Identification of Aneuploid Circulating Tumor Cells in Soft-Tissue Sarcoma Patients: A Pilot Study

Circulating tumor cells (CTCs) have been identified and shown to have prognostic and predictive roles in several types of carcinoma. More recently, aneuploid CTCs have become subject of a growing interest, as aneuploidy is considered a hallmark of cancer often associated with poor prognosis. Here, we aimed to identify for the first time aneuploid CTCs in soft-tissue sarcoma (STS) patients and show supportive in silico evidence on the prognostic role of aneuploidy in mesenchymal cancers.

In our pilot study, we collected blood from 4 metastatic STS patients and 4 age- and sex-matched healthy controls. After sample processing, cells were cyto-centrifuged onto glass slides and FISH was performed using 5 probes. The in silico analysis was performed using data from The Cancer Genome Atlas cohort of STS patients, using the validated Aneuploidy Score. We divided the patients in two populations (aneuploidy-high, Ane-Hi, and aneuploidy-low, Ane-Lo) using the median value of the Aneuploidy Score as a cutoff. Kaplan-Meier curves associated with log-rank test were used to compare progression-free and overall survival between groups. GraphPad Prism 8.0 (La Jolla, CA, USA) was used for statistical analyses.

Aneuploid CTCs were identified in all 4 STS patients and in none of the controls, with a median value of 4 (range 3-6) per 7 mL of blood. Ane-Hi patients showed a significantly worse progression-free and overall survival compared to Ane-Lo patients. The same trend was maintained when analyzing the data based on the different histologies.

We identified for the first time aneuploid CTCs in STS patients using fluorescence in situ hybridization in a surface marker-independent way. We also showed that the Aneuploidy Score has a prognostic value both in terms of progression-free survival and overall survival in STS patients using The Cancer Genome Atlas data, regardless of the histology.