Carcinoembryonic antigen messenger RNA expression in blood can predict relapse in gastric cancer

Identification of Combinations of Plasma lncRNAs and mRNAs as Potential Biomarkers for Precursor Lesions and Early Gastric Cancer

Patients with gastric cancer (GC) are usually first diagnosed at an advanced stage due to the absence of obvious symptoms at an early GC (EGC) stage. Therefore, it is necessary to identify an effective screening method to detect precursor lesions of GC (PLGC) and EGC to increase the 5-year survival rate of patients. Cell-free RNA, as a biomarker, has shown potential in early diagnosis, personalised treatment, and prognosis of cancer. In this study, six RNAs (CEBPA-AS1, INHBA-AS1, AK001058, UCA1, PPBP, and RGS18) were analysed via real-time quantitative polymerase chain reaction (RT-qPCR) using the plasma of patients with EGC and PLGC to identify diagnostic biomarkers. The receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic accuracy. Among the six RNAs, four lncRNAs (CEBPA-AS1, INHBA-AS1, AK001058, and UCA1) were upregulated and two mRNAs (PPBP and RGS18) were downregulated in the plasma of patients with PLGC and EGC. According to the findings of the ROC analysis, the four-RNA combination of INHBA-AS1, AK001058, UCA1, and RGS18 had the highest area under the curve (AUC) value for determining risk of GC in patients with PLGC and the six-RNA combination including CEBPA-AS1, INHBA-AS1, AK001058, UCA1, PPBP, and RGS18 had the highest AUC value for determining the risk of GC in patients with EGC. The results suggest the potential usefulness of noninvasive biomarkers for the molecular diagnosis of GC at earlier stages.

Circulating CEA-positive and EpCAM-negative tumor cells might be a predictive biomarker for recurrence in patients with gastric cancer

It has been reported that circulating tumor cells (CTCs) are beneficial for predicting tumor stage or treatment response. Although epithelial cell adhesion molecules (EpCAMs) and cytokeratin (CK) have been often used for the identification of CTCs, other tumor markers have not been fully investigated as detecting tools for CTCs. Thus, this study aims to clarify the significance of carcinoembryonic antigen (CEA, CD66e)-positive CTCs in patients with gastric cancer. A total of 150 patients with gastric cancer were enrolled in this study. The mononuclear fraction of peripheral blood was enriched by Ficoll. The number of cells was enumerated depending on the positivity of EpCAM and CEA or CK by flow cytometry. The association of these cells with clinicopathologic characteristics was investigated. The mean age was 70 (range 28-92). The macroscopic type of gastric cancer was classified as 0/1/2/3/4/5 in 59/11/22/38/16/4 patients, respectively. Seventy-one patients (47.3%) were diagnosed with intestinal-type cancer, while 76 patients (50.7%) were diagnosed with the diffuse type. The mean numbers of cells with EpCAM-CK+, EpCAM+CK-, EpCAM+CK+, EpCAM-CEA+, EpCAM+CEA-, and EpCAM+CEA+ were 618, 237, 19.9, 1147, 291, and 7.41, respectively. The number of EpCAM-CEA+cells was significantly higher in patients with stage II-III and IV than in patients with stage I. The 3-year RFS rate in patients with a high number of EpCAM-CEA+cells (>=622) was 57.5%, while it was 79.3% in patients with a low number of EpCAM-CEA+cells (<622) (log-rank p = 0.0079). Thus, we conclude that CEA-positive CTCs will be a clinically beneficial biomarker in patients with gastric cancer.

Association Between Liquid Biopsy and Prognosis of Gastric Cancer Patients: A Systematic Review and Meta-Analysis

Background: Reports regarding liquid biopsy and gastric cancer (GC) have emerged rapidly in recent decades, yet their prognostic value still remains controversial. This study was aimed to assess the impact of liquid biopsy, including circulating tumor cells (CTCs) and cell-free nucleic acids, on GC patients' prognosis.

Methods: PubMed, Medline, EMBASE, and ClinicalTrial.gov databases were searched for studies that report GC patient survival data stratified by CTC/circulating tumor DNA (ctDNA)/circulating miRNAs' status. The hazard ratios (HRs) and their 95% confidence intervals (CIs) for patients' overall survival (OS) and disease-free survival (DFS)/progression-free survival (PFS) were recorded or calculated depending on circulating target status.

Results: We initially identified 4,221 studies, from which 43 were eligible for further analysis, comprising 3,814 GC patients. Pooled analyses showed that detection of certain CTCs, ctDNA, and circulating miRNA was associated with poorer OS (CTCs: HR = 1.84, 95%CI 1.50–2.26, p < 0.001; ctDNA: HR = 1.78, 95%CI 1.36–2.34, p < 0.001; circulating miRNA: HR = 1.74, 95%CI 1.13–2.69, p < 0.001) and DFS/PFS (CTCs: HR = 3.39, 95%CI 2.21–5.20, p < 0.001; ctDNA: HR = 2.38, 95%CI 1.31–4.32, p = 0.004; circulating miRNA: HR = 3.30, 95%CI 2.39–4.55, p < 0.001) of GC patients, regardless of disease stage and time point at which sample is taken (at baseline or post-treatment).

Conclusions: The presence of CTCs and/or cellular components identifies a group of GC with poorer prognosis. Among circulating markers, CTCs demonstrated a stronger and more stable predictive value for late-stage disease and among Mongolian populations with GC. Less data are available for ctDNA and miRNA; however, their presence may also reflect aggressive biology and warrants further prospective study.

The potential of circulating cell free RNA as a biomarker in cancer

Introduction: It is now clear that circulating cell-free ribonucleic acids (ccfRNAs), including messenger RNA (mRNA) and miRNA, are potential cancer biomarkers. As ccfmiRNA is relatively more stable than ccfmRNA, research should concentrate on developing novel methods to preserve the stability of ccfmRNA and standardization of the protocol which includes extraction, detection, and multicenter validation. Areas covered: This literature review concentrates on the potential of ccfRNA being used as a biomarker in cancer, with special focus on mRNAs and microRNAs (miRNAs). Expert opinion: With the advancement of high-throughput technologies such as RNA sequencing, a panel of biomarkers will be used for the diagnosis, prognosis and therapeutic monitoring of cancer patients. In order to achieve this important target, bioinformatics education to pathologists, scientists, and technologists in molecular diagnostic laboratories is essential. Moreover, the panel of these new ccfRNAs biomarkers has to obtain approval or clearance from an authority such as the US Food and Drug Administration (FDA), and the standard of utilizing these new protocols has to be recognized via accreditation exercise. Therefore, there is still a long way to go before an extensively use of ccfRNA biomarkers in cancer patients can be realized.

Clinical significance of circulating tumor cells in gastric cancer patients

Circulating tumor cells (CTCs) are rare cancer cells released from tumors into the blood stream that are thought to have a key role in cancer metastasis. Investigation of CTCs is an exciting area of research but remains in its infancy, and the presence of CTCs has been associated with worse prognosis in several major cancer types. Gastric cancer (GC) is a highly lethal malignancy and a serious public health concern in East Asia especially in China. There is an urgent need for identifying new, better prognostic markers to enhance diagnosis and prognosis, facilitate drug development, and to improve the treatment of gastric cancer patients. There are considerable interests in gastric CTCs given their potential use as gastric cancer biomarkers. This review highlights recent advances in studies of gastric CTCs, including the isolation and biological molecular characteristics of gastric CTCs, and their clinical significance.

A novel splice variant of XIAP-associated factor 1 (XAF1) is expressed in peripheral blood containing gastric cancer-derived circulating tumor cells

BACKGROUND

XIAP-associated factor 1 (XAF1) is ubiquitously expressed in normal tissues, but its suppression in cancer cells is strongly associated with tumor progression. Although downregulation of XAF1 is observed in tumors, its expression profile in the peripheral blood of cancer patients has not yet been investigated. Here, we identified a novel XAF1 splice variant in cancer cells and then investigated the expression level of this variant in peripheral blood containing gastric cancer-derived circulating tumor cells (CTCs).

METHODS

To identify splice variants, RT-PCR and DNA sequencing were performed in mRNAs extracted from many cancer cells. We then carried out quantitative RT-PCR to investigate expression in peripheral blood from all 96 gastric cancer patients and 22 healthy volunteers.

RESULTS

The XAF1 variant harbored a premature termination codon (PTC) and was differentially expressed in highly metastatic cancer cells versus the parental cells, and that nonsense-mediated mRNA decay (NMD) was suppressed in the variant-expressing cells. Furthermore, splice variants of XAF1 were upregulated in peripheral blood containing CTCs. In XAF1 variant-expressing patients, the expression levels of other NMD-targeted genes also increased, suggesting that the NMD pathway was suppressed in CTCs.

CONCLUSIONS

Our study identified a novel splice variant of XAF1 in cancer cells. This variant was regulated through the NMD pathway and accumulated in NMD-suppressed metastatic cancer cells and peripheral blood containing CTCs. The presence of XAF1 transcripts harboring the PTC in the peripheral blood may be useful as an indicator of NMD inhibition in CTCs.

A pilot study assessing the incidence and clinical significance of circulating tumor cells in esophagogastric cancers

BACKGROUND

Circulating tumor cells (CTCs) have been found to be of clinical utility in predicting response to treatment and prognosis in several malignancies. Less is known of the prevalence and clinical relevance of CTCs in esophagogastric adenocarcinoma, with the available data arising from heterogeneous patient populations using varied detection methods.

PATIENTS AND METHODS

A pilot study was undertaken to assess the prevalence of CTCs in patients with advanced esophageal or gastric adenocarcinoma. Patients were eligible if they had advanced disease and either had received no prior therapy or had progressed after prior chemotherapy. Blood samples for CTC analysis were obtained at baseline and during the course of treatment. The CellSearch immunomagnetic CTC detection platform was used.

RESULTS

Twenty-two patients with metastatic esophageal or gastric adenocarcinoma were enrolled. Eighteen received first-line EOX (epirubicin/oxaliplatin/capecitabine) chemotherapy (± panitumumab) and had baseline samples suitable for CTC analysis. At baseline, ≥ 2 CTCs were detected in 8 patients (44%). Overall tumor response rate was 60% in patients with < 2 CTCs and 37.5% in patients with ≥ 2 CTCs. Median progression-free and overall survival were 6.1 and 10.5 months and 5.2 and 6.1 months in the groups of patients with < 2 CTCs and ≥ 2 CTCs, respectively. The study was prematurely discontinued, owing to the withdrawal of commercial support.

CONCLUSION

The incidence of CTCs in locally advanced or metastatic esophagogastric cancer may be clinically relevant. Investigation of the potential clinical utility of CTCs is warranted in a larger cohort of patients with esophagogastric cancer.

An isolation technique to prevent the spread of tumor cells during radical gastrectomy for gastric carcinoma located on the anterior wall of the gastric antrum

OBJECTIVE

To report an isolation technique for reducing the spread of tumor cells during radical gastrectomy for lesions located on the anterior wall of the gastric antrum.

METHODS

The isolation technique involves using linear cutting staplers and a waterproof membrane to completely "block" and isolate the area to be resected. Blood samples from the portal vein and peritoneal wash samples were obtained immediately after laparotomy and during surgical resection. RT-PCR was used to determine levels of carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20). Carbon nanoparticles were injected into the subserosa of the blocked region before resection to determine lymph flow out of the region.

RESULTS

A total of 76 patients (median age, 59 years; range, 22-73 years), with tumors on the anterior wall of the gastric antrum were included (blocking group, n = 40; non-blocking group, n = 36). In the blocking group, the carbon nanoparticles did not flow beyond the blocking line. There were no significant differences between the groups in CEA or CK20 mRNA levels in portal vein blood or peritoneal wash fluid immediately after laparotomy. CEA and CK20 levels were significantly lower in portal vein blood in the blocking group during tumor resection. During a median follow-up of 30 months, the incidence of metastasis or recurrence in the blocking group was lower than the non-blocking group, although it did not reach statistical significance (17.9% vs. 25.0%, respectively).

CONCLUSION

The blocking technique can reduce hematogenous and lymphatic spread of tumor cells into the systemic circulation, and may prevent metastasis or recurrence after radical gastrectomy for gastric carcinoma.

Over-expression of Metastasis-associated in Colon Cancer-1 (MACC1) Associates with Better Prognosis of Gastric Cancer Patients

OBJECTIVE

The aim of this study was to detect metastasis-associated in colon cancer-1 (MACC1) expression in Chinese gastric cancer and analyze the relationship between MACC1 expression and postoperative survival.

METHODS

The expression of MACC1 and c-MET protein in a sample of 128 gastric cancer tissues was detected by immunohistochemistry. A retrospective cohort study on the prognosis was carried out and data were collected from medical records.

RESULTS

The positive rate of MACC1 protein expression in gastric cancer was 47.66%, higher than that in adjacent noncancerous mucosa (P<0.001). MACC1 protein expression was not related to the clinicopathological variables involved. Kaplan-Meier analysis revealed that the survival of MACC1 positive group tended to be better than that of MACC1 negative group, particularly in patients with stage III carcinoma (P=0.032). Cox regression analysis revealed that MACC1 protein over-expression in gastric cancer tended to be a protective factor with hazard ratio of 0.621 (P=0.057). Immunohistochemical analysis showed that the positive rate of c-MET protein expression was much higher in cases with positive MACC1 expression in gastric cancer (P=0.002), but P53 expression was not associated with MACC1 expression.

CONCLUSION

MACC1 over-expression implies better survival and may be an independent prognostic factor for gastric cancer in Chinese patients.

The detection of gastric cancer cells in intraoperative peritoneal lavage using the reverse transcription--loop-mediated isothermal amplification method

INTRODUCTION

To detect a small number of malignant cells, we used a highly sensitive detection system that measures the expression levels of cytokeratin (CK) 19 messenger RNA by reverse transcription-loop-mediated isothermal amplification (RT-LAMP).

MATERIALS AND METHODS

We evaluated the clinical relevance of our novel diagnostic method with an RT-LAMP assay using CK19 as a target gene for the detection of free cancer cells in peritoneal lavage and assessed the clinical significance of the molecular diagnosis by survival analysis and frequency of recurrence, with a median follow-up period of 39 mo. We observed 52 patients with gastric cancer who underwent gastrectomy, bypass operation, and exploratory laparotomy.

RESULTS

Those 52 patients, who were subjected to both RT-LAMP and cytologic examination, were divided into the following three groups: (1) patients positive by cytology and RT-LAMP (CY+/LAMP+) (n = 9), (2) patients positive by LAMP and negative by cytology (CY-/LAMP+) (n = 12), and (3) patients negative by both cytology and LAMP (CY-/LAMP-) (n = 31). All patients with simultaneous peritoneal dissemination and positive cytology were positive on RT-LAMP. The results of RT-LAMP were statistically significant for recurrence by univariate analysis (P < 0.005). Cytology-positive cases had a very poor prognosis, and RT-LAMP-positive cases had a worse prognosis than RT-LAMP-negative cases.

CONCLUSIONS

Our findings suggest that CK19 RT-LAMP would be useful as an intraoperative diagnostic modality to detect patients with a high risk of recurrence even after clinically curative surgery, who thus require proper adjuvant therapy.

Evaluation of alpha 1-antitrypsin and the levels of mRNA expression of matrix metalloproteinase 7, urokinase type plasminogen activator receptor and COX-2 for the diagnosis of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of death from cancer in both men and women in the majority of developed countries. Molecular tests of blood could potentially provide this ideal screening tool.

AIM

Our objective was to assess the usefulness of serum markers and mRNA expression levels in the diagnosis of CRC.

METHODS

In a prospective study, we measured mRNA expression levels of 13 markers (carbonic anhydrase, guanylyl cyclase C, plasminogen activator inhibitor, matrix metalloproteinase 7 (MMP7), urokinase-type plasminogen activator receptor (uPAR), urokinase-type plasminogen activator, survivin, tetranectin, vascular endothelial growth factor (VEGF), cytokeratin 20, thymidylate synthase, cyclooxygenase 2 (COX-2), and CD44) and three proteins in serum (alpha 1 antitrypsin, carcinoembryonic antigen (CEA) and activated C3 in 42 patients with CRC and 33 with normal colonoscopy results.

RESULTS

Alpha 1-antitrypsin was the serum marker that was most useful for CRC diagnosis (1.79 ± 0.25 in the CRC group vs 1.27 ± 0.25 in the control group, P<0.0005). The area under the ROC curve for alpha 1-antitrypsin was 0.88 (0.79-0.96). The mRNA expression levels of five markers were statistically different between CRC cases and controls: those for which the ROC area was over 75% were MMP7 (0.81) and tetranectin (0.80), COX-2 (0.78), uPAR (0.78) and carbonic anhydrase (0.77). The markers which identified early stage CRC (Stages I and II) were alpha 1-antitrypsin, uPAR, COX-2 and MMP7.

CONCLUSIONS

Serum alpha 1-antitrypsin and the levels of mRNA expression of MMP7, COX-2 and uPAR have good diagnostic accuracy for CRC, even in the early stages.

Recovering circulating extracellular or cell-free RNA from bodily fluids

The presence of extracellular circulating or cell-free RNA in biological fluids is becoming a promising diagnostic tool for non invasive and cost effective cancer detection. Extracellular RNA or miRNA as biological marker could be used either for the early detection and diagnosis of the disease or as a marker of recurrence patterns and surveillance. In this review article, we refer to the origin of the circulating extracellular RNA, we summarise the data on the biological fluids (serum/plasma, saliva, urine, cerebrospinal fluid and bronchial lavage fluid) of patients suffering from various types of malignancies reported to contain a substantial amount of circulating extracellular (or cell-free) RNAs and we discuss the appropriate reagents and methodologies needed to be employed in order to obtain RNA material of high quality and integrity for the majority of the experimental methods used in RNA expression analysis. Furthermore, we discuss the advantages and disadvantages of the RT-PCR or microarray methodology which are the methods more often employed in procedures of extracellular RNA analysis.

Using detection of survivin-expressing circulating tumor cells in peripheral blood to predict tumor recurrence following curative resection of gastric cancer

BACKGROUND AND OBJECTIVES

The present study was designed to investigate the clinicopathological role of survivin-expressing circulating tumor cells (CTCs) and to determine whether the presence of survivin-expressing CTCs is an independent predictor of tumor recurrence following curative resection of gastric cancer.

METHODS

This study included 98 patients who underwent potentially curative resection. Reverse transcription polymerase chain reaction enzyme linked immunosorbent assay (RT-PCR ELISA) was used to measure survivin mRNA in peripheral blood.

RESULTS

Of the 98 patients studied, 45 (45.9%) were positive for survivin mRNA. Survivin mRNA expression correlated with Lauren classification (P < 0.001), pathological tumor (pT) stage (P < 0.001), pathological tumor node metastasis (pTNM) stage (P = 0.009), and degree of differentiation (P = 0.001). The pTNM stage and the status of survivin mRNA were independent prognostic factors of disease-free survival (P = 0.007 and <0.001, respectively).

CONCLUSIONS

The detection of CTCs expressing survivin mRNA could be a good clinical biomarker used to predict the prognosis of patients with curatively resected gastric cancer.

Expression of B7-H4 in blood of patients with gastric cancer predicts tumor progression and prognosis

BACKGROUND AND OBJECTIVES

B7-H4 is a novel molecular B7 ligand that plays an important role as a negative regulator of the T cell-mediated immune response. However, the clinical significance of B7-H4 expression in gastric cancer remains uncertain. Here, we assessed B7-H4 expression in blood of patients with gastric cancer to determine whether or not it can predict tumor progression and prognosis.

METHODS

We measured B7-H4 mRNA expression by quantitative RT-PCR in five gastric cell lines as well as in blood specimens from 94 patients with gastric cancer and from 22 healthy volunteers.

RESULTS

Significantly more B7-H4 mRNA copies were found in gastric cell lines and in blood from patients with gastric cancer than in blood from healthy volunteers (P < 0.0001 and P < 0.0001, respectively). B7-H4 expressed in 71 (75.5%) of 94 patients with gastric cancer significantly correlated with depth of tumor invasion, lymph node metastasis, and overall stage (P = 0.006, P = 0.001, and P < 0.001, respectively). The 5-year survival rate was significantly lower in patients with than without B7-H4 expression (P = 0.04).

CONCLUSIONS

The evaluation of B7-H4 expression in blood is a useful tool for predicting the progression of gastric cancer and prognosis.

Detection of carcinoembryonic antigen messenger RNA in blood using quantitative real-time reverse transcriptase-polymerase chain reaction to predict recurrence of gastric adenocarcinoma

Background

The existence of circulating tumor cells (CTCs) in peripheral blood as an indicator of tumor recurrence has not been clearly established, particularly for gastric cancer patients. We conducted a retrospective analysis of the relationship between CTCs in peripheral blood at initial diagnosis and clinicopathologic findings in patients with gastric carcinoma.

Methods

Blood samples were obtained from 123 gastric carcinoma patients at initial diagnosis. mRNA was extracted and amplified for carcinoembryonic antigen (CEA) mRNA detection using real-time RT-PCR. Periodic 3-month follow-up examinations included serum CEA measurements and imaging.

Results

The minimum threshold for corrected CEA mRNA score [(CEA mRNA/GAPDH mRNA) × 10⁶] was set at 100. Forty-five of 123 patients (36.6%) were positive for CEA mRNA expression. CEA mRNA expression significantly correlated with T stage and postoperative recurrence status (P = 0.001). Recurrent disease was found in 44 of 123 cases (35.8%), and 25 of these (56.8%) were positive for CEA mRNA. Of these patients, CEA mRNA was more sensitive than serum CEA in indicating recurrence. Three-year disease-free survival of patients positive for CEA mRNA was significantly poorer than of patients negative for CEA mRNA (P < 0.001). Only histological grade and CEA mRNA positivity were independent factors for disease-free survival using multivariate analysis.

Conclusions

CEA mRNA copy number in peripheral blood at initial diagnosis was significantly associated with disease recurrence in gastric adenocarcinoma patients. Real-time RT-PCR detection of CEA mRNA levels at initial diagnosis appears to be a promising predictor for disease recurrence in gastric adenocarcinoma patients.

Implications of cancer-associated systemic inflammation for biomarker studies

Highly sensitive molecular technologies provide new capacities for cancer biomarker research, but with sensitivity improvements marker specificity is significantly decreased, and too many false-positive results should disqualify the measurement from clinical use. Hence, of the thousands of potential cancer biomarkers only a few have found their way to clinical application. Differentiating false-positive results from true-positive (cancer-specific) results can indeed be difficult, if validation of a marker is performed against inadequate controls. We present examples of accumulating evidence that not only local but also systemic inflammatory reactions are implicated in cancer development and progression and interfere with the molecular image of cancer disease. We analyze several modern strategies of tumor marker discovery, namely, proteomics, metabonomics, studies on circulating tumor cells and circulating free nucleic acids, or their methylation degree, and provide examples of scarce, methodologically correct biomarker studies as opposed to numerous methodologically flawed biomarker studies, that examine cancer patients' samples against those of healthy, inflammation-free persons and present many inflammation-related biomarker alterations in cancer patients as cancer-specific. Inflammation as a cancer-associated condition should always be considered in cancer biomarker studies, and biomarkers should be validated against their expression in inflammatory conditions.