The Potential Clinical Implications of Circulating Tumor Cells and Circulating Tumor Microemboli in Gastric Cancer

BACKGROUND

Gastric adenocarcinoma (GAC) is the third deadliest malignant neoplasm worldwide, mostly because of late disease diagnosis, low chemotherapy response rates, and an overall lack of tumor biology understanding. Therefore, tools for prognosis and prediction of treatment response are needed. Quantification of circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) and their expression of biomarkers has potential clinical relevance. Our aim was to evaluate CTCs and CTM and their expression of HER2 and plakoglobin in patients with nonmetastatic GAC, correlating the findings to clinicopathological data.

MATERIALS AND METHODS

CTC enrichment was performed with isolation by size of epithelial tumor cells, and the analysis was performed with immunocytochemistry and microscopy. Two collections were made: one at diagnosis (55 samples before neoadjuvant treatment) and one after surgery and before adjuvant therapy (33 samples).

RESULTS

A high detection rate of CTCs (90%) was observed at baseline. We evaluated HER2 expression in 45/55 biopsy samples and in 42/55 CTC samples, with an overlap of 36 subjects. Besides the good agreement observed for HER2 expression in primary tumors and paired CTCs for 36 cases (69.4%; κ = 0.272), the analysis of HER2 in CTCs showed higher positivity (43%) compared with primary tumors (11%); 3/5 patients with disease progression had HER2-negative primary tumors but HER2-positive CTCs. A significant CTC count drop in follow-up was seen for CTC-HER2-positive cases (4.45 to 1.0 CTCs per mL) compared with CTC-HER2-negative cases (2.6 to 1.0 CTCs per mL). The same was observed for CTC-plakoglobin-positive cases (2.9 to 1.25 CTCs per mL).

CONCLUSION

CTC analysis, including their levels, plakoglobin, and HER2 expression, appears to be a promising tool in the understanding the biology and prognosis of GAC.

IMPLICATIONS FOR PRACTICE

The analysis of circulating tumor cell levels from the blood of patients with gastric adenocarcinoma, before and after neoadjuvant treatment, is useful to better understand the behavior of the disease as well as the patients more likely to respond to treatment.

EGFR expression in circulating tumor cells from high-grade metastatic soft tissue sarcomas

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.