CXCL12 expression promotes esophageal squamous cell carcinoma proliferation and worsens the prognosis

The CXCR4 might be a potential biomarker for esophageal squamous cell carcinoma: A meta-analysis

OBJECTIVE

To evaluate the relationship between CXCL12/CXCR4 and the progress, prognosis of esophageal squamous cell carcinoma (ESCC), providing evidence for potential early diagnosis, clinical treatment, prognosis evaluation, and therapeutic target of ESCC.

METHODS

Databases of PubMed, the Cochrane Library, Embase, and Web of Science were searched for the relationship between CXCL12/CXCR4 and clinicopathological characteristics and survival time of ESCC. Stata16.0 software was used to conduct meta-analysis.

RESULTS

A total of 10 studies involving 1216 cases of patients with ESCC were included in our study. The results indicated that high-level expression of CXCR4 was significantly correlated with tumor differentiation [OR = 0.69, 95% confidence interval (CI): (0.50, 0.97)], tumor infiltration [OR = 0.39, 95% CI: (0.25, 0.61)], lymph node metastasis [OR = 0.36, 95% CI: (0.21, 0.61)], clinical stage [OR = 0.33, 95% CI: (0.24, 0.45)] of ESCC. The expression of CXCR4 was also significantly correlated with OS [HR = 2.00, 95% CI: (1.63, 2.45)] and disease-free survival [HR = 1.76, 95% CI: (1.44, 2.15)] in patients of ESCC after surgical resection. No significant relationship was observed between the expression of CXCL12 and the clinicopathological characteristics of ESCC.

CONCLUSION

CXCR4 might be a potential biomarker for the progress and prognosis evaluation, and therapeutic target for ESCC.

Insulin receptor substrate 1(IRS1) is related with lymph node metastases and prognosis in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer-related mortality globally with a high risk of lymph node metastasis (LNM). In this study, weighted gene co-expression network analysis (WGCNA) showed the identification of 10 modules among which the significant module (turquoise), including 1352 genes, was correlated with LNM. A group 52 overlapping differentially expressed genes (DEGs) was identified based on the comparison of turquoise module with GSE23400 and GSE20347 datasets. Using Ctyohubba plugin, we identified 7 hub genes (ACTG2, SORBS1, MYH11, CXCL12, CNN1, IRS1 and CXCL8). IRS1 displayed significant correlation with metastasis. The decreased expression of IRS1 was also a predictor of poor OS of ESCC patients whereas the hub genes namely ACTG2, MYH11, CXCL8, CXCL12, IRS1 and CNN1 were associated with RFS of ESCC patients. These findings suggest that the altered expression of these hub genes are associated with prognosis and thus can be used as potential biomarkers for ESCC. Moreover, immunohistochemical staining and cell functional experiments displayed that the overexpression of IRS1 was negatively associated with metastasis in ESCC. In general, our research revealed several novel genes in ESCC especially the association of IRS1 with LNM in ESCC, which could provide novel insights into the initiation and progression of ESCC.

SDF-1α predicts poor prognosis in patients with locally advanced esophageal squamous cell carcinoma receiving definitive concurrent chemoradiotherapy

BACKGROUND

Stromal cell-derived factor-1α (SDF-1α) is a chemokine associated with tumor progression in various types of cancers. The current study aimed to evaluate whether pre-treatment or kinetics of SDF-1α can predict the prognosis in patients with esophageal squamous cell carcinoma (ESCC) receiving definitive concurrent chemoradiotherapy (CCRT).

METHODS

A total of 97 patients with ESCC were identified at Kaohsiung Chang Gung Memorial Hospital between January 2010 and December 2015. Serum concentration of SDF-1α was measured at day 0 (pre-treatment) and chemotherapy day 28 to determine its kinetics and the cut-off level of pre-chemotherapy SDF-1α was 1.5 ng/mL. Two ESCC cell lines, TE1 and KYSE30, were selected to evaluate the function of SDF-1α.

RESULTS

Univariate and multivariate analyses showed that pre-treatment SDF-1α ≥ 1.5 ng/mL and an increased SDF-1α level after treatment were significantly associated with worse progression-free survival (p = 0.021 and p = 0.008, respectively) and overall survival (p = 0.005 and p < 0.001, respectively). In addition, patients with pre-treatment SDF-1α ≥ 1.5 ng/mL and increased SDF-1α levels after treatment were found to have poor response to CCRT. Moreover, these cell lines were treated with chemotherapeutic agents (cisplatin or 5-FU) and SDF-1α, alone or in combination. Our in vitro study results showed SDF-1α promoted the proliferation of tumor cells and overcame the cytotoxic effect of chemotherapy (p < 0.001).

CONCLUSION

Our study suggested that SDF-1α plays an important role in ESCC disease progression and that pre-treatment SDF-1α level and kinetics of SDF-1α are the independent prognostic factors for ESCC patients receiving definitive CCRT. Periodic determinations of serum SDF-1α level may be valuable to predict prognosis of ESCC in clinical practice.

Chemokine-targeted therapies: An opportunity to remodel immune profiles in gastro-oesophageal tumours

Immunotherapies are transforming outcomes for many cancer patients and are quickly becoming the fourth pillar of cancer therapy. However, their efficacy of only ∼25% in gastro-oesophageal cancer has been disappointing. This is attributed to factors such as insufficient patient stratification and the pro-tumourigenic immune landscape of gastro-oesophageal tumours. The chemokine profiles of solid tumours and the availability of effector immune cells greatly influence the immune infiltrate, producing 'cold' or 'immune-excluded' tumours in which immunotherapies are unable to reinvigorate the immune response. Other biological functions for chemokines have emerged, such as promoting cell survival, polarising T cell responses, and supporting several hallmarks of cancer. Therefore, chemokine networks may be exploited with therapeutic intent to mobilise and polarise anti-tumour immune cells, with further utility as combination treatments to augment the efficacy of current cancer immunotherapies. Few studies have demonstrated the clinical benefit of chemokine-targeted therapies as monotherapies, and this review proposes their consideration as combination treatments. Herein, we explore the anti-tumour and pro-tumour implications of chemokine signalling in gastro-oesophageal cancer and discuss their value as prognostic and predictive biomarkers in response to treatment.

The biological role of the CXCL12/CXCR4 axis in esophageal squamous cell carcinoma

Esophageal cancer is the eighth most common malignant tumor and the sixth leading cause of cancer-related death worldwide. Esophageal squamous cell carcinoma (ESCC) is the main histological type of esophageal cancer, and accounts for 90% of all cancer cases. Despite the progress made in surgery, chemotherapy, and radiotherapy, the mortality rate from esophageal cancer remains high, and the overall 5-year survival rate is less than 20%, even in developed countries. The C-X-C motif chemokine ligand 12 (CXCL12) is a member of the CXC chemokine subgroup, which is widely expressed in a variety of tissues and cells. CXCL12 participates in the regulation of many physiological and pathological processes by binding to its specific receptor, C-X-C motif chemokine receptor type 4 (CXCR4), where it causes embryonic development, immune response, and angiogenesis. In addition, increasing evidence indicates that the CXCL12/CXCR4 axis plays an important role in the biological processes of tumor cells. Studies have shown that CXCL12 and its receptor, CXCR4, are highly expressed in ESCC. This abnormal expression contributes to tumor proliferation, lymph node and distant metastases, and worsening prognosis. At present, antagonists and imaging agents against CXCL12 or CXCR4 have been developed to interfere with the malignant process and monitor metastasis of tumors. This article summarizes the structure, function, and regulatory mechanism of CXCL12/CXCR4 and its role in the malignancy of ESCC. Current results from preclinical research targeting CXCL12/CXCR4 are also summarized to provide a reference for the clinical diagnosis and treatment of ESCC.

Prognostic Impact of CXCR7 and CXCL12 Expression in Patients with Esophageal Adenocarcinoma

BACKGROUND

Chemokines are major regulators of cell trafficking and adhesion. The chemokine CXCL12 and its receptors, CXCR4 and CXCR7, have been reported as biomarkers in various cancers, including esophageal cancer; however, there are few studies in esophageal adenocarcinoma (EAC). In this study, we investigated the relationship between expression of CXCL12, CXCR4, and CXCR7, and prognosis in patients with EAC.

METHODS

This study examined 55 patients with EAC who were treated in Toronto General Hospital from 2001 to 2010. Tissue microarray immunohistochemistry was used to evaluate the expression of CXCL12, CXCR4, and CXCR7. Evaluation of immunohistochemistry was performed by a pathologist without knowledge of patients' information and results were compared with the patients' clinicopathological features and survival.

RESULTS

High CXCR7 expression was significantly associated with lymphatic invasion (present vs absent, P = 0.005) and higher number of lymph node metastases (pN0-1 vs pN2-3, P = 0.0014). Patients with high CXCR7 expression (n = 23) were associated with worse overall (OS) and disease-free survival (DFS) (P = 0.0221, P = 0.0090, respectively), and patients with high CXCL12 (n = 24) tended to have worse OS and DFS (P = 0.1091, P = 0.1477, respectively). High expression of both CXCR7 and CXCL12 was an independent prognostic factor for OS and DFS on multivariate analysis (HR = 0.3, 95% CI: 0.1-0.9, P = 0.0246, HR = 0.3, 95% CI: 0.1-0.8, P = 0.0134, respectively).

CONCLUSIONS

High CXCR7 expression was associated with poor prognosis in patients with EAC, and high expression of CXCR7 with its ligand CXCL12 had a stronger association with prognosis. Further study of this potential biomarker using whole tissue samples and a larger sample size is warranted.

Pentixafor PET/CT for imaging of chemokine receptor 4 expression in esophageal cancer - a first clinical approach

Background

Expression of CXCR4, a chemokine (C-X-C motif) receptor that plays a central role in tumor growth and metastasis of circulating tumor cells, has been described in a variety of solid tumors. A high expression of CXCR4 has a prognostic significance with regard to overall and progression-free survival and offers a starting point for targeted therapies. In this context, [68]Ga-Pentixafor-Positron Emission Tomography/Computer Tomography (PET/CT) offers promising possibility of imaging the CXCR4 expression profile. We set out to compare a [18F] fluorodeoxyglucose (FDG)-PET/CT and a [68Ga]Pentixafor-PET/CT in (re-)staging and radiation planning of patients with localized esophageal cancer.

Materials and methods

In this retrospective analysis, ten patients, with adeno- or squamous cell carcinoma of the esophagus (n = 3 and n = 7, respectively), which were scheduled for radio (chemo) therapy, were imaged using both Pentixafor and FDG PET/CT examinations. All lesions were visually rated as Pentixafor and FDG positive or negative. For both tracers, SUVmax was measured all lesions and compared to background. Additionally, immunohistochemistry of CXCR4 was obtained in patients undergoing surgery.

Results

FDG-positive tumor-suspicious lesions were detected in all patients and a total of 26 lesions were counted. The lesion-based analysis brought equal status in 14 lesions which were positive for both tracers while five lesions were FDG positive and Pentixafor negative and seven lesions were FDG negative, but Pentixafor positive. Histopathologic correlation was available in seven patients. The CXCR4 expression of four non-pretreated tumour lesion samples was confirmed immunohistochemically.

Conclusion

Our data shows that additional PET/CT imaging with Pentixafor for imaging the CXCR4 chemokine receptor is feasible but heterogeneous in both newly diagnosed and pretreated recurrent esophageal cancer. In addition, the Pentixafor PET/CT may serve as complementary tool for radiation field expansion in radiooncology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00391-w.

Prognostic Value of SDF-1α Expression in Patients with Esophageal Squamous Cell Carcinoma Receiving Esophagectomy

Stromal cell-derived factor-1α (SDF-1α) is a chemokine that has been reported to be involved in tumor progression in several malignancies. This study aimed to evaluate the crucial role of SDF-1α in patients with esophageal squamous cell carcinoma (ESCC) who underwent esophagectomy. A total of 169 patients with ESCC were identified, including overexpression of SDF-1α in 60 patients and low expression of SDF-1α in 109 patients by immunohistochemical analysis. Two ESCC cell lines, TE1 and KYSE30, were selected to evaluate the tumor cell proliferative effect of SDF-1α. Univariate and multivariate analyses showed that high tumor (T) status, positive lymph node metastasis, tumors located in the upper esophagus, and SDF-1α overexpression were significantly related to worse disease-free survival and overall survival. In addition, the two cell lines were treated with SDF-1α, AMD3100 (an SDF-1α-ligand receptor antagonist), and chemotherapeutic agents (cisplatin). Our in vitro study results showed that SDF-1α promoted the proliferation of tumor cells, and blocking the SDF-1α pathway displayed a growth inhibition effect in a dose-dependent manner. SDF-1α plays an important role in the progression of ESCC and is an independent prognostic factor for ESCC patients who underwent esophagectomy.

Chemokines and their receptors as biomarkers in esophageal cancer

Esophageal cancer (EC) is one of the most lethal malignancies of the digestive tract and remains to be improved poor prognosis. Two histological subtypes, esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC), are major characteristics of EC. Deep understanding about both subtypes is essential to overcome EC. Here, we focus on chemokines and their receptors as biomarkers and their current applications for the prognosis in EC. We reviewed relevant articles identified using PubMed database for the chemokines and their receptors in EC analyzed by immunohistochemistry. The primary objective is to summarize evidences for them as prognostic biomarkers in EC. A total of twenty-one articles were reviewed after exclusion. Most studies have been done in ESCC, and less in EAC. CXCL12 and its receptor CXCR4 have been shown in both subtypes as biomarkers. CXCR7, CXCL8 and its receptor CXCR2, and CCL21 and its receptor CCR7 have been examined in ESCC. Although it was a small number of reports, CXCL10, CCL4, and CCL5 have been indicated to have anti-tumor effects in ESCC. Chemokines and their receptors have the potential to be the biomarkers in EC. Comparative studies between ESCC and EAC will reveal the similarity and difference in these two subtypes of EC. These studies may indicate whether these molecules play important roles in both subtypes or are unique to one or another.

Prognostic roles of miR-124-3p and its target ANXA7 and their effects on cell migration and invasion in hepatocellular carcinoma

Recent studies have indicated that ANXA7 promotes progression and metastasis of hepatocellular carcinoma (HCC). In this study we found a significant negative correlation between the levels of miR-124-3p and ANXA7 protein in HCC. Level of miR-124-3p in tumor tissues was negatively correlated, while ANXA7 protein was positively correlated, with TNM stage and tumor metastasis. Furthermore, we confirmed ANXA7 was a target gene of miR-124-3p by a dual luciferase reporter assay. In vitro, up-regulation of miR-124-3p promotes apoptosis and inhibits migration and invasion of Hca-F. Bcl-2 correlates X protein (Bax) protein level was up-regulated, while ANXA7, B-cell lymphoma-2 (Bcl-2), Matrix metalloproteinase (MMP-9) and C-X-C motif chemokine 12 (CXCL12) protein levels were suppressed relative to miR-124-3p over-expression. In vivo, up-regulation of miR-124-3p suppresses lymph node metastasis (LNM) and tumorigenicity of Hca-F cells. The expression of ANXA7, MMP-9, and CXCL12 protein in transplanted tumors was suppressed relative to miR-124-3p overexpression. In addition, we found the levels of Bcl-2, MMP-9, and CXCL12 in Hca-F cells decreased significantly after transfection of shRNA-Anxa7 in vitro. In conclusion, our study revealed miR-124-3p inhibits tumor growth, invasion, and lymphatic metastasis in HCC by down-regulation of ANXA7 gene, thereby reducing the expression of Bcl-2, MMP-9, and CXCL12.

Chemokines and their Receptors: Multifaceted Roles in Cancer Progression and Potential Value as Cancer Prognostic Markers

Chemokines are chemotactic cytokines that mediate immune cell chemotaxis and lymphoid tissue development. Recent advances have indicated that chemokines and their cognate receptors play critical roles in cancer-related inflammation and cancer progression. On the basis of these findings, the chemokine system has become a new potential drug target for cancer immunotherapy. In this review, we summarize the essential roles of the complex network of chemokines and their receptors in cancer progression. Furthermore, we discuss the potential value of the chemokine system as a cancer prognostic marker. The chemokine system regulates the infiltration of immune cells into the tumor microenvironment, which induces both pro- and anti-immunity and promotes or suppresses tumor growth and proliferation, angiogenesis, and metastasis. Increasing evidence indicates the promising prognostic value of the chemokine system in cancer patients. While CCL2, CXCL10, and CX3CL1/CX3CR1 can serve as favorable or unfavorable prognostic factors depending on the cancer types, CCL14 and XCL1 possess good prognostic value. Other chemokines such as CXCL1, CXCL8, and CXCL12 are poor prognostic markers. Despite vast advances in our understanding of the complex nature of the chemokine system in tumor biology, knowledge about the multifaceted roles of the chemokine system in different types of cancers is still limited. Further studies are necessary to decipher distinct roles within the chemokine system in terms of cancer progression and to validate their potential value in cancer prognosis.

Identification of the inhibitor of growth protein 4 (ING4) as a potential target in prostate cancer therapy

INhibitor of Growth protein 4 (ING4) is a potential chromatin modifier that has been implicated in several cancer-related processes. However, the role of ING4 in prostate cancer (PC) is largely unknown. This study aimed to assess ING4's role in global transcriptional regulation in PC cells to identify potential cellular processes associated with ING4 loss. RNA-Seq using next-generation sequencing (NGS) was used to identify altered genes in LNCaP PC cells following ING4 depletion. Ingenuity pathways analysis (IPA^®) was applied to the data to highlight candidates, ING4-regulated pathways, networks and cellular processes. Selected genes were validated using RT-qPCR. RNA-Seq of LNCaP cells revealed a total of 159 differentially expressed genes (fold change ≥ 1.5 or ≤ - 1.5, FDR ≤ 0.05) following ING4 knockdown. RT-qPCR used to validate the expression level of selected genes was in agreement with RNA-Seq results. Key genes, unique pathways, and biological networks were identified using IPA^® analysis. This is the first report of global gene regulation in PC cells by ING4. The resultant differential expression profile revealed the potential role of ING4 in PC pathogenesis possibly through modulation of key genes, pathways and biological networks that are central drivers of the disease. Collectively, these findings shed light on a novel transcriptional regulator of PC that ultimately may influence the disease progression and as a potential target in the disease therapy.

Study on miRNAs in Pan-Cancer of the Digestive Tract Based on the Illumina HiSeq System Data Sequencing

Objective

miRNA has gained attention as a therapeutic target in various malignancies. The proposal of this study was to investigate the biological functions of key miRNAs and target genes in cancers of the digestive tract which include esophageal carcinoma (ESCA), gastric adenocarcinoma (GAC), colon adenocarcinoma (COAD), and rectal adenocarcinoma (READ).

Materials and Methods

After screening differentially expressed miRNAs (DEMIs) and differentially expressed mRNAs (DEMs) in four digestive cancers from The Cancer Genome Atlas (TCGA) database, the diagnostic value of above DEMIs was evaluated by receiver-operating characteristic (ROC) curve analysis. Then, corresponding DEMIs' target genes were predicted by miRWalk 2.0. Intersection of predicted target genes and DEMs was taken as the target genes of DEMIs, and miRNA-mRNA regulatory networks between DEMIs and target genes were constructed. Meanwhile, the univariate Cox risk regression model was used to screen miRNAs with distinct prognostic value, and Kaplan-Meier analysis was used to determine their significance of prognosis. Furthermore, we performed bioinformatics methods including protein-protein interaction (PPI) networks, gene ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and gene group RIDA analysis by Gene-Cloud of Biotechnology Information (GCBI) to explore the function and molecular mechanisms of DEMIs and predicted target genes in tumor development.

Results

Eventually, 3 DEMIs (miR-7-3, miR-328, and miR-323a) with significant prognostic value were obtained. In addition, 3 DEMIs (miR-490-3p, miR-133a-3p, and miR-552-3p) and 281 target genes were identified, and the 3 DEMIs showed high diagnostic value in READ and moderate diagnostic value in ESCA, GAC, and COAD. Also, the miRNA-mRNA regulatory network with 3 DEMIs and 281 overlapping genes was successfully established. Functional enrichment analysis showed that 281 overlapping genes were mainly related to regulation of cell proliferation, cell migration, and PI3K-Akt signaling pathway.

Conclusion

The diagnostic value and prognostic value of significant DEMIs in cancers of the digestive tract were identified, which may provide a novel direction for treatment and prognosis improvement of cancers of the digestive tract.

MicroRNA-9 inhibits growth and invasion of head and neck cancer cells and is a predictive biomarker of response to plerixafor, an inhibitor of its target CXCR4

Head and neck squamous cell carcinomas (HNSCC) are associated with poor morbidity and mortality. Current treatment strategies are highly toxic and do not benefit over 50% of patients. There is therefore a crucial need for predictive and/or prognostic biomarkers to allow treatment stratification for individual patients. One class of biomarkers that has recently gained importance are microRNA (miRNA). MiRNA are small, noncoding molecules which regulate gene expression post‐transcriptionally. We performed miRNA expression profiling of a cohort of head and neck tumours with known clinical outcomes. The results showed miR‐9 to be significantly downregulated in patients with poor treatment outcome, indicating its role as a potential biomarker in HNSCC. Overexpression of miR‐9 in HNSCC cell lines significantly decreased cellular proliferation and inhibited colony formation in soft agar. Conversely, miR‐9 knockdown significantly increased both these features. Importantly, endogenous CXCR4 expression levels, a known target of miR‐9, inversely correlated with miR‐9 expression in a panel of HNSCC cell lines tested. Induced overexpression of CXCR4 in low expressing cells increased proliferation, colony formation and cell cycle progression. Moreover, CXCR4‐specific ligand, CXCL12, enhanced cellular proliferation, migration, colony formation and invasion in CXCR4‐overexpressing and similarly in miR‐9 knockdown cells. CXCR4‐specific inhibitor plerixafor abrogated the oncogenic phenotype of CXCR4 overexpression as well as miR‐9 knockdown. Our data demonstrate a clear role for miR‐9 as a tumour suppressor microRNA in HNSCC, and its role seems to be mediated through CXCR4 suppression. MiR‐9 knockdown, similar to CXCR4 overexpression, significantly promoted aggressive HNSCC tumour cell characteristics. Our results suggest CXCR4‐specific inhibitor plerixafor as a potential therapeutic agent, and miR‐9 as a possible predictive biomarker of treatment response in HNSCC.

Identification of molecular targets for esophageal carcinoma diagnosis using miRNA-seq and RNA-seq data from The Cancer Genome Atlas: a study of 187 cases

Esophageal carcinoma (ESCA) is one of the most common malignancies worldwide, and its pathogenesis is complex. In this study, we identified differentially expressed miRNAs (DEMs) and genes (DEGs) of ESCA from The Cancer Genome Atlas (TCGA) database. The diagnostic values of DEMs were determined by receiver operating characteristic (ROC) analyses and validated based on data from Gene Expression Omnibus (GEO). The top five DEMs with the best diagnostic values were selected, and their potential targets were predicted by various in silico methods. These target genes were then identified among the DEGs from TCGA. Furthermore, the overlapping genes were subjected to protein-protein interaction (PPI) analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The miRNA-transcription factor (TF) regulatory relations were determined using CircuitsDB and TransmiR. Finally, the regulatory networks of miRNA-TF and miRNA-gene were constructed and analyzed. A total of 136 DEMs and 3541 DEGs were identified in ESCA. The top five DEMs with the highest area under the receiver operating characteristic curve (AUC) values were miRNA-93 (0.953), miRNA-21 (0.928), miRNA-4746 (0.915), miRNA-196a-1 (0.906) and miRNA-196a-2 (0.906). The combined AUC of these five DEMs was 0.985. The KEGG analysis with 349 overlapping genes showed that the calcium signaling pathway and the neuroactive ligand-receptor interaction were the most relevant pathways. The regulatory networks of miRNA-TF and miRNA-gene, including 38 miRNA-TF and 560 miRNA-gene pairs, were successfully established. Our findings may provide new insights into the molecular mechanisms of ESCA pathogenesis. Future research will aim to explore the role of novel miRNAs in the pathogenesis and improve the early diagnosis of ESCA.

A meta-analysis of CXCL12 expression for cancer prognosis

Background:

CXCL12 (SDF1) is reported to promote cancer progression in several preclinical models and this is corroborated by the analysis of human tissue specimens. However, the relationship between CXCL12 expression and cancer survival has not been systematically assessed.

Methods:

We conducted a systematic review and meta-analysis of studies that evaluated the association between CXCL12 expression and cancer survival.

Results:

Thirty-eight studies inclusive of 5807 patients were included in the analysis of overall, recurrence-free or cancer-specific survival, the majority of which were retrospective. The pooled hazard ratios (HRs) for overall and recurrence-free survival in patients with high CXCL12 expression were 1.39 (95% CI: 1.17–1.65, P=0.0002) and 1.12 (95% CI: 0.82–1.53, P=0.48) respectively, but with significant heterogeneity between studies. On subgroup analysis by cancer type, high CXCL12 expression was associated with reduced overall survival in patients with oesophagogastric (HR 2.08; 95% CI: 1.31–3.33, P=0.002), pancreatic (HR 1.54; 95% CI: 1.21–1.97, P=0.0005) and lung cancer (HR 1.37; 95% CI: 1.08–1.75, P=0.01), whereas in breast cancer patients high CXCL12 expression conferred an overall survival advantage (HR 0.5; 95% CI: 0.38–0.66, P<0.00001).

Conclusions:

Determination of CXCL12 expression has the potential to be of use as a cancer biomarker and adds prognostic information in various cancer types. Prospective or prospective–retrospective analyses of CXCL12 expression in clearly defined cancer cohorts are now required to advance our understanding of the relationship between CXCL12 expression and cancer outcome.