Prognostic value of circulating tumor cells in esophageal cancer

Latest insights into the global epidemiological features, screening, early diagnosis and prognosis prediction of esophageal squamous cell carcinoma

As a highly invasive carcinoma, esophageal cancer (EC) was the eighth most prevalent malignancy and the sixth leading cause of cancer-related death worldwide in 2020. Esophageal squamous cell carcinoma (ESCC) is the major histological subtype of EC, and its incidence and mortality rates are decreasing globally. Due to the lack of specific early symptoms, ESCC patients are usually diagnosed with advanced-stage disease with a poor prognosis, and the incidence and mortality rates are still high in many countries, especially in China. Therefore, enormous challenges still exist in the management of ESCC, and novel strategies are urgently needed to further decrease the incidence and mortality rates of ESCC. Although the key molecular mechanisms underlying ESCC pathogenesis have not been fully elucidated, certain promising biomarkers are being investigated to facilitate clinical decision-making. With the advent and advancement of high-throughput technologies, such as genomics, proteomics and metabolomics, valuable biomarkers with high sensitivity, specificity and stability could be identified for ESCC. Herein, we aimed to determine the epidemiological features of ESCC in different regions of the world, especially in China, and focused on novel molecular biomarkers associated with ESCC screening, early diagnosis and prognosis prediction.

The use of an artificial intelligence algorithm for circulating tumor cell detection in patients with esophageal cancer

Despite recent advances in multidisciplinary treatments of esophageal squamous cell carcinoma (ESCC), patients frequently suffer from distant metastasis after surgery. For numerous types of cancer, circulating tumor cells (CTCs) are considered predictors of distant metastasis, therapeutic response and prognosis. However, as more markers of cytopathological heterogeneity are discovered, the overall detection process for the expression of these markers in CTCs becomes increasingly complex and time consuming. In the present study, the use of a convolutional neural network (CNN)-based artificial intelligence (AI) for CTC detection was assessed using KYSE ESCC cell lines and blood samples from patients with ESCC. The AI algorithm distinguished KYSE cells from peripheral blood-derived mononuclear cells (PBMCs) from healthy volunteers, accompanied with epithelial cell adhesion molecule (EpCAM) and nuclear DAPI staining, with an accuracy of >99.8% when the AI was trained on the same KYSE cell line. In addition, AI trained on KYSE520 distinguished KYSE30 from PBMCs with an accuracy of 99.8%, despite the marked differences in EpCAM expression between the two KYSE cell lines. The average accuracy of distinguishing KYSE cells from PBMCs for the AI and four researchers was 100 and 91.8%, respectively (P=0.011). The average time to complete cell classification for 100 images by the AI and researchers was 0.74 and 630.4 sec, respectively (P=0.012). The average number of EpCAM-positive/DAPI-positive cells detected in blood samples by the AI was 44.5 over 10 patients with ESCC and 2.4 over 5 healthy volunteers (P=0.019). These results indicated that the CNN-based image processing algorithm for CTC detection provides a higher accuracy and shorter analysis time compared to humans, suggesting its applicability for clinical use in patients with ESCC. Moreover, the finding that AI accurately identified even EpCAM-negative KYSEs suggested that the AI algorithm may distinguish CTCs based on as yet unknown features, independent of known marker expression.

Research Progress on the Predicting Factors and Coping Strategies for Postoperative Recurrence of Esophageal Cancer

Esophageal cancer is one of the malignant tumors with poor prognosis in China. Currently, the treatment of esophageal cancer is still based on surgery, especially in early and mid-stage patients, to achieve the goal of radical cure. However, esophageal cancer is a kind of tumor with a high risk of recurrence and metastasis, and locoregional recurrence and distant metastasis are the leading causes of death after surgery. Although multimodal comprehensive treatment has advanced in recent years, the prediction, prevention and treatment of postoperative recurrence and metastasis of esophageal cancer are still unsatisfactory. How to reduce recurrence and metastasis in patients after surgery remains an urgent problem to be solved. Given the clinical demand for early detection of postoperative recurrence of esophageal cancer, clinical and basic research aiming to meet this demand has been a hot topic, and progress has been observed in recent years. Therefore, this article reviews the research progress on the factors that influence and predict postoperative recurrence of esophageal cancer, hoping to provide new research directions and treatment strategies for clinical practice.

Squamous Cell Carcinoma of the Esophagus

Esophageal squamous cell carcinoma (ESCC) is common in the developing world with decreasing incidence in developed countries and carries significant morbidity and mortality. Major risk factors for ESCC development include significant use of alcohol and tobacco. Screening for ESCC can be recommended in high-risk populations living in highly endemic regions. The treatment of ESCC ranges from endoscopic resection therapy or surgery in localized disease to chemoradiotherapy in metastatic disease, and prognosis is directly related to the stage at diagnosis. New immunotherapies and molecular targeted therapies may improve the dismal survival outcomes in patients with metastatic ESCC.

Clinical Utility of Circulating Tumor Cells for Predicting Major Histopathological Response after Neoadjuvant Chemoradiotherapy in Patients with Esophageal Cancer

Background: A “surgery as needed” approach may be offered to patients with esophageal cancer (EC) who achieve major histopathological response (MaHR) after neoadjuvant chemoradiotherapy (nCRT). However, the utility of clinical response assessment (CRE) for predicting histopathological response to nCRT remains limited. Circulating tumor cells (CTCs) hold promise as biomarkers of response to nCRT. Methods: We analyzed the clinical utility of post-nCRT CTCs, alone or in combination with CRE, in the prediction of MaHR. We defined MaHR as either the lack or a limited presence (≤10%) of vital residual tumor cells in the resected esophageal specimen in the absence of nodal involvement. Results: Of the 48 study patients, 27 (56%) achieved MaHR. Patients with MaHR had a significantly lower CTCs count compared with those without (3.61 ± 4.53 versus 6.83 ± 5.22 per mL of blood, respectively; P = 0.027). Using a cutoff for positivity of 5 CTCs per mL of blood, the combination of CTCs and CRE allowed achieving a negative predictive value for MaHR of 93% (95% confidence interval [CI] = 70–99%) along with a false negative rate of 5% (95% CI = 1–33%). Conclusion: CTCs count assessed in combination with CRE can potentially help identify patients with EC who achieved MaHR after nCRT.

Bioinformatics analysis identifying FBXO45 gene as a potential oncogene in esophageal cancer

BACKGROUND

F-box protein 45 (FBXO45) is a member of the F-box protein family, and is reportedly involved in the progression of many diseases. However, its role in esophageal cancer (ESCA) remains unclear.

METHODS

The expression, clinical characteristics, gene function, pathway, and correlation between the infiltration of different immune cells were analyzed using public data. The pan-cancer expression of FBXO45 was assessed using the TIMER2 database. The expression of FBXO45 in different tumor stages and histology subtypes were evaluated using the UALCAN database. The protein-protein interaction (PPI) network was constructed using the STRING database. Immune cell infiltration data were downloaded from the ImmuCellAI database.

RESULTS

The top 300 genes most positively correlated with FBXO45 were screened into the enrichment analysis. The functional enrichment results showed that FBXO45 was mainly associated with proteasomal protein catabolic process and the regulation of DNA metabolic processing in the biological process (BP) category; spindle, chromosomal region, and focal adhesion in the cellular component category; and ATPase activity and ubiquitin-protein transferase activity terms in the molecular function category. FBXO45 was overexpressed in ESCA and other cancer types. FBXO45 expression was positively associated with the infiltration levels of immunosuppressive cells, such as CD8+ (cluster of differentiation 8+) T cells and NK (natural killer cell) cells, in ESCA. MYCBP2 and SKP1 were most associated with FBXO45.

CONCLUSIONS

Our results suggested that FBXO45 is a potential oncogene in ESCA. Elevated FBXO45 expression indicates a relatively immunosuppressive microenvironment.

Clinical Significance of TWIST-Positive Circulating Tumor Cells in Patients with Esophageal Squamous Cell Carcinoma

Background/Aims

Unlike other gastrointestinal tract cancers, there are relatively few reports on the clinical significance of circulating tumor cells (CTCs) and TWIST, a marker of epithelial-mesenchymal transition, in patients with esophageal squamous cell carcinoma (ESCC). This study aimed to evaluate the clinical significance of TWIST expression in CTCs in patients with ESCC.

Methods

Peripheral blood samples for CTC analyses were prospectively obtained from 52 patients with ESCC prior to treatment between September 2017 and September 2019. CTCs were detected using a centrifugal microfluidic system based on a fluid-assisted separation technique, and CTCs positive for TWIST on immunostaining were defined as TWIST (+) CTCs.

Results

Of the 52 patients with ESCC, CTCs and TWIST (+) CTCs were detected in 44 patients (84.6%) and 39 patients (75.0%), respectively. The CTC and TWIST (+) CTC counts were significantly higher in patients aged >65 years and those who had a large tumor (>3 cm) than in those aged ≤65 years and those who had a small tumor (≤3 cm), respectively. There were no differences in CTC and TWIST (+) CTC counts according to tumor location, histologic grade, or TNM stage. TWIST (+) CTCs were significantly associated with histologic grade; a proportion of TWIST (+) CTCs ≥0.5 was significantly associated with advanced histologic grade. Other clinicopathologic characteristics such as sex, age, tumor location, tumor size, and TNM stages were not significantly associated with TWIST (+) CTCs.

Conclusions

Our study showed that TWIST (+) CTCs were frequently detected in patients with ESCC, and a high proportion of TWIST (+) CTCs was associated with poor differentiation.

Comparative Analysis of Blood and Bone Marrow for the Detection of Circulating and Disseminated Tumor Cells and Their Prognostic and Predictive Value in Esophageal Cancer Patients

Hematogenic tumor cell spread is a key event in metastasis. However, the clinical significance of circulating tumor cells (CTC) in the blood and disseminated tumor cells (DTC) in bone marrow is still not fully understood. Here, the presence of DTC and CTC in esophageal cancer (EC) patients and its correlation with clinical parameters was investigated to evaluate the CTC/DTC prognostic value in EC. This study included 77 EC patients with complete surgical tumor resection. CTC and DTC were analyzed in blood and bone marrow using nested CK20 reverse transcription-nested polymerase chain reaction (RT-PCR) and findings were correlated with clinical data. Twenty-seven of 76 patients (36.5%) showed CK20 positivity in the blood, 19 of 61 patients (31.1%) in bone marrow, and 40 (51.9%) of 77 patients were positive in either blood or bone marrow or both. In multivariate analyses, only the DTC status emerged as independent predictor of overall and tumor specific survival. Our study revealed that, while the presence of CTC in blood is not associated with a worse prognosis, DTC detection in the bone marrow is a highly specific and independent prognostic marker in EC patients. Larger cohort studies could unravel how this finding can be translated into improved therapy management in EC.

Clinical significance of circulating tumor cells detection in renal cell carcinoma with thrombus: A STROBE-compliant study

The aim of the study was to evaluate the potential role of circulating tumor cell (CTC) detection in the surgical assessment of renal cell carcinoma (RCC) patients with thrombi.Nine patients diagnosed with renal mass and thrombi were enrolled from June 2018 to January 2019. Blood samples were collected for CTC detection using SE-iFISH assay. CD45, DAPI, programmed death ligand 1, and fluorescence in situ hybridization with the centromere of chromosome 8 (CEP8) were immune-stained for analysis. Patient demographics, clinical features, pathological characteristics, and CTC detection results were extracted for analysis.Seven of 9 patients (77.8%) had 12 detectable CTCs, 5 of which were with CEP8-positive signal ≥5 and the others were CEP8-positive signal = 3. All 3 patients (100%) with IVC invasion had detectable CTCs, whereas CTCs were detected in 4 of 6 patients (66.7%) without IVC invasion. CEP8 analysis revealed that CTCs in IVC invasion patients were all of CEP8-positive signal ≥5 status, whereas only half of the CTCs in patients without IVC invasion were of CEP8-positive signal ≥5 pattern.In conclusion, both CTC subtype and total CTC number may serve as a marker for predicting inferior vena cava invasion in RCC patients.

Karyotyping of circulating tumor cells for predicting chemotherapeutic sensitivity and efficacy in patients with esophageal cancer

Background

Aneuploidy of chromosome 8 in circulating tumor cells (CTCs) has been reported correlates with therapeutic efficacy and prognosis in patients with advanced gastric cancer. However, it is not clear whether it is also appropriate for other cancer. Therefore, in this study, we evaluate the clinical application aneuploidy of CTCs for esophageal cancer.

Methods

Peripheral blood were collected for karyotyping analysis before and after first 4-cycles chemotherapy from seventy nine patients with newly diagnosed esophageal cancer. Karyotyping of chromosome 8 in CTCs detected by SET-iFISH (Subtraction Enrichment-Immunostaining fluorescence in situ hybridizatio) in those patients were grouped into two categories according to CTC number: triploid group and non-triploid group. Pearson Chi-Square were used to compare the association between different aneuploidy type and chemotherapeutic sensitivity and efficacy.

Results

Among the 16 patients with triploid of chromosome 8, 4 patients benefit, and of the 63 patients with non-triploid, 54 patients benefit. Chi-square test analysis found that clinical benefit of non-triploid patients was significantly higher than triploid patients, suggesting non-triploid patients were more sensitive to chemotherapy than triploid patients. After 4-cycles chemotherapy, it is found that chemotherapeutic efficacy was positively correlated with non-triploid proportion. These results suggest that non-triploid proportion could be used as a candidate maker for assessing chemotherapeutic efficacy.

Conclusions

Monitoring aneuploidy of chromosome 8 in CTCs before and after chemotherapy may help predict sensitivity and efficacy of chemotherapy in patients with esophageal cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5850-7) contains supplementary material, which is available to authorized users.

Circulating tumor cells detected using fluid-assisted separation technique in esophageal squamous cell carcinoma

BACKGROUND AND AIM

Esophageal squamous cell carcinoma (ESCC) is one of the aggressive gastrointestinal tract cancers. Detection of circulating tumor cells (CTCs) in peripheral blood from patients with various malignancies has been reported to have diagnostic, prognostic, and therapeutic implications. We aimed to evaluate CTCs in patients with ESCC and assess the clinical significance of CTCs in the early diagnosis of ESCC.

METHODS

Peripheral blood samples for CTCs analyses were prospectively obtained from 73 patients with ESCC prior to treatment between March 2015 and June 2018. CTCs were detected using a centrifugal microfluidic system with a new fluid-assisted separation technique. Blood samples from 31 healthy volunteers were used as controls.

RESULTS

After creating a receiver operating characteristic curve to determine the optimal CTC threshold to differentiate patients with ESCC from healthy controls, sensitivity and specificity were most optimized at a CTC threshold of two per 7.5 mL of blood. Among 66 subjects with ≥ 2 CTCs per 7.5 mL of blood, 63 (95.5%) had ESCC. Among 38 subjects with < 2 CTCs per 7.5 mL of blood, 28 (73.7%) were healthy controls. When using this threshold, the sensitivity and specificity for differentiating patients with ESCC from healthy controls were 86.3% and 90.3%, respectively. CTC count was associated with tumor-node-metastasis stage, especially lymph node metastasis, but there was no correlation with any other relevant clinicopathologic variable.

CONCLUSIONS

Our results suggest that CTCs detected using fluid-assisted separation technique could be helpful for early diagnosis of ESCC. Further large-scale prospective studies are warranted to validate our findings.

Screening for esophageal squamous cell carcinoma: recent advances

Esophageal squamous cell carcinoma (ESCC) is the most common type of esophageal cancer worldwide, with a high mortality due to advanced stage at diagnosis. Although most common in an area known as the Asian Esophageal Cancer Belt, which extends from the Caspian Sea to northern China, and in parts of Africa, high-risk populations also exist elsewhere in the world. Screening for ESCC has been practiced in a few geographic areas and high-risk populations, with varying levels of success. Esophageal squamous dysplasia is recognized as the precursor lesion for ESCC. Endoscopic screening for ESCC/esophageal squamous dysplasia is expensive and not sufficiently available in many high-risk regions. Recent advances in non-endoscopic screening enhanced by biomarker-based disease detection have raised the prospect of improved accuracy and availability of screening for esophageal squamous dysplasia and early stage ESCC. Development of a cost-effective, accurate, and well-tolerated screening test, if applied in endemic areas and high-risk populations, has the potential to reduce mortality from this deadly disease worldwide. In this review, we summarize recent developments in endoscopic and non-endoscopic screening modalities.