Cancer therapy monitoring in xenografts by quantitative analysis of circulating tumor DNA.

Gorges TM, Schiller J, Schmitz A, Schuetzmann D, Schatz C, Zollner TM, Krahn T, von Ahsen O

Abstract

CONTEXT: Circulating tumor DNA (ctDNA) is a promising biomarker in cancer. MATERIALS AND METHODS We generated xenograft models of cancer and detected ctDNA in plasma by qRCR targeting human AluJ sequences. RESULTS Our assay reached single cell sensitivity in vitro and a correlation between ctDNA amount and tumor size was observed in vivo. Treatment with a mitogen activated protein kinase kinase (MEK)-inhibitor (BAY 869766) reduced ctDNA levels. Using this assay, we also confirmed that high levels of cell-free DNA are found in cancer patients compared to healthy individuals. DISCUSSION AND CONCLUSION: We show that ctDNA may be useful biomarker for monitoring tumor growth and treatment response.