Dynamic changes of different phenotypic and genetic circulating tumor cells as a biomarker for evaluating the prognosis of RCC

Liquid biopsy for renal cell carcinoma

Liquid biopsies offer a less invasive alternative to tissue biopsies for diagnosis, prognosis, and determining therapeutic potential in renal cell carcinoma (RCC). Unfortunately, clinical studies using liquid biopsy biomarkers in RCC are limited. Accordingly, we examine RCC biomarkers, derived from urine, plasma, serum and feces of potential impact and clinical outcome in these patients. A PRISMA checklist was used to identify valuable liquid biopsy biomarkers for diagnosis (plasma cfDNA, serum- or urine-derived circulating RNAs, exosomes and proteins), prognosis (plasma cfDNA, plasma- or serum-derived RNAs, and proteins), and therapeutic response (plasma- and serum-derived proteins). Although other analytes have been identified, their application for routine clinical use remains unclear. In general, panels appear more effective than single biomarkers. Important considerations included proof of reproducibility. Unfortunately, many of the examined studies were insufficiently large and lacked multi-center rigor. Cost-effectiveness was also not available. Accordingly, it is clear that more standardized protocols need to be developed before liquid biopsies can be successfully integrated into clinical practice in RCC.

Epithelial-mesenchymal plasticity in cancer: signaling pathways and therapeutic targets

Currently, cancer is still a leading cause of human death globally. Tumor deterioration comprises multiple events including metastasis, therapeutic resistance and immune evasion, all of which are tightly related to the phenotypic plasticity especially epithelial-mesenchymal plasticity (EMP). Tumor cells with EMP are manifest in three states as epithelial-mesenchymal transition (EMT), partial EMT, and mesenchymal-epithelial transition, which orchestrate the phenotypic switch and heterogeneity of tumor cells via transcriptional regulation and a series of signaling pathways, including transforming growth factor-β, Wnt/β-catenin, and Notch. However, due to the complicated nature of EMP, the diverse process of EMP is still not fully understood. In this review, we systematically conclude the biological background, regulating mechanisms of EMP as well as the role of EMP in therapy response. We also summarize a range of small molecule inhibitors, immune-related therapeutic approaches, and combination therapies that have been developed to target EMP for the outstanding role of EMP-driven tumor deterioration. Additionally, we explore the potential technique for EMP-based tumor mechanistic investigation and therapeutic research, which may burst vigorous prospects. Overall, we elucidate the multifaceted aspects of EMP in tumor progression and suggest a promising direction of cancer treatment based on targeting EMP.

Serum and Urine Metabolic Fingerprints Characterize Renal Cell Carcinoma for Classification, Early Diagnosis, and Prognosis

Renal cell carcinoma (RCC) is a substantial pathology of the urinary system with a growing prevalence rate. However, current clinical methods have limitations for managing RCC due to the heterogeneity manifestations of the disease. Metabolic analyses are regarded as a preferred noninvasive approach in clinics, which can substantially benefit the characterization of RCC. This study constructs a nanoparticle-enhanced laser desorption ionization mass spectrometry (NELDI MS) to analyze metabolic fingerprints of renal tumors (n = 456) and healthy controls (n = 200). The classification models yielded the areas under curves (AUC) of 0.938 (95% confidence interval (CI), 0.884-0.967) for distinguishing renal tumors from healthy controls, 0.850 for differentiating malignant from benign tumors (95% CI, 0.821-0.915), and 0.925-0.932 for classifying subtypes of RCC (95% CI, 0.821-0.915). For the early stage of RCC subtypes, the averaged diagnostic sensitivity of 90.5% and specificity of 91.3% in the test set is achieved. Metabolic biomarkers are identified as the potential indicator for subtype diagnosis (p < 0.05). To validate the prognostic performance, a predictive model for RCC participants and achieve the prediction of disease (p = 0.003) is constructed. The study provides a promising prospect for applying metabolic analytical tools for RCC characterization.

Unlocking Precision Medicine: Liquid Biopsy Advancements in Renal Cancer Detection and Monitoring

Renal cell carcinoma (RCC) remains a formidable diagnostic challenge, especially in the context of small renal masses. The quest for non-invasive screening tools and biomarkers has steered research towards liquid biopsy, focusing on microRNAs (miRNAs), exosomes, and circulating tumor cells (CTCs). MiRNAs, small non-coding RNAs, exhibit notable dysregulation in RCC, offering promising avenues for diagnosis and prognosis. Studies underscore their potential across various biofluids, including plasma, serum, and urine, for RCC detection and subtype characterization. Encouraging miRNA signatures show correlations with overall survival, indicative of their future relevance in RCC management. Exosomes, with their diverse molecular cargo, including miRNAs, emerge as enticing biomarkers, while CTCs, emanating from primary tumors into the bloodstream, provide valuable insights into cancer progression. Despite these advancements, clinical translation necessitates further validation and standardization, encompassing larger-scale studies and robust evidence generation. Currently lacking approved diagnostic assays for renal cancer, the potential future applications of liquid biopsy in follow-up care, treatment selection, and outcome prediction in RCC patients are profound. This review aims to discuss and highlight recent advancements in liquid biopsy for RCC, exploring their strengths and weaknesses in the comprehensive management of this disease.

Diagnostic liquid biopsy biomarkers in renal cell cancer

The clinical presentation of renal cell cancer (RCC) is shifting towards incidental and early detection, creating new challenges in RCC diagnosis. Overtreatment might be reduced with the development of new diagnostic biomarkers to distinguish benign from malignant small renal masses (SRMs). Differently from tissue biopsies, liquid biopsies are obtained from a patient's blood or urine and, therefore, are minimally invasive and suitable for longitudinal monitoring. The most promising types of liquid biopsy biomarkers for RCC diagnosis are circulating tumour cells, extracellular vesicles (EVs) and cell-free DNA. Circulating tumour cell assays have the highest specificity, with low processing time and costs. However, the biological characteristics and low sensitivity limit the use of these markers in SRM diagnostics. Cell-free DNA might complement the diagnosis of high-volume RCC, but the potential for clinical application in SRMs is limited. EVs have the highest biological abundance and the highest sensitivity in identifying low-volume disease; moreover, the molecular characteristics of these markers make EVs suitable for multiple analytical applications. Thus, currently, EV assays have the greatest potential for diagnostic application in RCC (including identification of SRMs). All these liquid biomarkers have potential in clinical practice, pending validation studies. Biomarker implementation will be needed to also improve characterization of RCC subtypes. Last, diagnostic biomarkers might be extended to prognostic or predictive applications.

Chasing the Role of miRNAs in RCC: From Free-Circulating to Extracellular-Vesicle-Derived Biomarkers

Renal cell carcinoma (RCC) is the second most common cancer of the urinary system. The current therapeutic strategies are based on partial or total nephrectomy and/or targeted therapies based on immune checkpoint inhibitors to which patients are often refractory. Preventive and screening strategies do not exist and the few available biomarkers for RCC are characterized by a lack of sensitivity, outlining the need for novel noninvasive and sensitive biomarkers for early diagnosis and better disease monitoring. Blood liquid biopsy (LB) is a non- or minimally invasive procedure for a more representative view of tumor heterogeneity than a tissue biopsy, potentially allowing the real-time monitoring of cancer evolution. Growing interest is focused on the extracellular vesicles (EVs) secreted by either healthy or tumoral cells and recovered in a variety of biological matrices, blood included. EVs are involved in cell-to-cell crosstalk transferring their mRNAs, microRNAs (miRNAs), and protein content. In particular, transferred miRNAs may regulate tumorigenesis and proliferation also impacting resistance to apoptosis, thus representing potential useful biomarkers. Here, we present the latest efforts in the identification of circulating miRNAs in blood samples, focusing on the potential use of EV-derived miRNAs as RCC diagnostic and prognostic markers.

Clinical Validation of a Size-Based Microfluidic Device for Circulating Tumor Cell Isolation and Analysis in Renal Cell Carcinoma

Renal cell carcinoma (RCC) presents as metastatic disease in one third of cases. Research on circulating tumor cells (CTCs) and liquid biopsies is improving the understanding of RCC biology and metastases formation. However, a standardized, sensitive, specific, and cost-effective CTC detection technique is lacking. The use of platforms solely relying on epithelial markers is inappropriate in RCC due to the frequent epithelial-mesenchymal transition that CTCs undergo. This study aimed to test and clinically validate RUBYchip™, a microfluidic label-free CTC detection platform, in RCC patients. The average CTC capture efficiency of the device was 74.9% in spiking experiments using three different RCC cell lines. Clinical validation was performed in a cohort of 18 patients, eight non-metastatic (M0), five metastatic treatment-naïve (M1TN), and five metastatic progressing-under-treatment (M1TP). An average CTC detection rate of 77.8% was found and the average (range) total CTC count was 6.4 (0-27), 101.8 (0-255), and 3.2 (0-10), and the average mesenchymal CTC count (both single and clustered cells) was zero, 97.6 (0-255), and 0.2 (0-1) for M0, M1TN, and M1TP, respectively. CTC clusters were detected in 25% and 60% of M0 and M1TN patients, respectively. These results show that RUBYchip™ is an effective CTC detection platform in RCC.

Liquid biopsy at the frontier in renal cell carcinoma: recent analysis of techniques and clinical application

Renal cell carcinoma (RCC) is a major pathological type of kidney cancer and is one of the most common malignancies worldwide. The unremarkable symptoms of early stages, proneness to postoperative metastasis or recurrence, and low sensitivity to radiotherapy and chemotherapy pose a challenge for the diagnosis and treatment of RCC. Liquid biopsy is an emerging test that measures patient biomarkers, including circulating tumor cells, cell-free DNA/cell-free tumor DNA, cell-free RNA, exosomes, and tumor-derived metabolites and proteins. Owing to its non-invasiveness, liquid biopsy enables continuous and real-time collection of patient information for diagnosis, prognostic assessment, treatment monitoring, and response evaluation. Therefore, the selection of appropriate biomarkers for liquid biopsy is crucial for identifying high-risk patients, developing personalized therapeutic plans, and practicing precision medicine. In recent years, owing to the rapid development and iteration of extraction and analysis technologies, liquid biopsy has emerged as a low cost, high efficiency, and high accuracy clinical detection method. Here, we comprehensively review liquid biopsy components and their clinical applications over the past 5 years. Additionally, we discuss its limitations and predict its future prospects.

Correlation between mesenchymal circulating tumor cells and prognosis of urologic malignancies: a single-center retrospective analysis

OBJECTIVE

To evaluate the correlation of circulating tumor cells (CTCs) and mesenchymal CTCs (M-CTCs) with clinical characteristics and survival of patients with urologic malignancies.

METHODS

The clinical data of 52 patients with urinary system malignancy in Henan Provincial People's Hospital were retrospectively analyzed (40 cases of renal malignant tumor, 7 cases of prostate cancer, 3 cases of urothelial carcinoma, 1 case of testis cancer, and 1 case of penile cancer). The CTC counts of patients were collected, and the expression of epithelial-mesenchymal transition phenotype in CTCs was evaluated. The relationship of different types of CTC counts with tumor stage, location, size, metastasis, and differentiation, as well as their effect on progression-free survival (PFS) were analyzed.

RESULTS

We detected CTCs in all patients with urinary system malignancy. The positive rates of epithelial CTCs (E-CTC), M-CTCs, and epithelial/mesenchymal CTCs (E/M-CTCs) were 34.62%, 26.92% and 94.23%, respectively. Total CTCs (T-CTCs), M-CTCs and E/M-CTCs were correlated with distant metastasis (Z=-3.052, -3.574, -2.898; all P<0.005). M-CTC count was correlated with lymph node metastasis (Z=-3.125; P=0.002). Furthermore, the presence of T-CTCs ≥13.5, M-CTC ≥0.5 or E/M-CTCs ≥9.5 per 5 ml of blood was correlated with worse PFS in patients with urinary system malignancy.

CONCLUSIONS

M-CTC and E/M-CTC counts correlate with the prognosis of patients with urinary system malignancy. Higher M-CTC and E/M-CTC counts are risk factors for worse prognosis in patients with urinary system malignancies. All in all, M-CTC count is a valuable tumor biomarker for urologic malignancies.

Circulating Tumor Cells as Biomarkers for Renal Cell Carcinoma: Ready for Prime Time?

Renal cell carcinoma (RCC) is among the 15 most common cancers worldwide, with rising incidence. In most cases, this is a silent disease until it reaches advance stages, demanding new effective biomarkers in all domains, from detection to post-therapy monitoring. Circulating tumor cells (CTC) have the potential to provide minimally invasive information to guide assessment of the disease's aggressiveness and therapeutic strategy, representing a special pool of neoplastic cells which bear metastatic potential. In some tumor models, CTCs' enumeration has been associated with prognosis, but there is a largely unexplored potential for clinical applicability encompassing screening, diagnosis, early detection of metastases, prognosis, response to therapy and monitoring. Nonetheless, lack of standardization and high cost hinder the translation into clinical practice. Thus, new methods for collection and analysis (genomic, proteomic, transcriptomic, epigenomic and metabolomic) are needed to ascertain the role of CTC as a RCC biomarker. Herein, we provide a critical overview of the most recently published data on the role and clinical potential of CTCs in RCC, addressing their biology and the molecular characterization of this remarkable set of tumor cells. Furthermore, we highlight the existing and emerging techniques for CTC enrichment and detection, exploring clinical applications in RCC. Notwithstanding the notable progress in recent years, the use of CTCs in a routine clinical scenario of RCC patients requires further research and technological development, enabling multimodal analysis to take advantage of the wealth of information they provide.

Emerging roles of cystathionine β-synthase in various forms of cancer

The expression of the reverse transsulfuration enzyme cystathionine-β-synthase (CBS) is markedly increased in many forms of cancer, including colorectal, ovarian, lung, breast and kidney, while in other cancers (liver cancer and glioma) it becomes downregulated. According to the clinical database data in high-CBS-expressor cancers (e.g. colon or ovarian cancer), high CBS expression typically predicts lower survival, while in the low-CBS-expressor cancers (e.g. liver cancer), low CBS expression is associated with lower survival. In the high-CBS expressing tumor cells, CBS, and its product hydrogen sulfide (H₂S) serves as a bioenergetic, proliferative, cytoprotective and stemness factor; it also supports angiogenesis and epithelial-to-mesenchymal transition in the cancer microenvironment. The current article reviews the various tumor-cell-supporting roles of the CBS/H₂S axis in high-CBS expressor cancers and overviews the anticancer effects of CBS silencing and pharmacological CBS inhibition in various cancer models in vitro and in vivo; it also outlines potential approaches for biomarker identification, to support future targeted cancer therapies based on pharmacological CBS inhibition.

Prognostic value of circulating tumor cells and immune-inflammatory cells in patients with renal cell carcinoma

PURPOSE

The relationships among circulating tumor cells (CTCs), inflammatory cells, and platelets in patients with renal cell carcinoma (RCC) are not transparent. We evaluated the correlations among CTCs, blood inflammatory cells, and platelets in patients with RCC and their prognostic value for metastasis-free survival.

METHODS

CTC and typical tumor cell chip data were collected and analyzed by the GEO database. The baseline data, survival data, CTCs data, and blood test results were statistically analyzed.

RESULTS

Bioinformatics analysis showed that the function of the differentially expressed genes between CTCs and normal tumor cells mainly involved platelets and immune inflammation. A total of 82 patients whose follow-up time was 3 to 68 months were included in the analysis. Clinical data of the patients confirmed that there is a correlation between platelets and mesenchymal CTCs. Simultaneously, there was a correlation between immune inflammatory cells and platelets. The univariate Cox proportional hazards model indicated that staging, mesenchymal CTCs, and the monocyte-to-neutrophil ratio (MNR) had prognostic value. The multivariate Cox proportional hazards model indicated that staging and the MNR had prognostic value and high accuracy.

CONCLUSIONS

Bioinformatics analysis showed that CTCs were related to platelets and immune-inflammatory cells. Furthermore, the clinical data confirmed that platelets were correlated with mesenchymal CTCs and immune-inflammatory cells in the blood. By using mesenchymal CTCs, the MNR, or staging respectively, it is possible to predict the risk of postoperative metastasis in RCC patients. As a compound prognostic factor, staging, and the MNR can provide more convenient and accurate condition monitoring.

Determining programmed cell death ligand 1 expression in circulating tumor cells of patients with clear cell renal cell carcinoma and its correlation with response to programmed cell death protein 1 inhibitors

OBJECTIVE

There is a great interest in determining whether the expression of the programmed cell death ligand 1 is correlated with the efficacy of immune checkpoint inhibitors in patients with clear cell renal cell carcinoma; however, primary tumor biopsies can only provide limited information. Therefore, we explored the expression of programmed cell death ligand 1 on circulating tumor cells, which is a potential predictor of therapeutic response.

METHODS

Circulating tumor cells were isolated from 20 clear cell renal cell carcinoma patients based on cell surface markers targeting clear cell renal cell carcinoma using IsoFlux device, followed by identification according to cell morphology and immunofluorescence studies. Programmed cell death ligand 1 expression status and clinical correlations were also analyzed.

RESULTS

Before treatment with programmed cell death protein 1 inhibitors, circulating tumor cells were detected in all patients, ranging from 1 to 22 (median 7), with 75% (15/20) of the patients having programmed cell death ligand 1 + circulating tumor cells. Circulating tumor cell programmed cell death ligand 1 expression did not correlate with the immunohistochemical staining of programmed cell death ligand 1 in primary tumors. During treatment with programmed cell death protein 1 inhibitors, the disease control rate was much higher in the patients harboring programmed cell death ligand 1 + circulating tumor cells (73%, 11/15) than others (20%, 1/5). We also found that changes in total circulating tumor cell numbers and programmed cell death ligand 1 + circulating tumor cell counts correlated well with the disease outcome.

CONCLUSION

We showed that the presence of programmed cell death ligand 1 + circulating tumor cells before programmed cell death protein 1 inhibition treatment could be a prognosis predictive factor and that the dynamic changes in circulating tumor cell numbers may be used to monitor the therapeutic response. Our study confirms the possibility of programmed cell death ligand 1 + circulating tumor cell detection in clear cell renal cell carcinoma patients' blood samples, which can potentially be used as an individualized immunotherapy molecular biomarker for real-time exploration.

The clinical significance of circulating tumor cells and T lymphocyte subtypes in pancreatic cancer patients

Circulating tumor cells (CTCs) are sensitive and reliable biomarkers for tracing relapsed and metastatic cancer. Here, we explore the clinical significance of CTCs and T lymphocyte subtypes in patients with pancreatic cancer. A total of 106 patients with the pancreatic cancer were enrolled in this study. The enrichment and identification of CTCs were achieved before treatment by a PatrolCTC detection technique. Flow cytometry (FACS) was used to characterize CD4, CD8, natural killer (NK) cells, and Tregulatory (Treg) lymphocyte subtypes. Interleukin-2 (IL-2), Interleukin-4 (IL-4), Interleukin-17A (IL-17A), Interleukin-10 (IL-10), and Interferon γ (IFN-γ) were measured by meso-scale discovery (MSD) assay. Among these patients, 44 (41.5%) patients with pancreatic ductal adenocarcinoma (PDAC) were female and 62 (58.5%) cases were male. Case numbers with II-IV tumor-node-metastasis (TNM) stages were 32 (30.2%), 50 (47.2%), and 24 (22.6%), respectively. The positive rate of CTCs before surgery was 37.5% (12/32), 88.0% (44/50) and 100% (24/24) in stage II, III, and IV patients, respectively. Total CTCs, mixed CTCs, and mesenchymal CTCs (MCTCs) were strongly relevant to shorter progression-free survival (PFS) of the patients. In addition, total CTCs (≥6) and positive MCTCs were also significantly correlated with recurrence and metastasis. The patients with high CTCs also had low levels of CD4, CD4/CD8 ratio, NK cells, IL-2, and IFNγ. In contrast, Treg cells had significant elevation in PDAC patients. These results indicated that CTCs number in PDAC patients was an independent indicator for worse PFS. High CTCs also had strong correlation with weak cellular immunity functions.

Clinical Significance of Circulating Tumor Cells (CTCs) and Survivin on Predicting Prognosis in Thyroid Cancer Patients

Background. Clinical significance of circulating tumor cell (CTC) count, mesenchymal CTCs (MCTCs), and survivin in patients with thyroid cancer remains unclear. We evaluated the relationship between the expression of different CTC subtypes or survivin and the prognosis in patients with thyroid cancer. Patients and Methods. This study enrolled 164 patients with thyroid cancer who were diagnosed from January 2013 to September 2020 in our hospital. Among these patients, there were 73 cases with papillary thyroid cancer (PTC), 60 cases with follicular thyroid cancer (FTC), 12 medullary thyroid cancers (MTC), 10 poorly differentiated thyroid cancers (PDTC), 9 anaplastic thyroid cancers, and 10 control patients with nonmalignant thyroid nodules based on their histopathological characteristics. Only 5 milliliters (mL) of peripheral blood from the patients with thyroid cancer and control was used to detect the CTC cell number via CanPatrol capture technique before treatments. We also isolated mononuclear cells (MNC) from the peripheral blood and performed quantity reverse transcriptase polymerase chain reaction (qPCR) for survivin gene expression among these patients. Results. The overall positive rates of CTC at diagnosis were 56.1%. The relapse and metastasis rates in PTC and FTC patients with more than 6 CTCs and positive MCTCs were significantly higher than those in the patients with 6 or less than 6 CTCs and MCTCs. It was also found that these patients with >6 CTCs and MCTCs had shorter progression-free survival (PFS). Additionally, the survivin level of the patients with thyroid cancer was strongly relative to differentiation grades of thyroid cancers. Conclusions. The detection of more than six of total CTCs and positive MCTCs in the patients with differentiated thyroid cancer is an excellent biomarker for predicting the prognosis of patients. Survivin also is a good biomarker for thyroid cancer differentiation.

Potential Use of CTCs as Biomarkers in Renal Cancer Patients

We demonstrated that the CellCollector is an appropriate tool for detecting CTCs in RCC patients. We examined EpCAM and MUC1 expression levels in RCC tissues and cell lines and analyzed the detection rate of CTCs in blood samples ex vivo using an anti-EpCAM antibody-covered straight or spiraled CellCollector. Eight matched samples were examined for affinity to the anti-EpCAM vs. anti-EpCAM/anti-MUC1 antibody-covered wire. The use of this combination of antibodies allowed us to classify patients with lung metastasis. Finally, four patients were analyzed in vivo. In conclusion, both straight (ex vivo, in vivo) and spiraled (ex vivo) wires detected CTCs.

Perioperative Circulating Tumor Cells (CTCs), MCTCs, and CTC-White Blood Cells Detected by a Size-Based Platform Predict Prognosis in Renal Cell Carcinoma

To explore the clinical significance of the perioperative counts of circulating tumor cells (CTCs), mesenchymal CTCs (MCTCs), and CTC- white blood cells (WBCs) in renal cell carcinoma patients. A total of 131 patients with renal cancer who underwent operation excision from our hospital were enrolled. In addition, 20 patients with benign renal diseases were recruited as a control. Blood samples were collected from the 131 patients, before operation and 3 months after surgery. Samples were also obtained simultaneously from the control group. CanPatrol CTC detection technique was used to enrich and identify CTCs, MCTCs, and CTC-WBCs. All enrolled patients were T1-3N0M0. From these, 52 patients with renal cancer underwent radical resection, while other 79 patients underwent nephron-sparing surgery. The positive rate of CTC, MCTC, and CTC-WBC before surgery were 95.4% (125/131), 61.1% (80/131), and 11.5% (15/131), respectively. Preoperative total CTCs, MCTCs, or CTC-WBCs were poorly correlated with patients' parameters. Preoperative CTC, MCTC, or CTC-WBC showed no association with progression-free survival (PFS). In contrast, postoperative total CTCs (≥6), positive MCTCs, and positive CTC-WBCs significantly correlated with recurrence and metastasis. These results remained independent indicators for worse PFS. In addition, the increased CTC and MCTC count after surgery also correlated with unfavorable PFS. The detection of six or more total CTCs, MCTC, or CTC-WBCs in peripheral blood after surgery might help to identify a subset of patients that have higher recurrent risk than the overall population of patients with at different stages of renal cancer.

The prognostic value of circulating tumour cells (CTCs) and CTC white blood cell clusters in patients with renal cell carcinoma

Purpose

Circulating tumour cell (CTC) and CTC-white blood cell (CTC-WBC) clusters are related to the prognosis of tumour patients. However, the relationship between CTC-WBC clusters and prognosis in renal cell carcinoma (RCC) patients is not clear. We evaluated the prognostic value of CTC-WBC clusters using metastasis-free survival (MFS) and overall survival (OS) in patients with RCC.

Materials and methods

The baseline, survival, and CTC data of patients with RCC were statistically analysed by R.

Results

The Cox risk proportional regression model suggests that the total CTCs, pathology type, and CTC-WBC clusters can be used as prognostic indicators for the MFS of RCC patients. Total CTCs and solid tumour diameter can be used as prognostic indicators for the OS of RCC patients. Using Kaplan–Meier survival analysis, we found that patients with total CTCs, pathology, and CTC-WBC clusters greater than the cut-off value had a worse MFS, and patients with total CTCs greater than the cut-off value had a worse OS.

Conclusion

The analysis of the clinical sample data in patients with RCC shows that CTC-WBC clusters play an important role in monitoring the prognosis of RCC. Among them, total CTCs, pathology, and CTC-WBC clusters were combined as prognostic factors for the MFS of RCC patients. Total CTCs and solid tumour diameter can be combined as prognostic factors for the OS of RCC patients. These prognostic factors provide more convenient and accurate condition monitoring for renal cancer patients and can be used to actively improve the prognosis of patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08463-7.

Programmed Cell Death Ligand 1 Expression in Circulating Tumor Cells as a Predictor of Treatment Response in Patients with Urothelial Carcinoma

Simple Summary

Programmed cell death ligand 1 (PD-L1) inhibitors are commonly used in treating advanced-stage urothelial carcinoma. Contrary to evaluating PD-L1 expression in tumor biopsy samples, this study assessed whether PD-L1 expression in circulating tumor cells (CTCs) can be a predictor of treatment response to PD-L1 inhibitors. The current study proved that there was no statistically significant correlation between the presence of PD-L1-positive CTCs and PD-L1 expression in tumor tissues. Moreover, PD-L1-positive CTCs at baseline could be used as a biomarker to identify patients suitable for PD-L1 blockade therapy. Dynamic changes in PD-L1-positive CTCs during the course of treatment are predictive factors of immunotherapy response and prognostic factors of disease control.

Abstract

Programmed cell death ligand 1 (PD-L1) inhibitors are commonly used in treating advanced-stage urothelial carcinoma (UC). Therefore, this study evaluated the relationship between PD-L1 expression in circulating tumor cells (CTCs) and treatment response to PD-L1 inhibitors using blood samples collected from patients with UC (n = 23). Subsequently, PD-L1 expression and its clinical correlation were analyzed. All patients had CTCs before PD-L1 inhibitory treatment, of which 15 had PD-L1-positive CTCs. However, PD-L1-positive expression in CTCs was not correlated with PD-L1 expression in tumor biopsy samples. Patients with PD-L1-positive CTCs had better disease control (DC) rates than those without PD-L1-positive CTCs. Moreover, changes in the proportion of PD-L1-positive CTCs were associated with disease outcomes. Furthermore, the PD-L1-positive CTC count in 9 of 11 patients who achieved DC had significantly decreased (p = 0.01). In four patients with progressive disease, this was higher or did not change. PD-L1-positive CTCs at baseline could be used as a biomarker to identify patients suitable for PD-L1 blockade therapy. Dynamic changes in PD-L1-positive CTCs during the course of treatment are predictive factors of immunotherapy response and prognostic factors of disease control. Hence, PD-L1-positive CTCs could be employed as a real-time molecular biomarker for individualized immunotherapy.

Clinical significance of circulating tumour cells and Ki-67 in renal cell carcinoma

Background

Renal cell carcinoma (RCC) is a common malignant tumour of the genitourinary system. We aimed to analyse the potential value of metastasis-related biomarkers, circulating tumour cells (CTCs) and the proliferative marker Ki-67 in the diagnosis of RCC.

Methods

Data from 24 laparoscopic radical nephrectomies (RNs) and 17 laparoscopic partial nephrectomies (PNs) were collected in 2018. The numbers and positive rates of CTCs and circulating tumour microemboli (CTM) in the peripheral blood were obtained at three different time points: just before surgery, immediately after surgery and 1 week after surgery. Ki-67 protein expression was evaluated in the RCC tissue by immunohistochemistry.

Results

Except for the statistically significant association between the preoperative CTC counts and tumour size, no association between the number and positive rate of perioperative CTCs and clinicopathological features was found. The CTC counts gradually decreased during the perioperative period, and at 1 week after surgery, they were significantly lower than those before surgery. High Ki-67 expression was significantly positively correlated with preoperative CTC counts. In addition, Ki-67 expression was higher in the high CTC group (≥ 5 CTCs).

Conclusion

Our results suggest that surgical nephrectomy is associated with a decrease in CTC counts in RCC patients. CTCs can act as a potential biomarker for the diagnosis and prognosis of RCC. A careful and sufficient long-term follow-up is needed for patients with high preoperative CTC counts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02268-5.

Biomarkers for Renal Cell Carcinoma Recurrence: State of the Art

PURPOSE OF REVIEW

We aim to summarize the current state of art about the possible use of biomarkers for predicting renal cell carcinoma (RCC) recurrence after curative treatment. In addition, we aim to provide a snapshot about the clinical implication of biomarkers use for follow-up planification.

RECENT FINDINGS

A wide variety of biomarkers have been proposed. RCC biomarkers have been individuated in tumoral tissue, blood, and urine. A variety of molecules, including proteins, DNA, and RNA, warrant a good accuracy for RCC recurrence and progression prediction. Their use in prediction models might warrant a better patients' risk stratification. Future prognostic models will probably include a combination of classical features (tumor grade, stage, etc.) and novel biomarkers. Such models might allow a more accurate treatment and follow-up planification.

Circulating tumor cell detection methods in renal cell carcinoma: A systematic review

Circulating tumor cells (CTCs) have a potential role as the missing renal cell carcinoma (RCC) biomarker. However, the available evidence is limited, and detection methods lack standardization, hindering clinical use. We performed a systematic review on CTC enrichment and detection methods, and its role as a biomarker in RCC. Full-text screening identified 54 studies. Reviewed studies showed wide heterogeneity, low evidence level, and high risk of bias. Various CTC detection platforms and molecular markers have been used, but none has proven to be superior. CTC detection and CTC count seem to correlate with staging and survival outcomes, although evidence is inconsistent. CTC research is still in an exploratory phase, particularly in RCC. Further studies are still necessary to achieve a standardization of techniques, molecular markers, CTC definitions, and terminology. This is essential to ascertain the role of CTCs as a biomarker and guide future liquid biopsy research in RCC.

Steps in metastasis: an updated review

Metastasis is the most complex and deadly event. Tumor-stromal interface is a place where invasion of tumor cells in the form of single-cell or collective migration occurs, with the latter being less common but more efficient. Initiation of metastasis relies on the tumor cell cross-talking with stromal cells and taking an epithelial-mesenchymal transition (EMT) in single cells, and a hybrid EMT in collective migratory cells. Stromal cross-talking along with an abnormal leaky vasculature facilitate intravasation of tumor cells, here the cells are called circulating tumor cells (CTCs). Tumor cells isolated from the primary tumor exploit several mechanisms to maintain their survival including rewiring metabolic demands to use sources available within the new environments, avoiding anoikis cell death when cells are detached from extracellular matrix (ECM), adopting flow mechanic by acquiring platelet shielding and immunosuppression by negating the activity of suppressor immune cells, such as natural killer (NK) cells. CTCs will adhere to the interstituim of the secondary organ/s, within which the newly arrived disseminative tumor cells (DTCs) undergo either dormancy or proliferation. Metastatic outgrowth is under the influence of several factors, such as the activity of macrophages, impaired autophagy and secondary site inflammatory events. Metastasis can be targeted by multiple ways, such as repressing the promoters of pre-metastatic niche (PMN) formation, suppressing environmental contributors, such as hypoxia, oxidative and metabolic stressors, and targeting signaling and cell types that take major contribution to the whole process. These strategies can be used in adjuvant with other therapeutics, such as immunotherapy.

Postoperative circulating tumor cells: An early predictor of extrahepatic metastases in patients with hepatocellular carcinoma undergoing curative surgical resection

BACKGROUND

Postoperative extrahepatic metastases (EHM) contribute to a grim outcome in patients with hepatocellular carcinoma (HCC) who are undergoing curative surgical resection. The current study investigated the clinical value of circulating tumor cells (CTCs) in predicting EHM after curative surgery.

METHODS

A total of 197 patients with HCC who were undergoing curative surgical resection were assigned to a retrospective training cohort (144 patients) or a prospective validation cohort (53 patients). The CELLSEARCH system was used for the detection of CTCs prior to surgical resection and 1 month thereafter. The cutoff value of CTCs was estimated using receiver operating characteristic analysis. Bonferroni correction was applied for multiple testing in a Cox proportional hazards regression model.

RESULTS

In the training cohort, EHM was found to be associated with a higher postoperative CTC burden compared with no EHM (mean: 4.33 vs 0.52; P < .001). Receiver operating characteristic analysis demonstrated a postoperative CTC count ≥3 as the optimal cutoff value for the prediction of EHM. Patients with a postoperative CTC count ≥3 experienced a higher EHM risk (56.3% vs 5.5%) and a shorter median overall survival (31.25 months vs not reached) (all P < .001). The prognostic significance of a postoperative CTC count ≥3 also applied to patient subgroups with a low EHM risk, such as those with an α-fetoprotein level ≤400 ng/mL, absence of vascular invasion, well differentiation, and early tumor stage, and its predictive value was retained in patients with a continuous normal α-fetoprotein level during postoperative follow-up (all P < .05). The results were confirmed in the validation cohort.

CONCLUSIONS

A postoperative CTC count ≥3 appears to be a surrogate marker for the prediction of EHM after curative surgical resection of HCC. More careful surveillance should be recommended to patients with a high CTC load to ensure the greater possibility of early interventions for postoperative EHM.

Rapid Label-Free Isolation of Circulating Tumor Cells from Patients' Peripheral Blood Using Electrically Charged Fe3O4 Nanoparticles

Isolation of circulating tumor cells (CTCs) in peripheral blood from cancer patients bears critical importance for evaluation of therapeutic efficacy. The current CTC isolation strategies are majorly relying on either protein biomarkers or dimensional features of CTCs. In this study, we present a new methodology for CTC detection and isolation based on the surface charge of cancer cells, a bioelectrical manifestation of the "Warburg effect." Negative surface charge is a direct consequence of glycolysis of cancer cells, which can be utilized as an effective biophysical marker for CTC detection and isolation. Upon cancer cells-nanoparticle interaction via optimum incubation, serum protein-coated electrically charged nanoparticles can trap different cancer cells independent of their epithelial protein expression. In fetal bovine serum , the poly(ethyleneimine)-functionalized Fe₃O₄ nanoparticles, surface-decorated with protein corona, are able to efficiently capture CTCs from blood samples of colorectal cancer patients.  2-8 CTCs has been isolated from 1 mL of blood and identified by immunostaining fluorescence in situ hybridization and immunofluorescence staining in all 25 colorectal cancer patients at varied stages, while only 0-1 CTC was detected from blood samples of 10 healthy donors. Diverse CTC subpopulations of heteroploids and biomarker expression can also be detected in this strategy. The label-free, charge-based CTC method shows promise in cancer diagnosis and prognosis paving a new path for liquid biopsy.

Perioperative Detection of Circulating Tumor Cells in Radical or Partial Nephrectomy for Renal Cell Carcinoma

BACKGROUND

The current study was conducted to clarify the frequency of systemic circulating tumor cells (CTCs) appearing after surgery for renal cell carcinoma and to evaluate the differences in postoperative CTCs between different surgical procedures.

METHODS

This prospective, cohort study included 60 consecutive patients who underwent laparoscopic radical nephrectomy (RN) (n = 22), laparoscopic partial nephrectomy (PN) (n = 19), open RN (n = 8), or open PN (n = 11). In this study CTCs were measured by the FISHMAN-R system, and CTCs drawn from a peripheral artery were collected just before and immediately after surgery. The number of pre- and postoperative CTCs and the perioperative changes in CTCs were measured for each surgical method.

RESULTS

Six patients were excluded from the current analyses. Preoperative CTCs did not differ significantly by surgical approach (laparoscopic RN: 3.4 ± 4.2; laparoscopic PN: 3.4 ± 4.1; open RN: 7.7 ± 6.8; open PN: 6.0 ± 7.6; P = 0.19). Open RN resulted in a significantly greater number of postoperative CTCs (laparoscopic RN: 4.8 ± 3.7; laparoscopic PN: 7.9 ± 9.1; open RN: 22.5 ± 26.3; open PN: 6.4 ± 6.3; P < 0.001) and perioperative changes in CTCs (laparoscopic RN: 1.3 ± 5.3; laparoscopic PN: 4.5 ± 9.6; open RN: 14.7 ± 25.0; open PN: 0.4 ± 6.3; P < 0.001). No significant differences in these were observed among the three groups except in the open RN group. In the multivariate analysis, the surgical approach was significantly correlated with the number of postoperative CTCs (P = 0.016) and the perioperative change in CTCs (P = 0.01).

CONCLUSIONS

This proof-of-concept study indicated that after surgery, more cancer cells can be expelled into the bloodstream, especially after open RN. Sufficient and careful follow-up assessment for the emergence of distant metastases is needed for patients undergoing open RN.