CNA profiling of single CTCs in locally advanced esophageal cancer patients during therapy highlights unexplored molecular pathways.
Abstract Locally advanced esophageal cancer (EC) is an aggressive disease with a dismal prognosis. The role of circulating tumor cells (CTC) in the EC metastatic process is still an unaddressed question. Here we monitored the evolution of CTCs spread in 11 patients affected by locally advanced EC who were undergoing neoadjuvant chemo-radio therapy followed by surgery. We developed an ad hoc assay named ‘Grab-all’ assay using DEPArray system. Longitudinal monitoring allowed the identification of CTCs expressing epithelial, mesenchymal or mixed phenotype markers, in at least one time-point per patient. Through single cell copy number aberration (CNA) analysis, we revealed that individual CTCs from relapsed patients displayed higher degree of genomic imbalance compared to disease-free patients' ones. Post-neoadjuvant therapy CTCs show genomic aberrations previously reported in EC, namely 23/23 amplifications and 13/19 deletions. Notably the phenomenon was not restricted to the group of relapsed patients. In-depth analysis showed that networks enrichment in all time-points CTCs were inherent to innate immune system. At variance, transcription/gene regulation, post-transcriptional and epigenetic modifications were uniquely affected in CTCs of relapsed patients. Collectively, our data add clues to the comprehension of the role of CTCs in EC aggressiveness: chromosomal aberrations on genes related to innate immune system behave as relevant to the onset of CTC-status, whilst pathways of transcription / gene regulation, post-transcriptional and epigenetic modifications seem linked to patients’ outcome.