controls (p&lt;0.001). Treatment of Panc1 and BxPC3 cells with DKK3 stimulated migration and invasion by 100-300% (p&lt;0.001) and proliferation of DKK3-silenced Panc1 cells was decreased by 80% (p&lt;0.001). Overexpression of DKK3 in L3.6pl cells increased colony formation in gemcitabine by &gt;90% (p&lt;0.001) with 65% reduction in apoptosis (p&lt;0.01), indicating that DKK3 contributes to PDAC resistance to chemotherapy. When we ablated DKK3 in KPC mice by breeding with DKK3-knockout mice, tumor growth was inhibited and survival increased by 45% (p=0.0002). In addition, fewer PanIN lesions developed in DKK3-null mice suggesting that DKK3 may contribute to the early developmental stages of PDAC. DKK3 neutralizing mAbs abrogated DKK3-mediated induction of PDAC cell migration, invasion and resistance to gemcitabine in vitro. Furthermore, treatment with DKK3 mAb significantly inhibited primary tumor growth, reduced peritoneal metastases and prolonged survival in an orthotopic model of PDAC by 43% compared to control mAb (p=0.005; HR 0.24, 95% CI 0.01-0.30).

Conclusions: These data are the first report, to our knowledge, of a tumor-promoting function of DKK3 and our results suggest that neutralization of DKK3 may be an effective approach as a primary treatment for PDAC and to enhance responsiveness to chemotherapy.

Citation Format: Liran Zhou, Hongmei Husted, Todd Moore, Mason Lu, Defeng Deng, Yan Liu, Vijaya Ramachandran, Thiruvengadam Arumugam, Baoan Ji, Huamin Wang, Jeffrey E. Lee, Craig D. Logsdon, Rosa F. Hwang. Targeting stromal-derived Dickkopf-3 (DKK3) for the treatment of pancreatic ductal adenocarcinoma (PDAC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2961. doi:10.1158/1538-7445.AM2017-2961

Factors impacting the accuracy of intra-operative evaluation of sentinel lymph nodes in breast cancer

Sentinel lymph node dissection (SLND) is a standard axillary staging technique in breast cancer and intraoperative sentinel lymph node (SLN) assessment is important for decision-making regarding additional treatment and reconstruction. This study was undertaken to investigate clinicopathologic factors impacting the accuracy of intraoperative SLN evaluation. Records of patients with clinically node-negative, invasive breast cancer who underwent SLND with frozen section intraoperative pathologic evaluation from 2004 to 2007 were reviewed. Intraoperative SLN assessment results were compared to final pathology. Patients with positive SLNs that were initially reported as negative during intraoperative assessment were considered false negative (FN) events. Primary tumor histology, grade, receptor status, size, lymphovascular invasion (LVI), multifocality, neoadjuvant chemotherapy or hormonal therapy, number of SLNs retrieved, and SLN metastasis size were evaluated. The study included 681 patients, of whom 262 (38%) received neoadjuvant therapy. There were 183 (27%) patients who had a positive SLN on final pathology, of whom 60 (33%) had FN events. On univariate analysis, lobular histology, favorable histology, absence of LVI and micrometastasis were associated with a higher FN rate. On multivariate analysis, favorable and lobular histology and micrometastasis were independent predictors of FN events whereas LVI and receipt of neoadjuvant therapy were not statistically significant predictors. The accuracy of intraoperative SLN evaluation for breast cancer is affected by primary tumor histology and size of the SLN metastasis. There was no significant association between neoadjuvant therapy and the FN rate by intraoperative assessment. This information may be helpful in counseling patients about their risk for a FN intraoperative SLN assessment and for planning for immediate breast reconstruction in patients undergoing mastectomy.

Contemporary breast conservation patient outcomes for ductal carcinoma in situ and margins < 2 mm

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Background: Recent national consensus guidelines regarding optimal margin width for the management of DCIS have been published; however, controversy remains for managing margins <2mm. The relationship between margin width and locoregional recurrence (LRR) was determined in a contemporary cohort of patients. Methods: 1504 patients with DCIS undergoing definitive breast conserving surgery from 1996 to 2010 were analyzed for clinical and pathologic characteristics from a prospectively managed comprehensive academic cancer center database. Cox proportional hazard models were used to examine the relationship between margin width (<2mm or ≥2mm) and LRR by adjuvant radiation therapy (RT). Patients with positive margins (n=11) were excluded. Results: Overall, 3.4% of patients had a LRR at a median follow-up of 8.7 years. Univariate analysis of age, family history, grade, tumor size, comedonecrosis, RT, adjuvant hormonal therapy, ER status, and margin width found younger age (< 40 yr, p=0.02), no RT (n=299, p=0.005), and margin width <2mm(n=138, p=0.005) to be associated with LRR. The association between margin width and LRR differed by adjuvant radiation therapy status (p=0.02 for the interaction). There was no statistical significant difference in LRR for patients with margins <2mm vs ≥2 mm who received RT, (10-year LRR 6.0% vs 3.2%, respectively; HR 1.5, 95% CI 0.5-4.2, p=0.48). For patients who did not receive RT (n=299), those with margins < 2 mm were significantly more likely to develop a LRR than those with margins ≥2mm (10-year LRR 35.7% vs. 4.6%, respectively; HR 7.2, 95%CI 2.6-19.4, p=0.0001). Conclusions: In patients with <2mm margins receiving adjuvant radiation therapy, there is no difference in locoregional recurrence when compared to patients with ≥2mm margins. Additional surgery for wider margins of resection are not routinely justified in this group of patients but should be obtained for patients with <2mm margins who forego radiotherapy.

Lipocalin-2 Promotes Pancreatic Ductal Adenocarcinoma by Regulating Inflammation in the Tumor Microenvironment

Lipocalin-2 (LCN2) promotes malignant development in many cancer types. LCN2 is upregulated in patients with pancreatic ductal adenocarcinoma (PDAC) and in obese individuals, but whether it contributes to PDAC development is unclear. In this study, we investigated the effects of Lcn2 depletion on diet-induced obesity, inflammation, and PDAC development. Mice with acinar cell-specific expression of KrasG12D were crossed with Lcn2-depleted animals and fed isocaloric diets with varying amounts of fat content. Pancreas were collected and analyzed for inflammation, pancreatic intraepithelial neoplasia (PanIN), and PDAC. We also used a syngeneic orthotopic PDAC mouse model to study tumor growth in the presence or absence of Lcn2 expression. In addition, to understand the mechanistic role of how LCN2 could be mediating PDAC, we studied LCN2 and its specific receptor solute carrier family 22 member 17 (SLC22A17) in human pancreatic cancer stellate cells (PSC), key mediators of the PDAC stroma. Depletion of Lcn2 diminished extracellular matrix deposition, immune cell infiltration, PanIN formation, and tumor growth. Notably, it also increased survival in both obesity-driven and syngeneic orthotopic PDAC mouse models. LCN2 modulated the secretion of proinflammatory cytokines in PSC of the PDAC tumor microenvironment, whereas downregulation of LCN2-specific receptor SLC22A17 blocked these effects. Our results reveal how LCN2 acts in the tumor microenvironment links obesity, inflammation, and PDAC development. Cancer Res; 77(10); 2647-60. ©2017 AACR.

Abstract P2-01-05: A phase II clinical trial of VST-1001 (dilute fluorescein) in lymphatic mapping and sentinel lymph node localization in clinically node negative breast cancer

Background: Combined use of a radiocolloid and a vital blue dye is recommended for accurate lymphatic mapping and sentinel lymph node (SLN) identification in breast cancer. However, vital blue dyes can cause tattooing, skin necrosis and severe allergic reactions. Moreover, the vital blue dyes are only able to detect 70% or less of SLNs in large multi-center trials. Hence, there is an unmet need to develop new lymphatic mapping agents that could potentially replace vital blue dyes. We have previously, in a Phase I trial, reported on the safety of VST-1001 (dilute fluorescein) in SLN identification. Here we report the Phase II data of VST-1001 and direct visualization devices in lymphatic mapping, SLN identification, and safety in clinically node negative breast cancer.

Methods: This prospective Phase II, multi-center, non-randomized, single-arm, open-label, single-dose clinical trial enrolled patients (pts) with DCIS and clinical stage I/II breast cancer eligible for SLN biopsy. All pts had SLN localization with technetium-99m-sulfur colloid (Tc99mSC) and intraoperative lymphatic mapping with 0.1% VST-1001 injected peritumorally, periareolarly, and/or intradermally. SLN radioactivity was identified with a gamma probe, and VST-1001 fluorescence was induced by light emitting diodes and detected as yellowish-green fluorescence in the visible light range with notch filter spectacles. The primary endpoint was the ability of VST-1001 to localize lymph nodes. SLN concordance of Tc99mSC radioactivity and VST-1001 fluorescence, and safety were also assessed.

Results: Eighty-seven women and 2 men with a median age of 60 yrs (range, 37-77) were enrolled. Primary tumor T-stage was: 12.4% T0, 62.9% T1, 23.6% T2, and 1.1% T3. Of the 89 pts, 87 (97.8%) had at least 1 radioactive SLN, and 86 (96.6%) at least 1 fluorescent SLN. Of a total of 198 SLN identified (mean 2.2 SLN/pt), 74.2% were fluorescent and radioactive, 11.6% were radioactive only, 8.6% were fluorescent only, and 5.1% were not radioactive or fluorescent. 82.8% of all SLNs were fluorescent. Twelve (13.5%) pts had microscopic metastatic breast cancer in 14 (7.1%) SLNs. Of the 14 SLNs with metastasis, 12 (85.7%) were both radioactive and fluorescent, 1 (7.1%) fluorescent only and 1 (7.1%) not radioactive or fluorescent and only suspicious on palpation. The fluorescent only SLN was identified in a patient with only 1 SLN and without VST-1001 the metastasis would have been missed. The only adverse event related to VST-1001 was intraoperative grade 2 allergic reaction of the ipsilateral breast in one pt. Intravenous anti-histamines were administered and the erythema resolved.

Conclusions: VST-1001 safely localized lymph nodes in breast cancer. VST-1001 was able to localize lymph nodes that were not radioactive and had a high co-localization concordance with Tc99mSC. VST-1001 also appears to have a higher rate of SLN localization compared to that historically reported for vital blue dyes. In light of these data, VST-1001 may be an alternative SLN localizing agent to be used in conjunction with Tc99mSC in breast cancer pts, eliminating many of adverse events observed when using vital blue dyes without compromising SLN identification.

Citation Format: Ross MI, Black DM, Mittendorf EA, Porretta JM, Bedrosian I, Caudle AS, Hwang RF, Meric-Bernstam F, Babiera GV, Brulotte M, Andtbacka RHI, Matsen CB. A phase II clinical trial of VST-1001 (dilute fluorescein) in lymphatic mapping and sentinel lymph node localization in clinically node negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-01-05.

BET inhibitors block pancreatic stellate cell collagen I production and attenuate fibrosis in vivo

The fibrotic reaction, which can account for over 70%-80% of the tumor mass, is a characteristic feature of human pancreatic ductal adenocarcinoma (PDAC) tumors. It is associated with activation and proliferation of pancreatic stellate cells (PSCs), which are key regulators of collagen I production and fibrosis in vivo. In this report, we show that members of the bromodomain and extraterminal (BET) family of proteins are expressed in primary PSCs isolated from human PDAC tumors, with BRD4 positively regulating, and BRD2 and BRD3 negatively regulating, collagen I expression in primary cancer-associated PSCs. We show that the inhibitory effect of pan-BET inhibitors on collagen I expression in primary cancer-associated PSCs is through blocking of BRD4 function. Importantly, we show that FOSL1 is repressed by BRD4 in primary cancer-associated PSCs and negatively regulates collagen I expression. While BET inhibitors do not affect viability or induce PSC apoptosis or senescence, BET inhibitors induce primary cancer-associated PSCs to become quiescent. Finally, we show that BET inhibitors attenuate stellate cell activation, fibrosis, and collagen I production in the EL-KrasG12D transgenic mouse model of pancreatic tumorigenesis. Our results demonstrate that BET inhibitors regulate fibrosis by modulating the activation and function of cancer-associated PSCs.

Abstract A21: Chemokine directed migration of activated stellate cells in pancreatic ductal adenocarcinoma

Multiple studies have shown that the extreme desmoplasia observed in pancreatic tumors modulates the effectiveness of chemotherapeutic agents. Despite this, the specific mechanisms by which stroma develops in pancreatic tumors are unknown and the role that it plays in pathogenesis of the disease is unsettled. Chemokines are a family of nearly 50 different secreted proteins playing a key role in the recruitment of a wide variety of cell types in health and disease. While we and others have extensively explored the role of the chemokine CXCL12 in pancreatic cancer, the expression and potential role of other chemokines, or their cognate receptors, in pancreatic cancer remains an area of active exploration. To this end, we profiled the expression of the chemokine family in pancreatic cancer. RT-PCR of a battery of established human pancreatic cancer cell lines revealed elevated transcript levels of the chemokine ligands CCL28 and CXCL16, as well as their cognate receptors CCR10 and CXCR6, respectively. These results were mirrored in cell lines derived from transgenic murine models of pancreatic cancer. Immunohistochemical analysis of both diseased and normal human pancreatic tissue showed that the expression of CCL28, CXCL16, CCR10, and CXCR6 proteins were upregulated in pancreatic adenocarcinoma compared with normal exocrine ductal epithelium. Interestingly, CCR10 and CXCR6 were also expressed in pancreatic tumor fibroblasts, while their cognate ligands, CCL28 and CXCL16 were absent in the stromal compartment. Based on those data we hypothesized that expression of chemokines in cancer cells with the concomitant expression of their cognate receptors by activated fibroblasts facilitates recruitment of those cancer-associated fibroblasts into the tumor microenvironment. Analysis of tissue from patients with pancreatitis revealed that CCL28/CCR10, but not CXCL16/CXCR6, proteins were upregulated. Consistent with its known regulation by inflammatory mediators, we found that interferon-gamma stimulated significant increases in CCL28 secretion by human pancreatic cancer cell lines. In contrast, interferon-gamma had little if any effect on CCL28 secretion by an immortalized activated human pancreatic stellate cell (HPSC) line. Stimulation with exogenous CCL28 elicited the prototypical dose dependent calcium signaling expected of a ligand activated chemokine receptor. CCL28 stimulated the dose dependent directional migration of HPSC without altering cell viability. These data are consistent with HPSC being a functional target for the chemokine. Finally, in a 2-D co-culture model, CCL28 secreted from human pancreatic cancer cells induced HPSC chemotactic migration. Pretreatment with neutralizing antibody to the chemokine blocked HPSC chemotaxis toward the cancer cells. Together, these data suggest that the CCL28-CCR10 chemokine axis plays a role in the inflammation-mediated recruitment of cancer-associated fibroblasts into the stromal compartment of pancreatic tumors. More broadly, we have demonstrated a new role for chemokines in the pancreatic tumor microenvironment, suggestive of their potential role in stromal remodeling in pancreatic cancer. This is the first study to establish the differential expression and functional role for the CCL28 chemokine in pancreatic disease.

Citation Format: Ishan Roy, Kathleen A. Boyle, A Craig Mackinnon, Rosa F. Hwang, Susan Tsai, Douglas B. Evans, Michael B. Dwinell.{Authors}. Chemokine directed migration of activated stellate cells in pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr A21.

Oncogenic Functions of Gli1 in Pancreatic Adenocarcinoma Are Supported by Its PRMT1-Mediated Methylation

The oncogenic transcription factor Gli1 is a critical effector in the Hedgehog (Hh) pathway, which is necessary for the development and progression of pancreatic ductal adenocarcinoma (PDAC). Although TGFβ and K-Ras are known regulators of Gli1 gene transcription in this setting, it is not understood how Gli1 functional activity is regulated. Here, we report the identification of Gli1 as a substrate for the protein arginine N-methyltransferase PRMT1 in PDAC. We found that PRMT1 methylates Gli1 at R597, promoting its transcriptional activity by enhancing the binding of Gli1 to its target gene promoters. Interruption of Gli1 methylation attenuates oncogenic functions of Gli1 and sensitizes PDAC cells to gemcitabine treatment. In human PDAC specimens, the levels of both total Gli1 and methylated Gli1 were correlated positively with PRMT1 protein levels. Notably, PRMT1 regulated Gli1 independently of the canonical Hh pathway as well as the TGFβ/Kras-mediated noncanonical Hh pathway, thereby signifying a novel regulatory mechanism for Gli1 transcriptional activity. Taken together, our results identified a new posttranslational modification of Gli1 that underlies its pivotal oncogenic functions in PDAC. Cancer Res; 76(23); 7049-58. ©2016 AACR.

Generation of an in vitro 3D PDAC stroma rich spheroid model

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a prominent desmoplastic/stromal reaction, which contributes to the poor clinical outcome of this disease. Therefore, greater understanding of the stroma development and tumor-stroma interactions is highly required. Pancreatic stellate cells (PSC) are myofibroblast-like cells located in exocrine areas of the pancreas, which as a result of inflammation produced by PDAC migrate and accumulate in the tumor mass, secreting extracellular matrix components and producing the dense PDAC stroma. Currently, only a few orthotopic or ectopic animal tumor models, where PDAC cells are injected into the pancreas or subcutaneous tissue layer, or genetically engineered animals offer tumors that encompass some stromal component. Herein, we report generation of a simple 3D PDAC in vitro micro-tumor model without an addition of external extracellular matrix, which encompasses a rich, dense and active stromal compartment. We have achieved this in vitro model by incorporating PSCs into 3D PDAC cell culture using a modified hanging drop method. It is now known that PSCs are the principal source of fibrosis in the stroma and interact closely with cancer cells to create a tumor facilitatory environment that stimulates local and distant tumor growth. The 3D micro-stroma models are highly reproducible with excellent uniformity, which can be used for PDAC-stroma interaction analysis and high throughput automated drug-screening assays. Additionally, the increased expression of collagenous regions means that molecular based perfusion and cytostaticity of gemcitabine is decreased in our Pancreatic adenocarcinoma stroma spheroids (PDAC-SS) model when compared to spheroids grown without PSCs. We believe this model will allow an improved knowledge of PDAC biology and has the potential to provide an insight into pathways that may be therapeutically targeted to inhibit PSC activation, thereby inhibiting the development of fibrosis in PDAC and interrupting PSC-PDAC cell interactions so as to inhibit cancer progression.

Pancreatic stellate cells support tumour metabolism through autophagic alanine secretion

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease characterized by an intense fibrotic stromal response and deregulated metabolism. The role of the stroma in PDAC biology is complex and it has been shown to play critical roles that differ depending on the biological context. The stromal reaction also impairs the vasculature, leading to a highly hypoxic, nutrient-poor environment. As such, these tumours must alter how they capture and use nutrients to support their metabolic needs. Here we show that stroma-associated pancreatic stellate cells (PSCs) are critical for PDAC metabolism through the secretion of non-essential amino acids (NEAA). Specifically, we uncover a previously undescribed role for alanine, which outcompetes glucose and glutamine-derived carbon in PDAC to fuel the tricarboxylic acid (TCA) cycle, and thus NEAA and lipid biosynthesis. This shift in fuel source decreases the tumour’s dependence on glucose and serum-derived nutrients, which are limited in the pancreatic tumour microenvironment. Moreover, we demonstrate that alanine secretion by PSCs is dependent on PSC autophagy, a process that is stimulated by cancer cells. Thus, our results demonstrate a novel metabolic interaction between PSCs and cancer cells, in which PSC-derived alanine acts as an alternative carbon source. This finding highlights a previously unappreciated metabolic network within pancreatic tumours in which diverse fuel sources are used to promote growth in an austere tumour microenvironment.

Operative and Oncologic Outcomes in 9861 Patients with Operable Breast Cancer: Single-Institution Analysis of Breast Conservation with Oncoplastic Reconstruction

BACKGROUND

Oncoplastic reconstruction is an approach that enables patients with locally advanced or adversely located tumors to undergo breast conserving surgery (BCS). The objectives were to identify the use of BCS with oncoplastic reconstruction (BCS + R) and determine the operative and oncologic outcomes compared with other breast surgical procedures for breast cancer.

METHODS

This retrospective cohort study interrogated a single institution's prospectively maintained databases to identify patients who underwent surgery for breast cancer between 2007 and 2014. Surgeries were categorized as BCS, BCS + R, total mastectomy (TM), or TM with immediate reconstruction (TM + R). Demographic and clinicopathologic characteristics and postoperative complications were analyzed.

RESULTS

There were 10,607 operations performed for 9861 patients. Median follow-up was 3.4 years (range, 0-9.1 years). The use of BCS + R had a nearly fourfold increase in the percentage of all breast cancer surgeries during the study period; 75 % of patients who underwent BCS + R had a T1 or T2 tumor. There was no difference in the use of BCS + R compared with BCS for any quadrant of the breast except the lower outer quadrant (11.1 vs. 6.8 %; p < .0001). BCS + R had a lower rate of seroma formation (13.4 vs. 18 %; p = .002) and positive or close margins compared with BCS (5.8 vs. 8.3 %; p = .04). There was no difference in overall survival or recurrence-free survival when comparing BCS and BCS + R.

CONCLUSIONS

Patients undergoing BCS + R are not disadvantaged in terms of complications and short-term (3-year) outcomes compared with BCS patients or patients who underwent TM.

A Phase II Trial Exploring the Success of Cryoablation Therapy in the Treatment of Invasive Breast Carcinoma: Results from ACOSOG (Alliance) Z1072

BACKGROUND

Cryoablation is a well-established technique to treat fibroadenomas. Pilot studies suggest this could be an effective non-surgical treatment for breast cancer. American College of Surgeons Oncology Group Z1072 is a phase II trial exploring the effectiveness of cryoablation in the treatment of breast cancers.

METHODS

The primary endpoint of Z1072 was the rate of complete tumor ablation, defined as no remaining invasive breast cancer (IBC) or ductal carcinoma in situ (DCIS) on pathologic examination of the targeted lesion. A secondary objective was to evaluate the negative predictive value of magnetic resonance imaging (MRI) to determine residual IBC or DCIS. Eligible patients included those with unifocal invasive ductal breast cancer ≤2 cm, with <25 % intraductal component and tumor enhancement on MRI. A total of 19 centers contributed 99 patients, of which 86 patients (87 breast cancers) were evaluable for data analysis.

RESULTS

Final pathology results, regardless of whether residual IBC/DCIS was in the targeted ablation zone or elsewhere in the breast, showed successful ablation in 66/87 (75.9 %) cancers. The 90 % confidence interval for the estimate of successful cryoablation was 67.1-83.2, with the one-sided lower-sided 90 % CI of 69.0. The negative predictive value of MRI was 81.2 % (90 % CI 71.4-88.8). When multifocal disease outside of the targeted cryoablation zone was not defined as an ablation failure, 80/87 (92 %) of the treated cancers had a successful cryoablation.

CONCLUSION

Further studies with modifications on the Z1072 protocol could be considered to evaluate the role for cryoablation as a non-surgical treatment of early-stage breast cancer.

Value-Based Breast Cancer Care: A Multidisciplinary Approach for Defining Patient-Centered Outcomes

PURPOSE

Value in healthcare-i.e., patient-centered outcomes achieved per healthcare dollar spent-can define quality and unify performance improvement goals with health outcomes of importance to patients across the entire cycle of care. We describe the process through which value-based measures for breast cancer patients and dynamic capture of these metrics via our new electronic health record (EHR) were developed at our institution.

METHODS

Contemporary breast cancer literature on treatment options, expected outcomes, and potential complications was extensively reviewed. Patient perspective was obtained via focus groups. Multidisciplinary physician teams met to inform a 3-phase process of (1) concept development, (2) measure specification, and (3) implementation via EHR integration.

RESULTS

Outcomes were divided into 3 tiers that reflect the entire cycle of care: (1) health status achieved, (2) process of recovery, and (3) sustainability of health. Within these tiers, 22 patient-centered outcomes were defined with inclusion/exclusion criteria and specifications for reporting. Patient data sources will include the Epic Systems EHR and validated patient-reported outcome questionnaires administered via our institution's patient portal.

CONCLUSIONS

As healthcare costs continue to rise in the United States and around the world, a value-based approach with explicit, transparently reported patient outcomes will not only create opportunities for performance improvement but will also enable benchmarking across providers, healthcare systems, and even countries. Similar value-based breast cancer care frameworks are also being pursued internationally.

Implementing value-based cancer care: A multidisciplinary approach to defining breast cancer outcomes

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Background: Value in healthcare (patient-centered outcomes achieved per dollar spent) unifies performance improvement goals with health outcomes of importance to patients. We describe the process through which value-based measures for breast cancer patients and dynamic capture of these metrics via our new electronic health record (EHR) were developed at our institution. Methods: A review of the breast cancer literature was conducted on treatment options as well as expected outcomes and potential treatment complications. Patient perspective was obtained via focus groups. Multidisciplinary teams met to inform a 3-phase process of (1) concept development, (2) measure specification, and (3) implementation via EHR integration, planned for spring 2016. Results: Outcomes were divided into 3 previously defined tiers (NEJM 2010; 363:2477-2481) that reflect the entire cycle of care (Table).Within these tiers, 22 patient-centered outcomes were defined with inclusion/exclusion criteria, specifications for reporting, and sources for data including the EHR and validated patient-reported outcome questionnaires (e.g., FACT-B+4) administered via our patient portal. Conclusions: A value-based approach to cancer care with transparently reported patient outcomes not only creates opportunity for performance improvement but also enables benchmarking within and across providers, healthcare systems, and even countries. Our value-based framework for breast cancer is the first of its kind in the United States, with a similar model being pursued internationally as well. [Table: see text]

Abstract P3-01-09: A phase I clinical trial of VST-1001 (dilute fluorescein) in lymphatic mapping and sentinel lymph node localization in clinically node negative breast cancer

Background: Combined use of a radiocolloid and a vital blue dye is recommended for accurate lymphatic mapping and sentinel lymph node (SLN) identification. However, vital blue dyes can cause tattooing, skin necrosis and allergic reactions. Hence, there is a great need for new lymphatic mapping agents. Here we describe the novel use of VST-1001 (dilute fluorescein) and direct visualization devices in lymphatic mapping and SLN identification.

Methods: A prospective, non randomized, single arm, open label, single dose, dose-finding Phase I clinical trial in patients (pts) with high-grade DCIS and clinical stage I/II breast cancer eligible for SLN biopsy was performed. All pts had SLN localization with technetium-99m-sulfur colloid (Tc99mSC) and intraoperative lymphatic mapping with VST-1001 injected peritumorally, periareolarly, and/or intradermally. SLN radioactivity was identified with a gamma probe, and VST-1001 fluorescence was induced by light emitting diodes and detected as a yellowish-green fluorescence in the visible light range with notch filter spectacles. The primary endpoints were safety, ability of VST 1001 to localize lymph nodes, and the optimal dose of VST-1001. SLN concordance of Tc99mSC radioactivity and VST-1001 fluorescence was also assessed.

Results: Fifteen women with a median age of 60 yrs (range, 43-80) were enrolled. In cohort 1, 5 pts received 0.01% VST-1001. All patients had at least 1 SLN that was fluorescent and radioactive. A total of 22 SLNs were identified, many with faint fluorescence. Per protocol, the dose of VST-1001 was increased, and in cohort 2, 10 patients received 0.1% VST-1001. All 10 (100%) pts in cohort 2 had at least 1 SLN that was fluorescent and radioactive. Of a total of 24 SLNs identified, 20 (83%) were fluorescent and radioactive, 2 (8%) were radioactive only, and 2 (8%) were fluorescent only. Four SLNs in 3 patients contained micrometastatic breast cancer; all 4 SLNs were radioactive and fluorescent. There were no adverse events related to VST-1001. A Phase II clinical trial is currently accruing.

Conclusions: VST-1001 safely localized lymph nodes in breast cancer. VST-1001 was able to localize lymph nodes that were not radioactive and had a high concordance with Tc99mSC. VST-1001 may be a novel alternative to vital blue dyes in lymphatic mapping and lymph node localization.

Citation Format: Ross MI, Bedrosian I, Black DM, Mittendorf EA, Caudle AS, Babiera GV, Hwang RF, Meric-Bernstam F, Grissom CB, Brulotte M, Andtbacka RHI. A phase I clinical trial of VST-1001 (dilute fluorescein) in lymphatic mapping and sentinel lymph node localization in clinically node negative 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 P3-01-09.

Improved Axillary Evaluation Following Neoadjuvant Therapy for Patients With Node-Positive Breast Cancer Using Selective Evaluation of Clipped Nodes: Implementation of Targeted Axillary Dissection

PURPOSE

Placing clips in nodes with biopsy-confirmed metastasis before initiating neoadjuvant therapy allows for evaluation of response in breast cancer. Our goal was to determine if pathologic changes in clipped nodes reflect the status of the nodal basin and if targeted axillary dissection (TAD), which includes sentinel lymph node dissection (SLND) and selective localization and removal of clipped nodes, improves the false-negative rate (FNR) compared with SLND alone.

METHODS

A prospective study of patients with biopsy-confirmed nodal metastases with a clip placed in the sampled node was performed. After neoadjuvant therapy, patients underwent axillary surgery and the pathology of the clipped node was compared with other nodes. Patients undergoing TAD had SLND and selective removal of the clipped node using iodine-125 seed localization. The FNR was determined in patients undergoing complete axillary lymphadenectomy (ALND).

RESULTS

Of 208 patients enrolled in this study, 191 underwent ALND, with residual disease identified in 120 (63%). The clipped node revealed metastases in 115 patients, resulting in an FNR of 4.2% (95% CI, 1.4 to 9.5) for the clipped node. In patients undergoing SLND and ALND (n = 118), the FNR was 10.1% (95% CI, 4.2 to 19.8), which included seven false-negative events in 69 patients with residual disease. Adding evaluation of the clipped node reduced the FNR to 1.4% (95% CI, 0.03 to 7.3; P = .03). The clipped node was not retrieved as an SLN in 23% (31 of 134) of patients, including six with negative SLNs but metastasis in the clipped node. TAD followed by ALND was performed in 85 patients, with an FNR of 2.0% (1 of 50; 95% CI, 0.05 to 10.7).

CONCLUSION

Marking nodes with biopsy-confirmed metastatic disease allows for selective removal and improves pathologic evaluation for residual nodal disease after chemotherapy.

Palladin expression is a conserved characteristic of the desmoplastic tumor microenvironment and contributes to altered gene expression

The stroma surrounding solid tumors contributes in complex ways to tumor progression. Cancer-associated fibroblasts (CAFs) are the predominant cell type in the tumor stroma. Previous studies have shown that the actin-binding protein palladin is highly expressed in the stroma of pancreas tumors, but the interpretation of these results is complicated by the fact that palladin exists as multiple isoforms. In the current study, the expression and localization of palladin isoform 4 was examined in normal specimens and adenocarcinomas of human pancreas, lung, colon, and stomach samples. Immunohistochemistry with isoform-selective antibodies revealed that expression of palladin isoform 4 was higher in adenocarcinomas versus normal tissues, and highest in CAFs. Immunohistochemistry staining revealed that palladin was present in both the cytoplasm and the nucleus of CAFs, and this was confirmed using immunofluorescence staining and subcellular fractionation of a pancreatic CAF cell line. To investigate the functional significance of nuclear palladin, RNA Seq analysis of palladin knockdown CAFs versus control CAFs was performed, and the results showed that palladin regulates the expression of genes involved in the biosynthesis and assembly of collagen, and organization of the extracellular matrix. These results suggested that palladin isoform 4 may play a conserved role in establishing the phenotype of CAFs in multiple tumor types.

Cyclopamine-loaded core-cross-linked polymeric micelles enhance radiation response in pancreatic cancer and pancreatic stellate cells

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Cyclopamine (CPA), a potent inhibitor for sonic hedgehog pathway (SHH), shows great promises in PDAC treatment, including the disruption of tumor-associated stroma, and enhancement of radiation therapy. However, CPA is insoluble in water and therefore requires a nanometric delivery platform to achieve satisfactory performance. We herein encapsulated CPA in a core-cross-linked polymeric micelle system (M-CPA). M-CPA was combined with Cs-137 radiation and evaluated in vitro in PDAC cell lines and a human pancreatic stellate cell line. The results showed that M-CPA had higher cytotoxicity than CPA, abolished Gli-1 expression (a key component of SHH), and enhanced the radiation therapy of Cs-137. M-CPA radiosensitization correlated with its ability to disrupt the repair of radiation-induced DNA damage. These findings indicate that the combination therapy of M-CPA and radiation is an effective strategy to simultaneously treat pancreatic tumors and tumor-associated stroma.

Bisphosphonates inhibit stellate cell activity and enhance antitumor effects of nanoparticle albumin-bound paclitaxel in pancreatic ductal adenocarcinoma

Pancreatic stellate cells (PSC) have been recognized as the principal cells responsible for the production of fibrosis in pancreatic ductal adenocarcinoma (PDAC). Recently, PSCs have been noted to share characteristics with cells of monocyte-macrophage lineage (MML cells). Thus, we tested whether PSCs could be targeted with the nitrogen-containing bisphosphonates (NBP; pamidronate or zoledronic acid), which are potent MML cell inhibitors. In addition, we tested NBPs treatment combination with nanoparticle albumin-bound paclitaxel (nab-paclitaxel) to enhance antitumor activity. In vitro, we observed that PSCs possess α-naphthyl butyrate esterase (ANBE) enzyme activity, a specific marker of MML cells. Moreover, NBPs inhibited PSCs proliferation, activation, release of macrophage chemoattractant protein-1 (MCP-1), and type I collagen expression. NBPs also induced PSCs apoptosis and cell-cycle arrest in the G1 phase. In vivo, NBPs inactivated PSCs; reduced fibrosis; inhibited tumor volume, tumor weight, peritoneal dissemination, angiogenesis, and cell proliferation; and increased apoptosis in an orthotopic murine model of PDAC. These in vivo antitumor effects were enhanced when NBPs were combined with nab-paclitaxel but not gemcitabine. Our study suggests that targeting PSCs and tumor cells with NBPs in combination with nab-paclitaxel may be a novel therapeutic approach to PDAC.

Timing of infectious complications following breast-conserving therapy with catheter-based accelerated partial breast irradiation

BACKGROUND

Accelerated partial breast irradiation (APBI) has been used as an alternative to whole-breast irradiation as part of breast-conserving therapy. Indications and outcomes are topics of ongoing investigation. Previous publications have focused on early postoperative infections and reported low rates of delayed infection. We investigated the pattern of infection after catheter-based APBI at our institution.

METHODS

Patients who underwent single-entry catheter-based APBI were identified from an institutional prospective registry including data regarding comorbidities and outcomes. Time of infection was calculated from the date of definitive catheter insertion and classified as early (≤30 days) or delayed.

RESULTS

A total of 91 breast cancer patients were treated with APBI and enrolled in the registry from 2009 to 2011. The median follow-up was 484 days. Breast infection occurred in 13 (14.3 %), with 3 (3.3 %) occurring within 30 days of catheter placement and 10 (11.0 %) in a delayed fashion. Four patients required hospital admission, five underwent percutaneous aspiration, and one underwent incision and drainage. Eight were treated as outpatients with oral antibiotics alone.

CONCLUSIONS

Consistent with other reports, we found an overall infection rate of 14.3 % with single-entry catheter-based APBI. There were substantially fewer infections in the early postoperative period than reported elsewhere, but there were more delayed infections. The intensive follow-up in our study likely identified late infections that may not have otherwise been recognized. Vigilance for infectious complications must continue beyond the immediate treatment period in patients undergoing catheter-based APBI. These infections can range in severity but typically can be managed in an outpatient setting.