Introduction: Soft tissue Sarcomas (STS) are rare malignances, with high mortality rates. Half of patients develop metastasis. The presence of isolated Circulating Tumor Cells (CTCs) and Circulating Tumor Microemboli (CTM) in the blood may be early markers of tumor invasion. Epidermal Growth Factor (EGF) family receptors can also influence this process.
Objectives: to quantify CTCs and identify CTM as well as the EGF Receptor (EGFR) protein expression in these cells and correlate with clinical outcome in metastatic STS.
Materials and methods: Approximately 8mL of blood was prospectively collected from patients with different types of high-grade STS, before the beginning of chemotherapy. The samples were processed and filtered by ISET (Rarecells, France) for the isolation and quantification of CTCs and CTMs. EGFR expression was analyzed by immunocytochemistry (ICC) on CTCs/ CTMs.
Results: We analyzed 18 patients with median age of 49 years (18-77 y). The positivity for EGFR protein expression in CTCs was observed in 93.75% of the patients. This result shows that targeting EGFR positive CTCs from STS origen can be translated in clinical benefit for some patients. In addition, if target therapy is chosen, the EGFR expression in CTCs can be used in follow-up to measure treatment effectiveness.
Conclusions: This is the first study to demonstrate the expression of EGFR protein in CTCs from sarcoma patients. It may open an area for future investigations. The next step is to characterize CTCs in a larger cohort of patients to better understand the role of EGFR in sustaining tumor metastasis in sarcomas.
Keywords: EGFR; circulating tumor cells; circulating tumor microemboli; soft-tissue-sarcomas.