Size-based detection of sarcoma circulating tumor cells and cell clusters.

Masanori Hayashi,Cha-Mei Tang,Gregory Mccarty,Peixuan Zhu,Adam Levin,Catherine M Albert,Christine A Pratilas,Christian F Meyer,Kyle W Jackson,Carol D Morris,David M Loeb

doi:10.18632/oncotarget.20697

Abstract

Metastatic disease is the most important factor in determining the survival of sarcoma patients. Since sarcoma metastasis is predominantly hematogenous, we hypothesized that detection and quantification of circulating tumor cells (CTCs) could reflect response to therapy and risk of metastatic relapse. We evaluated the presence of CTCs using a novel animal model and in the blood of patients with high grade sarcomas utilizing the CellSieve™ size-based low pressure microfiltration system. Sarcoma CTCs were identified based on antibody staining patterns and nuclear morphology. Additionally, RNA was extracted from the CTCs for molecular analysis including demonstration of an EWS-FLI1 translocation, identification of a previously unrecognized p53 mutation in a patient with Ewing sarcoma, and single cell RNA sequencing of CTC from a child with alveolar rhabdomyosarcoma. In mouse xenograft models, the presence of CTC correlates with disease burden and with clinically silent metastases. In human patients, CTCs were readily detected at diagnosis, decreased with successful treatment, and were detectable in the blood of patients with no radiographic evidence of disease prior to the development of overt metastasis. Although evaluation of CTC is established in the care of patients with carcinomas, this technology has yet to be effectively applied to the evaluation and treatment of sarcoma patients. Our work demonstrates that the CellSieve™ microfiltration system can be used to study the biology of CTC in both mouse models and human sarcoma patients, with the potential for application to the monitoring of disease response and prediction of metastatic relapse.

Highlights

Metastatic disease is the most common cause of death in patients with high-grade sarcoma
Our work demonstrates that the CellSieveTM microfiltration system can be used to study the biology of circulating tumor cells (CTCs) in both mouse models and human sarcoma patients, with the potential for application to the monitoring of disease response and prediction of metastatic relapse
The analyses presented in this pilot study demonstrate that we can reliably detect and collect sarcoma CTC with minimal manipulation of the retrieved cells, and provide proof of principle that this method can be used to monitor disease response, to identify patients in radiographic remission who are destined to relapse, as well as to study CTC biology

Summary

Introduction

Metastatic disease is the most common cause of death in patients with high-grade sarcoma. Despite effective local control in virtually all such patients, only a very small subset will avoid the development of distant metastasis and survive long term with surgical resection or radiation alone [1, 2]. With the introduction of neoadjuvant and adjuvant chemotherapy, long term survival for patients with localized disease has dramatically improved, ranging up to 70%, supporting the presence of micrometastatic disease (and presumably circulating tumor cells) at diagnosis in most patients [3, 4]. The ability to quantify, isolate, and study circulating tumor cells (CTCs), the presumed agents of hematogenous metastasis, would improve our ability to monitor disease response to treatment, predict metastatic recurrence, and develop new therapies based on a deeper understanding of the biology of metastasis

Methods

Results

Conclusion