Circulating Tumor Cells Counts Research Articles

A Randomized Controlled Trial Assessing the Release of Circulating Tumor and Mesenchymal Cells in No-Touch Radical Nephrectomy

Background: Circulating tumor cells (CTCs) may be the missing renal cell carcinoma (RCC) biomarker. No-touch (NT) resection has shown benefit in several tumors. Methods: A randomized controlled trial comparing CTC and circulating mesenchymal cell (CMC) release in no-touch (NT) vs. conventional (C) laparoscopic RN. Blood samples were collected at operation room arrival (S0), specimen extraction (S1), postoperative D1, and D30. CTCs were isolated and analyzed using RUBYchip™. Results: Thirty-four patients were included. No significant differences were found between groups in CTC and CMC counts, count variations between time points, complications, and survival. The total circulating cell detection rates in the NT, C, and overall RCC groups were 58.3%, 80.0%, and 70.4% at S0; 41.6%, 86.7%, and 66.7% at S1; 50.0%, 64.3%, and 60.0% at D1; and 54.5%, 42.9%, and 44.0% at D30, respectively. A progressive decrease in CMCs was observed in the C group after surgery, especially at D1 (4.78 to 1.64 CMCs/7.5 mL blood, p = 0.035). Healthy controls had no circulating cells; however, high CMC counts were found in chronic inflammation controls and oncocytoma patients, with no significant difference from RCC patients (p = 0.460). Conclusions: NT RN did not reduce circulating cell release nor improve survival compared to C RN.

Detection of circulating tumor cells in non-metastatic prostate cancer through integration of a microfluidic CTC enrichment system and multiparametric flow cytometry.

Prostate cancer (PCa) is the second most common cancer among men and the fifth leading cause of cancer death. Circulating tumor cell (CTC) enumeration and characterisation in PCa has been shown to provide valuable information on prognosis of disease, therapy management and detection of resistance. Here, Cellsway's microfluidic platform for high-throughput enrichment of intact CTC populations was used to isolate CTCs from the blood of 20 localised PCa patients and 10 healthy donor samples to evaluate the clinical performance of the technology. To enumerate and characterise CTCs, a multi-parameter flow cytometry analysis was performed on the enriched CTC suspension using CTC-specific biomarkers. CTCs were detected in 17 of 20 patient samples, which corresponds to 85% CTC positivity. The median CTC count per 7.5 ml blood was 2 (1-9). In 80% of patients (n = 16), the number of CTCs ranged from 1 to 5, and in 5% of patients (n = 1) the number of CTCs was above 5. No CTCs were observed in the blood samples of 10 healthy volunteers, demonstrating the high specificity and low risk of false positives of the technology.

Circulating Tumor Cell Count and Overall Survival in Patients With Metastatic Hormone-Sensitive Prostate Cancer

In metastatic hormone-sensitive prostate cancer (mHSPC), new first-line combination therapies have enhanced overall survival (OS), but clinical outcomes for individual patients vary greatly and are difficult to predict. Peripheral blood circulating tumor cell (CTC) count is the most extensively validated prognostic liquid biomarker in metastatic castration-resistant prostate cancer (mCRPC), and recent studies have suggested that it may also be informative in mHSPC. To examine the prognostic value of CTC count in men with mHSPC. In this prognostic study, peripheral blood was drawn at registration (baseline) and at progression to mCRPC in the S1216 study (March 1, 2013, to July 15, 2017), a phase 3, prospective, randomized clinical trial in men with mHSPC. The CTCs were enumerated using a US Food and Drug Administration-cleared isolation platform. Counts were categorized as 0, 1 to 4, or 5 or more CTCs per 7.5 mL based on the prognostic value of these cut points in prior studies. The data analysis was performed between October 28, 2022, and June 15, 2023. Metastatic hormone-sensitive prostate cancer. Circulating tumor cell count was evaluated for an association with 3 prespecified trial end points: OS, progression-free survival, and 7-month prostate-specific antigen, after adjusting for other baseline covariates using proportional hazards and logistic regression models. Of 1313 S1216 participants (median [IQR] age, 68 [44-92] years), evaluable samples from 503 (median [IQR] age, 69 [46-90] years) with newly diagnosed mHSPC were collected at baseline, and 93 samples were collected at progression. Baseline counts were 5 or more CTCs per 7.5 mL in 60 samples (11.9%), 1 to 4 CTCs per 7.5 mL in 107 samples (21.3%), and 0 CTCs per 7.5 mL in 336 samples (66.8%). Median OS for men with 5 or more CTCs per 7.5 mL was 27.9 months (95% CI, 24.1-31.2 months) compared with 56.2 months (95% CI, 45.7-69.8 months) for men with 1 to 4 CTCs per 7.5 mL and not reached at 78.0 months follow-up for men with 0 CTCs per 7.5 mL. After adjusting for baseline clinical covariates, men with 5 or more CTCs per 7.5 mL at baseline had a significantly higher hazard of death (hazard ratio, 3.22; 95% CI, 2.22-4.68) and disease progression (hazard ratio, 2.46; 95% CI, 1.76-3.43) and a lower likelihood of prostate-specific antigen complete response (odds ratio, 0.26; 95% CI, 0.12-0.54) compared with men with 0 CTCs per 7.5 mL at baseline. Adding baseline CTC count to other known prognostic factors (covariates only: area under the curve, 0.73; 95% CI, 0.67-0.79) resulted in an increased prognostic value for 3-year survival (area under the curve, 0.79; 95% CI, 0.73-0.84). In this prognostic study, the findings validate CTC count as a prognostic biomarker that improved upon existing prognostic factors and estimated vastly divergent survival outcomes regardless of subsequent lines of therapy. As such, baseline CTC count in mHSPC may serve as a valuable noninvasive biomarker to identify men likely to have poor survival who may benefit from clinical trials of intensified or novel regimens.

Cellular liquid biopsy provides unique chances for disease monitoring, preclinical model generation and therapy adjustment in rare salivary gland cancer patients.

While cell-free liquid biopsy (cfLB) approaches provide simple and inexpensive disease monitoring, cell-based liquid biopsy (cLB) may enable additional molecular genetic assessment of systemic disease heterogeneity and preclinical model development. We investigated 71 blood samples of 62 patients with various advanced cancer types and subjected enriched circulating tumor cells (CTCs) to organoid culture conditions. CTC-derived tumoroid models were characterized by DNA/RNA sequencing and immunohistochemistry, as well as functional drug testing. Results were linked to molecular features of primary tumors, metastases, and CTCs; CTC enumeration was linked to disease progression. Of 52 samples with positive CTC counts (≥1) from eight different cancer types, only CTCs from two salivary gland cancer (SGC) patients formed tumoroid cultures (P = 0.0005). Longitudinal CTC enumeration of one SGC patient closely reflected disease progression during treatment and revealed metastatic relapse earlier than clinical imaging. Multiomics analysis and functional invitro drug testing identified potential resistance mechanisms and drug vulnerabilities. We conclude that cLB might add a functional dimension (to the genetic approaches) in the personalized management of rare, difficult-to-treat cancers such as SGC.

Improving the Prognostic and Predictive Value of Circulating Tumor Cell Enumeration: Is Longitudinal Monitoring the Answer?

Circulating tumor cell (CTC) numbers in the blood of cancer patients can indicate the progression and invasiveness of tumors, and their prognostic and predictive value has been repeatedly demonstrated. However, the standard baseline CTC count at the beginning of treatment, while informative, is not completely reliable and may not adequately reflect the state of the disease. A growing number of studies indicate that the long-term monitoring of CTC numbers in the same patient provides more comprehensive prognostic data and should be incorporated into clinical practice, as a factor that contributes to therapeutic decisions. This review describes the current status of CTC enumeration as a prognostic and predictive factor, highlights the shortcomings of current solutions, and advocates for longitudinal CTC analysis as a more effective method of the evaluation of developing disease, treatment efficacy, and the long term-monitoring of the minimal residual disease. As evidenced by the described reports, the longitudinal monitoring of CTCs should provide a better and more sensitive prediction of the course of the disease, and its incorporation in clinical practice should be beneficial.

Nanoparticles as a novel key driver for the isolation and detection of circulating tumour cells

Circulating tumour cells (CTCs), derived from primary tumours, play a pivotal role in cancer metastasis by migrating into the peripheral bloodstream. These cells are paramount in clinical research, serving as early diagnostic markers for metastatic cancer. Analysing CTC counts and their biomarker characteristics can provide invaluable insights into tumour identification, profiling, and metastatic capabilities. However, the rarity and diverse nature of CTCs in the bloodstream present significant challenges to their isolation and detection, especially in the initial stages of metastasis. Recent advancements in nanotechnology have led to the development of innovative CTC separation and detection methods. This review focuses on applying nanoparticles, nanomaterials, and microfluidic platforms to simplify the isolation and detection of CTCs. The infusion of nanotechnology in this field marks a crucial turning point, enabling the necessary progress to advance CTC research.

Clinical Implications of Circulating Tumor Cells in Patients with Esophageal Squamous Cell Carcinoma: Cancer-Draining Blood Versus Peripheral Blood.

Circulating tumor cells (CTCs) in cancer-draining veins have diagnostic and prognostic value. However, studies on esophageal squamous cell carcinoma (ESCC) are limited. This study aimed to compare CTCs obtained from different sampling sites (peripheral vein vs. cancer-draining azygos vein) and to investigate their association with the clinicopathological characteristics of ESCC patients. Blood samples were collected preoperatively from both veins in 40 ESCC patients at Pusan National University Hospital from June 2020 to April 2022. CTCs were detected using a centrifugal microfluidic method with fluid-assisted separation. CTCs and TWIST (+) CTCs were detected more frequently in the azygos vein blood than in the peripheral vein blood; however, the difference was not statistically significant (85.0% [34/40] vs. 77.5% [31/40], p = 0.250 and 82.5% [33/40] vs. 75.0% [30/40], p = 0.586, respectively). CTC and TWIST (+) CTC counts were significantly higher in the azygos vein blood than in the peripheral vein blood (7 vs. 3, p < 0.001, and 6 vs. 2, p < 0.001, respectively). CTCs and TWIST (+) CTCs from peripheral and azygos veins showed no association with clinicopathological characteristics. Further large-scale studies are needed to clarify their role as predictive biomarkers for prognosis and chemotherapy responses in ESCC patients.

Exploring the diagnostic and prognostic significance of circulating tumor cells in stage II-IV colorectal cancer using a nano-based detection method.

Colorectal cancer (CRC) is a leading cause of cancer mortality globally, underscoring the urgency for a noninvasive and effective biomarker to enhance patient prognosis. Circulating tumor cells (CTCs), a potential marker for real-time tumor monitoring, are limited in clinical utility due to the low sensitivity of existing detection methods. Previously, we introduced a novel Nano-based CTCs detection method that relies on the electrical properties of cell surfaces, thus eliminating thereby obviating the need for specific molecular biomarkers. In this study, we employed this technique to evaluate the diagnostic and prognostic value of CTCs in stage II-IV CRC. A total of 194 participants were included, consisting of 136 CRC patients and 58 healthy individuals. The peripheral blood of the participants was collected, and CTCs enumeration was performed utilizing the Nano-based detection method that we newly developed. The Receiver Operating Characteristic (ROC) curve and multivariate Cox proportional-hazards analysis were employed to assess the effectiveness of CTCs for diagnosing CRC and predicting patient prognosis. The Nano-based method demonstrated an ability to differentiate CRC patients from healthy individuals with a sensitivity of 84.6% and a specificity of 94.8%. Furthermore, baseline CTCs levels were predictive of progression-free survival (PFS) in CRC patients, with lower levels associated with longer PFS compared to higher levels (4.5 months vs. 8.0 months at 15 CTCs/mL, p = 0.016; 4.4 months vs. 8.0 months at 20 CTCs/mL, p = 0.028). We also explored the dynamic changes in the number of CTCs after 1-5 cycles of chemotherapy. Patients with increasing CTCs levels typically experienced disease progression (PD), while those with decreasing levels often achieved a partial response (PR) or maintained stable disease (SD). These findings suggest that the dynamic fluctuations in CTCs counts are closely tied to the clinical course of the disease. Our study indicates the potential of Nano-based CTCs detection in diagnosing and predicting outcomes for patients with stage II-IV CRC.

Characterization of circulating tumor cells in patients with metastatic bladder cancer utilizing functionalized microfluidics

Assessing the molecular profiles of bladder cancer (BC) from patients with locally advanced or metastatic disease provides valuable insights, such as identification of invasive markers, to guide personalized treatment. Currently, most molecular profiling of BC is based on highly invasive biopsy or transurethral tumor resection. Liquid biopsy takes advantage of less-invasive procedures to longitudinally profile disease. Circulating tumor cells (CTCs) isolated from blood are one of the key analytes of liquid biopsy. In this study, we developed a protein and mRNA co-analysis workflow for BC CTCs utilizing the graphene oxide (GO) microfluidic chip. The GO chip was conjugated with antibodies against both EpCAM and EGFR to isolate CTCs from 1 mL of blood drawn from BC patients. Following CTC capture, protein and mRNA were analyzed using immunofluorescent staining and ion-torrent-based whole transcriptome sequencing, respectively. Elevated CTC counts were significantly associated with patient disease status at the time of blood draw. We found a count greater than 2.5 CTCs per mL was associated with shorter overall survival. The invasive markers EGFR, HER2, CD31, and ADAM15 were detected in CTC subpopulations. Whole transcriptome sequencing showed distinct RNA expression profiles from patients with or without tumor burden at the time of blood draw. In patients with advanced metastatic disease, we found significant upregulation of metastasis-related and chemotherapy-resistant genes. This methodology demonstrates the capability of GO chip-based assays to identify tumor-related RNA signatures, highlighting the prognostic potential of CTCs in metastatic BC patients.

Early Evaluation of Risk Stratification and Clinical Outcomes for Patients with Advanced Breast Cancer through Combined Monitoring of Baseline Circulating Tumor Cells and DNA.

Early evaluation of tumor heterogeneity related to metastasis and outcomes is a major challenge in the management of advanced breast cancer (BCa) in the clinic. In this study, we introduced the value of baseline circulating tumor cells (CTC) and ctDNA for early differentiation of clinical stages, tumor heterogeneity, and prognosis in clinic. A total of 292 patients with BCa were enrolled in this study, including 254 Stage IV and 38 Stage III patients, and examined the baseline levels of CTCs, CTC-clusters, and plasma ctDNA before initiating therapies. Outcomes including progression-free survival (PFS) and overall survival were evaluated using proportional hazards regression analysis. The baseline CTCs, including HER2+ CTCs, in Stage IV patients were approximately 9.5 times higher than those detected in Stage III patients. Baseline CTC counts with a cutoff of 5 were significantly associated with the prognosis. Within each stage, patients with <5 CTCs had significantly longer PFS. Stage III patients with no CTCs exhibited the longest survival compared with patients with ≥1 CTC. CTC-clusters were only found in Stage IV patients, among whom 15 Stage IV patients with ≥5 CTC-clusters had the worst PFS compared with the 239 Stage IV patients with <5 CTC-clusters. Similar outcomes were observed in 28 out of 254 Stage IV patients who had at least one CTC-cluster detected, as these patients had shorter PFS compared with CTC-cluster negative group. The major differences in ctDNA mutations between patients with Stage III and Stage IV BCa were in PIK3CA and ESR1, which were associated with specific organ metastasis and worse outcomes. Assessing the baseline levels of CTCs, CTC-clusters, and mutational ctDNA profile could reliably aid in differentiation of clinical stage and early prediction of metastasis and outcomes in advanced BCa.

Monocytes-to-lymphocytes ratio increases the prognostic value of circulating tumor cells in non-small cell lung cancer: a prospective study.

Circulating tumor cells (CTCs) has shown important prognostic value in non-small cell lung cancer (NSCLC). However, the present low sensitivity of CTC capture technology restricts their clinical application. This study aims to explore the feasibility of combining the peripheral blood cell (PBC)-derived inflammation-based score with CTCs to increase the prognostic value of CTCs in NSCLC. Sixty volunteers diagnosed with NSCLC were recruited. CTC count and six inflammation-based scores were examined and the association with progression-free survival (PFS) and overall survival (OS) was explored. The changes in the CTC counts before and after the immunotherapy were observed. Multivariate analysis showed that CTCs >7 [hazard ratio (HR) =9.07; 95% confidence interval (CI): 3.68-22.37, P<0.001] and monocytes-to-lymphocytes ratio (MLR) > 0.2 (HR =3.07; 95% CI: 1.21-7.84; P=0.01) were associated with shorter OS and PFS in patients with NSCLC. Patients with CTCs >7 and MLR >0.2 had 12.30 times increased risk of death (P<0.001) and 6.10 times increased risk of disease progression (P=0.002) compared with those with CTCs ≤7 and MLR ≤0.2. Decreased CTC counts after immunotherapy were closely related to disease control (r=0.535, P=0.01). CTCs and MLR are both independent risk factors for prognosis in patients with NSCLC. The combination of CTCs with MLR significantly increased the prognostic value of CTCs, which would contribute to stratification of NSCLC patients and providing precise treatment. Dynamic monitoring of CTCs efficiently shows the immunotherapy response in NSCLC.

Changes of circulating tumor cells expressing CD90 and EpCAM in early-phase of atezolizumab and bevacizumab for hepatocellular carcinoma

Circulating tumor cells (CTCs) are noninvasive biomarkers that can indicate the therapeutic response and prognosis. The study aimed to investigate the cellular characteristics of CTCs focusing on monitoring during atezolizumab and bevacizumab (Atezo-Bev) therapy in patients with hepatocellular carcinoma (HCC). Peripheral blood samples were collected from 10 healthy controls and 40 patients with HCC. CTCs enriched using RosetteSep™ Human CD45 depletion cocktail were analyzed by multiparametric flow cytometry. CTC isolation was based on PanCK(+)CD45(−) cells, and CTCs exhibiting markers CD90, CD133, EpCAM, or vimentin. The total number of CTCs and the number of CTCs expressing CD90, CD133, EpCAM, and vimentin were correlated with the BCLC stage of HCC. The change in total CTC count accurately reflected the initial response to Atezo-Bev therapy. The numbers and mean fluorescence intensity of the CTC subsets expressing CD90 and EpCAM molecules decreased in patients with partial response/stable disease, and increased in patients with progressive disease and were markedly correlated with overall survival. CD90(+) and EpCAM(+) CTCs may be candidate biomarkers for the early prediction of the treatment response and the overall survival of patients with HCC receiving Atezo-Bev therapy.

Serial Changes of Circulating Tumor Cells in Patients with Hepatocellular Carcinoma Treated with Atezolizumab Plus Bevacizumab.

Immune checkpoint inhibitors have promising outcomes in patients with hepatocellular carcinoma (HCC); however, there is no reliable biomarker for predicting disease progression. Circulating tumor cells (CTCs) derived from peripheral blood have attracted attention in monitoring therapeutic efficacy. In this study, CTCs were serially collected from HCC patients undergoing atezolizumab plus bevacizumab (Atezo+Bev), and changes in molecular expression and CTC numbers were analyzed to identify effective biomarkers. Changes in CTC numbers during Atezo+Bev reflected the tumor volume. Targeted RNA sequencing with next-generation sequencing (NGS) revealed that patients with elevated transforming growth factor (TGF)-β signaling molecules had a poorer response, whereas those with elevated apoptosis signaling molecules had a favorable response. In addition, compared with changes in CTC counts, changes in TGF-β signaling molecule expression in CTCs accurately and promptly predicted treatment response. Overall, NGS analysis of CTC-derived RNA showed that changes in TGF-β signaling molecules predict treatment response earlier than changes in CTC counts. These findings suggest that changes in the expression of TGF-β molecules in CTCs could serve as novel biomarkers for the early prediction of therapeutic response in patients with unresectable HCC undergoing Atezo+Bev.

Therapeutic Apheresis Using a β2-Microglobulin Removal Column Reduces Circulating Tumor Cell Count.

An elevated serum β2-microglobulin (β2M) level is indicative of impaired glomerular filtration and prerenal diseases, such as malignant tumors, autoimmune disorders, and liver diseases. An elevated serum β2M level has been shown to promote metastasis via the induction of epithelial-mesenchymal transition (EMT) in cancer cells. However, the therapeutic potential of targeting β2M remains unclear. Here, we aimed to investigate the efficacy of Filtor, a small polymethyl methacrylate fiber-based β2M removal column, in reducing the β2M level and suppressing cancer cell-induced EMT and metastasis. We assessed the effects of Filtor on the changes in metastasis based on the number of circulating tumor cells (CTCs), which reflects the post-EMT cancer cell population. We performed therapeutic apheresis using Filtor on a male patient with sinonasal neuroendocrine carcinoma, a female patient with a history of colorectal cancer, and another female patient with a history of pancreatic ductal adenocarcinoma. Significantly low serum β2M levels and CTC counts were observed immediately and 4 weeks after treatment compared with those in the pretreatment phase. Moreover, the CTC count immediately after therapeutic intervention was markedly reduced, likely because Filtor had trapped CTCs directly. These findings suggest that therapeutic apheresis with Filtor can prevent cancer metastasis and recurrence by directly removing CTCs.

Pilot study to evaluate isolation by size of circulating tumour cells in canine oral melanoma.

Liquid biopsy for circulating tumour cell (CTC) detection is generally unexplored in veterinary medicine. Dogs with highly aggressive and heterogeneous tumours, such as oral malignant melanoma (OMM), could benefit from studies involving size-based isolation methods for CTCs, as they do not depend on specific antibodies. This pilot study aimed to detect CTCs from canine OMM using Isolation by Size of Epithelial Tumor Cells (ISET), a microfiltration methodology, followed by immunocytochemistry (ICC) with Melan-A, PNL2, and S100 antibodies. Ten canine patients diagnosed by histopathology and confirmed as OMM by immunohistochemistry were enrolled, their prognostic data was assessed, and blood samples were collected for CTC analysis. Results have shown the detection of intact cells in 9/10 patients. ICC has shown 3/9 Melan-A-positive, 3/9 PNL2-positive, and 8/9 S100-positive patients, confirming the importance of opting for a multimarker assay. A significant number of negative-stained CTCs were found, suggesting their high heterogeneity in circulation. Microemboli stained with either PNL2 or S100 were found in a patient with a high isolated cell count and advanced clinical stage. Preliminary statistical analysis shows a significant difference in CTC count between patients with and without lymph node metastasis (p < .05), which may correlate with tumour metastatic potential. However, we recommend further studies with more extensive sampling to confirm this result. This pilot study is the first report of intact CTC detection in canine OMM and the first application of ISET in veterinary medicine, opening new possibilities for liquid biopsy studies in canine OMM and other tumours.

Detection and surveillance of circulating tumor cells in sarcoma for predicting therapy response and prognosis.

e23573 Background: Generally sarcomas are categorized as soft tissue and bone sarcomas and represent heterogenous group of malignancies with more than 70 distinct histologic subtypes. Due to their rarity and heterogeneity, sarcomas present particular challenges for accurate diagnosis, prognosis, and treatment. The presence and persistence of circulating tumor cells (CTCs) in the peripheral blood are believed to be associated with poor prognosis and distant metastases. A blood-based CTCs test is thus greatly needed for monitoring disease progression and predicting clinical outcomes. Methods: In this study, we developed a CTCs test for the detection and surveillance of sarcoma patients’ CTCs, and subsequently explored its clinical value. 123 patients with sarcomas were enrolled as the cohort for serial CTCs tests. Dynamic CTCs counting, in combination with therapy evaluation and post-treatment follow-up, was used to explore predicting pre- and post-chemotherapy evaluation and prognosis. Results: Quantification of CTCs demonstrated a significant increase in sarcoma patients compared to healthy individuals. Furthermore, patients in stage III-IV had a higher CTC count than those in stage I-II (p&lt;0.01), suggesting a correlation between CTCs and disease development. Remarkably, there was variation in the quantity of CTCs among different types of sarcomas. The highest number of CTCs was observed in undifferentiated small round cell sarcoma, followed by soft tissue tumor, while bone tumors had the lowest number. In addition, the number of CTCs in patients with positive PD-L1 expression was considerably greater than in those with negative expression (p&lt;0.01). The count of CTCs shown a substantial decrease following neoadjuvant chemotherapy treatment. There was a decline in the number of CTCs both before and after postoperative adjuvant chemotherapy treatment, however, there was no significant statistical discrepancy. The number of CTCs at the baseline was shown to be considerably larger in the group of patients with progressive disease or stable disease (PD+SD) compared to the group with partial response or complete response (PR+CR) (p&lt;0.05). This difference was particularly pronounced for interstitial-type CTCs (p&lt;0.01). Conclusions: The rate of presence of CTCs in the peripheral blood of sarcoma patients is high, and patients with an increased percentage of CTCs after treatment have a poor treatment effect. The dynamic monitoring of changes in CTCs counts after treatment has clinical significance for the timely detection of recurrence or metastasis. CTCs also showed a clinical value in prediction of therapy efficiency or prognosis, and may be clinically valuable for the whole course management of patients.

Circulating tumor cells enumeration and characterization in patients with lung cancer treated with immunotherapy.

e15030 Background: Programmed death-ligand 1 (PD-L1) is a predictive biomarker for immunotherapy in the treatment of non-small cell lung cancer (NSCLC). Assessing PD-L1 expression from the tumor specimen can be challenging because of tissue accessibility, heterogeneity, and dynamic changes in PD-L1 expression that may impact the status of PD-L1 during disease evolution and treatment. Hence, assessing PD-L1 status from archival tumor might not reflect its actual state on the tumor and having a real-time assessment of its expression with the use of non-invasive techniques such circulating tumor cells (CTCs) is useful. Methods: We conducted a single centre prospective study to detect CTCs in the blood of patients with stage III-IV NSCLC treated with immunotherapy using the standard CellSearch technology for CTC enumeration and the Epic Sciences technology for CTCs enumeration and assessment of PD-L1 protein expression on CTCs. CTCs were detected at baseline before treatment initiation and after 2 cycles of treatment. Study endpoints included CTCs detection and concordance between the 2 technologies, PD-L1 expression assessment on CTCs with the Epic Sciences technology, and concordance with tissue-based expression. Comparisons were made using Pearson correlation coefficient (PCC) and intraclass correlation coefficient (ICC) for count data and percentage of perfect agreement. Results: Between 2019 and 2022, 48 patients treated with immunotherapy were enrolled in the study. The mean ± standard deviation (SD) age was 66.8 ± 10.3 years, 63% were females, 42% received combination chemotherapy and immunotherapy, and 44% had adenocarcinoma histology. The tissue PD-L1 expression was high (≥50%), intermediate (1-49%), and low (&lt;1%) in 36%, 31% and 33% of patients respectively. The mean ± SD baseline CTCs count per 7.5ml was 1.97 ± 4 with CellSearch and 1.38 ± 2.72 per ml with Epic Sciences. After 2 treatment cycles, 22% and 41% of patients had an increase in their CTCs count with CellSearch and Epic Sciences, respectively and 30% and 29% had a decrease in their CTCs. The PCC and ICC for baseline CTCs detected by CellSearch and Epic Sciences were 0.72 and 0.61, respectively and for CTCs detected after 2 cycles of treatment by the 2 technologies were -0.16 and 0.45 respectively. One patient had PD-L1 expression on their CTCs with the Epic Sciences technology and there was no association between the PD-L1 expression on CTCs and on matched tissue samples. Conclusions: This study showed a moderate to strong correlation between the 2 technologies for baseline CTCs detection and moderate to poor correlation for CTCs detection after 2 cycles of therapy. No association was found between CTCs and tissue PD-L1 expression. Future work needs to further investigate the role of PD-L1 expression on CTCs.

Enhancing liquid biopsy potential: The impact of the R3CE 3D culture platform.

e15032 Background: The ability to expand and preserve tumor cells ex vivo has been an important aspect of cancer research, offering insights into tumor biology and the advancement of personalized therapies. However, expanding rare tumor cells, such as circulating tumor cells (CTCs) and needle biopsies, remains challenging. Methods: We present the R3CE (Reproducible, Rapid, Rare Cell Expansion) 3D culture platform, a novel system that enhances the conventional tissue culture plate with a coating of polyelectrolyte multilayer. This approach can reliably cultivate various tumor specimens, including CTCs, needle biopsies, and surgical tissues, into tumor spheroids. Results: Our platform achieved over a 90% success rate (n = 305) in producing tumor spheroids with uniform size and preserved mutational profiles across diverse cancer types such as breast, lung, and colorectal cancers. In comparison to traditional tissue biopsies, liquid biopsies are less invasive and contain CTCs that offer a more comprehensive representation of heterogeneous tumor cell populations. We show that the proliferative capacity of cultured CTCs, rather than the initial CTC counts, have a strong correlation with lung adenocarcinoma prognosis (n = 124), highlighting the clinical potential of the R3CE platform (1). Furthermore, we have successfully employed cultured CTCs for drug screening for various cancers (breast cancer, cholangiocarcinoma, colon cancer, EMPD, gastric cancer, hepatoma, lung cancer, mucosal melanoma, pancreatic cancer, and urinary bladder cancer, n = 80), resulting in measurement of ex vivo response to chemotherapy and targeted drugs. For instance, R3CE-cultured CTCs have been used in predicting response to neoadjuvant chemotherapeutic drugs in breast cancer, as evidenced by an ROC curve analysis with an AUC of 0.963, 100% sensitivity, 87.5% specificity, P=0.02. Also in an exploratory analysis of immunotherapy efficacy, involving co-culture of R3CE-cultured CTCs (n = 6) and tumor tissue-derived organoids (n = 6) with immune cells such as CAR-T and autologous NK cells, has shown promising outcomes for selected cancers. Conclusions: The R3CE 3D culture platform represents a potentially transformative tool above and beyond CTC enumeration, significantly enhancing 1) the expansion of tumor cells ex vivo and, more importantly, informing phenotypic and genotypic characterization of CTCs, thereby holding promise for advancing cancer care and treatment efficacy. 1. Che et al., Lung Cancer, 2023; 178:198-205.

Molecular profiling of serial liquid biopsy specimens utilizing cell free DNA (cfDNA) and circulating tumor cells (CTCs) in TBCRC041: A phase II study of alisertib in endocrine resistant metastatic breast cancer (MBC).

1037 Background: TBCRC041, a randomized phase 2 trial of alisertib (A) ± fulvestrant (F) in women with HR+/HER2- MBC demonstrated promising clinical activity for alisertib (1). Interrogation of baseline (PreC1) and end of cycle 1 (EOC1) cfDNA and CTCs may identify biomarkers associated with response to A±F. Methods: Plasma cfDNA was sequenced using the Guardant INFINITY platform, which includes genomic and methylated tumor fraction (mTF) analysis. Pathogenic variants were determined using publicly available databases and Mayo Clinic annotation pipelines. CTCs were identified as nucleated, EpCAM+/ cytokeratin+/ CD45- cells and assessed for ER/HER2 staining (RareCyte, Seattle). PFS was defined as the time from randomization to progression or death. EOC1-PFS differs from PFS as time starts at C2D1. Stratified log-rank tests and conditional Cox modeling were used to assess whether PFS or EOC1-PFS differed by mutations in ESR1 or PIK3CA, pre-CTC ≥ 5, or mTF&gt;1%. Results: Of the 91 eligible pts, 84 progressed, and 73 were deceased. In the 86 pts with PreC1-cfDNA results, variants were identified in ESR1 (42; 48.8%), PIK3CA (36; 41.9%), AKT1 (7; 8.1%), PTEN(7; 8.1%), BRCA1 (4; 4.7%), and BRCA2 (7; 8.1%). Pts with a PIK3CAmut had significantly decreased PFS (HR 1.8; 95%CI: 1.1 -2.9, p=0.014) but not by ESR1mut status (p=0.583). PreC1 and EOC1-mTF were determined for 78 and 76 pts, respectively. PreC1-mTF was 0-1% in 21; 1.1-10.0% in 27; and 10.1-100% in 30. mTF levels remained between 0-1% in 17 pts fell to 0-1% in 11 pts, and was 0-1% in 5 pts without a preC1-mTF determination. PFS did not differ with respect to PreC1-mTF (p=0.210), but EOC1-PFS was worse in pts with mTF &gt;1% (HR 3.0; 95%CI: 1.6 -5.2, p&lt;0.001). PreC1 and EOC1-CTC were determined for 78 and 76 pts. 36 (46.2%) pts had a PreC1 CTC count ≥ 5. EOC1-CTC levels remained at (n=17) or increased to (n=1) ≥ 5 and was ≥ 5 in 2 pts without a preC1-CTC determination. EOC1-PFS was not significantly different for EOC1-CTC ≥ 5 (p=0.065), but was significantly decreased in pts with PreC1-CTC≥5 (HR=1.8; 95%CI: 1.1-3.0; p=0.018). Broader cfDNA NGS panel and CTC-derived ER/HER2 staining results will be presented at the meeting. Conclusions: Among patients receiving A±F, PFS varied based on the PIK3CAmutation status. cfDNA and CTC assessment PreC1 and EOC1 provided complementary information. Further validation in larger datasets is needed. 1. JAMA Oncol 2023;9:815. Clinical trial information: NCT02860000 .

Investigating surface proteins and antibody combinations for detecting circulating tumor cells of various sarcomas

Circulating tumor cells (CTCs) have gathered attention as a biomarker for carcinomas. However, CTCs in sarcomas have received little attention. In this work, we investigated cell surface proteins and antibody combinations for immunofluorescence detection of sarcoma CTCs. A microfluidic device that combines filtration and immunoaffinity using gangliosides 2 and cell surface vimentin (CSV) antibodies was employed to capture CTCs. For CTC detection, antibodies against cytokeratins 7 and 8 (CK), pan-cytokeratin (panCK), or a combination of panCK and CSV were used. Thirty-nine blood samples were collected from 21 patients of various sarcoma subtypes. In the independent samples study, samples were subjected to one of three antibody combination choices. Significant difference in CTC enumeration was found between CK and panCK + CSV, and between panCK and panCK + CSV. Upon stratification of CK+ samples, those of metastatic disease had a higher CTC number than those of localized disease. In the paired samples study involving cytokeratin-positive sarcoma subtypes, using panCK antibody detected more CTCs than CK. Similarly, for osteosarcoma, using panCK + CSV combination resulted in a higher CTC count than panCK. This study emphasized deliberate selection of cell surface proteins for sarcoma CTC detection and subtype stratification for studying cancers as heterogeneous as sarcomas.