Circulating Tumor Cells with Aberrant ALK Copy Number Predict Progression-Free Survival during Crizotinib Treatment in ALK-Rearranged Non-Small Cell Lung Cancer Patients

Use of circulating tumor cells in prospective clinical trials for NSCLC patients – standardization of the pre-analytical conditions

Background:

Circulating tumor cells (CTCs) hold potential for noninvasive diagnosis, prognosis and prediction testing in non-small cell lung cancer (NSCLC) patients. Minimizing degradation or loss of CTCs is pivotal for detection and profiling of the low abundance and fragile CTCs, particularly in clinical trials. We prospectively investigated (NCT02372448) whether a new blood collection device performed better compared to commonly used K3EDTA tubes, when subjected to long-term sample storage.

Methods:

Blood samples were drawn into K3EDTA and blood collection tubes (BCT) (Streck), and filtered by the Isolation by SizE of Tumor/Trophoblastic Cells (ISET® system), for CTC detection in two study populations of NSCLC patients; the training set of 14 patients with stage II/IV NSCLC, and the validation set of 36 patients with stage IV NSCLC). MET expression was evaluated by immunocytochemistry (ICC) and anaplastic lymphoma kinase (ALK) gene rearrangement by break-apart fluorescence in situ hybridization (FISH) on ISET-enriched CTCs.

Results:

Blood processed after 24 h and 48 h in BCT tubes showed stable CTCs counts and integrity, whereas CTCs in K3EDTA tubes showed an altered morphology in all patients. CTCs recovered in BCT or K3EDTA tubes at 24 and 48 h were evaluable by ICC for MET expression and by FISH for ALK rearrangement.

Conclusions:

The BCT tubes gave a high yield and preserved the integrity of CTCs after 24 and 48 h of storage at room temperature, which facilitate their molecular characterization in NSCLC patients entering clinical trials.

Detecting an ALK Rearrangement via Liquid Biopsy Enabled a Targeted Therapy-based Approach for Treating a Patient with Advanced Non-small Cell Lung Cancer

Initial diagnostic biopsy procedures often yield insufficient tissue for molecular testing, and invasive surgical biopsies can be associated with significant cost as well as risk to the patient. Liquid biopsy offers an alternative and economical means for molecular characterization of tumors via a simple peripheral blood draw. This case report describes the ability of liquid biopsy to detect an ALK translocation where tissue analysis by fluorescence in situ hybridization was negative for the genetic alteration. Identification of an ALK rearrangement in circulating tumor cells from a blood specimen led to sequential targeted therapies that included crizotinib followed by alectinib. The patient demonstrated outstanding clinical response during treatment with each of the prescribed ALK inhibitors. This case demonstrates the clinical utility of Biocept’s liquid biopsy to detect actionable biomarkers by surveying the systemic landscape of a patient’s disease where identification of the same genetic drivers may be missed in analyses of heterogeneous tumor tissue.

The applications of liquid biopsy in resistance surveillance of anaplastic lymphoma kinase inhibitor

With the clinical promotion of precision medicine and individualized medical care, molecular targeted medicine has been used to treat non-small cell lung cancer (NSCLC) patients and proved to be significantly effective. Anaplastic lymphoma kinase (ALK) inhibitor is one of the most important specific therapeutic agents for patients with ALK-positive NSCLC. It can extend the survival of patients. However, resistance to the ALK inhibitor inevitably develops in the application process. So, the real-time resistance surveillance is particularly important, and liquid biopsy is one of the most potential inspection methods. Circulating tumor cells, circulating free tumor DNA and exosome in body fluid are used as the main detection biomarkers to reflect the occurrence of resistance in real time through sequencing or counting and then to guide the follow-up treatment.

Liquid Biopsy and Therapeutic Targets: Present and Future Issues in Thoracic Oncology

The practice of liquid biopsy (LB) has revolutionized the care of patients with metastatic lung cancer. Many oncologists now use this approach in daily practice, applying precise procedures for the detection of activating or resistance mutations in EGFR. These tests are performed with plasma DNA and have been approved as companion diagnostic test for patients treated with tyrosine kinase inhibitors. ALK is another important target in lung cancer since it leads to treatment of patients who are positive for a rearrangement in ALK identified with tumor tissue. By analogy with EGFR, LB for detection of genomic alterations in ALK (rearrangements or mutations) has been rapidly adopted in the clinic. However, this promising approach has some limitations and has not yet been disseminated as much as the blood test targeting EGFR. In addition to these two therapeutic targets LB can be used for evaluation of the genomic status of other genes of interest of patients with lung cancer (ROS1, RET, NTRK MET, BRAF, HER2, etc.). LB can be performed to evaluate a specific target or for a more or less complex panel of genes. Considering the number of potential targets for clinical trials, techniques of next-generation sequencing of circulating DNA are on the rise. This review will provide an update on the contribution of LB to care of patients with metastatic lung cancer, including the present limits of this approach, and will consider certain perspectives.

[Current progress in research of circulating tumor cells]

Circulating tumor cells are tumor cells that spontaneously or, following operations, migrate into the peripheral blood circulation from the primary tumor or metastatic tumor. As diagnostic, prognostic and predictive biomarkers in many types of cancers including breast cancer, lung cancer, pancreatic cancer and colorectal cancer, circulating tumor cells contribute to the early diagnosis of cancers, drug resistance monitoring, prognostic assessment, survival analysis, detection of tumor recurrence and evaluation of drug efficacy to assist in treatment decision?making and adjustment of treatment plans. However, the current approaches to the detection of circulating tumor cells still have limitations, and the development of new detection methods with higher sensitivity and specificity will be helpful for better use of these cells. Herein the authors review the research progress in circulating tumor cells in terms of the detection techniques, clinical applications of circulating tumor cells, and their prospects in future clinical practice.

Critical issues in the clinical application of liquid biopsy in non-small cell lung cancer

Current therapeutic options for non-small cell lung cancer (NSCLC) patients are chemotherapy and targeted therapy directed mainly against epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements. Targeted therapy relies on the availability of tumor biopsies for molecular profiling at diagnosis and to longitudinally monitor treatment response and resistance development. Unfortunately, tumor biopsy might be invasive, recover poor material of suboptimal quality, and cause sample bias due to tumor heterogeneity. Many studies have illustrated the potential of liquid biopsy as minimal invasive approach to respond to the urgent need for real time monitoring, stratification, and personalized optimized treatment in NSCLC patients. In principle, the liquid biopsy could provide the genetic landscape of primary and metastatic cancerous lesions, detecting "druggable" genomic alterations or associated with treatment resistance. Moreover, it would guarantee the prognostic/predictive biomarkers evaluation in patients for whom biopsies are inaccessible or difficult to repeat. At this regard, the prognostic value of circulating tumor cells (CTCs) in NSCLC patients has been largely investigated, but still their clinical utility as tumor biomarker is hampered by the lack of a consensus on the criteria necessary and sufficient to define them and on the standard operating procedures (SOPs) for their assessment. This review will summarize current developments on liquid biopsy in NSCLC, addressing the technology issues that contribute to the poor ability to track CTCs in the blood of NSCLC patients, thus limiting their extensive use in the clinical practice, and analyzing the solutions adopted to overcome such limits, on the road towards the clinical validation.

Liquid biopsy for monitoring anaplastic lymphoma kinase inhibitors in non-small cell lung cancer: two cases compared

Three to seven percent of non-small cell lung cancer (NSCLC) patients show anaplastic lymphoma kinase (ALK)-translocation and could be treated with ALK-inhibitors. However, under crizotinib, a first-generation ALK-inhibitor, patients develop drug resistance after a median of 12 months. To overcome crizotinib resistance, several next-generation ALK inhibitors have been developed. In NSCLC, liquid biopsy allowed important improvements in the detection of the epidermal growth factor receptor (EGFR) mutation. The ability of liquid biopsy to detect oncogenic gene/protein fusions is a newly investigated field, and is not routinely applied yet. We here present two NSCLC patients, both rearranged for echinoderm microtubule associated-protein like 4-anaplastic lymphoma kinase (EML4-ALK) and treated accordingly, who differed in the clinical outcome. We analyzed the predictive value of the liquid biopsy components, namely epithelial cellular adhesion molecule (EpCAM)+ circulating tumor cells (CTCs), EpCAM low/neg CTCs, EML4-ALK rearranged CTCs, and cell-free mRNA (cfmRNA), during ALK-inhibitors treatment. This analysis showed a potential association between the liquid biopsy biomarkers, patients' outcome and response to treatment, thus suggesting their combined use in the clinical practice, as proposed here. This approach would allow longitudinal monitoring and consequent identification of putative drug-resistance mechanisms, in the light of improving high-risk patient management.

ALK Status Assessment with Liquid Biopsies of Lung Cancer Patients

Patients with advanced stage non-small cell lung carcinoma (NSCLC) harboring an anaplastic lymphoma kinase ALK gene rearrangement, detected from a tissue sample, can benefit from targeted ALK inhibitor treatment. However, while treatment is initially effective in most cases, relapse or progression occurs due to different resistance mechanisms including mutations in the tyrosine kinase domain of echinoderm microtubule-associated protein-like 4 (EML44)-ALK. The liquid biopsy concept has recently radically changed the clinical care of NSCLC patients, in particular for those harboring an epidermal growth factor receptor (EGFR) gene mutation. Therefore, liquid biopsy is an alternative or complementary method to tissue biopsy for the detection of some resistance mutations in EGFR arising during tyrosine kinase inhibitor treatment. Moreover, in some frail patients, or if the tumor lesion is not accessible to a tissue biopsy, a liquid biopsy can also detect some activating mutations in EGFR on initial assessment. Recent studies have evaluated the possibility of also using a liquid biopsy approach to detect an ALK rearrangement and/or the emergence during inhibitor treatment of some resistance mutations in ALK. These assessments can be performed by studying circulating tumor cells by fluorescent in situ hybridization and by immunocytochemistry and/or after the isolation of RNA from plasma samples, free or associated with platelets. Thus, the liquid biopsy may be a complementary or sometimes alternative method for the assessment of the ALK status in certain NSCLC patients, as well as a non-invasive approach for early detection of ALK mutations. In this review, we highlight the current data concerning the role of the liquid biopsy for the ALK status assessment for NSCLC patients, and we compare the different approaches for this evaluation from blood samples.

Routine clinical use of circulating tumor cells for diagnosis of mutations and chromosomal rearrangements in non-small cell lung cancer-ready for prime-time?

In non-small cell lung cancer (NSCLC), diagnosis of predictive biomarkers for targeted therapies is currently done in small tumor biopsies. However, tumor biopsies can be invasive, in some cases associated with risk, and tissue adequacy, both in terms of quantity and quality is often insufficient. The development of efficient and non-invasive methods to identify genetic alterations is a key challenge which circulating tumor cells (CTCs) have the potential to be exploited for. CTCs are extremely rare and phenotypically diverse, two characteristics that impose technical challenges and impact the success of robust molecular analysis. Here we introduce the clinical needs in this disease that mainly consist of the diagnosis of epidermal growth factor receptor (EGFR) activating alterations and anaplastic lymphoma kinase (ALK) rearrangement. We present the proof-of-concept studies that explore the detection of these genetic alterations in CTCs from NSCLC patients. Finally, we discuss steps that are still required before CTCs are routinely used for diagnosis of EGFR-mutations and ALK-rearrangements in this disease.