Methodology for the Isolation and Analysis of CTCs

The rare circulating tumor microemboli as a biomarker contributes to predicting early colorectal cancer recurrences after medical treatment

Early prognosis of cancer recurrence remains difficult partially due to insufficient and ineffective screening biomarkers or regimes. This study evaluated the rare circulating tumor microemboli (CTM) from liquid biopsy individually and together with circulating tumor cells (CTCs) and serum CEA/CA19-9 in a panel, on early prediction of colorectal cancer (CRC) recurrence. Stained CTCs/CTM were detected by a microfluidic chip-based automatic rare-cell imaging platform. ROC, AUC, Kaplan-Meier survival, and Cox proportional hazard models regarding 4 selected biomarkers were analyzed. The relative risk, odds ratio, predictive accuracy, and positive/negative predictive value of biomarkers individually and in combination, to predict CRC recurrence were assessed and preliminarily validated. The EpCAM+Hochest+CD45- CTCs/CTM could be found in all cancer stages, where more recurrences were observed in late-stage cases. Significant correlations between CTCs/CTM with metastatic stages and clinical treatment were illustrated. CA19-9 and CTM could be seen as independent risk factors in patient survivals, while stratified patients by grouped biomarkers on the Kaplan-Meier analyses presented more significant differences in predicting CRC recurrences. By monitoring the panel of selected biomarkers, disease progressions of 4 CRC patients during follow-up visits after first treatments within 3 years were predicted successfully. This study unveiled the value of rare CTM on clinical studies and a panel of selected biomarkers on predicting CRC recurrences in patients at the early time after medical treatment, in which the CTM and serum CA19-9 could be applied in clinical surveillance and CRC management to improve the accuracy.

Significance of circulating tumor cells detection in tumor diagnosis and monitoring

To detect circulating tumor cells (CTCs) in the peripheral blood of patients with tumor, and to analyze the significance of CTC detection in tumor diagnosis and monitoring. In the present study, peripheral blood was collected from 125 patients with tumor, and CTCs were isolated and identified. Differences in CTC number and subtype detection were analyzed for different tumor diseases and stages. CTCs were detected in 122 of the 125 patients with tumor, with a positive rate of 97.6%. The number of CTCs increases in patients with vascular metastasis. The number of mesenchymal CTCs increases in patients with lymph node or vascular metastasis. The average ratio of epithelial CTCs in each positive sample decreases in the later stages of cancer compared with the earlier stages, while the average ratio of mesenchymal CTCs increases in the later stages of cancer compared with the earlier stages. The results showed that CTCs with mesenchymal phenotypes are closely related to lymph node or vascular metastasis. CTC detection can help with early diagnosis of tumor diseases. Continuous monitoring of changes in CTCs number and subtypes can assist clinical judgment of tumor disease development status and prognosis.

Epigenetic markers and therapeutic targets for metastasis

The last few years have seen an increasing number of discoveries which collectively demonstrate that histone and DNA modifying enzyme modulate different stages of metastasis. Moreover, epigenomic alterations can now be measured at multiple scales of analysis and are detectable in human tumors or liquid biopsies. Malignant cell clones with a proclivity for relapse in certain organs may arise in the primary tumor as a consequence of epigenomic alterations which cause a loss in lineage integrity. These alterations may occur due to genetic aberrations acquired during tumor progression or concomitant to therapeutic response. Moreover, evolution of the stroma can also alter the epigenome of cancer cells. In this review, we highlight current knowledge with a particular emphasis on leveraging chromatin and DNA modifying mechanisms as biomarkers of disseminated disease and as therapeutic targets to treat metastatic cancers.

Circulating EGFR Mutations in Patients with Lung Adenocarcinoma by Circulating Tumor Cell Isolation Systems: A Concordance Study

Background: We developed a hybrid platform using a negative combined with a positive selection strategy to capture circulating tumor cells (CTCs) and detect epidermal growth factor receptor (EGFR) mutations in patients with metastatic lung adenocarcinoma. Methods: Blood samples were collected from patients with pathology-proven treatment-naïve stage IV lung adenocarcinoma. Genomic DNA was extracted from CTCs collected for EGFR mutational tests. The second set of CTC-EGFR mutational tests were performed after three months of anti-cancer therapy. Results: A total of 80 samples collected from 28 patients enrolled between July 2016 and August 2018. Seventeen patients had EGFR mutations, including Exon 19 deletion (n = 11), L858R (n = 5), and de-novo T790 and L858R (n = 1). Concordance between tissue and CTCs before treatment was 88.2% in EGFR- mutant patients and 90.9% in non-mutant patients. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of EGFR mutation tests for CTCs were 89.3%, 88.2%, 90.9%, 93.8%, and 83.3%, respectively. Conclusions: CTCs captured by a hybrid platform using a negative and positive selection strategy may serve as a suitable and reliable source of lung cancer tumor DNA for detecting EGFR mutations, including T790M.

Detection of circulating tumor cells: Advances and critical concerns

Metastasis is the main cause of cancer-related death and the major challenge in cancer treatment. Cancer cells in circulation are termed circulating tumor cells (CTCs). Primary tumor metastasis is likely due to CTCs released into the bloodstream. These CTCs extravasate and form fatal metastases in different organs. Analyses of CTCs are clarifying the biological understanding of metastatic cancers. These data are also helpful to monitor disease progression and to inform the development of personalized cancer treatment-based liquid biopsy. However, CTCs are a rare cell population with 1-10 CTCs per ml and are difficult to isolate from blood. Numerous approaches to detect CTCs have been developed based on the physical and biological properties of the cells. The present review summarizes the progress made in detecting CTCs.