Positive Circulating Tumor Cells Research Articles

Frequency and Prognostic Value of Circulating Tumor Cells in Cancer of Unknown Primary.

Cancer of unknown primary (CUP) is defined as a primary metastatic malignancy, in which the primary tumor remains elusive in spite of a comprehensive diagnostic workup. The frequency and prognostic value of circulating tumor cells (CTCs), which are considered to be the source of metastasis, has not yet been systematically evaluated in CUP. A total of 110 patients with a confirmed diagnosis of CUP according to the European Society for Medical Oncology (ESMO) guidelines, who presented to our clinic between July 2021 and May 2023, provided blood samples for CTC quantification using CellSearch methodology. CTC counts were correlated with demographic, clinical, and molecular data generated by comprehensive genomic profiling of tumor tissue. CTCs were detected in 26% of all patients at initial presentation to our department. The highest CTC frequency was observed among patients with unfavorable CUP (35.5%), while patients with single-site/oligometastatic CUP harbored the lowest CTC frequency (11.4%). No statistically significant association between CTC positivity and the number of affected organs (P = 0.478) or disease burden (P = 0.120) was found. High CTC levels (≥5 CTCs/7.5 mL; 12/95 analyzed patients) predicted for adverse overall survival compared to negative or low CTC counts (6-months overall survival rate 90% vs 32%, log-rank P < 0.001; HR 5.43; 95% CI 2.23-13.2). CTC dynamics were also prognostic for overall survival by landmark analysis (log-rank P < 0.001, HR 10.2, 95% CI 1.95-52.9). CTC frequency is a strong, independent predictor of survival in patients with CUP. CTC quantification provides a useful prognostic tool in the management of these patients.

Detection of circulating tumor cells in patients with pancreatic cancer by novel nano microfluidic chips and comprehensive nursing intervention.

It was to explore the detection efficiency of novel nano microfluidic chips on circulating tumor cells (CTCs) in pancreatic cancer (PC) patients and the effect of comprehensive nursing intervention on the life indicators of patients after PC surgery. PC, benign pancreas, and healthy volunteers were enrolled. The number and positive rate of CTCs in the subjects, the relationship between the number of CTCs in PC patients and clinical data, the recurrence rate, and the life indicators of patients after intervention were sorted out and analyzed. The positive rate of CTCs was 96.67% in PC group (29/30), 16.67% in benign pancreas group (5/30), and 0% in healthy controls. The positive CTCs in PC patients were correlated with vascular invasion (P<0.05). The recurrence rate after PC resection was 56.67% (17/30). The positive detection rate of nano microfluidic chip was 30/30 (100%), which was higher than against CellSeach 7/30 (23.33%), P<0.05. The physiological function score of intervention group (93.67±1.48) was higher as against controls (60.45±2.03), P<0.05. The social function score of intervention group (91.26±0.44) was higher as against controls (54.92±2.98), P<0.05. The novel nano microfluidic chip has high sensitivity and specificity for the detection of CTCs in PC patients. Postoperative comprehensive nursing intervention can improve the quality of life (QoL) and functional status of PC patients.

Sensitivity and specificity of folate receptor α-positive circulating tumour cells in gastric cancer.

We aimed to investigate whether folate receptor α (FRα)-positive circulating tumour cells (CTCs) could be used as a noninvasive liquid biopsy approach in gastric cancer (GC). Tissue microarray and bioinformatic analyses were used to evaluate FRα expression in GC. Patients with FRα-positive CTC examinations at our institute between July 2021 and May 2022 were retrospectively evaluated. Receiver operating characteristic curves were used to evaluate the diagnostic performance of FRα-positive CTCs in GC. FRα was highly expressed and associated with poor prognosis in GC based on public database. Data for 163 patients (20 with benign disease and 143 with GC) were retrospectively collected. FRα-positive CTC levels were significantly higher in the GC group than in the benign disease group (12.15 ± 1.47 FU/3ml vs. 10.47 ± 1.63 FU/3ml, P < 0.01). FRα-positive CTC levels were also elevated in GC patients with vessel/neuron invasion or extra-nodal tumour deposits (12.31 ± 1.47 FU/3ml vs. 11.77 ± 1.38 FU/3ml, P = 0.037). Areas under the curve of FRα-positive CTC levels for GC and early GC were 0.774 (P < 0.001) and 0.736 (P = 0.005). With a cut-off value of 10.95 FU/3ml, the Youden indexes for GC and early GC were 0.502 (sensitivity = 85.2% and specificity = 65.0%) and 0.450 (sensitivity = 80.0% and specificity = 65.0%), respectively. FRα-positive CTC detection by noninvasive liquid biopsy is a useful and effective approach for screening of patients with GC.

Evaluation of cell surface vimentin positive circulating tumor cells as a prognostic biomarker for stage III/IV colorectal cancer

Currently, little is known about the phenotypes of circulating tumor cells (CTCs), particularly epithelial and mesenchymal phenotypes, and their impact on the prognosis of colorectal cancer (CRC) patients. This study aims to investigate the CTC phenotypes and their prognostic implications in stage III/IV CRC. Patients who were diagnosed with CRC and underwent CTC detection at two hospitals were included. CTCs were detected using a mesenchymal CTC kit, and the clinical and pathological characteristics of CTCs were compared with those of cell surface vimentin-positive CTCs (CSV-CTCs). Disease-free survival (DFS) was assessed and used as an indicator of CTC phenotype-related prognosis. Univariate and multivariate Cox regression analyses were made to identify risk factors, and nomogram models were employed for prognostic prediction. A total of 82 patients were enrolled, with a CTC detection rate of 86.6%. Among the detected CTCs, 60% were CSV-CTCs. The CSV-CTC count showed a positive correlation with the T-stage, the M-stage, and the location of the primary tumor (P = 0.01, P = 0.014, and P = 0.01, respectively). Kaplan–Meier survival analysis revealed that CSV-CTCs were associated with worse DFS in patients receiving first-line oxaliplatin chemotherapy (hazard ratio (HR) = 3.78, 95% CI 1.55–9.26, p = 0.04). When the cut-off value of the CSV-CTC count was 3, the optimal prognostic prediction was achieved. Compound models considering CSV-CTCs, TNM staging, the site of the primary tumor and the Ras gene status yielded the best results in both the receiver operating characteristic (ROC) analysis and the decision curve analysis (DCA). This study indicates that CSV-CTCs predominate in CTCs of CRC patients, and a count of CSV-CTCs ≥ 3 is an independent risk factor for worse prognosis.

A Novel Filtration Membrane for Clustered Circulating Tumor Cell Extraction: A Prospective Feasibility Study.

Circulating tumor cells (CTCs) have garnered attention as biomarkers for therapeutic response and prognosis in malignant neoplasms. Nonetheless, existing literature predominantly relies on surrogate markers of tumor cells or focuses on single-cell CTC, failing to adequately address the challenge of detecting cluster-forming CTCs, which bear considerable prognostic implications. This prospective study aims to validate the efficacy of a novel filtration membrane, namely Soft Micro Pore Filter (S-MPF®), for rare cell recovery in detecting CTCs through the analysis of clinical samples. Patients with confirmed lung cancer or highly suspected lung cancer based on specific criteria (solid tumor size >2.0 cm, serum carcinoembryonic level >7.5 ng/ml, maximum standard uptake value derived from fluorodeoxyglucose-position emission tomography >2.9) were included in the study. CTCs were extracted from preoperative peripheral arterial blood samples using S-MPF®, and the validity of the filtration system was positively verified. Out of the 25 enrolled patients, 23 had lung cancer. CTC positivity was observed in 17 cases (73.9%), whereas cluster CTC positivity was observed in 16 cases (69.6%), with a median count of two clusters. Single CTC positivity was observed in 11 cases (52.1%), with a median count of one cell. The utilization of the newly developed S-MPF® filtration membrane exhibited a high rate of CTC identification, demonstrating its suitability for clinical applications.

Effect of various hepatectomy procedures on circulating tumor cells in postoperative patients: a case-matched comparative study.

The objective of this study is to elucidate the prevalence of systemic circulating tumor cells (CTCs) prior to and following resection of hepatocellular carcinoma (HCC), and to compare the disparities in postoperative CTCs in terms of quantity and classifications between the open liver resection (OPEN) and laparoscopic liver resection (LAP) cohorts. From September 2015 to May 2022, 32 consecutive HCC patients who underwent laparoscopic liver resection at Southwest Hospital were retrospectively enrolled in this study. The clinicopathological data were retrieved from a prospectively collected computer database. Patients in the OPEN group matched at a 1:1 ratio with patients who underwent open liver resection during the study period on age, gender, tumor size, number of tumors, tumor location, hepatitis B surface antigen (HBsAg) positivity, alpha-fetoprotein (AFP) level, TNM and Child-Pugh staging from the database of patients to form the control group. The Can-Patrol CTC enrichment technique was used to enrich and classify CTCS based on epithelial-mesenchymal transformation phenotypes. The endpoint was disease-free survival (DFS), and the Kaplan-Meier method and multiple Cox proportional risk model were used to analyze the influence of clinicopathological factors such as total CTCs and CTC phenotype on prognosis. The mean age of the 64 patients with primary liver cancer was 52.92 years (23-71), and 89.1% were male. The postoperative CTC clearance rate was more significant in the OPEN group. The total residual CTC and phenotypic CTC of the LAP group were significantly higher than those of the OPEN group (p = 0.017, 0.012, 0.049, and 0.030, respectively), which may increase the possibility of metastasis (p = 0.042). In Kaplan-Meier analysis, DFS was associated with several clinicopathological risk factors, including Barcelona Clinical Liver Cancer (BCLC) stage, tumor size, and vascular invasion. Of these analyses, BCLC Stage [p = 0.043, HR (95% CI) =2.03(1.022-4.034)], AFP [p = 0.007, HR (95% CI) =1.947 (1.238-3.062)], the number of positive CTCs [p = 0.004, HR (95% CI) =9.607 (2.085-44.269)] and vascular invasion [p = 0.046, HR (95% CI) =0.475 (0.22-1.023)] were significantly associated with DFS. In comparison to conventional OPEN technology, LAP technology has the capacity to augment the quantity of epithelial, mixed, and mesenchymal circulating tumor cells (CTCs). Following the surgical procedure, there was a notable increase in the total CTCs, epithelial CTCs, and mixed CTCs within the LAP group, indicating a potential drawback of LAP in facilitating the release of CTCs.

Prognostic Role of Circulating Tumor Cells in Patients with Metastatic Castration-Resistant Prostate Cancer Receiving Cabazitaxel: A Prospective Biomarker Study.

Circulating tumor cells (CTCs) appear to be a promising tool for predicting the clinical outcome and monitoring the response to treatment in patients with solid tumors. The current study assessed the clinical relevance of monitoring CTCs in patients with metastatic castration resistant prostate cancer (mCRPC) treated with cabazitaxel. Patients with histologically confirmed mCRPC who were previously treated with a docetaxel-containing regimen and experienced disease progression were enrolled in this multicenter prospective study. CTC counts were enumerated using the CellSearch system at baseline (before cabazitaxel initiation), after one cabazitaxel cycle (post 1st cycle) and at disease progression (PD). Patients were stratified into predetermined CTC-positive and CTC-negative groups. The phenotypic characterization was performed using double immunofluorescence staining with anti-CKs and anti-Ki67, anti-M30 or anti-vimentin antibodies. The median PFS and OS were 4.0 (range, 1.0-17.9) and 14.5 (range, 1.2-33.9) months, respectively. At baseline, 48 out of 57 (84.2%) patients had ≥1 CTCs/7.5 mL of peripheral blood (PB) and 37 (64.9%) had ≥5 CTCs/7.5 mL of PB. After one treatment cycle, 30 (75%) out of the 40 patients with available measurements had ≥1 detectable CTC/7.5 mL of PB and 24 (60%) ≥ 5CTCs/7.5 mL of PB; 12.5% of the patients with detectable CTCs at the baseline sample had no detectable CTCs after one treatment cycle. The detection of ≥5CTCs/7.5 mL of PB at baseline and post-cycle 1 was associated with shorter PFS and OS (p = 0.002), whereas a positive CTC status post-cycle 1 strongly correlated with poorer OS irrespective of the CTC cut-off used. Multivariate analysis revealed that the detection of non-apoptotic (CK+/M30-) CTCs at baseline is an independent predictor of shorter OS (p = 0.005). In patients with mCRPC treated with cabazitaxel, CTC counts both at baseline and after the first cycle retain their prognostic significance, implying that liquid biopsy monitoring might serve as a valuable tool for predicting treatment efficacy and survival outcomes.

Phenotypic characteristics of circulating tumor cells and predictive impact for efficacy of chemotherapy in patients with pancreatic cancer: a prospective study.

Early chemoresistance and tumor mass progression are associated with poor prognosis in pancreatic ductal adenocarcinoma (PDAC). Circulating tumor cells (CTCs) have been studied as potential predictors of treatment response and prognosis in PDAC; however, this approach has yet to be applied in clinical practice. The aim of our study was to investigate the phenotypic characteristics of CTCs and determine their predictive value for PDAC progression. We prospectively enrolled 40 patients who were pathologically diagnosed with PDAC and collected blood samples at diagnosis, 2 months after diagnosis, and during disease progression or recurrence. We used a microfabricated filter-based enrichment system to retrieve and analyze CTCs, which were classified using immunofluorescence staining (CD45, EpCAM, and vimentin). Our study included 20 women and 20 men (median age, 66 years). Overall, 45% of the patients (18/40) had disseminated disease, and 77.5% (31/40) received chemotherapy. Multivariate analysis revealed that the total CTC count and carbohydrate antigen 19-9 level at 2 months after diagnosis were associated with disease progression (P<0.05). Linear mixed model analysis revealed that the total CTC count and vimentin-positive CTCs were significantly correlated with treatment response during chemotherapy (P=0.024 and 0.017, respectively). Kaplan-Meier analysis showed that total CTC positivity at 2 months was significantly associated with poor progression-free survival (P=0.038). Our study's findings suggest that CTCs can serve as predictive biomarkers of clinical outcomes in patients with PDAC receiving palliative chemotherapy. In particular, the total CTC count and vimentin-positive CTCs showed changes associated with the chemotherapy response.

Circulating Tumor Cells are an Independent Risk Factor for Poor Prognosis in Patients with Gallbladder Adenocarcinoma.

The study aimed to evaluate the prognostic impact of circulating tumor cells (CTCs) in patients with gallbladder adenocarcinoma after resection. Between January 2018 and January 2021, 101 consecutive patients with gallbladder adenocarcinoma were included. CTCs were detected and enumerated using the CanPatrol® technique. The follow-up period ended in January 2023. The cancer-specific survival (CSS) and disease-free survival (DFS) were calculated using log-rank and Cox regression analyses. CTCs were detected positively in 61.54% (8/13) of the patients in the non-operation group and 13.64% (12/88) in the operation group. In the operation group, the median CSS for CTCs-positive and CTCs-negative patients was 5.0 and 9.5 months (P < 0.001), respectively, and DFS was 2.8 and 5.0 months at stage III (P < 0.001), respectively. In the non-operation group, the median CSS for CTCs-positive and CTCs-negative patients was 3.5 and 6.5 months (P = 0.0031), respectively. The median CSS for CTCs-positive patients in the operation group was similar to that in the non-operation group (P = 0.67). Multivariate analyses showed that positive CTCs was an independent risk factor for poor CSS (HR 0.066, 95% CI 0.021-0.206, P < 0.001) as well as lymph infiltration (HR 0.320, 95% CI 0.110-0.930, P = 0.036), without R0 curative resection (HR 7.520, 95% CI 2.100-26.931, P = 0.002), and without adjuvant chemotherapy (HR 7.730, 95% CI 2.416-24.731, P < 0.001). Positive CTCs was an independent predictor of poor prognosis after resection in patients with gallbladder adenocarcinoma. Preoperative detection of CTCs may play an important guiding role in formulating treatment strategies for these patients.

A Prospective Long-Term Follow-Up Study: The Application of Circulating Tumor Cells Analysis to Guide Adjuvant Therapy in Stage II Colorectal Cancer.

The efficacy of circulating tumor cells (CTCs) in the selection of stage II colorectal cancer (CRC) patients for adjuvant chemotherapy remains inconclusive. The aim of this study was to validate the necessity of adjuvant chemotherapy for stage II CRC patients with positive postoperative CTCs. The clinicopathological features and overall survival (OS) of a cohort of 70 patients with confirmed CRC were collected and analyzed. The total rate of positive CTCs was 55.7%, while the average OS was 70.8months and the OS rate was 75.7% (53/70). These 70 patients were divided into four subgroups, including a CTC-negative group with non-adjuvant chemotherapy (CHEMO-/CTC-) versus a CTC-positive group with non-adjuvant chemotherapy (CHEMO-/CTC+), CHEMO+/CTC- versus CHEMO+/CTC+, CHEMO-/CTC- versus CHEMO+/CTC-, and CHEMO+/CTC+ versus CHEMO-/CTC+; the total numbers in each subgroup were 25 versus 32, 6 versus 7, 25 versus 6, and 7 versus 32, respectively. The average OS of the CHEMO-/CTC- and CHEMO-/CTC+ groups was 82.0 and 68.1months, respectively (p = 0.020); the average OS of the CHEMO+/CTC- and CHEMO+/CTC+ groups was 83.6months and 76.4months, respectively (p = 0.963); the average OS of the CHEMO-/CTC- and CHEMO+/CTC- groups was 82.0months and 83.6months, respectively (p = 0.999); and the average OS of the CHEMO+/CTC+ and CHEMO-/CTC+ groups was 76.4months and 68.1months, respectively (p = 0.247). Positive CTCs are a potential prognostic marker for stage II CRC.

Association of survivin positive circulating tumor cell levels with immune escape and prognosis of osteosarcoma.

Function of survivin protein (encoded by BIRC5) in circulating tumor cells (CTCs) of osteosarcoma (OS) has not been investigated. The goal of this study is to determine whether the expression of survivin protein of CTCs is associated with circulating immune cell infiltration and disease prognosis of OS. Blood samples of 20 patients with OS were collected. CanPatrol™ CTC enrichment technology combined with in situ hybridization (ISH) was applied to enrich and test CTCs and survivin protein. Bioinformation analysis combined with data of routine blood test was used to verify the association between survivin and immune cell infiltration in circulatory system. To screen independent prognostic factors, Kaplan-Meier survival curve, univariate and multivariable Cox regression analyses were performed. Bioinformatics analysis showed that BIRC5 was strongly negatively related to lymphocyte, including T cell, NK cell and B cell, which released that BIRC5 played a key role in immune escape via reducing immune cell infiltration in circulatory system. Meanwhile, the number of survivin+ CTCs was significantly negatively connection with lymphocyte count (R = -0.56, p = 0.011), which was consistent with bioinformatics analysis. Kaplan-Meier curve showed that the overall survival rate in high survivin+ CTCs group was significantly lower than low group (88.9% vs 36.4%, p = 0.04). Multivariable Cox regression analyses showed that survivin+ CTCs were an independent prognostic factor (p = 0.019). These findings suggested that survivin protein played a key role in immune escape of CTCs and the presence of survivin+ CTCs might be a promising prognostic factor in OS patients.

Presence of Circulating Tumor Cells Predates Imaging Detection of Relapse in Patients with Stage III Melanoma.

Stage III melanoma includes nodal metastasis or in-transit disease. Five-year survival rates vary between 32% and 93%. The identification of high-risk patients is important for clinical decision making. We demonstrated previously that ≥1 circulating tumor cells (CTCs) at baseline was associated with recurrence. In this study, we investigated how frequently CTCs were identified prior to radiologically detected recurrence. Stage III patients (n = 325) had imaging at baseline and q 3 months. Baseline and q 6-12 months blood draws (7.5 mL) were performed to identify CTCs up to 3.5 years from diagnosis. CTC assessment was performed using the immunomagnetic capture of CD146-positive cells and anti-MEL-PE. The presence of one or more CTCs was considered positive. We analyzed the cohort of patients with relapse confirmed by radiologic imaging. CTC collection dates were assessed to determine the lead time for CTC detection. CTC-negative patients were significantly less likely to relapse compared to patients positive for CTCs (p-value < 0.001). Within the 325-patient cohort, 143 patients (44%) had recurrence, with a median follow-up of 52 months from diagnosis. The cohort (n = 143) with positive imaging and CTC results revealed 76% of patients (108/143) had CTC+ results before the radiological identification of relapse. The median time between positive CTC and positive imaging was 9 months. CTCs were positive in >75% of patients prior to relapse at a median of 9 months before radiologic detection.

Abstract B016: Liquid biopsy biomarker analysis of a phase II trial of sacituzumab govitecan in castrate resistant metastatic prostate cancer

Abstract Background: Sacituzumab Govitecan (SG) is an antibody-drug conjugate targeting Trop-2 and has been approved for use in breast and bladder cancers. Trop-2 has been shown to be overexpressed in multiple solid tumors including prostate cancer. Here we report an interim analysis of longitudinal liquid biopsies collected in a phase II clinical trial of SG to identify biomarkers of response and resistance. Methods: We collected longitudinal blood samples from 20 patients for circulating tumor cell (CTC) and cell-free DNA (cfDNA) analysis as part of an open label Phase II trial of SG in patients with mCRPC (ClinicalTrials.gov Identifier: NCT03725761). Eligibility criteria for the trial included rising PSA and radiographic progression on abiraterone acetate or enzalutamide in the mCRPC setting. Liquid biopsies were collected at baseline, C1D8, and then every 3 cycles until disease progression. cfDNA was sequenced using a custom 822 gene targeted capture panel (IDT). CTCs were isolated with antibodies to either EpCAM or Trop-2 followed by parallel enumeration, EpCAM and Trop-2 protein phenotyping and RNA extraction for AR/NEPC marker transcriptional profiling. Results: Although no PSA50 responses were observed, the 6-month rPFS rate was 45% (64% in chemotherapy naïve patients). For this analysis, these patients will be termed responding patients. The number of Trop-2-postive CTCs at baseline was significantly higher in responding (24.3 ±13.4 per 7.5 mL blood) than non-responding (10.0±3.8) patients. During treatment the number of Trop-2 positive CTCs in responders significantly decreased by C3D1 to 10.0 ±3.8. Interestingly, while the number of Trop-2 positive CTCs continued to decline to 2.8±1.99 cells/7.5 mL, EpCAM-positive CTCs increased from 12.5±10.52 cells/7.5 mL to 23.2±19.49 at end of trial. Gene expression analysis demonstrated high expression of genes specific to adenocarcinoma including AR-splice variants, TMPRSS2, KLK2 and KLK3 in the majority of patients, with conversion to AR-variant negative CTCs identified in responders. Preliminary cfDNA analysis identified one patient with a mutation acquired in the gene encoding topoisomerase 1 (TOP1) upon progression on SG, with additional analysis ongoing. Conclusions: Patients who responded to SG had a more Trop-2 positive CTCs with adenocarcinoma characteristics with expression of AR pathway genes. Longitudinal analysis of liquid biopsy biomarkers identified multiple mechanisms of acquired SG resistance. Decline in Trop2-CTC population with parallel expansion of EpCAM-CTC population in multiple patients suggests loss of Trop2 surface protein expression as resistance mechanism, while identification of a cfDNA TOP1 mutation in one patient at time of progression is consistent with acquired resistance to the topoisomerase inhibitor payload as has been reported in metastatic triple negative breast cancer. Citation Format: Jamie M. Sperger, Amy K. Taylor, Yue Shi, Charlotte N. Stahlfeld, Kyle Helzer, Matthew Bootsma, Katherine R. Kaufmann, Marina N. Sharifi, Christos E. Kyriakopoulos, Susan Slovin, Scott Tagawa, Scott Dehm, Shuang G. Zhao, Joshua M. Lang. Liquid biopsy biomarker analysis of a phase II trial of sacituzumab govitecan in castrate resistant metastatic prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B016.

Circulating tumor cells (CTCs) and hTERT gene expression in CTCs for radiotherapy effect with lung cancer

BackgroundCirculating tumor cells (CTCs) are important biological indicators of the lung cancer prognosis, and CTC counting and typing may provide helpful biological information for the diagnosis and treatment of lung cancer.MethodsThe CTC count in blood before and after radiotherapy was detected by the CanPatrol™ CTC analysis system, and the CTC subtypes and the expression of hTERT before and after radiotherapy were detected by multiple in situ hybridization. The CTC count was calculated as the number of cells per 5 mL of blood.ResultsThe CTC positivity rate in patients with tumors before radiotherapy was 98.44%. Epithelial–mesenchymal CTCs (EMCTCs) were more common in patients with lung adenocarcinoma and squamous carcinoma than in patients with small cell lung cancer (P = 0.027). The total CTCs (TCTCs), EMCTCs, and mesenchymal CTCs (MCTCs) counts were significantly higher in patients with TNM stage III and IV tumors (P < 0.001, P = 0.005, and P < 0.001, respectively). The TCTCs and MCTCs counts were significantly higher in patients with an ECOG score of > 1 (P = 0.022 and P = 0.024, respectively). The TCTCs and EMCTCs counts before and after radiotherapy affected the overall response rate (ORR) (P < 0.05). TCTCs and ECTCs with positive hTERT expression were associated with the ORR of radiotherapy (P = 0.002 and P = 0.038, respectively), as were TCTCs with high hTERT expression (P = 0.012). ECOG score (P = 0.006) and post-radiation TCTCs count (P = 0.011) were independent factors for progression-free survival (PFS) and TNM stage (P = 0.054) and pre-radiation EMCTCs count (P = 0.009) were independent factors of overall survival (OS).ConclusionThis study showed a high rate of positive CTC detection in patients with lung cancer, and the number, subtype, and hTERT-positive expression of CTCs were closely related to patients’ ORR, PFS, and OS with radiotherapy. EMCTCs, hTERT-positive expression of CTCs are expected to be important biological indicators for predicting radiotherapy efficacy and the prognosis in patients with lung cancer. These results may be useful in improving disease stratification for future clinical trials and may help in clinical decision-making.

Association Between Obesity and Circulating Tumor Cells in Early Breast Cancer Patients

BackgroundObesity and the presence of circulating tumor cells (CTCs) before and/or after chemotherapy are associated with poor outcome in breast cancer (BC) patients. The activation of oncogenic pathways in fatty tissue leads to cell proliferation, suggesting a possible link between obesity and CTCs. Materials and MethodsIn the phase III SUCCESS A trial, 3754 patients with early BC were randomized to 3 cycles of fluorouracil, epirubicin and cyclophosphamide followed by 3 cycles of docetaxel with or without gemcitabine. Data of 1088 patients with CTC assessments (CellSearch-System; Menarini Silicon Biosystems, Italy) and body mass index (BMI) measurements both before and after chemotherapy were available. Patients were classified according to the WHO's international definitions as underweight, normal weight, overweight, or obese, and according to their weight-change during chemotherapy into a weight-loss group (> 5% decrease), stable-weight group (≤ 5% weight-change) or weight-gain group (>5% increase). Associations between CTC positivity and, BMI or weight-change group were analyzed using frequency-table methods. ResultsAt study entry, 47.4% patients were underweight or normal weight, 33.6% were overweight and 18.9% were obese. Before and after chemotherapy, CTCs were detected in 20.1% and 22.6% of patients, respectively. There was no association between CTC positivity and BMI before (P = 0.104) or after (P = 0.051) chemotherapy. Furthermore, there was no association between weight-change group and CTC status before/after chemotherapy (P = 0.332). ConclusionsAccording to our analysis, the risk factors obesity and prevalence of CTCs are not associated and may represent independent prognostic factors.

Abstract 1031: Specific gene alterations of HER2 positive single circulating tumor cell (CTC) compared to autologous leukocytes in metastatic breast cancer (MBC)

Abstract Introduction: Monitoring of CTC in MBC showed ability to predict treatment resistance and outcome. HER2 is one of the most important tumor markers which is associated with rapid cell division and the metastasis and prognosis of MBC in the clinic. More recently, we reported single CTC gene mutation is a key point to distinguish metastasis capability in MBC (2022 AACR and 2022 ASCO). Herein, we report specific gene alterations in HER2+ single CTC compared to autologous leukocytes in MBC. Methods: Whole blood sample (7.5ml/each) was collected from MBC patient before therapy. CTC enumeration was performed in FDA approved CellSearch™ System and then the single HER2+ CTC and leukocytes were isolated by using DEPArrayTM System (Menarini). The single cell DNA was isolated and then the initial library was prepared by using Ampli1™ Whole Genome Amplification, Ampli1™ QC Kit (Menarini) and AMPure XP kit (Beckman Coulter). The exome capture was performed by TruSeq DNA Exome kit (illumine). The sequencing was prepared by NextSeq 500 mid output V2.5 kit and was performed on the NextSeq 500 (Illumina). Results: We identified 107 CTCs including 55 HER2+ CTCs and 14 CTC-clusters. Autologous single HER2+ CTC (HER2+CK+CD45−, Group 1), HER2+CK−CD45+ leukocyte (Group 2) and HER2−CK−CD45+ leukocyte (Group 3) were isolated and sequenced respectively. The sequencing data was processed following the GATK pipeline and annotated using SnpEff. There were 486,119 counts (56.69%) for intron variants, 175,819 counts (20.51%) for intergenic variants, 70,334 counts (8.20%) for exon variants, 50,370 counts (5.87%) for downstream genes, 45,915 counts (5.36%) for upstream genes and others (3.37%) in HER2+ CTC. Meanwhile, there were 71,848 (8.76%) and 0 counts for exon variants found in Group 2 and Group 3 respectively. There were 79 gene variants ((SNP and Ins-Del) identified to have the highest impact effect (≥20) on HER2+ CTC chromosome, when there were 85 and 0 highest impact gene variants were identified in Group 2 and Group 3 respectively. The specific gene alterations in Group 1 compared to Group 2 includes CCNA2, FOLH1, BRD4, SAMHD1, CYP17A1, IDE, HPGDS and CTNNB1 Among the top 50 high impact gene variants, there were 26 genes alteration sites are same in both Group 1 and Group 2, including FECH, HDAC8, CYP11B2, TTN(6 sites), RAN, CD207, HK1, CASP1(2 sites), BRCA1, PIK3CG (3 sites), APEX1(4 sites), KIF11, SIRT5 (2 sites), XYLB and CHKA. Conclusion: Genomic characterization of HER2 positive single CTCs elucidated specific gene alterations associated with disease metastasis compared to autologous leukocytes in MBC. The newfound HER2+CK−CD45+ cells with gene alterations maybe a new kind of cancer transformed leukocytes which need further validation. Specific gene alterations will help to develop novel drugs aimed at the eradication of CTCs using molecularly driven therapies for disease metastasis. Citation Format: Qiang Zhang, Lorenzo Gerratana, Zhe Ji, Xinkun Wang, Paolo D’Amico, Seema Singhal, Youbin Zhang, Andrew A. Davis, Ami N. Shah, William Gradishar. Specific gene alterations of HER2 positive single circulating tumor cell (CTC) compared to autologous leukocytes in metastatic breast cancer (MBC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1031.

Abstract 2300: Non-invasive liquid biopsy assay for the detection of ASCL1 expression in CTCs of patients with lung cancer

Abstract Background: Lung cancer (LC) is the deadliest cancer worldwide, with small cell LC (SCLC) and neuroendocrine (NE) LC being the most aggressive and lethal forms. The transcription factor, achaete-scute homolog 1 (ASCL1), regulates neuronal and NE cell development, and is a hallmark of the ASCL1(+) SCLC subtype. Further, investigating subtype has become increasingly important as new drug candidates emerge for SCLC that may be efficacious in only some patients. ASCL1 by IHC tissue biopsy is highly specific, detecting patients who have transformed from NSCLC to SCLC and have acquired resistance to EGFR tyrosine kinase inhibitor therapy in NSCLC. Quantification of ASCL1 on circulating tumor cells (CTCs) is a blood-based, non-invasive alternative to tissue biopsy that provides functional protein-level expression data to monitor lung cancer patients across the disease continuum, informing patient treatment. Methods: A 4-color immunofluorescence (IF) assay was developed to detect ASCL1 expression in CTCs from routine blood samples, comprising detection of nucleated cells (DAPI), cytokeratin positive CTCs, CD45(+) white blood cells (WBC), and ASCL1(+) cells. During validation, cancer cell lines (SHP-77 [ASCL(+)] and U2-OS [ASCL1(-)]) were spiked into normal blood at a ratio of 1:10,000 (CLC/WBC) and plated onto coated glass slides. Slides were stained, imaged, and CTC candidates were identified with a proprietary imaging algorithm. The threshold of ASCL1 positivity (316 MFI) included 99% of all ASCL1(-), U2-OS cells. Assay specificity, sensitivity, overall accuracy, and subcellular localization of biomarker expression were assessed. The ability of the assay to quantify ASCL1 expression in CTCs was confirmed using 31 samples from 11 Extensive Stage SCLC patients. Results: The ASCL1 CTC assay achieved an overall accuracy of 0.992 (95% CI 0.081, 0.993), and an analytical specificity and sensitivity of 0.990 and 0.995, respectively. The assay displayed a positive predictive value and a negative predictive value of 0.979 and 0.998, respectively, determined by evaluating ASCL1 expression in SHP-77 (N=4062) and U2-OS (N=8645). ASCL1 expression was detected in the nucleus of all SHP-77 and majority of SCLC patient CTCs. Of the 11 Extensive Stage SCLC patients tested, 9 (82%) showed at least one conventional CTC (0.02 - 9.63 CTCs/mL), and all 9 (100%) had at least 1 ASCL1(+) CTC (0.06 - 5.5 CTCs/mL). Conclusion: This blood based ASCL1 assay is a highly specific and sensitive approach to monitor ASCL1 expression on CTCs isolated from the blood of lung cancer patients. Citation Format: Luisa Fernandez, Andrew Kunihiro, Mark Frilles, Alisa Tubbs, Jason Christiansen, David Bourdon. Non-invasive liquid biopsy assay for the detection of ASCL1 expression in CTCs of patients with lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2300.

Abstract 5592: Expansion and characterization on ALK positive NSCLC circulating tumor cells isolated using a size based inertial microfluidic Labyrinth device

Abstract Introduction Lung cancer (LC) is the leading cause of cancer deaths. 85% of LC are non-small cell lung cancer (NSCLC). Fusions involving anaplastic lymphoma kinase (ALK) are oncogenic drivers in ~ 7% of NSCLC. Previous studies have shown that drug resistance develops within ~2 years after ALK tyrosine kinase inhibitor targeted therapy. Due to resistance mechanisms and the biological heterogeneity that evolves over the treatment of ALK+ NSCLC, it is important to monitor and study those dynamic changes through the clinical treatment course to understand cancer progression. Circulating tumor cells (CTCs) are rare cells, shed from cancer lesions into the bloodstream. They can be isolated from a patient's peripheral blood sample (~20ml) to enable study of tumor characteristics at multiple time points. They are promising biomarkers that not only offer phenotypic and genotypic information, but also present a potential to expand into patient derived ex vivo tumor models. In this study, we use a high throughput label-free microfluidic device, Labyrinth, developed in the Nagrath lab for cell size based CTC enrichment, followed by expansion of CTCs in organoid models, further molecular characterization, and growth in patient-derived xenograft (PDX) models. Methods Blood samples were collected from patients (n=22), three with known ALK status. CTC isolation was performed using Labyrinth at 2.0 mL/min. A part of the isolated CTCs were immunofluorescently stained for pan cytokeratin (pan CK), CD45, DAPI, epithelial cell adhesion molecule (EpCAM), and vimentin markers for enumeration. Others were processed for expansion in ultralow attachment plates with three types of organoid culture media. The rest of the CTCs were used for molecular characterizations. Growth curves were produced on expanded samples on Day 0, 7, 14, and 21 in different culture conditions. A live/dead assay and in situ hybridization (FISH) were also performed. On Day 7, selected samples were injected into NSG™ mice. Bulk RNA sequencing was conducted on the original tumor, Day 0 and 7 CTCs, and PDX samples. Results The median CTC concentration in this cohort (n=22) was 316.2 CTCs/ml of blood. Isolated CTCs from ALK+ NSCLC patients showed ALK fusions by FISH. We observed that the number of ALK CTCs was reduced over time consistent with decreased tumor size in CT scans. There were significant differences (p&amp;lt;0.05) for vimentin positive CTCs compared to the other three types of CTCs, which indicated a higher prevalence of a mesenchymal state of NSCLC CTCs. One of the two samples successfully developed into PDX after two months. In summary, we demonstrated a successful workflow to enrich and expand CTCs from ALK+ NSCLC patients. The expanded CTCs can be further characterized and can generate tumors in PDX models. Citation Format: Yuru Chen, Shamileh Fouladdel, Harrison Ball, Xu Cheng, Liwei Bao, Habib Serhan, Albert Liu, Bryce Vandenburg, Laura Goo, Nathan Merrill, Aaron Udager, Angel Qin, Sofia D. Merajver, Sunitha Nagrath. Expansion and characterization on ALK positive NSCLC circulating tumor cells isolated using a size based inertial microfluidic Labyrinth device. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5592.

MicroRNA expression profile in isolated circulating tumor cells in colorectal cancer

Introduction. Colorectal cancer is a frequently diagnosed disease being in the third place among oncological diseases both in incidence and mortality. Currently, researchers focus on development of more accessible and reliable biomarkers of colorectal cancer to overcome the problems in diagnosis and progression prognosis of this pathology.Aim. To investigate characteristics of microRNA expression in circulating tumor cells (CTC) of patients with colorectal cancer. Materials and methods. The study included blood samples from 299 patients with colon cancer, stages II (T3–4N0M0), III (T1–4N1–2M0) and IV (T1–4N0–2M1). Circulating tumor cells were identified using EpCAM marker detection system. Relative expression of hsa-let-7i-5p, hsa-miR-126-5p, hsa-miR-143-3p, hsa-miR-21-5p, hsa-miR-25-3p, hsa-miR-26a-5p, hsa-miR-92a-3p micro RNA in CTC was measured using polymerase chain reaction.Results. Positive CTC status was observed in 188 (62.9 %) of 299 patients, negative in 111 (37.1 %). In the patient group with pT1–2 tumors, the majority of patients did not have CTC (53.3 %). In other patients with pT1–2 disease, the number of CTC was 1.2 and 4.4 times lower than in patients with pT3 and pT4 disease, respectively. In pT4, 1–3 CTC were found 2.7 and 1.7 times more frequently, 3 CTC 1.4 times more frequently than in pT1–2 and pT3, respectively (p ≤0.05). Presence of metastatic lesions increases the probability of CTC detection by the factor of 2.1: in metastases, &gt;3 CTC were observed 60.1 times more frequently than in M0 (p ≤0.05). Expression of hsa-miR-143-3p and hsa-miR-26a-5p microRNA in CTC of patients with stage III colorectal cancer was respectively 2.5 and 5 times lower than in patients with stage II disease (p &lt;0.05) and expression of hsa-miR-21-5p and hsa-miR-92a-3p microRNA was respectively 3.2 and 3 times higher (p &lt;0.05). In CTC of patients with stage IV colorectal cancer, the relative level of expression of hsa-miR-143-3p and hsa-miR-26a-5p was respectively 4.6 and 5.3 times lower (p &lt;0.05) compared to the level of expression in stage II disease, and hsa-miR-126-5p, hsa-miR-21-5p, hsa-miR-25-3p and hsa-miR-92a-3p expression levels were respectively 2.6, 4.6, 2.6 and 5.0 times higher (p&lt;0.05) (statistically significant results).Conclusion. The level of microRNA expression in CTC can be used for differential diagnosis of regional and distant metastases.

Dynamics of CXCR4 positive circulating tumor cells in prostate cancer patients during radiotherapy.

Ablative radiotherapy is a highly efficient treatment modality for patients with metastatic prostate cancer (PCa). However, a subset of patients does not respond. Currently, this subgroup with bad prognosis cannot be identified before disease progression. We hypothesize that markers indicative of radioresistance, stemness and/or bone tropism may have a prognostic potential to identify patients profiting from metastases-directed radiotherapy. Therefore, circulating tumor cells (CTCs) were analyzed in patients with metastatic PCa (n=24) during radiotherapy with CellSearch, multicolor flow cytometry and imaging cytometry. Analysis of copy-number alteration indicates a polyclonal CTC population that changes after radiotherapy. CTCs were found in 8 out of 24 patients (33.3%) and were associated with a shorter time to biochemical progression after radiotherapy. Whereas the total CTC count dropped after radiotherapy, a chemokine receptor CXCR4-expressing subpopulation representing 28.6% of the total CTC population remained stable up to 3 months. At once, we observed higher chemokine CCL2 plasma concentrations and proinflammatory monocytes. Additional functional analyses demonstrated key roles of CXCR4 and CCL2 for cellular radiosensitivity, tumorigenicity and stem-like potential in vitro and in vivo. Moreover, a high CXCR4 and CCL2 expression was found in bone metastasis biopsies of PCa patients. In summary, panCK+ CXCR4+ CTCs may have a prognostic potential in patients with metastatic PCa treated with metastasis-directed radiotherapy.