Prognostic significance of isolated tumor cells in patients with colorectal cancer in recent 10-year studies

Identification and validation of a pyroptosis-related prognostic model for colorectal cancer

In this study, we explored the pyroptosis-related biomarkers and signatures of colorectal cancer (CRC). Gene expression profiles were downloaded from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA)-COADREAD and were analyzed for differentially expressed genes (DEGs). DEGs in CRC‒pyroptosis-related genes (CRC‒PRGs) were obtained by intersecting DEGs associated with CRC and PRGs. The CRC‒PRGs were verified; functional enrichment analysis was performed with Gene Ontology (GO) followed by cluster analysis. Cox analyses and LASSO regression were used in TCGA dataset to construct a prognostic model for patients with CRC. A prognostic risk assessment model was constructed and efficacy was evaluated. Decision curve analysis was utilized to assess the role of the Lasso-Cox regression prognostic model for clinical utility at 1, 3, and 5 years. Twelve CRC‒PRGs were identified as prognostic pyroptosis-related DEGs. CXCL8, IL13RA2, MELK, and POP1 were selected as prognostic genes to construct features with a good prognostic performance in GEO and TCGA. Functional enrichment indicated that the 4-gene signature might be involved in CRC tumorigenesis and development through various pathways by playing a prognostic role in CRC. Furthermore, the results of the immune landscape analysis showed that the expression of CXCL8 and IL13RA2 in TCGA-COADREAD dataset was positively correlated with significant differential enrichment of most immune cells. A novel prognostic model consisting of four key genes, CXCL8, IL13RA2, MELK, and POP1, can accurately predict the survival of patients with CRC. This finding may provide a new perspective for the treatment of pyroptosis-related CRC.

Integrated analysis of RNA-binding proteins in human colorectal cancer

Background

Although RNA-binding proteins play an essential role in a variety of different tumours, there are still limited efforts made to systematically analyse the role of RNA-binding proteins (RBPs) in the survival of colorectal cancer (CRC) patients.

Methods

Analysis of CRC transcriptome data collected from the TCGA database was conducted, and RBPs were extracted from CRC. R software was applied to analyse the differentially expressed genes (DEGs) of RBPs. To identify related pathways and perform functional annotation of RBP DEGs, Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were carried out using the database for annotation, visualization and integrated discovery. Protein-protein interactions (PPIs) of these DEGs were analysed based on the Search Tool for the Retrieval of Interacting Genes (STRING) database and visualized by Cytoscape software. Based on the Cox regression analysis of the prognostic value of RBPs (from the PPI network) with survival time, the RBPs related to survival were identified, and a prognostic model was constructed. To verify the model, the data stored in the TCGA database were designated as the training set, while the chip data obtained from the GEO database were treated as the test set. Then, both survival analysis and ROC curve verification were conducted. Finally, the risk curves and nomograms of the two groups were generated to predict the survival period.

Results

Among RBP DEGs, 314 genes were upregulated while 155 were downregulated, of which twelve RBPs (NOP14, MRPS23, MAK16, TDRD6, POP1, TDRD5, TDRD7, PPARGC1A, LIN28B, CELF4, LRRFIP2, MSI2) with prognostic value were obtained.

Conclusions

The twelve identified genes may be promising predictors of CRC and play an essential role in the pathogenesis of CRC. However, further investigation of the underlying mechanism is needed.

Occult Tumour Cells in Lymph Nodes from Gastric Cancer Patients: Should Isolated Tumour Cells Also Be Considered?

INTRODUCTION

Regional lymph node metastasis is an important prognostic factor for patients with gastric cancer. Occult tumour cells (OTCs), including either micrometastases (MMs) or isolated tumour cells (ITCs), may be a key factor in the development of cancer recurrence in pN0 patients.

AIMS

We aimed to determine the frequency and prognostic significance for disease recurrence of OTCs.

MATERIALS AND METHODS

This retrospective cohort study included all consecutive patients with pN0 gastric adenocarcinoma between January 2000 and December 2011 (n = 73). Immunohistochemistry using the pan-cytokeratin antibody AE1/AE3 was used to detect OTCs in 1257 isolated lymph nodes.

RESULTS

OTCs were identified in 30 patients (41%), including 20 cases with MMs (27%) and 10 cases with ITCs (14%). Disease recurrence and cancer-related death were observed in 24 (33%) and 20 patients (27%), respectively, and both were significantly associated with the detection of OTCs. A significant difference was also observed for the mean survival time between patients with OTCs and those without OTCs [100 vs 158 months (p = 0.015)]. The presence of OTCs was statistically significantly associated with the Lauren classification, tumour size and lymphatic permeation. Multivariate analyses revealed that only age, T stage and the presence of ITCs in lymph nodes were independent factors for recurrence. The presence of ITCs increased the risk for recurrence by 11.1-fold.

CONCLUSIONS

In a significant proportion of patients diagnosed as stage pN0, OTCs may be identified in lymph nodes if carefully searched for, which can negatively affect their prognosis. The presence of ITCs was found to be an independent factor for recurrence and after proper validation should be considered during lymph node assessment for prognosis definition.

The Developing Story of Predictive Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the third most common malignancy worldwide. Surgery remains the most important treatment for non-metastatic CRC, and the administration of adjuvant chemotherapy depends mainly on the disease stage, which is still the strongest prognostic factor. A refined understanding of the genomics of CRC has recently been achieved thanks to the widespread use of next generation sequencing with potential future therapeutic implications. Microsatellite instability (MSI) has been suggested as a predictive marker for response to anti-programmed-cell-death protein 1 (PD-1) therapy in solid tumors, including CRC. It should be noted that not all cancers with MSI phenotype respond to anti-PD-1 immunotherapy, highlighting the urgent need for even better predictive biomarkers. Mitogen-Activated Protein Kinase (MAPK) pathway genes KRAS, NRAS, and BRAF represent important molecular targets and could serve as independent prognostic biomarkers in CRC, and identify those who potentially benefit from anti-epidermal growth factor receptor (EGFR) treatment. Emerging evidence has attributed a significant role to inflammatory markers including blood cell ratios in the prognosis and survival of CRC patients; these biomarkers can be easily assessed in routine blood exams and be used to identify high-risk patients or those more likely to benefit from chemotherapy, targeted therapies and potentially immunotherapy. Analysis of cell-free DNA (cfDNA), circulating tumor cells (CTC) and/or micro RNAs (miRNAs) could provide useful information for the early diagnosis of CRC, the identification of minimal residual disease and, the evaluation of the risk of recurrence in early CRC patients. Even the selection of patients suitable for the new targeted therapy is becoming possible with the use of predictive miRNA biomarkers. Finally, the development of treatment resistance with the emergence of chemo-resistance clones after treatment remains the most important challenge in the clinical practice. In this context it is crucial to identify potential biomarkers and therapeutic targets which could lead to development of new and more effective treatments.

Prognostic value of pre- and post-operative circulating tumor cells detection in colorectal cancer patients treated with curative resection: a prospective cohort study based on ISET device

Background

Circulating tumor cells (CTCs) have been regarded as a promising biomarker for colorectal cancer (CRC); however, the prognostic value of post-operative (op) CTCs is still unclear. This study aimed to compare the recurrence prediction value of pre- and post-op CTCs in CRC patients treated with curative resection.

Patients and methods

Consecutive CRC patients treated with curative resection from January 2014 to March 2015 were identified. CTCs from 2.5 mL peripheral blood were enumerated with an ISETdevice-CTCBIOPSY^® before and after surgery. Based on the status of pre- and post-op CTCs, the included patients were grouped into four cohorts: pre- and post-op CTCs−, pre-op CTCs− but post-op CTCs+, pre-op CTCs+ but post-op CTCs−, and pre- and post-op CTCs+. The 3-year recurrence-free survival (RFS) rate of patients was analyzed.

Results

A total of 138 patients (79 [57.2%] male; median age=62 [43–75] years) were enrolled. Patients with pre-op CTCs− had a 19.2% higher 3-year RFS rate (86.2%) than the combined cohorts with pre-op CTCs+ (67.0%) (P=0.038). Patients with post-op CTCs+ had aa 25.6% lower 3-year RFS rate (57.1%) than the combined cohorts with post-op CTCs− (82.7%) (P=0.001). Moreover, patients with pre- and post-op CTCs+ had a 25.1% lower 3-year RFS rate (53.8%) than patients with pre-op CTCs+ but post-op CTCs− (78.9%) (P=0.004). Multivariate analyses confirmed that post-op CTCs+ (HR=2.82, 95% CI=1.39–5.75, P=0.004), but not but pre-op CTCs+ (HR=2.17, 95% CI=0.75–6.31, P=0.153), was independently associated with shorter 3-year RFS rate.

Conclusion

Post-op CTCs+, but not pre-op CTCs+, is an independent indicator of poor prognosis for CRC patients treated with curative resection. Patients with post-op CTCs+ have a higher risk of recurrence those with pre-op CTCs+. Evaluation of post-op, rather than pre-op, CTCs is warranted.

Genomic heterogeneity in primary colorectal carcinomas and their metastases: born bad or brought up a villain?

Progression of solid cancers, colorectal carcinomas among them, from their primaries to metastatic lesions traditionally is thought to proceed by a stepwise acquisition of and selection for genomic aberrations. To test if patterns of genomic aberrations would be consistent with this model, we studied 10 colorectal carcinoma primary-metastasis pairs, 9 with 1 liver metastasis each and 1 with 2 metastases. Next-generation targeted sequencing (50-gene panel) with samples obtained from different regions of the primaries and their metastases demonstrated 1-11 gene mutations per lesion. But only in 2 tumors were there seen mutations in all samples from the metastasis and not any of the primaries (BRAF^D594N and SMARCB1^R377C mutation, respectively). However, allelotyping the multiregional samples with polymorphous microsatellite markers (17p13.1, D9S942, D9S1748, D5S346, D5S1385) and DNA methylation studies with a marker panel (MLH1, CDNK2A, NEUROG1, CRABP1, CACNA1G, IGF2, RUNX3, SOCS1) showed remarkably "insular" genomic aberrations in all cases for at least some of the analyses. The marked preponderance of mutations shared by the primaries and their metastases throughout the lesions over mutations private to metastases suggests that, at least in many cases, colorectal carcinomas might be endowed with a mutational load sufficient for fully fledged metastases even at a very early stage ("born bad"). But the very focal allelic imbalances and methylations observed here, hypothetically, could play a role in clinically metastasizing disease, a process of years rather than months and very much a matter of tumor-host interactions when tumor cells adapt to the host microenvironment.

Current and future biomarkers in colorectal cancer

Colorectal cancer (CRC), one of the leading causes of death among cancer patients, is a heterogeneous disease and is characterized by diversions in multiple molecular pathways throughout its evolutionary process. To date, specific mutations in RAS and RAF genes are tested in everyday clinical practice along with mismatch repair gene deficiency, serving either as prognostic or predictive biomarkers, providing information for patient risk stratification and the choice of appropriate therapy. However, ongoing studies are focusing on the potential role of recently discovered genetic and epigenetic alterations in the management of CRC patients and their potential prognostic or predictive value. To overcome the problem of tumor heterogeneity as well as the practical obstacles of access to tumor tissue, and to achieve real-time monitoring of disease and therapy efficacy, liquid biopsies constitute a novel technology worth exploring. CRC screening and management is entering a new era where molecular testing will be applied to genomic material extracted from easily accessible bodily fluids.

Are disseminated tumor cells in bone marrow and tumor-stroma ratio clinically applicable for patients undergoing surgical resection of primary colorectal cancer? The Leiden MRD study

Purpose

Current TNM staging does not appropriately identify high-risk colorectal cancer (CRC) patients. The aim of this study was to evaluate whether the presence of disseminated tumor cells (DTCs) in the bone marrow (BM) and the presence of stroma in the primary tumor, i.e., the tumor-stroma ratio (TSR), in patients undergoing surgical resection of primary CRC provides information relevant for disease outcome.

Methods

Patients with primary CRC (n = 125), consecutively admitted for curative resection between 2001 and 2007, were included in the study. All patients underwent BM aspiration before surgery. Detection of tumor cells was performed using immunocytochemical staining for cytokeratin (CK-ICC). The TSR was determined on diagnostic H&E stained sections of primary tumors.

Results

DTCs were detected in the BM of 23/125 patients (18 %). No association was found between BM status and overall survival (HR 0.97 (95 % CI 0.45–2.09), p = 0.93). Also, no significant difference was found in their 5-year survival rate (resp. 72 % and 68 % for BM-positive versus BM-negative patients). The TSR was found to be associated with a worse overall survival (HR 2.16, 95 % CI 1.02–4.57, p = 0.04) with 5-year survival rates of 84 % versus 62 % for stroma-low and stroma-high patients, respectively. No relation was found between the presence of DTCs and TSR.

Conclusions

Our data indicate that the presence of DTCs in the BM of CRC patients is not associated with disease outcome. The TSR was, however, found to be associated with a worse overall survival, which indicates that for CRC the tumor microenvironment plays an important role in its behavior and prognosis.

New trends in molecular and cellular biomarker discovery for colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer death worldwide, which is consequence of multistep tumorigenesis of several genetic and epigenetic events. Since CRC is mostly asymptomatic until it progresses to advanced stages, the early detection using effective screening approaches, selection of appropriate therapeutic strategies and efficient follow-up programs are essential to reduce CRC mortalities. Biomarker discovery for CRC based on the personalized genotype and clinical information could facilitate the classification of patients with certain types and stages of cancer to tailor preventive and therapeutic approaches. These cancer-related biomarkers should be highly sensitive and specific in a wide range of specimen(s) (including tumor tissues, patients’ fluids or stool). Reliable biomarkers which enable the early detection of CRC, can improve early diagnosis, prognosis, treatment response prediction, and recurrence risk. Advances in our understanding of the natural history of CRC have led to the development of different CRC associated molecular and cellular biomarkers. This review highlights the new trends and approaches in CRC biomarker discovery, which could be potentially used for early diagnosis, development of new therapeutic approaches and follow-up of patients.

Blood-based biomarkers for diagnosis, prognosis and treatment of colorectal cancer

The global burden of colorectal cancer (CRC)-associated morbidity and mortality is increasing, in part due to a lack of early detection. Direct structural examination techniques, such as colonoscopy, are invasive and can therefore affect the willingness of patients to participate in screening. Recently, the use of "liquid biopsy" has gained considerable attention as a novel source of biomarkers. Blood-based biomarkers could prove to be practical tools for CRC detection, as the monitoring of biomarkers in biological fluids offers many advantages, including minimal invasiveness and easy accessibility. Biomarkers with high specificity and sensitivity can enable the detection of CRC at an early stage, thereby improving prognosis, prediction of treatment response, and recurrence risk. In this review, we summarize that the biomarkers currently thought to have potential for the early detection and monitoring of CRC, including circulating tumor cells, DNA, RNA and proteins.

MicroRNA-217 functions as a prognosis predictor and inhibits colorectal cancer cell proliferation and invasion via an AEG-1 dependent mechanism

Background

Recent studies have indicated the possible function of miR-217 in tumorigenesis. However, the roles of miR-217 in colorectal cancer (CRC) are still largely unknown.

Methods

We examined the expression of miR-217 and AEG-1 in 50 CRC tissues and the corresponding noncancerous tissues by qRT-PCR. The clinical significance of miR-217 was analyzed. CRC cell lines with miR-217 upregulation and AEG-1 silencing were established and the effects on tumor growth in vitro and in vivo were assessed. Dual-luciferase reporter gene assays were also performed to investigate the interaction between miR-217 and AEG-1.

Results

Our data demonstrated that miR-217 was significantly downregulated in 50 pairs of colorectal cancer tissues. MiR-217 expression levels were closely correlated with tumor differentiation. Moreover, decreased miR-217 expression was also associated with shorter overall survival of CRC patients. MiR-217 overexpression significantly inhibited proliferation, colony formation and invasiveness of CRC cells by promoting apoptosis and G0/G1 phase arrest. Interestingly, ectopic miR-217 expression decreased AEG-1 expression and repressed luciferase reporter activity associated with the AEG-1 3′-untranslated region (UTR). AEG-1 silencing resulted in similar biological behavior changes to those associated with miR-217 overexpression. Finally, in a nude mouse xenografted tumor model, miR-217 overexpression significantly suppressed CRC cell growth.

Conclusions

Our findings suggest that miR-217 has considerable value as a prognostic marker and potential therapeutic target in CRC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1438-z) contains supplementary material, which is available to authorized users.

Comparative analysis between multilevel sectioning with conventional haematoxylin and eosin staining and immunohistochemistry for detecting nodal micrometastases with stage I and II colorectal cancers

Management of patients with stage II colorectal carcinomas remains challenging as 20 - 30% of them will develop recurrence. It is postulated that these patients may harbour nodal micrometastases which are imperceptible by routine histopathological evaluation. The aims of our study were to evaluate (1) the feasibility of multilevel sectioning method utilizing haematoxylin and eosin stain and immunohistochemistry technique with cytokeratin AE1/AE3, in detecting micrometastases in histologically-negative lymph nodes, and (2) correlation between nodal micrometastases with clinicopathological parameters. Sixty two stage I and II cases with a total of 635 lymph nodes were reviewed. Five-level haematoxylin and eosin staining and one-level cytokeratin AE1/AE3 immunostaining were performed on all lymph nodes retrieved. The findings were correlated with clinicopathological parameters. Two (3.2%) lymph nodes in two patients (one in each) were found to harbour micrometastases detected by both methods. With cytokeratin AE1/AE3, we successfully identified four (6.5%) patients with isolated tumour cells, but none through the multilevel sectioning method. Nodal micrometastases detected by both multilevel sectioning and immunohistochemistry methods were not associated with larger tumour size, higher depth of invasion, poorer tumour grade, disease recurrence or distant metastasis. We conclude that there is no difference between the two methods in detecting nodal micrometastases. Therefore it is opined that multilevel sectioning is a feasible and yet inexpensive method that may be incorporated into routine practice to detect nodal micrometastases in centres with limited resources.