The prognostic significance of growth factors and growth factor receptors in gastric adenocarcinoma

Gastric Cancer: Mechanisms, Biomarkers, and Therapeutic Approaches

Gastric cancer (GC) remains one of the most common deadly malignancies worldwide. Recently, several targeted therapeutics for treating unresectable or metastatic GC have been developed. Comprehensive characterization of the molecular profile and of the tumor immune microenvironment of GC has allowed researchers to explore promising biomarkers for GC treatment and has enabled a new paradigm in precision-targeted immunotherapy. In this article, we review established and promising new biomarkers relevant in GC, with a focus on their clinical implications, diagnostic methods, and the efficacy of targeted agents.

HER2 Positive Gastric Carcinomas and Their Clinico-Pathological Characteristics

BACKGROUND:

HER2 protein expression in gastric carcinoma, in correlation with existing, acknowledged prognostic factors which include the parameters that determine the TNM stage of the disease, could become the basis for ongoing research in the field of molecular targeted and personalised therapy.

AIM:

To determine the expression of the HER2 protein in gastric carcinoma and to correlate the expression of a HER2 protein with clinicopathological characteristics of the disease.

MATERIAL AND METHODS:

The data of HER2 protein expression and the parameters of the TNM classification were obtained from the histopathological reports of the Institute of Pathology in Skopje, and for the clinical stage we used patient’s files from the University Clinic for Abdominal Surgery in Skopje.

RESULTS:

The analysis of the correlation of HER2 protein expression and TNM classification parameters pointed out a significant correlation between HER2 protein expression and intragastric localisation of gastric carcinoma (P = 0.005), and the tumour grade of differentiation (P = 0.034). There was also a positive correlation between HER2 protein expression pattern and positive lymph nodes in patients with gastric carcinoma (P = 0.03). The expression pattern of HER2 +++ was significantly more common registered in patients with positive lymph nodes (P = 0.03)

CONCLUSION:

The expression of HER2 protein could represent a biological marker with prognostic and predictive value in patients with gastric carcinoma. Considering the high mortality rate in patients with gastric carcinoma and lack of international standardised therapeutic approach, research of the role and significance of HER2 overexpression and Trastuzumab therapy may prove useful in the development of new therapeutic strategies.

Loss of cyclin-dependent kinase-like 2 predicts poor prognosis in gastric cancer, and its overexpression suppresses cells growth and invasion

Cyclin-dependent kinase-like 2 (CDKL2), a new member of the cyclin-dependent kinase family, may be involved in gastric cancer (GC) progression. Thus, we conducted this study to explore the clinical effect of CDKL2 in GC. Immunohistochemistry was used to measure CDKL2 levels in gastric tissues. The association of a high CDKL2 level with clinical and pathological characteristics, and the correlation between the CDKL2 level and disease-free and overall survival were analyzed. Transfection was employed to overexpress CDKL2 in GC cells and to investigate the effect of CDKL2 overexpression on cell proliferation and invasion. Loss of CDKL2 was positively correlated with several clinical and pathological characteristics, and patients with a low CDKL2 level had significantly poorer disease-free and overall survival than those with a high level (P = .005 and .001, respectively). Univariate analysis using the Cox proportional hazards model indicated that a low CDKL2 level was a prognosticator for inferior disease-free survival (P = .007). Based on immmunoblotting data, AGS and HGC-27 GC cells were chosen for CDKL2 overexpression. Cellular studies revealed that CDKL2 overexpression impaired cell proliferation and invasion. Loss of CDKL2 may serve as a biomarker for predicting GC patient outcomes and a potential therapeutic target for GC treatment.

VEGFR-2 as a novel predictor of survival in gastric cancer: A systematic review and meta-analysis

BACKGROUND

Expression of VEGFRs may affect cancer prognosis. The aim of this work is to evaluate the prognostic significance of VEGFRs of patients with gastric cancer.

METHODS

The databases PubMed, Embase, Web of Science, and Cochrane Library as well as ASCO and ESMO were searched systematically for articles reporting the prognostic significance of tissue VEGFRs in gastric cancer. The statistical analyses were carried out using Stata version 12.0.

RESULTS

A total of 8 articles comprising 950 patients were eligible for meta-analysis. The combined HR of studies evaluating total VEGFRs overexpression was 1.42 (95% CI 1.01-2.00, P = 0.044), suggesting that it had prognosis significance in overall survival of gastric cancer. Subgroup analysis showed that it was VEGFR-2 (HR 1.81, 95% CI 1.31-2.49, P < 0.001) but not VEGFR-3 (HR 0.91, 95% CI 0.45-1.82, P = 0.787) overexpression was associated with an increased risk of median overall survival (mOS) and it can be a potentially predictive biomarker for gastric cancer.

CONCLUSIONS

VEGFR-2 overexpression is a promising negative prognosis predictor for patients with gastric cancer. The prognosis significance of VEGFR-3 still need further study.

Cytokine expression associated with Helicobacter pylori and Epstein-Barr virus infection in gastric carcinogenesis

Helicobacter pylori and Epstein-Barr virus (EBV) infection, and associated cytokines are involved in gastric carcinogenesis. We investigated the expression of these cytokines and their relationship with clinicopathological characteristics. The study included specimens from 207 patients with gastric adenocarcinoma, 56 with chronic gastritis, 32 with metaplasia, and 30 with low-grade epithelial dysplasia. Tissue microarrays were constructed and immunohistochemical staining for IL-1β, IL-6, IL-10, IL-17, p16, p21, TNF-α, and TNFR1 was performed. EBV and H. pylori infection status was determined. IL-1β, IL-6, IL-17, p16, and p21 protein expression was significantly higher in adenocarcinoma cases than in the other cases (p < 0.05). EBV was only noted in adenocarcinoma (13 cases, 6.3%). The H. pylori infection rate in adenocarcinoma was significantly higher than that in the other cases (p < 0.005). IL-6 expression was associated with improved survival (p < 0.05), whereas IL-17 expression was associated with decreased survival (p < 0.05). IL-6 expression was inversely associated with angioinvasion, and disease stage (p < 0.05), whereas IL-17 expression was associated with disease stage (p < 0.05). IL-10 expression was correlated with IL-1β and TNF-α expression, and p16 expression was correlated with IL-17 and EBV status. Our results indicate that IL-6 and IL-17 are associated with gastric carcinogenesis and may be considered prognostic factors.

Follow-up after curative resection for gastric cancer: Is it time to tailor it?

There is still no consensus on the follow-up frequency and regimen after curative resection for gastric cancer. Moreover, controversy exists regarding the utility of follow-up in improving survival, and the recommendations of experts and societies vary considerably. The main reason to establish surveillance programs is to diagnose tumor recurrence or metachronous cancers early and to thereby provide prompt treatment and prolong survival. In the setting of gastric malignancies, other reasons have been put forth: (1) the detection of adverse effects of a previous surgery, such as malnutrition or digestive sequelae; (2) the collection of data; and (3) the identification of psychological and/or social problems and provision of appropriate support to the patients. No randomized controlled trials on the role of follow-up after curative resection of gastric carcinoma have been published. Herein, the primary retrospective series and systematic reviews on this subject are analyzed and discussed. Furthermore, the guidelines from international and national scientific societies are discussed. Follow-up is recommended by the majority of institutions; however, there is no real evidence that follow-up can improve long-term survival rates. Several studies have demonstrated that it is possible to stratify patients submitted to curative gastrectomy into different classes according to the risk of recurrence. Furthermore, promising studies have identified several molecular markers that are related to the risk of relapse and to prognosis. Based on these premises, a promising strategy will be to tailor follow-up in relation to the patient and tumor characteristics, molecular marker status, and individual risk of recurrence.

Molecular targeting of VEGF/VEGFR signaling by the anti-VEGF monoclonal antibody BD0801 inhibits the growth and induces apoptosis of human hepatocellular carcinoma cells in vitro and in vivo

Hepatocellular carcinoma (HCC) is the third-leading cause of cancer-related deaths with 750,000 newly diagnosed cases each year. Surgery, radiotherapy, and chemotherapy constitute the main treatment modalities for HCC, but liver cirrhosis and damage often occur. Molecular targeted drugs have been recently developed to treat HCC. Vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) autocrine signaling is closely related to the growth, progression, and metastasis of HCC, making the VEGF/VEGFR axis an ideal target for the development of molecular targeted agents. Here, we report the effects of the novel anti-VEGF humanized monoclonal antibody BD0801 on the growth of HCC cells in vitro and in vivo as well as the underlying mechanisms. BD0801 significantly inhibited the proliferation of HepG2, SMMC-7721, and Bel7402 cells in vitro, accompanied with an induction of apoptosis and cell cycle arrest at the G1 phase. BD0801 potently suppressed AKT, Erk1/2, and retinoblastoma (Rb) phosphorylation, while increasing p21 and decreasing cyclin D1 protein levels. BD0801 significantly inhibited growth in mouse tumor xenografts and induced cell apoptosis of HepG2 and SMMC-7721 tumor xenografts. Furthermore, BD0801 effectively reduced the vascular density and tumor tissue microvessel density (MVD). Similarly, BD0801 decreased AKT, Erk1/2, and Rb phosphorylation and cyclin D1 expression whereas it increased p21 protein expression in mouse HCC tumor xenografts. Importantly, BD0801 showed a better effect than Bevacizumab (Bev) on the inhibition of cell growth and induction of apoptosis in HCC cells in vitro and in vivo. These findings suggest that BD0801 is a potent anti-VEGF monoclonal antibody for the treatment of HCC.

Influence of the HER receptor ligand system on sensitivity to cetuximab and trastuzumab in gastric cancer cell lines

Purpose

Gastric cancer remains a major health concern, and improvement of the therapeutic options is crucial. Treatment with targeted therapeutics such as the EGFR-targeting antibody cetuximab or the HER2-targeting antibody trastuzumab is either ineffective or moderately effective in this disease, respectively. In this study, we analysed the involvement of the HER receptor ligands amphiregulin (AREG), epidermal growth factor (EGF), heparin-binding epidermal growth factor (HB-EGF) and transforming growth factor alpha (TGFα) in the responsiveness of gastric cancer cell lines to cetuximab and trastuzumab.

Methods

A panel of 11 gastric cancer cell lines was characterized for cetuximab and trastuzumab sensitivity, ligand secretion and expression and activation of the HER receptors using WST-1 cell proliferation assays, ELISAs and Western blot analyses. We further investigated the effects of an exogenous ligand application on the cetuximab and trastuzumab sensitivity.

Results

We found no correlation between TGFα secretion and the sensitivity to cetuximab or trastuzumab. For AREG, we confirmed previous results indicating that this ligand is a positive predictor of cetuximab sensitivity. Exogenous HB-EGF was effective in rescuing sensitive cell lines from inhibition of cell proliferation by both, cetuximab and trastuzumab.

Conclusions

Our data indicate that HB-EGF may be a useful marker for the prediction of trastuzumab sensitivity in gastric cancer.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-016-2308-z) contains supplementary material, which is available to authorized users.

Biomarkers for gastric cancer: Progression in early diagnosis and prognosis (Review)

Gastric cancer is one of leading causes of cancer-related mortality worldwide and is a notable disease due to its heterogeneity. Recently, numerous studies have investigated the molecular basis of gastric cancer, involving the alteration of pathogenesis, and invasion and metastasis. With the development of modern technologies, various novel biomarkers had been identified that appear to possess diagnostic and prognostic value; therefore, the present review describes our current knowledge of biomarkers for the early diagnosis and prognosis of gastric cancer. Classic biomarkers for gastric cancer diagnosis include carcinoembryonic antigen and cancer antigen 19-9, while microRNA and DNA hypomethylation are proposed as novel biomarkers. Excluding classical biomarkers, biomarkers for determining the progression and prognosis of gastric cancer focus on targeting microRNAs, epigenetic alterations and genetic polymorphisms.

Serum transforming growth factor-beta1 levels may have predictive and prognostic roles in patients with gastric cancer

Transforming growth factor-beta1 (TGF-beta1) plays an important role in the pathogenesis of multiple malignancies, and also, its expression strongly affects the outcomes of cancer patients. The objective of this study was to determine the clinical significance of the serum levels of TGF-beta1 in gastric cancer patients. A total of 63 patients with a pathologically confirmed diagnosis of gastric cancer were enrolled into this study. Serum TGF-beta1 concentrations were determined by the solid-phase sandwich ELISA method. Thirty healthy age- and sex-matched controls were included in the analysis. The median age at diagnosis was 62 years, range 28 to 82 years. There was no significant difference in baseline serum TGF-beta1 levels between gastric cancer patients and the healthy control group (p = 0.08). The known clinical variables including age of patient, gender, site of lesion, histology, histological grade, stage of disease, and serum levels of lactate dehydrogenase (LDH), CEA, and carbohydrate antigen (CA) 19.9 were not found to be correlated with serum TGF-beta1 concentrations (p > 0.05). However, the chemotherapy-responsive patients had higher serum TGF-beta1 levels compared with chemotherapy-unresponsive ones (median values 330.50 v 49.54 pg/mL, respectively, p = 0.01). Moreover, patients with elevated serum TGF-beta1 concentrations had significantly favorable overall survival compared with those with lower levels (median 71.1 v 39.9 weeks, respectively, p = 0.04). In conclusion, serum levels of TGF-beta1 may have predictive and prognostic roles in patients with gastric cancer.