Advancing cancer patient care by integrating circulating tumor cell technology to understand the spatial and temporal dynamics of cancer

Circulation of rare events in the liquid biopsy for early detection of lung mass lesions

BACKGROUND

Lung cancer screening with low-dose computed tomography (CT) scans (LDCT) has reduced mortality for patients with high-risk smoking histories, but it has significant limitations: LDCT screening implementation remains low, high rates of false-positive scans, and current guidelines exclude those without smoking histories. We sought to explore the utility of liquid biopsy (LBx) in early cancer screening and diagnosis of lung cancer.

METHODS

Using the high-definition single-cell assay workflow, we analyzed 99 peripheral blood samples from three cohorts: normal donors (NDs) with no known pathology (n = 50), screening CT patients (n = 25) with Lung-RADS score of 1-2, and biopsy (BX) patients (n = 24) with abnormal CT scans requiring tissue biopsy.

RESULTS

For CT and BX patients, demographic information was roughly equivalent; however, average pack-years smoked differed. A total of 14 (58%) BX patients were diagnosed with primary lung cancer (BX+). The comparison of the rare event enumerations among the cohorts revealed a greater incidence of total events, rare cells, and oncosomes, as well as specific cellular phenotypes in the CT and BX cohorts compared with the ND cohort. LBx analytes were also significantly elevated in the BX compared with the CT samples, but there was no difference between BX+ and BX- samples.

CONCLUSIONS

The data support the utility of the LBx in distinguishing patients with an alveolar lesion from those without, providing a potential avenue for prescreening before LDCT.

Preanalytical Variables for the Genomic Assessment of the Cellular and Acellular Fractions of the Liquid Biopsy in a Cohort of Breast Cancer Patients

Liquid biopsy allows assessment of multiple analytes, providing temporal information with potential for improving understanding of cancer evolution and clinical management of patients. Although liquid biopsies are intensely investigated for prediction and response monitoring, preanalytic variables are of primary concern for clinical implementation, including categories of collection method and sample storage. Herein, an integrated high-density single-cell assay workflow for morphometric and genomic analysis of the liquid biopsy is used to characterize the effects of preanalytical variation and reproducibility of data from a breast cancer cohort. Following prior work quantifying performance of commonly used blood collection tubes, this study completes the analysis of four time points to assay (24, 48, 72, and 96 hours), demonstrating precision up to 48 hours after collection for assay sensitivity, highly reproducible rare cell enumeration, morphometric characterization, and high efficiency and capacity for single-cell genomic analysis. For the cell-free analysis, both freezing and use of fresh plasma produced similar quality and quantity of cell-free DNA for sequencing. The genomic analysis (copy number variation and single-nucleotide variation) described herein is broadly applicable to liquid biopsy platforms capable of isolating cell-free and cell-based DNA. Morphometric parameters and genomic signatures of individual circulating tumor cells were evaluated in relation to patient clinical response, providing preliminary evidence of clinical validity as a potential biomarker aiding clinical diagnostics or monitoring progression.

Opportunities and Challenges in Implementation of Multiparameter Single Cell Analysis Platforms for Clinical Translation

The high-content interrogation of single cells with platforms optimized for the multiparameter characterization of cells in liquid and solid biopsy samples can enable characterization of heterogeneous populations of cells ex vivo. Doing so will advance the diagnosis, prognosis, and treatment of cancer and other diseases. However, it is important to understand the unique issues in resolving heterogeneity and variability at the single cell level before navigating the validation and regulatory requirements in order for these technologies to impact patient care. Since 2013, leading experts representing industry, academia, and government have been brought together as part of the Foundation for the National Institutes of Health (FNIH) Biomarkers Consortium to foster the potential of high-content data integration for clinical translation.

Circulating Tumor Cell and Cell-free Circulating Tumor DNA in Lung Cancer

Circulating tumor cells (CTCs) are tumor cells that are separated from the primary site or metastatic lesion and disseminate in blood circulation. CTCs are considered to be part of the long process of cancer metastasis. As a 'liquid biopsy', CTC molecular examination and investigation of single cancer cells create an important opportunity for providing an understanding of cancer biology and the process of metastasis. In the last decade, we have seen dramatic development in defining the role of CTCs in lung cancer in terms of diagnosis, genomic alteration determination, treatment response and, finally, prognosis prediction. The aims of this review are to understand the basic biology and to review methods of detection of CTCs that apply to the various types of solid tumor. Furthermore, we explored clinical applications, including treatment monitoring to anticipate therapy resistance as well as biomarker analysis, in the context of lung cancer. We also explored the potential use of cell-free circulating tumor DNA (ctDNA) in the genomic alteration analysis of lung cancer.