Detection of circulating tumor cells by p75NTR expression in patients with esophageal cancer. World J Surg Oncol. 2016;14:40. [PMID: 26897248 PMCID: PMC4761417 DOI: 10.1186/s12957-016-0793-9]

Liquid biopsy of oesophageal squamous cell carcinoma: implications in diagnosis, prognosis, and treatment monitoring

Oesophageal squamous cell carcinoma (ESCC) is a common malignant tumour of the gastrointestinal tract. Early detection and access to appropriate treatment are crucial for the long-term survival of patients. However, limited diagnostic and monitoring methods are available for identifying early stage ESCC. Endoscopic screening and surgical resection are commonly used to diagnose and treat early ESCC. However, these methods have disadvantages, such as high recurrence, lethality, and mortality rates. Therefore, methods to improve early diagnosis of ESCC and reduce its mortality rate are urgently required. In 1961, Gary et al. proposed a novel liquid biopsy approach for clinical diagnosis. This involved examining exosomes, circulating tumour cells, circulating free DNA, and circulating free RNA in body fluids. The ability of liquid biopsy to obtain samples repeatedly, wide detection range, and fast detection speed make it a feasible option for non-invasive tumour detection. In clinical practice, liquid biopsy technology has gained popularity for early screening, diagnosis, treatment efficacy monitoring, and prognosis assessment. Thus, this is a highly promising examination method. However, there have been no comprehensive reviews on the four factors of liquid biopsy in the context of ESCC. This review aimed to analyse the progress of liquid biopsy research for ESCC, including its classification, components, and potential future applications.

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.

Pilot Investigation on p75ICD Expression in Laryngeal Squamous Cell Carcinoma

We investigated the p75 Neurotrophin Receptor (p75NTR) expression and cleavage product p75NTR Intracellular Domain (p75ICD) as potential oncogenic and metastatic markers in human Laryngeal Squamous Cell Carcinoma (LSCC). p75NTR is highly expressed in Cancer Stem Cells (CSCs) of the laryngeal epithelia and it has been proposed as a marker for stemness, cell migration, and chemo-resistance in different squamous carcinomas. To investigate the clinical significance of p75NTR cleavage products in solid tumors, full-length and cleaved p75NTR expression was analyzed in laryngeal primary tumors from different-stage LSCC patients, diagnosed at the Policlinico Umberto I Hospital. Molecular and histological techniques were used to detect the expressions of p75NTR and p75ICD, and ATP Binding Cassette Subfamily G Member 2 (ABCG2), a CSC marker. We found regulated p75NTR cleavage during squamous epithelial tumor progression and tissue invasion. Our preliminary investigation suggests p75ICD expression and localization as possible features of tumorigenesis and metastaticity. Its co-localization with ABCG2 in squamous cells in the parenchyma invaded by the tumor formation allows us to hypothesize p75NTR and p75ICD roles in tumor invasion and CSC spreading in LSCC patients. These data might represent a starting point for a comprehensive analysis of p75NTR cleavage and of its clinical relevance as a potential molecular LSCC signature, possibly helping diagnosis, and improving prognosis and personalized therapy.

Cell Lines of Circulating Tumor Cells: What Is Known and What Needs to Be Resolved

The importance of circulating tumor cells (CTC) is well recognized. However, the biological characteristics of CTC in the bloodstream have not yet been examined in detail, due to the limited number of CTC cell lines currently available. Thirty-nine CTC cell lines were reported by 2021. For successful cell culturing, these CTC cell lines were reviewed. Previous studies on short-term cultures of CTC also analyzed approaches for establishing the long-term culture of CTC. Negative selection, hypoxic conditions, three-dimensional conditions, and careful management are preferable for the long-term culture of CTC. However, the establishment of CTC cell lines is dependent on the specific characteristics of each cell type. Therefore, a method to establish CTC cell lines has not yet been developed. Further efforts are needed to resolve this issue.

Downregulation of OIP5-AS1 affects proNGF-induced pancreatic cancer metastasis by inhibiting p75NTR levels

We aimed to explore the mechanism by which long non-coding RNA (lncRNA) OIP5-AS1 affects proNGF (precursor nerve growth factor)-induced pancreatic cancer metastasis by targeting the miR-186-5p/NGFR axis. Bioinformatics was used to analyse whether OIP5-AS1 targets miR-186-5p/NGFR and their expression characteristics in pancreatic cancer. OIP5-AS1 and NGFR were overexpressed in pancreatic cancer, and their levels showed a significant positive correlation. Clinical trials also demonstrated that high expression of OIP5-AS1 and NGFR and low expression of miR-186-5p played a pro-cancer role in pancreatic cancer. MiR-186-5p inhibited the migration and invasion of colon cancer cells by targeting NGFR-regulated p75NTR. OIP5-AS1 regulated the action of miR-186-5p on NGFR mRNA and p75NTR by targeting miR-186-5p. Downregulation of NGFR inhibited the expression of p75NTR protein and blocked the role of proNGF in promoting the migration and invasion of pancreatic cancer cells. Animal experiments also showed that the knockdown of miR-186-5p promoted cancer via the expression of NGFR mRNA and p75NTR protein, while the downregulation of proNGF blocked the effects. OIP5-AS1, as a ceRNA, promotes the progression of pancreatic cancer by targeting miR-186-5p/NGFR and affecting the prognosis of patients, which may be related to the action of proNGF.

Linking Cancer Stem Cell Plasticity to Therapeutic Resistance-Mechanism and Novel Therapeutic Strategies in Esophageal Cancer

Esophageal cancer (EC) is an aggressive form of cancer, including squamous cell carcinoma (ESCC) and adenocarcinoma (EAC) as two predominant histological subtypes. Accumulating evidence supports the existence of cancer stem cells (CSCs) able to initiate and maintain EAC or ESCC. In this review, we aim to collect the current evidence on CSCs in esophageal cancer, including the biomarkers/characterization strategies of CSCs, heterogeneity of CSCs, and the key signaling pathways (Wnt/β-catenin, Notch, Hedgehog, YAP, JAK/STAT3) in modulating CSCs during esophageal cancer progression. Exploring the molecular mechanisms of therapy resistance in EC highlights DNA damage response (DDR), metabolic reprogramming, epithelial mesenchymal transition (EMT), and the role of the crosstalk of CSCs and their niche in the tumor progression. According to these molecular findings, potential therapeutic implications of targeting esophageal CSCs may provide novel strategies for the clinical management of esophageal cancer.

Prognostic impact of lymphovascular invasion in lymph node-negative superficial esophageal squamous cell carcinoma

The relationship between lymphovascular invasion (LVI) and prognosis in patients with superficial esophageal squamous cell carcinoma (SESCC) is unclear. The aim of this study is to evaluate prognostic factors in patients with lymph node-negative SESCC. A total of 195 patients with pathologically confirmed T1a-MM, T1b, and lymph node-negative SESCC were retrospectively reviewed in this study. Overall, the disease-free survival (DFS) rate was poorer in the lymphatic invasion-positive group than in the lymphatic invasion-negative group (p = 0.002) and a multivariate analysis suggested that lymphatic invasion was the only independent prognostic factor of DFS in patients with lymph node-negative SESCC (HR = 4.075, p = 0.005). Distant organ recurrence occurred in one patient (1/52, 1.9%) in the T1b-SM2 group and in six patients (6/61, 9.7%) in the T1b-SM3 group; all of these patients had LVI. LVI-positive patients had a poorer DFS than invasion-negative patients in the T1b-SM2 and SM3 groups (p = 0.026), and a multivariate analysis suggested that LVI was the only independent prognostic factor of DFS in patients with lymph node-negative SM2 and SM3 SESCC (HR = 5.165, p = 0.031). Lymph node-positive patients had a significantly poorer DFS rate than lymph node negative and LVI positive patients among the SM2 and SM3 SESCC patients (p = 0.018). The present results suggested that LVI was an independent prognostic factor in patients with SM2 and SM3 lymph node-negative SESCC; however their prognosis was not worse than that of patients with lymph node-positive SM2 and SM3 SESCC, for whom adjuvant therapy is indicated as a standard treatment.

Colorectal cancer mutational profiles correlate with defined microbial communities in the tumor microenvironment

Variation in the gut microbiome has been linked to colorectal cancer (CRC), as well as to host genetic variation. However, we do not know whether, in addition to baseline host genetics, somatic mutational profiles in CRC tumors interact with the surrounding tumor microbiome, and if so, whether these changes can be used to understand microbe-host interactions with potential functional biological relevance. Here, we characterized the association between CRC microbial communities and tumor mutations using microbiome profiling and whole-exome sequencing in 44 pairs of tumors and matched normal tissues. We found statistically significant associations between loss-of-function mutations in tumor genes and shifts in the abundances of specific sets of bacterial taxa, suggestive of potential functional interaction. This correlation allows us to statistically predict interactions between loss-of-function tumor mutations in cancer-related genes and pathways, including MAPK and Wnt signaling, solely based on the composition of the microbiome. In conclusion, our study shows that CRC microbiomes are correlated with tumor mutational profiles, pointing towards possible mechanisms of molecular interaction.

Prognostic value of circulating tumor cells in esophageal cancer

AIM

To perform a meta-analysis of the related studies to assess whether circulating tumor cells (CTCs) can be used as a prognostic marker of esophageal cancer.

METHODS

PubMed, Embase, Cochrane Library and references in relevant studies were searched to assess the prognostic relevance of CTCs in patients with esophageal cancer. The primary outcome assessed was overall survival (OS). The meta-analysis was performed using the random effects model, with hazard ratio (HR), risk ratio (RR) and 95% confidence intervals (95%CIs) as effect measures.

RESULTS

Nine eligible studies were included involving a total of 911 esophageal cancer patients. Overall analyses revealed that CTCs-positivity predicted disease progression (HR = 2.77, 95%CI: 1.75-4.40, P < 0.0001) and reduced OS (HR = 2.67, 95%CI: 1.99-3.58, P < 0.00001). Further subgroup analyses demonstrated that CTCs-positive patients also had poor OS in different subsets. Moreover, CTCs-positivity was also significantly associated with TNM stage (RR = 1.48, 95%CI: 1.07-2.06, P = 0.02) and T stage (RR = 1.44, 95%CI: 1.13-1.84, P = 0.003) in esophageal cancer.

CONCLUSION

Detection of CTCs at baseline indicates poor prognosis in patients with esophageal cancer. However, this finding relies on data from observational studies and is potentially subject to selection bias. Prospective trials are warranted.

Flow Cytometric Detection of Circulating Tumor Cells Using a Candidate Stem Cell Marker, p75 Neurotrophin Receptor (p75NTR)

The most widely studied detection for circulating tumor cells (CTCs) in peripheral blood of cancer patients has been based on immunomagnetic enrichment using antibodies against epithelial cell adhesion molecule (EpCAM), which is overexpressed in epithelial cells. A neurotrophin receptor p75 (p75NTR) is expressed in a candidate stem cell fraction in esophageal squamous cell carcinoma (ESCC), which shows significantly higher colony formation, enhanced tumor formation in mice, along with strong expression of epithelial mesenchymal transition-related genes. Here, we describe a method to detect CTCs in ESCC based on the combined expression of EpCAM and p75NTR using flow cytometry, demonstrating the feasibility of expression analysis of multiple cell surface markers in viable cells.

Clinical Relevance of a Candidate Stem Cell Marker, p75 Neurotrophin Receptor (p75NTR) Expression in Circulating Tumor Cells

Despite advances in its diagnosis and multimodal therapies, the prognosis of esophageal squamous cell carcinoma (ESCC) patients remains poor, because of high incidences of metastasis . Recent reports suggested that circulating tumor stem cells (CTSCs), rather than circulating tumor cells (CTCs), were more accurate diagnostic marker for metastasis, because tumor stem cells or cancer stem cells (CSCs) are more responsible for metastasis through processes such as epithelial mesenchymal transition (EMT) and tumor initiation. A neurotrophin receptor p75 (p75NTR) is expressed in a candidate CSC s in ESCC, which possess enhanced tumorigenicity along with strong expression of EMT-related genes. Our recent report using two-color flow cytometry demonstrated that CTC counts based on a combined expression of epithelial cell adhesion molecule (EpCAM) and p75NTR was significantly higher in peripheral blood samples of ESCC patients than healthy controls. In addition, EpCAM + p75NTR+, but not EpCAM + p75NTR- CTC counts, correlated with clinically diagnosed distant metastasis and pathological venous invasion in surgically resected primary ESCC tumors. Malignant cytology of the isolated EpCAM + p75NTR+ cells was microscopically confirmed as well. These results demonstrated that EpCAM + p75NTR+ CTC count was a more accurate diagnostic marker than EpCAM+ CTC count, suggesting the highly metastatic potential of CTCs with p75NTR expression.Investigation using the isolated EpCAM + p75NTR+ CTCs to assess their stem cell properties may shed light on their roles in tumor metastasis in ESCC.Further investigations based on large-scale prospective studies with long term follow up may provide us with evidences for its clinical use.