Analysis of the serial circulating tumor cell count during neoadjuvant chemotherapy in breast cancer patients.

We evaluated the prognostic implications of the circulating tumor cell (CTC) count in non-metastatic, HER2-negative breast cancer patients who failed to achieve pathologic complete response (pCR) after neoadjuvant chemotherapy (NCT). A total of 173, non-metastatic breast cancer patients treated with NCT were prospectively enrolled. CTCs were obtained from blood drawn pre-NCT and post-NCT using a SMART BIOPSY SYSTEM isolation kit (Cytogen Inc., Seoul, Korea) with immunofluorescence staining. Excluding 26 HER2-positive patients, Relapse-free survival (RFS) and overall survival (OS) related to the CTC count and the association of the CTC count with the treatment response to given therapy were analyzed in 147 HER2-negative patients. Among 147 HER2-negative patients, 28 relapses (19.0%) and 13 deaths (8.8%, all breast cancer-specific) were observed during a median follow-up of 37.3 months. One hundred and seven patients (72.8%) were hormone receptor-positive, and 40 patients (27.2%) had triple-negative breast cancer (TNBC). One or more CTCs were identified in 88 of the 147 patients (59.9%) before NCT and 77 of the 134 patients (52.4%) after NCT. In the entire HER2-negative patient cohort, the initial nodal status was the most significant factor influencing RFS and OS. In TNBC, 11 patients (27.5%) achieved pCR and patients that failed to achieve pCR with ≥ 5 CTCs after NCT, showed worse RFS (HR, 10.66; 95% CI, 1.80-63.07; p = 0.009) and OS (HR, 14.00; 95% CI, 1.26-155.53; p = 0.032). The patients with residual tumor and a high number of the CTCs after NCT displayed the worse outcome. These findings could provide justification to launch a future, well designed trial with longer follow-up data to obtain regulatory approval for clinical use of the assay, especially for the ER-positive, HER2-negative breast cancer subset.

Clinical Utility of Combined Circulating Tumor Cell and Circulating Tumor DNA Assays for Diagnosis of Primary Lung Cancer.

BACKGROUND/AIM: Although it has been suggested that circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) might be used in a complementary manner in lung cancer diagnosis, limited confirmatory data are available. In this prospective study, we evaluated the diagnostic performance of each assay separately and in combination. PATIENTS AND METHODS: From March 2018 to January 2019, patients with suspected primary lung cancer, who underwent routine lung cancer work-up and peripheral blood sampling, were prospectively enrolled in the study. Epithelial cell adhesion molecule and cytokeratin served as markers of CTCs. In terms of ctDNA analysis, single-nucleotide variants were evaluated via next-generation sequencing. RESULTS: We analyzed 111 patients, including 99 with primary lung cancer and 12 with benign pulmonary disease. The median number of CTCs in 10 ml of blood was 3. The most frequently detected single nucleotide variants of ctDNA were TP53, CDKN2A, and EGFR. The diagnostic sensitivity of conventional tumor marker (combination of carcinoembryonic antigen/CYFRA 21-1/neuron-specific enolase) was 66.7%, while those of the ctDNA and CTC assays were 72.7% and 65.7%, respectively. The sensitivity of the CTC/ctDNA combination (95.0%) was significantly greater than those of the CTC (p<0.001), ctDNA (p<0.001), or conventional tumor marker (p<0.001) alone. Subgroup analysis revealed that the sensitivity of the combination assay was greater than those of the CTC or ctDNA assays alone, regardless of tumor stage or histopathology type. CONCLUSION: The CTC/ctDNA combination assay enhanced the sensitivity of primary lung cancer diagnosis. The combination assay strategy may be clinically useful and could enhance the early detection of lung cancer (ClinicalTrials.gov number: NCT03479099).

Circulating Tumor Cell Counts in Patients With Localized Prostate Cancer Including Those Under Active Surveillance.

AIM: To evaluate the clinical efficacy of a circulating tumor cell (CTC) test by comparison between healthy volunteers and patients with localized prostate cancer including those under active surveillance. MATERIALS AND METHODS: CTC counts in peripheral blood were compared between patients with prostate cancer (n=45) and healthy volunteers (n=17). CTCs were identified based on the expression of epithelial cell adhesion molecule (EpCAM) and counted using a SMART BIOPSY™ SYSTEM. RESULTS: The number of EpCAM+ cells was significantly higher in patients with cancer than in healthy volunteers. Among the low-risk patients (n=9), two had up-staging and six had up-grading. Among those up-staged, there was one case which was EpCAM+ Among those cases up-graded, three were EpCAM+ In those with stage T2 tumors, the presence of Gleason pattern 5 was positively correlated with EpCAM positivity (rho=0.59, p<0.001). CONCLUSION: CTC counts in localized prostate cancer were associated with Gleason pattern 5. Active treatment should be considered for patients with low-risk disease during active surveillance who are found to have EpCAM+ CTCs because of a risk of up-staging and up-grading.

Identification of circulating tumor cells with EML4-ALK translocation using fluorescence in situ hybridization in advanced ALK-positive patients with lung cancer.

[This retracts the article DOI: 10.3892/ol.2018.8480.].

Cancer panel analysis of circulating tumor cells in patients with breast cancer.

Liquid biopsy using circulating tumor cells (CTCs) is a noninvasive and repeatable procedure, and is therefore useful for molecular assays. However, the rarity of CTCs remains a challenge. To overcome this issue, our group developed a novel technology for the isolation of CTCs on the basis of cell size difference. The present study isolated CTCs from patients with breast cancer using this method, and then used these cells for cancer gene panel analysis. Blood samples from eight patients with breast cancer were collected, and CTCs were enriched using size-based filtration. Enriched CTCs were counted using immunofluorescent staining with an epithelial cell adhesion molecule (EpCAM) and CD45 antibodies. CTC genomic DNA was extracted, amplified, and screened for mutations in 400 genes using the Ion AmpliSeq Comprehensive Cancer Panel. White blood cells (WBCs) from the same patient served as a negative control, and mutations in CTCs and WBCs were compared. EpCAM+ cells were detected in seven out of eight patients, and the average number of EpCAM+ cells was 8.6. The average amount of amplified DNA was 32.7 µg, and the percentage of reads mapped to any targeted region relative to all reads mapped to the reference was 98.6%. The detection rate of CTC-specific mutations was 62.5%. The CTC-specific mutations were enhancer of zeste polycomb repressive complex 2 subunit, notch 1, AT-rich interaction domain 1A, serine/threonine kinase 11, fms related tyrosine kinase 3, MYCN proto-oncogene, bHLH transcription factor, APC, WNT signaling pathway regulator, and phosphatase and tensin homolog. The technique used by the present study was demonstrated to be effective at isolating CTCs at a sufficiently high purity for genomic analysis, and supported the use of comprehensive cancer panel analysis as a potential application for precision medicine.

Identification of circulating tumor cells with EML4-ALK translocation using fluorescence in situ hybridization in advanced ALK-positive patients with lung cancer.

Analysis of anaplastic lymphoma kinase (ALK) rearrangement in non-small cell lung cancer (NSCLC) is considered to be a useful tool when considering predictive biomarker detection for evaluating eligibility for targeted therapy. It is not always possible to perform a tumor biopsy in patients. Isolation and culturing of circulating tumor cells (CTCs) may be an alternative to tumor biopsies for the diagnosis of ALK rearrangement. Blood was collected from 22 patients with NSCLC harboring ALK rearrangement and was divided into two groups: One for immunofluorescence staining and the other for culture. Samples were filtered by size and cultured CTCs were analyzed for echinoderm microtubule-associated protein-like 4-ALK translocation using fluorescence in situ hybridization. CTCs positive for epithelial cell adhesion molecule and CTCs exhibiting ALK rearrangement were detected. Therefore, CTCs may be used as a potential alternative method to tissue biopsy for diagnosing ALK rearrangement. Additionally, this method may have clinical applications including serial blood sampling for the development of personalized cancer therapy based on individual genomic information.

Cancer gene panel analysis of cultured circulating tumor cells and primary tumor tissue from patients with breast cancer.

Although numerous effective therapies have improved the survival rate of patients with breast cancer, a number of patients present with tumor recurrence and metastasis. A liquid biopsy of circulating tumor cells (CTC) is a non-invasive method to obtain tumor cells and may be used as substitute for a tumor tissue biopsy. The present study focuses on determining whether CTC culture is an optimal method of obtaining sufficient amounts of CTCs for molecular analysis. The current study demonstrates a method of isolating and culturing CTCs from patients with breast cancer and the construction of a molecular profile of cultured cells using the Ion AmpliSeq Cancer Gene Panel V2. Gene mutations that were observed in cultured CTCs were compared with those observed in primary tumor tissues. CTCs were isolated and cultured from the blood of six patients with breast cancer. Mutations from the Catalogue Of Somatic Mutation In Cancer (COSMIC) were detected in Platelet-Derived Growth Factor Receptor Alpha, MET (also known as Hepatocyte Growth Factor Receptor), Phosphatase and Tensin Homolog, Harvey Rat Sarcoma Viral Oncogene Homolog, SWI/SNF Related, Matrix Associated, Actin Dependent Regulator of Chromatin Subfamily B Member 1, Cyclin Dependent Kinase Inhibitor 2A and MutL Homolog 1 genes in 5/6 samples. A comparison between mutations detected in cultured CTCs and mutations detected in primary tumor tissues demonstrated that a large number of mutations that were identified in CTCs were also detected in primary tumor tissues. The results from the current study describe a novel cell culture approach that may be used to obtain an optimal number of CTCs for molecular analysis. This novel approach is able to be used as a tool for liquid biopsy during breast cancer treatment.

Evaluation of a novel approach to circulating tumor cell isolation for cancer gene panel analysis in patients with breast cancer.

Liquid biopsy isolation of circulating tumor cells (CTCs) allows the genomic analysis of CTCs, which is useful in the determination of personalized cancer therapy. In the present study, CTCs from patients with breast cancer were enriched and successfully analyzed using cancer gene panel analysis. Blood samples from 11 patients with breast cancer were collected and CTCs enriched for using size-based filtration. The enriched CTCs were analyzed using immunofluorescence staining with antibodies directed against epithelial cell adhesion molecule (EpCAM) and cluster of differentiation 45. The genomic DNA of CTCs was extracted, amplified and 50 genes screened for mutations using the Ion AmpliSeq™ Cancer Hotspot Panel v2. EpCAM staining detected CTCs in 10/11 patients and the average CTC count was 3.9 in 5 ml blood. The average purity of enriched CTCs was 14.2±29.4% and the average amount of amplified DNA was 28.6±11.9 µg. Catalogue Of Somatic Mutations In Cancer mutations were detected in the CTCs and included IDH2, TP53, NRAS, IDH1, PDGFRA, HRAS, STK11, EGFR, PTEN, MLH1, PIK3CA, CDKN2A, KIT and SMARCB1. In conclusion, a novel size-based filtration approach for the isolation of CTCs was evaluated and successfully applied for the genomic analysis of CTCs from patients with breast cancer.

Complete plastid genome of an ecologically important brown alga Sargassum thunbergii (Fucales, Phaeophyceae).

The brown algal species Sargassum thunbergii (Fucales, Phaeophyceae) is widely distributed in coastal area of East Asia. This alga is ecologically and economically important seaweeds; however, no genome data was reported thus far. To get a better understanding of organellar genome of S. thunbergii, we sequenced and annotated its complete plastid genome. The circular plastid genome is 124,592bp in size with 30.4% GC content, which is composed of a large single-copy (LSC) region of 73,668bp, a small single-copy (SSC) region of 40,032bp, and two inverted repeat (IR) of 5446bp each. The plastid genome of S. thunbergii includes 139 protein-coding genes, six ribosomal RNA (rRNA) operons, 28 transfer RNA (tRNA) sequences, and one intron (214bp) in tRNA-Leu (trnL) gene. Five overlapping genes were identified in the compact plastid genome. Base on the comparison with previously published five brown algae plastid genomes, we found that the gene content and gene order of S. thunbergii are identical to that of other Fucales species Fucus vesiculosus.

Enrichment of cancer cells from whole blood using a microfabricated porous filter.

Enrichment of circulating tumor cells (CTCs) from whole blood is very challenging due to its rarity. We have developed a new CTC enrichment method using a microfabricated filter. The filter was designed to fractionate tumor cells by cell size and optimized to have high porosity and proper pore distribution. When cancer cells were spiked in whole blood, the average recovery rate was 82.0 to 86.7% and the limit of detection by filtration process was approximately 2 cancer cells in a testing volume of blood. The results indicate that the microfabricated filter-based enrichment would be useful to retrieve and analyze CTCs in practice.