Scott V. Bratman

Noninvasive monitoring of diffuse large B-cell lymphoma by immunoglobulin high-throughput sequencing

Recent studies have shown limited utility of routine surveillance imaging for diffuse large B-cell lymphoma (DLBCL) patients achieving remission. Detection of molecular disease by immunoglobulin high-throughput sequencing (Ig-HTS) from peripheral blood provides an alternate strategy for surveillance. We prospectively evaluated the utility of Ig-HTS within 311 blood and 105 tumor samples from 75 patients with DLBCL, comparing Ig-HTS from the cellular (circulating leukocytes) and acellular (plasma cell-free DNA) compartments of peripheral blood to clinical outcomes and (18)fluoro-deoxyglucose positron emission tomography combined with computed tomography (PET/CT; n = 173). Clonotypic immunoglobulin rearrangements were detected in 83% of patients with adequate tumor samples to enable subsequent monitoring in peripheral blood. Molecular disease measured from plasma, compared with circulating leukocytes, was more abundant and better correlated with radiographic disease burden. Before treatment, molecular disease was detected in the plasma of 82% of patients compared with 71% in circulating cells (P = .68). However, molecular disease was detected significantly more frequently in the plasma at time of relapse (100% vs 30%; P = .001). Detection of molecular disease in the plasma often preceded PET/CT detection of relapse in patients initially achieving remission. During surveillance time points before relapse, plasma Ig-HTS demonstrated improved specificity (100% vs 56%, P < .0001) and similar sensitivity (31% vs 55%, P = .4) compared with PET/CT. Given its high specificity, Ig-HTS from plasma has potential clinical utility for surveillance after complete remission.

FACTERA: a practical method for the discovery of genomic rearrangements at breakpoint resolution

UNLABELLEDnFor practical and robust de novo identification of genomic fusions and breakpoints from targeted paired-end DNA sequencing data, we developed Fusion And Chromosomal Translocation Enumeration and Recovery Algorithm (FACTERA). Our method has minimal external dependencies, works directly on a preexisting Binary Alignment/Map file and produces easily interpretable output. We demonstrate FACTERAs ability to rapidly identify breakpoint-resolution fusion events with high sensitivity and specificity in patients with non-small cell lung cancer, including novel rearrangements. We anticipate that FACTERA will be broadly applicable to the discovery and analysis of clinically relevant fusions from both targeted and genome-wide sequencing datasets.nnnAVAILABILITY AND IMPLEMENTATIONnhttp://factera.stanford.edu.

Galectin-1 mediates radiation-related lymphopenia and attenuates NSCLC radiation response.

Purpose: Radiotherapy can result in lymphopenia, which has been linked to poorer survival. Here, we test the hypothesis that radiotherapy-induced lymphopenia is mediated by a tumor-secreted factor, Galectin-1 (Gal-1), which possesses T-cell proapoptotic activities. Experimental Design: Matched Gal-1 wild-type (WT) or null mice were implanted with Lewis lung carcinoma (LLC-1) that either expressed Gal-1 or had Gal-1 stably downregulated. Tumors were irradiated locally and circulating Gal-1 and T cells were measured. Tumor growth, lung metastasis, intratumoral T-cell apoptosis, and microvessel density count were quantified. Thiodigalactoside (TDG), a Gal-1 inhibitor, was used to inhibit Gal-1 function in another group of mice to validate the observations noted with Gal-1 downregulation. Lymphocyte counts, survival, and plasma Gal-1 were analyzed in cohorts of radiotherapy-treated lung [non–small cell lung cancer (NSCLC)] and head and neck cancer patients. Results: LLC irradiation increased Gal-1 secretion and decreased circulating T cells in mice, regardless of host Gal-1 expression. Inhibition of tumor Gal-1 with either shRNA or thiodigalactoside ablated radiotherapy-induced lymphopenia. Irradiated shGal-1 tumors showed significantly less intratumoral CD8+ T-cell apoptosis and microvessel density, which led to marked tumor growth delay and reduced lung metastasis compared with controls. Similar observations were made after thiodigalactoside treatment. Radiotherapy-induced lymphopenia was associated with poorer overall survival in patients with NSCLC treated with hypofractionated radiotherapy. Plasma Gal-1 increased whereas T-cell decreased after radiation in another group of patients. Conclusions: Radiotherapy-related systemic lymphopenia appeared to be mediated by radiotherapy-induced tumor Gal-1 secretion that could lead to tumor progression through intratumoral immune suppression and enhanced angiogenesis. Clin Cancer Res; 20(21); 5558–69. ©2014 AACR.

Neuregulin Autocrine Signaling Promotes Self-Renewal of Breast Tumor-Initiating Cells by Triggering HER2/HER3 Activation

Currently, only patients with HER2-positive tumors are candidates for HER2-targeted therapies. However, recent clinical observations suggest that the survival of patients with HER2-low breast cancers, who lack HER2 amplification, may benefit from adjuvant therapy that targets HER2. In this study, we explored a mechanism through which these benefits may be obtained. Prompted by the hypothesis that HER2/HER3 signaling in breast tumor-initiating cells (TIC) promotes self-renewal and survival, we obtained evidence that neuregulin 1 (NRG1) produced by TICs promotes their proliferation and self-renewal in HER2-low tumors, including in triple-negative breast tumors. Pharmacologic inhibition of EGFR, HER2, or both receptors reduced breast TIC survival and self-renewal in vitro and in vivo and increased TIC sensitivity to ionizing radiation. Through a tissue microarray analysis, we found that NRG1 expression and associated HER2 activation occurred in a subset of HER2-low breast cancers. Our results offer an explanation for why HER2 inhibition blocks the growth of HER2-low breast tumors. Moreover, they argue that dual inhibition of EGFR and HER2 may offer a useful therapeutic strategy to target TICs in these tumors. In generating a mechanistic rationale to apply HER2-targeting therapies in patients with HER2-low tumors, this work shows why these therapies could benefit a considerably larger number of patients with breast cancer than they currently reach.

Evolving trends in the initial locoregional management of male breast cancer

The locoregional management of breast cancer in men has evolved over time. Multimodality treatment regimens currently in use are based primarily on large randomized trials that exclusively enrolled women with breast cancer. We retrospectively reviewed cases of male breast cancer treated with radiotherapy at Stanford University Medical Center with an emphasis on 22 patients treated with surgery and locoregional radiotherapy. We report trends in the surgical techniques as well as in the use of adjuvant radiotherapy, chemotherapy, and hormonal therapy. There were no isolated locoregional failures in this cohort, and 5-year disease-free survival was 65%. The use of contemporary surgical and radiotherapeutic techniques in men is discussed. We conclude that treatment guidelines designed for women should be applied to the locoregional management of breast cancer in men. However, large international prospective registries and inclusion of men in cooperative group randomized trials will be important to confirm the safety and efficacy of modern treatment modalities for male breast cancer.

Overcoming Radioresistance of Lung Cancer Stem Cells

Every year lung cancer claims more lives than any other cancer type. Poor outcomes in this disease are linked to the development of resistance to existing treatments, including radiotherapy. Radioresistance in lung cancer may be driven by a population of cancer cells with properties in common with normal stem cells, including limitless self-renewing potential. These “cancer stem cells” are capable of reconstituting tumors following treatment and of seeding metastatic sites. In this chapter, we review the evidence implicating cancer stem cells in the radioresistance of cancers of the lung and other tissues. Strategies for interfering with mechanisms of radioresistance within cancer stem cells are discussed. Therapeutic modifications that augment the effects of radiotherapy on CSCs are likely to improve outcomes for lung cancer patients.

Abstract 848: Galectin-1 mediates radiation-related lymphopenia in non-small cell lung cancer and attenuates tumor radiation response

Decreased circulating lymphocytes after tumor irradiation has been linked to worse outcomes in several cancers treated with fractionated radiotherapy. The mechanism underlying radiation (RT)-induced lymphopenia is not well understood. Here, we show that lymphopenia also occurs after stereotactic ablative radiotherapy for early stage non-small cell lung cancer, and that it is associated with reduced survival. We provide evidence that RT-induced secretion of Galectin-1 (Gal-1), a b-galactoside binding protein, can potentially explain for this phenomenon. Using matched Gal-1 wild type and null mice together with Lewis lung carcinoma cells stably knocked-down of Gal-1 or scramble control, we show that irradiation of Gal-1 expressing tumor increases Gal-1 secretion in the blood and that it is linked to decreased circulating T-lymphocytes. This was ablated by either genetic down regulation of Gal-1 in the tumor or inhibition of Gal-1 activity by TDG. Moreover, Gal-1 down regulation resulted in enhanced radiation sensitivity in vitro as well as less intratumoral T cell apoptosis and angiogenesis in vivo, resulting in marked tumor growth delay and reduced spontaneous lung metastases when combined with radiotherapy. Similar results were noted when Gal-1 function was inhibited with TDG in vivo. Together, our data identify Gal-1 as an important mediator of RT-related lymphopenia and its proangiogenic and T cell proapototic effect may explain for the poorer outcome associated with RT-related lymphopenia. Gal-1 is therefore a new potential therapeutic target to combine with radiotherapy. Citation Format: Peiwen Kuo, Scott Bratman, David Shultz, Rie von Eyben, Cato Chan, Ziwei Wang, Carmen Say, Aparna Gupta, Bill W. Loo, Amato Giaccia, Albert Koong, Maximilian Diehn, Quynh-Thu Le. Galectin-1 mediates radiation-related lymphopenia in non-small cell lung cancer and attenuates tumor radiation response. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 848. doi:10.1158/1538-7445.AM2014-848