Detection of Circulating Tumour Cells for use as Prognostic, Predictive and Pharmacodynamic biomarkers in Neuroblastoma


Year:

Session type:

Theme:

Swathi Merugu1,Lindi Chen2,David Jamieson2,Deborah Tweddle2
1Newcastle university,2Newcastle University

Abstract

Background

Introduction: Neuroblastoma (NB) is the commonest extracranial childhood solid tumour. New treatments and a better understanding of drug resistance are needed to improve survival. Circulating tumour cells (CTCs) may provide a source of tumour cells for genetic biomarkers, give insights into tumour load and serve as pharmacodynamic (PD) biomarkers for new treatments.

Aims: 1) To detect CTCs from blood and disseminated tumour cells (DTC) from bone marrow (BM) from NB patients using the Imagestream imaging flow cytometer (ISx)

2) To use these cells for genetic and PD biomarker studies for novel targeted therapies.

Method

A panel of NB cell lines (n=6) cloned into neuronal (N) and substrate-adherent (S) types were used to determine expression of NB cell surface markers (GD2 and NCAM) using the ISx. Western blotting and fluorescence activated cell sorting (FACS) were used to validate NCAM and GD2 expression respectively. 20 paired NB patient blood and BM samples were analysed for CTCs and DTCs and two unpaired blood samples were analysed for CTCs using the ISx to detect GD2 +ve and CD45-ve cells.

Results

Using the ISx 80-90% of N-type cells immunostained positive for GD2 compared to 0.8 -10% of S-type cells confirmed by FACS.  CTCs were detected in 19/26 patient samples and DTCs in 17/22 cases. The numbers of CTCs ranged from 10-522/ml blood and DTCs from 57-35,515/ml of bone marrow.

Conclusion

This the first study to show that DTCs and CTCs are detectable in NB patient samples using the ISx. Future work will involve genetic characterisation and development of PD biomarkers for Phase I clinical trials