Circulating Tumor Cells as a Screening and Diagnostic Marker for Early-Stage Non-Small Cell Lung Cancer

Abstract

Background: Circulating tumor cells (CTCs) have become potential diagnostic biomarker for several types of cancer, including lung cancer. In this study, we aim to determine whether CTCs detected by CellCollector can be used for early-stage diagnosis of lung cancer.

Methods: In this study, we recruited 64 volunteers, among whom 44 were suspected lung cancer patients requiring surgical treatment and 20 were healthy volunteers. We simultaneously analyzed PD-L1 expression in CTCs isolated using the GILUPI CellCollector and copy number variation by next-generation sequencing (NGS).

Results: We enrolled a total of 44 patients with suspected lung cancer who required surgery and 20 healthy volunteers. The patients were classified into 4 groups based on their pathological results: benign disease, in situ cancer, microinvasive, and invasive. The CTCs detection rate for each group was 10.00% (1/10), 45% (5/11), 50% (7/14), and 67% (6/9), respectively. Among the patients with lung cancer, the CTCs detection rate increased with disease progression. The rate of CTCs positivity was 52.94% (18/34) in patients who were diagnosed with lung cancer by pathology and 10% (1/10) in patients with benign disease. CTCs were not detected in the control group. The area under the receiver operating characteristic (ROC) curve, a measure for distinguishing patients with primary lung cancer, was 0.715 (95% CI 0.549-0.880, P=0.041). The sensitivity and specificity of the in vivo CTCs detection strategy for the diagnosis of early-stage lung cancer were 52.94% and 90%, respectively. CTCs were associated with clinical pathology but not with the size and location of the nodules.

Conclusion: CTCs isolation using the CellCollector in vivo detection method might be effective for distinguishing between benign and malignant nodules and may be used for early-stage diagnosis of lung cancer.

Keywords: CellCollector; circulating tumor cells; early-stage diagnosis; in vivo; lung cancer.

Conflict of interest statement

The authors have no conflicts of interest to declare.

© 2020 Duan et al.

Figures

Figure 1

Experimental flow chart.

Figure 2

Collection and determination of CTCs. (A) CellCollector in vivo CTCs detection system. A medical stainless steel wire with a 2-cm-long functional domain coated with EpCAM antibody and a hydrogel stratum. The sampling probe was inserted into cubital vein peripheral blood through a 20G catheter with the functional domain exposed to the peripheral blood and placed in vivo for 30 min to capture tumor cells. (B) Determination of tumor cells by CK7/19/panCK (green channel). Hoechst was used for nuclear counterstaining (blue channel), and white cells were determined by CD45 staining (red channel). PD-L1 expression in CTCs was determined by PD-L1 staining (orange channel). Scale bar: 10 μm. WBC indicates white blood cell. (C) Collection and determination of CTCs in the recruited patients by CellCollector. Two CTCs were collected in patient number 36, 3 CTCs in patient number 39, and 1 CTC in patient numbers 42 and 44. P indicates patient. (D) Imaging and pathological results for patient number 39. A pulmonary nodule was found in the right lung. The patient was diagnosed with invasive adenocarcinoma by pathology.

Figure 3

CTCs detection in suspected lung cancer patients and healthy controls. (A) CTCs counts and detection rate in suspected lung cancer patients and healthy controls. (B) CTCs counts and detection rate in patients diagnosed with lung cancer and benign disease by pathology. (C) CTCs counts and detection rate in different groups of patients (benign disease group, in situ cancer group, microinvasive group, and invasive group). Bar values represent the median and interquartile range. (D) ROC curve using CTC counts to distinguish benign and malignant nodules.