Usefulness of transcription-reverse transcription concerted reaction method for detecting circulating tumor cells in patients with colorectal cancer

CTCs and liquid biopsies in patients with colorectal cancer

Liquid biopsy, which includes both circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) has become a valuable tool for cancer diagnosis and monitoring. It offers a less invasive approach than traditional tissue biopsy and recent technological advancements have enabled their use in comprehensive analysis of tumor molecular characteristics. By capturing the dynamic nature of tumors through repeated sampling, liquid biopsy addresses the limitations of tissue biopsy and provides insights into tumor heterogeneity over time. It is being extensively studied in patients with advanced colorectal cancer because it can aid in diagnosis, predict disease course, and guide treatment selection. Furthermore, as personalized medicine becomes more common, identifying genetic changes that cause cancer cells to become resistant to treatment is crucial. This chapter explores the emerging field of liquid biopsy, with a particular focus on the role and potential of circulating tumor cells (CTCs) in the context of colorectal cancer.

Phenotypic diversity of CTCs and tdEVs in liquid biopsies of tumour-draining veins is linked to poor prognosis in colorectal cancer

BACKGROUND

Circulating tumour cells (CTCs) and tumour-derived extracellular vesicles (tdEVs) have great potential for monitoring therapy response and early detection of tumour relapse, facilitating personalized adjuvant therapeutic strategies. However, their low abundance in peripheral blood limits their informative value. In this study, we explored the presence of CTCs and tdEVs collected intraoperatively from a tumour-draining vein (DV) and via a central venous catheter (CVC) prior to tumour resection.

METHODS

CellSearch analyses of 395 blood samples from 306 patients with gastrointestinal tumours and 93 blood samples from healthy donors were used to establish and validate gates for the automated detection of CTCs and tdEVs with ACCEPT software and R scripts. The selected gate settings were applied to 227 samples of 142 patients with colorectal cancer (CRC) from two independent collectives. Phenotypic features were obtained via numeric analysis of their fluorescence signals (e.g. size, shape, and intensity) and were used for calculating diversity using Shannon index (SI) of clusters generated via the k-means algorithm after Uniform Manifold Approximation and Projection (UMAP) pre-processing, and standard deviation (SD).

RESULTS

CTCs and tdEVs were more abundant in the DV samples compared to CVC samples (p < 0.05). tdEVs were detected in higher numbers than CTCs in both compartments. Importantly, tdEVs in CVCs were associated with tumor spread, whereas CTCs in DVs were linked to tumor size. In both compartments, the prognostic value of tdEVs for overall survival (OS) surpassed that of CTCs, as demonstrated by univariate, multivariate, and Kaplan-Meier analyses. CTCs and tdEVs in DVs were phenotypically distinct, being larger, more eccentric, and displaying stronger cytokeratin intensities (p < 0.05) compared to those in CVC samples. Furthermore, increased diversity in CTC and tdEV phenotypes was significantly associated with shorter survival, validating the prognostic relevance of the SD-diversity metric.

CONCLUSION

Our study demonstrates that DV sampling significantly enhances the detection of prognostically relevant CTCs and tdEVs in CRC patients, underscoring the superior prognostic significance of tdEVs compared to CTCs. Importantly, the combined phenotypic diversity of both markers emerges as a more powerful biomarker than their enumeration alone. These findings suggest that comprehensive, automated analysis of CTCs and tdEVs in DVs may open new avenues for tailoring individualized therapies in CRC patients.

Using the polymeric circulating tumor cell chip to capture circulating tumor cells in blood samples of patients with colorectal cancer

The current study clarified the accuracy of a circulating tumor cell (CTC) detection system to diagnose colorectal cancer using blood samples. The system uses the 'polymeric CTC-chip,' (CTC-chip), which is a microfluidic device that is used for CTC isolation. CTCs are considered sensitive diagnostic biomarkers. However, their concentration in the peripheral blood is low and requires highly sensitive and specific capturing techniques. The capture efficiency of the polymeric CTC-chip was first assessed using cell suspensions of the colorectal cancer cell line HCT-116, which was reported as 90.9% in a phosphate-buffered saline suspension and 65.0% in the blood. The CTC-chip was then used to detect CTCs in blood samples obtained from 13 patients with stage II-IV colorectal cancer. On average, the CTCs/ml was lower in patients with stages II and III colorectal cancer (3.3±2.3) than in those with stage IV (7.0±6.2). In patients with stages II-IV, 92% had ≥1 CTC per ml, which was significantly higher than the positive rate (15%) detected using the carbohydrate antigen 19-9 test (CA19-9). Furthermore, CTCs were detected in all patients with stage II and III colorectal cancer, including a number of patients with negative results for the carcinoembryonic antigen (CEA) and CA19-9 tests. With the polymeric CTC-chip detection system, CTCs can be effective cancer markers, particularly for patients with stage II and III colorectal cancer who often exhibit negative conventional serum marker test results. The CTC-chip system may also facilitate the detection of cancer progression based on CTC concentration.

Common molecular markers between circulating tumor cells and blood exosomes in colorectal cancer: a systematic and analytical review

Nearly half of patients with colorectal cancer (CRC), the third leading cause of cancer deaths worldwide, are diagnosed in the late stages of the disease. Appropriate treatment is not applied in a timely manner and nearly 90% of the patients who experience metastasis ultimately die. Timely detection of CRC can increase the five-year survival rate of patients. Existing histopathological and molecular classifications are insufficient for prediction of metastasis, which limits approaches to treatment. Detection of reliable cancer-related biomarkers can improve early diagnosis, prognosis, and treatment response prediction and recurrence risk. Circulating tumor cells (CTCs) and exosomes in peripheral blood can be used in a liquid biopsy to assess the status of a tumor. Exosomes are abundant and available in all fluids of the body, have a high half-life and are released by most cells. Tumor-derived exosomes are released from primary tumors or CTCs with selective cargo that represents the overall tumor. The current systematic review highlights new trends and approaches in the detection of CRC biomarkers to determine tumor signatures using CTC and exosomes. When these are combined, they could be used to guide molecular pathology and can revolutionize detection tools. Relevant observational studies published until July 24, 2019 which evaluated the expression of tumor markers in CTCs and exosomes were searched in PubMed, Scopus, Embase, and ISI Web of Science databases. The extracted biomarkers were analyzed using String and EnrichR tools.

Six-gene Assay as a new biomarker in the blood of patients with colorectal cancer: establishment and clinical validation

Colorectal cancer (CRC) is the second most common cancer in men and the third most common cancer in women. Although long-term survival has improved over the past 30 years, at least 50% of patients with CRC will develop metastases after diagnosis. In this study, we examined whether quantifying the mRNA of six CRC-related genes in the blood could improve disease assessment through detection of circulating tumor cells (CTC), and thereby improve progression prediction in relapsed CRC patients. Cell spiking assay and RT-PCR were performed with blood samples from healthy volunteers spiked with six CRC cell lines to generate an algorithm, herein called the Six-gene Assay, based on six genes (CEA, EpCAM, CK19, MUC1, EGFR and C-Met) for CTC detection. The CTCs of 50 relapsed CRC patients were then respectively measured by CEA Gene Assay (single-gene assay control) and Six-gene Assay. Subsequently, receiver operating characteristic analysis of the CTC panel performance in diagnosing CRC was conducted for both assays. Moreover, the 2-year progression-free survival (PFS) of all patients was collected, and the application of CEA Gene Assay and Six-gene Assay in predicting PFS was carefully evaluated with different CTC cutoff values. Encouragingly, we successfully constructed the first multiple gene-based algorithm, named the Six-gene Assay, for CTC detection in CRC patients. Six-gene Assay was more sensitive than CEA Gene Assay; for instance, in 50 CRC patients, the positive rate of Six-gene Assay in CTC detection was 82%, whereas that of CEA Gene Assay was only 70%. Moreover, Six-gene Assay was more sensitive and accurate than CEA Gene Assay in diagnosing CRC as well as predicting the 2-year PFS of CRC patients. Statistical analysis demonstrated that CTC numbers measured by Six-gene Assay were significantly associated with 2-year PFS. This novel Six-gene Assay improves the definition of disease status and correlates with PFS in relapsed CRC, and thus holds promise for future clinical applications.

Hydroxyethyl starch 200/0.5 decreases circulating tumor cells of colorectal cancer patients and reduces metastatic potential of colon cancer cell line through inhibiting platelets activation

Platelets play an important role in metastasis of circulating tumor cells (CTCs). It has been demonstrated that hydroxyethyl starch (HES) inhibits platelets function. However, the effect of HES on CTCs in patients with colorectal cancer remains unclear. We compared the effects of HES 200/0.5 and HES 130/0.4 on CTCs and platelets activation of colorectal patients in this study. Additionally, the effects of HES 200/0.5 or HES 130/0.4 on metastasis ability of colon cancer cell line that stimulated by activated platelets have been explored. In vivo, 90 patients undergoing colorectal cancer radical surgery received randomly 15 mL/kg of HES 200/0.5 (n = 45) or HES 130/0.4 (n = 45) infusion before surgery. Platelet glycoprotein IIb/IIIa (GPIIb/IIIa), CD62P and platelets aggregation rate (PAR) were evaluated pre-, intra- and postoperatively. Cytokeratin-20 (CK-20) mRNA was detected by reverse transcriptase polymerase chain reaction before and after surgery. In vitro, colon cancer SW480 cells were incubated with activated platelets in the presence or absence HES 200/0.5 or HES 130/0.4. The metastasis ability of SW480 cells was assessed by Transwell assay. The results showed that CK-20 mRNA positive rate in HES 200/0.5 group after surgery was decreased significantly as compared to group HES 130/0.4 (χ (2) = 6.164, P = 0.013). Simultaneously, a more pronounced inhibition of platelets activation was observed in group HES 200/0.5. A positive correlation between platelets activation marker and CK-20 mRNA positive rate was found. In vitro, HES 200/0.5, but not HES 130/0.4, decreased the invasion and migration ability of SW480 cells that induced by activated platelets. Besides, the expression of GPIIb/IIIa, CD62P and PAR was inhibited more strongly in group HES 200/0.5 than those in group HES 130/0.4. In summary, we found that HES 200/0.5 significantly decreased CTCs of patients undergoing colorectal cancer radical surgery as compared to HES 130/0.4, which might be associated with inhibiting platelets activation of HES 200/0.5. Furthermore, HES 200/0.5, but not HES 130/0.4, reduced the metastatic potential of colon cell line stimulated by activated platelets through depressing platelets activation. Modulation of platelets activity may be a novel strategy to minimize the risk of metastasis during surgery.

Meta-analysis of the prognostic value of circulating tumor cells detected with the CellSearch System in colorectal cancer

BACKGROUND

The prognostic value of circulating tumor cells (CTCs) detected with the CellSearch System in patients with colorectal cancer (CRC) is controversial. The aim of our meta-analysis was to evaluate whether the detection of CTCs in the peripheral blood with the standardized CellSearch System has prognostic utility for patients with CRC.

METHODS

The PubMed, Science Citation Index, Cochrane Database, Embase, and the references in relevant studies were systematically searched (up to December, 2014). No search restrictions were imposed. Our meta-analysis was performed in Stata software, version 12.0 (2011) (Stata Corp, College Station, TX, USA), with the odds ratio (OR), risk ratio (RR), hazard ratio (HR), and 95% confidence interval (95% CI) as the effect measures. Subgroup and sensitivity analyses were also conducted.

RESULTS

Eleven studies containing 1847 patients with CRC were analyzed. There was a significantly higher incidence of CTCs in the metastasis-positive group than in the metastasis-negative group (OR = 4.06, 95% CI [1.74, 9.50], P < 0.01, I(2) = 0%). For hepatic metastasis, a type of metastasis, a higher incidence of CTCs was observed in the hepatic-metastasis-positive group than in the -negative group (OR = 2.61, 95% CI [1.73, 3.96], P < 0.01, I(2) = 0%). The presence of CTCs was significantly related to overall survival (HR = 2.00, 95% CI [1.49, 2.69], P < 0.01, I(2) = 67.1%) and progression-free survival (HR = 1.80, 95% CI [1.52, 2.13], P < 0.01, I(2) = 43.9%) of patients with CRC, regardless of the sampling time. The response rate for the CTC(+) groups was significantly lower than that for the CTC(-) groups at baseline and during treatment (baseline: 33% versus 39%, RR = 0.79, 95% CI [0.63, 0.99], P = 0.04, I(2) = 7.0%; during treatment: 17% versus 46%, RR = 0.41, 95% CI [0.22, 0.77], P = 0.01, I(2) = 0.0%;).

CONCLUSIONS

Our meta-analysis indicates that the detection of CTCs in the peripheral blood with the CellSearch System has prognostic utility for patients with CRC.

Detection of carcinoembryonic antigen mRNA in peritoneal lavage by the transcription-reverse transcription concerted method indicates poor prognosis in patients with stage II and III colon cancer

BACKGROUND

Peritoneal dissemination and positive peritoneal lavage cytology are associated with poor prognosis in colorectal cancer. Carcinoembryonic antigen (CEA) messenger RNA (mRNA) is often used as a marker to detect micrometastases. We aimed to evaluate the prognostic significance of CEA mRNA in the peritoneal lavage of colon cancer patients.

METHODS

Colon cancer patients (n = 201) who underwent curative operative resection between August 2009 and February 2013 were enrolled. CEA mRNA in peritoneal lavage was measured using the transcription-reverse transcription concerted method, a quantitative RNA amplification method. The correlation between CEA mRNA and overall and peritoneal recurrence-free survival was evaluated.

RESULTS

Positive CEA mRNA in peritoneal lavage was an independent risk factor for overall recurrence-free survival in colon cancer (P < .0001). Positive CEA mRNA was a risk factor for poorer overall recurrence in stage II and III patients (P = .04 and P = .02, respectively). Moreover, among stage III patients with positive CEA mRNA, the postoperative chemotherapy group had significantly lower overall and peritoneal recurrence rates than the no postoperative chemotherapy group (P = .001).

CONCLUSION

Positive CEA mRNA in peritoneal lavage was associated with high overall recurrence rates in stage II and III colon cancer. Further study is necessary to determinate the efficacy of aggressive postoperative chemotherapy for stage II and III colon cancer patients with positive CEA mRNA.

Clinical impact of minimal cancer cell detection in various colorectal cancer specimens

Detection of cancer cells using molecular targets is achieved by combining immunochemical reactions with gene amplification techniques. This enables the detection of cancer cells in specimens that are traditionally determined to be cancer-free. These improvements in detection can lead to prognoses that are different from those derived by conventional pathological staging. Survival is worse when cancer cells are detected in regional lymph nodes compared to when the nodes are cancer-free. Furthermore, the circulating tumor cell (CTC) count increases as the cancer progresses. Consequently, there is a correlation between CTC count and prognosis. However, large-scale prospective studies are required to confirm this. The development of more convenient and cost-effective analysis techniques will facilitate the practical application of these findings.

Role of β1-Integrin in Colorectal Cancer: Case-Control Study

Purpose

In the metastatic process, interactions between circulating tumor cells (CTCs) and the extracellular matrix or surrounding cells are required. β₁-Integrin may mediate these interactions. The aim of this study was to investigate whether β₁-integrin is associated with the detection of CTCs in colorectal cancer.

Methods

We enrolled 30 patients with colorectal cancer (experimental group) and 30 patients with benign diseases (control group). Blood samples were obtained from each group, carcinoembryonic antigen (CEA) mRNA for CTCs marker and β₁-integrin mRNA levels were estimated by using reverse transcription-polymerase chain reaction, and the results were compared between the two groups. In the experimental group, preoperative results were compared with postoperative results for each marker. In addition, we analyzed the correlation between the expressions of β₁-integrin and CEA.

Results

CEA mRNA was detected more frequently in colorectal cancer patients than in control patients (P = 0.008). CEA mRNA was significantly reduced after surgery in the colorectal cancer patients (P = 0.032). β₁-Integrin mRNA was detected more in colorectal cancer patients than in the patients with benign diseases (P < 0.001). In colorectal cancer patients, expression of β₁-integrin mRNA was detected more for advanced-stage cancer than for early-stage cancer (P = 0.033) and was significantly decreased after surgery (P < 0.001). In addition, expression of β₁-integrin mRNA was significantly associated with that of CEA mRNA in colorectal cancer patients (P = 0.001).

Conclusion

In conclusion, β₁-integrin is a potential factor for forming a prognosis following surgical resection in colorectal cancer patients. β₁-Integrin may be a candidate for use as a marker for early detection of micrometastatic tumor cells and for monitoring the therapeutic response in colorectal cancer patients.

Alternatives for the intensive follow-up after curative resection of colorectal cancer. Potential novel biomarkers for the recommendations

Early diagnosis of recurrence and metastasis of colorectal cancer following surgery of curative intent is of vital importance in terms of survival and quality of life. The consistent implementation of appropriate patient follow-up strategy is therefore essential. Debates over the methodology, evaluation and strategy of follow-up have been known for many years, and continue today. By introducing several follow-up models, the present paper offers different options featuring certain individual, national and international, conceptual and financial aspects. Colorectal cancer is an important public health concern due to its destructive nature and frequency, it is therefore essential to develop new monitoring strategies, involving new biomarkers and extensive clinical validation. Since the recurrence rate is very high in high-risk patients, the improvement of individual patient risk estimates and the utilization of a corresponding follow-up model require broad international co-operation and common practice, along with the determination of optimal levels of evidence.

Essentials of circulating tumor cells for clinical research and practice

The major cause of death due to cancer is its metastatic deposit in numerous tissues and organs. The metastatic process requires the migration of malignant cells from primary sites to distant environments. Even for tumors initially spreading through lymphatic vessels, hematogenous transport is the most common metastatic pathway. The detachment of cancer cells from a primary tumor into the blood stream is called epithelial-mesenchymal transition (EMT). As these cells circulate further in the bloodstream they are known as circulating tumor cells (CTCs). The CTC population is highly resilient, enabling the cells to colonize a foreign microenvironment. Alternatively, cancer stem cells (CSCs) may arise from differentiated cancer cells through EMT and an embryonic transdifferentiation process. The presence of CTCs/CSCs in blood seems to be a determining factor of metastasis. This paper reviews various methods of clinical cancer detection as well as the biology and molecular characterization of CTCs/CSCs. Our goal was to summarize clinical studies which used CTC/CSCs for prognosis in patients with breast, colorectal, prostate, lung, ovarian, and bladder cancer.

Progress in circulating tumor cell capture and analysis: implications for cancer management

The hematogenous dissemination of cancer and development of distant metastases is the cause of nearly all cancer deaths. Detection of circulating tumor cells (CTCs) as a surrogate biomarker of metastases has gained increasing interest. There is accumulating evidence on development of novel technologies for CTC detection, their prognostic relevance and their use in therapeutic response monitoring. Many clinical trials in the early and metastatic cancer setting, particularly in breast cancer, are including CTCs in their translational research programs and as secondary end points. We summarize the progress of detection methods in the context of their clinical importance and speculate on the possibilities of wider implementation of CTCs as a diagnostic oncology tool, the likelihood that CTCs will be used as a useful biomarker, especially to monitor therapeutic response, and what may be expected from the future improvements in technologies.

Lack of evidence for increased level of circulating urothelial cells in the peripheral blood after transurethral resection of bladder tumors

PURPOSE

Aggressive intervention against the bladder wall during transurethral resection of bladder tumors (TURBT) causes damage and leakage from blood vessels to the bladder lumen. The aim of this study was to determine whether TURBT could increase the level of circulating urothelial cells.

METHODS

Expression of tumor markers, discriminative for nucleated blood cells and urothelium, was evaluated by quantitative (q) RT-PCR on RNA isolated from peripheral blood samples of 51 patients who underwent TURBT for ≥cT1c bladder tumors.

RESULTS

Four of 14 studied genes, epidermal growth factor receptor (EGFR), Collagen α-1(I) chain, Mast/stem cell growth factor receptor (KIT) and CD47, exhibited significant differences in gene expression between controls and cancer patients. While TURBT did not significantly increase the number of PCR-positive results of any transcripts, positive RT-PCR detection for EGFR was significantly less frequent on day 30 compared to results obtained before surgery.

CONCLUSIONS

Although the results of our study do not provide evidence for increased tumor cell release into the peripheral blood after TURBT, they seem to indicate that EGFR mRNA measurement in the blood may provide useful information for urologists.