Immunohistochemical analysis of RTKs expression identified HER3 as a prognostic indicator of gastric cancer

Decoding driver and phenotypic genes in cancer: Unveiling the essence behind the phenomenon

Gray hair, widely regarded as a hallmark of aging. While gray hair is associated with aging, reversing this trait through gene targeting does not alter the fundamental biological processes of aging. Similarly, certain oncogenes (such as CXCR4, MMP-related genes, etc.) can serve as markers of tumor behavior, such as malignancy or prognosis, but targeting these genes alone may not lead to tumor regression. We pioneered the name of this class of genes as "phenotypic genes". Historically, cancer genetics research has focused on tumor driver genes, while genes influencing cancer phenotypes have been relatively overlooked. This review explores the critical distinction between driver genes and phenotypic genes in cancer, using the MAPK and PI3K/AKT/mTOR pathways as key examples. We also discuss current research techniques for identifying driver and phenotypic genes, such as whole-genome sequencing (WGS), RNA sequencing (RNA-seq), RNA interference (RNAi), CRISPR-Cas9, and other genomic screening methods, alongside the concept of synthetic lethality in driver genes. The development of these technologies will help develop personalized treatment strategies and precision medicine based on the characteristics of relevant genes. By addressing the gap in discussions on phenotypic genes, this review significantly contributes to clarifying the roles of driver and phenotypic genes, aiming at advancing the field of targeted cancer therapy.

HER3 protein expression as a risk factor for post-operative recurrence in patients with early-stage adenocarcinoma and adenosquamous carcinoma of the cervix

Patients with cervical adenocarcinoma (AC) and adenosquamous carcinoma (ASC) have a poorer prognosis than those with squamous cell carcinoma (SCC). Erb-b2 receptor tyrosine kinase 3 (HER3) is a member of the epidermal growth factor receptor family and its expression is associated with unfavorable prognosis in several cancer types, including SCC of the cervix. As there is limited information on the prognostic value of HER3 for AC and ASC of the cervix, the present study aimed to evaluate the expression of HER3 and its impact on post-operative recurrence in patients with AC and ASC of the cervix. This retrospective study included 39 patients with early-stage AC and ASC who underwent primary surgery between January 1997 and December 2017. Immunohistochemical staining for HER3 was performed on formalin-fixed paraffin-embedded surgical specimens. The possible influence of HER3 expression on disease-free survival (DFS) was studied by using multivariate Cox regression with adjustment for established risk factors of post-operative recurrence. High expression of HER3 (HER3-high) was detected in 85.1% of cases of AC (23/27) and in 58.3% of cases of ASC (7/12). The median follow-up duration was 63.1 months and Kaplan-Meier analysis indicated that the 5-year DFS rates of patients with AC and ASC of the cervix were 56.7% in patients with HER3-high and 77.8% in patients with HER3-low (log rank, P=0.20). On multivariate analysis, HER3-high [hazard ratio (HR)=6.32, 95% CI: 1.10–36.26, P=0.039), pelvic lymph node metastasis (HR=7.61, 95% CI: 2.07–28.00, P=0.002) and vascular invasion (HR=4.28, 95% CI: 1.12–16.31, P=0.033) were indicated to be independent predictors of DFS. To date, the present study is the most comprehensive analysis to evaluate the expression of HER3 in patients with early-stage AC and ASC of the cervix. The results suggested that HER3 overexpression may be an independent risk factor for post-operative recurrence. However, these results and the prognostic value of HER3 should be confirmed in a larger sample.

HER2-targeted therapies - a role beyond breast cancer

HER2 is an established therapeutic target in a large subset of women with breast cancer; a variety of agents including trastuzumab, pertuzumab, lapatinib, neratinib and trastuzumab emtansine (T-DM1) have been approved for the treatment of HER2-positive breast cancer. HER2 is also overexpressed in subsets of patients with other solid tumours. Notably, the addition of trastuzumab to first-line chemotherapy has improved the overall survival of patients with HER2-positive gastric cancer, and has become the standard-of-care treatment for this group of patients. However, trials involving pertuzumab, lapatinib and T-DM1 have failed to provide significant improvements in the outcomes of patients with HER2-positive gastric cancer. HER2-targeted therapies are also being tested in patients with other solid tumours harbouring HER2 overexpression, and/or amplifications or other mutations of the gene encoding HER2 (ERBB2), including biliary tract, colorectal, non-small-cell lung and bladder cancers. The experience with gastric cancer suggests that the successes observed in HER2-positive breast cancer might not be replicated in these other tumour types, owing to differences in the level of HER2 overexpression and other aspects of disease biology. In this Review, we describe the current role of HER2-targeted therapies beyond breast cancer and also highlight the potential of novel HER2-targeted agents that are currently in clinical development.

CRM197 reverses paclitaxel resistance by inhibiting the NAC-1/Gadd45 pathway in paclitaxel-resistant ovarian cancer cells

Heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF) is a new promising target for the treatment of ovarian cancer. Our previous study showed that cross‐reacting material 197 (CRM197), a specific HB‐EGF inhibitor, significantly reverses resistance against paclitaxel in paclitaxel‐resistant ovarian cancer cells. However, the mechanism of the effect of CRM197 on the reversion of paclitaxel resistance was unclear. In this study, in vitro and in vivo data suggested that CRM197 treatment sensitized paclitaxel‐resistant ovarian cancer cells to paclitaxel, at least in part, via nucleus accumbens‐1 (NAC‐1) and its downstream pathway, DNA damage‐inducible 45‐γ interacting protein (Gadd45gip1)/growth arrest and DNA damage‐inducible 45 (Gadd45), in A2780/Taxol and SKOV3/Taxol cells. The results also showed that CRM197 activated the proapoptotic JNK/p38MAPK pathway to enhance caspase‐3 activity and apoptosis by downregulation of the NAC‐1/Gadd45gip1/Gadd45 pathway, leading to reversion of paclitaxel resistance in A2780/Taxol and SKOV3/Taxol cells. This study provides the first mechanism through which CRM197 significantly reverses resistance against paclitaxel by modulating the NAC‐1/Gadd45gip1/Gadd45 pathway in paclitaxel‐resistant ovarian cancer cells, and the mechanism of HB‐EGF inhibition as a novel therapeutic strategy for patients with paclitaxel‐resistant ovarian cancer.

Vasopressin augments TNBS-induced colitis through enteric neuronal V1a receptor-mediated COX-2-dependent prostaglandin release from mast cells in mice

BACKGROUND

Inflammatory bowel disease (IBD) is a functional disorder with chronic and relapsing clinical features. Vasopressin (VP) is a hormone responsible for water and stress homeostasis and also regulates gastrointestinal inflammation and motility. We explored whether VP was related to IBD pathogenesis and its possible pathway.

METHODS

Colitis was induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in mice. The disease activity and colonic damage were evaluated through a scoring system. Locations of the V_1a receptor were revealed by immunochemistry method in colon. Ussing chamber technique was performed for the electrophysiological characterization by using rat ileum. The (Arg⁸ )-Vasopressin (AVP)-evoked short-circuit current (Isc) was recorded in the presence of conivaptan (V_1a and V₂ receptor antagonist), tolvaptan (V_1b receptor antagonist), tetrodotoxin (TTX), atropine, cyclooxygenase (COX) inhibitors (indomethacin, nonspecific COX antagonist; SC560, COX-1 antagonist; NS560, COX-2 antagonist), and a stabilizer of mast cell (cromolyn sodium), respectively.

KEY RESULTS

TNBS resulted in the obvious loss of body weight and tissue damages in mice. AVP significantly aggravated the TNBS-induced colitis, which was attenuated by conivaptan but not tolvaptan. V_1a receptors were found immunopositive in neurons among the enteric nervous system. AVP evoked a pulsatile response in Isc. Its amplitude, frequency, and cycle duration were around 8-15 µA/cm² , 10-11 mHz, and 1.5 minutes, respectively. Notably, the AVP-evoked change in Isc was abolished by TTX, atropine, conivaptan, indomethacin, NS560, and cromolyn sodium, respectively.

CONCLUSIONS AND INFERENCES

VP-V_1a receptor played the proinflammatory role in TNBS-induced colitis by promoting COX-2-dependent prostaglandin release from mucosal mast cells, which was mediated by the cholinergic pathway.

Clinical significance of overexpression of NRG1 and its receptors, HER3 and HER4, in gastric cancer patients

BACKGROUND

Neuregulin 1 (NRG1), a ligand for human epidermal growth factor (HER) 3 and HER4, can activates cell signaling pathways to promote carcinogenesis and metastasis.

METHODS

To investigate the clinicopathologic significance of NRG1 and its receptors, immunohistochemistry was performed for NRG1, HER3, and HER4 in 502 consecutive gastric cancers (GCs). Furthermore, HER2, microsatellite instability (MSI), and Epstein-Barr virus (EBV) status were investigated. NRG1 gene copy number (GCN) was determined by dual-color fluorescence in situ hybridization (FISH) in 388 available GCs.

RESULTS

NRG1 overexpression was observed in 141 (28.1%) GCs and closely correlated with HER3 (P = 0.034) and HER4 (P < 0.001) expression. NRG1 overexpression was significantly associated with aggressive features, including infiltrative tumor growth, lymphovascular, and neural invasion, high pathologic stage, and poor prognosis (all P < 0.05), but not associated with EBV, MSI, or HER2 status. Multivariate analysis identified NRG1 overexpression as an independent prognostic factor for survival (P = 0.040). HER3 and HER4 expressions were observed in 157 (31.3%) and 277 (55.2%), respectively. In contrast to NRG1, expression of these proteins was not associated with survival. NRG1 GCN gain (GCN ≥ 2.5) was detected in 14.7% patients, including two cases of amplification, and was moderately correlated with NRG1 overexpression (κ, 0.459; P < 0.001).

CONCLUSIONS

Although our results indicate a lack of prognostic significance of HER3 and HER4 overexpression in GC, overexpression of their ligand, NRG1, was associated with aggressive clinical features and represented an independent unfavorable prognostic factor. Therefore, NRG1 is a potential prognostic and therapeutic biomarker in GC patients.

Robust vascular invasion concurrent with intense EGFR immunostaining can predict recurrence in patients with stage IB node-negative gastric cancer

PURPOSE

The prognosis of most patients with stage IB node-negative gastric cancer is good without postoperative chemotherapy; however, about 10% suffer recurrence and inevitably die. We conducted this study to establish the optimal indications for postoperative adjuvant chemotherapy in patients at risk of recurrence.

METHODS

The subjects of this retrospective study were 124 patients with stage IB node-negative gastric cancer, who underwent gastrectomy at the Kitasato University East Hospital, between 2001 and 2010. We reviewed EGFR immunohistochemistry (IHC) as well as clinicopathological factors.

RESULTS

Of the 124 patients, 47 (38%) showed intense EGFR IHC (2+ or 3+), with significantly less frequency than in stage II/III advanced gastric cancer (p < 0.001). According to univariate analysis, intense EGFR IHC was significantly associated with relapse-free survival (RFS) (p = 0.023) and associated with overall survival (OS) (p = 0.045) as well as vascular invasion (p = 0.031). On the multivariate Cox proportional hazards model, intense EGFR IHC(p = 0.016) was an independent prognostic predictor for RFS, and both vascular invasion (p = 0.033) and intense EGFR IHC (p = 0.031) were independent prognostic predictors for OS. The combination of both factors increased the risk of recurrence (p = 0.001).

CONCLUSIONS

In stage IB node-negative gastric cancer, vascular invasion and intense EGFR IHC increase the likelihood of recurrence. We recommend adjuvant chemotherapy for such patients because of the high risk of metachronous recurrence.

Prognostic relevance of FGFR2 expression in stage II/III gastric cancer with curative resection and S-1 chemotherapy

Curative gastrectomy and adjuvant chemotherapy using S-1 is a standard treatment for stage II/III gastric cancer in Japan. The purpose of the present study was to evaluate the prognostic relevance of fibroblast growth factor receptor (FGFR)2 expression in patients with stage II/III gastric cancer that underwent postoperative adjuvant chemotherapy with S-1. Formalin-fixed paraffin-embedded surgical specimens were retrospectively examined in 167 patients with stage II/III gastric cancer that underwent curative gastrectomy followed by adjuvant S1 chemotherapy. FGFR2 expression was measured using immunohistochemistry (IHC) staining. The IHC results for FGFR2 were as follows: Grade 1+, 32; grade 2+, 80; grade 3+, 55 patients. The FGFR2 expression level was not significantly associated with relapse-free or overall survival rates. However, in the diffuse type, the FGFR2 expression level tended to be negatively correlated with relapse-free survival. In particular, the proportion of patients who recurred >5 years following surgery was significantly larger in the FGFR2 grade 3+ group than in the grade 1+, 2+ group (4/22 vs. 1/35; P=0.047). The recurrent sites of long-term failure were mostly peritoneum among the diffuse type. To the best of our knowledge, the present study indicated for the first time that FGFR2 could predict long-term failure of adjuvant S-1 chemotherapy in curative advanced gastric cancer. There was no interaction between FGFR2 expression and patient survival outcomes in stage II/III gastric cancer. Patients with FGFR2 3+ in stage II/III gastric cancer should carefully be followed-up for >5 years after surgery.

Prevalence of programmed death-1 ligand-1 (PD-L1) and infiltrating lymphocytes in human gastric carcinogenesis

OBJECTIVE

The PD-1/PD-L1 pathway plays a key role in the immune evasion of tumor cells from the host immune system. This study aimed to examine PD-L1 expression and prevalence of infiltrating T cellin gastric diseases, and elucidate the relevance of PD-L1 and prevalence of infiltrating T cell in the pathogenesis of gastric carcinoma.

METHODS

Immunohistochemistry and HE staining were used to investigate the in situ expression of PD-L1, CD4 and CD8 in paraffin-embedded gastric tissues from patients with gastric ulcer (n=21), intestinal metaplasia/atrophic gastritis (n=26) and gastric carcinoma tissues (n=38).

RESULTS

The expression of PD-L1 was found to be most prevalent in gastric carcinoma and, by comparison, decreased in gastric tissues from patients with gastric ulcer or intestinal metaplasia/atrophic gastritis. The overexpression of PD-L1 was notably more prevalent in cancer tissues and tissues from cases of intestinal metaplasia/atrophic gastritis, with the highest prevalence observed in intestinal metaplasia/atrophic gastritis. Meanwhile, decreasing prevalence was observed for CD4 and CD8 expression in gastric carcinoma. Therefore, PD-L1 expression in gastric carcinoma appeared to be inversely correlated with prevalence of infiltrating T cell.

CONCLUSION

PD-L1 expression was more prevalent while CD4 and CD8 expression were decreased in gastric carcinoma compared with gastric ulcer and intestinal metaplasia/atrophic gastritis. As the activated immunological status in gastric ulcerappears to switch to one of immunological suppression in intestinal metaplasia/atrophic gastritis and gastric carcinoma, this may suggest that the immune evasion associated with the PD-L1 pathway may be triggered in the pathogenesis of human gastric carcinoma.

Phenformin inhibits growth and epithelial-mesenchymal transition of ErbB2-overexpressing breast cancer cells through targeting the IGF1R pathway

Reports suggest that metformin, a popular anti-diabetes drug, prevents breast cancer through various systemic effects, including insulin-like growth factor receptor (IGFR) regulation. Although the anti-cancer properties of metformin have been well-studied, reports on a more bioavailable/potent biguanide, phenformin, remain sparse. Phenformin exerts similar functional activity to metformin and has been reported to impede mammary carcinogenesis in rats. Since the effects of phenformin on specific breast cancer subtypes have not been fully explored, we used ErbB2-overexpressing breast cancer cell and animal models to test the anti-cancer potential of phenformin. We report that phenformin (25-75 μM) decreased cell proliferation and impaired cell cycle progression in SKBR3 and 78617 breast cancer cells. Reduced tumor size after phenformin treatment (30 mg/kg/day) was demonstrated in an MMTV-ErbB2 transgenic mouse syngeneic tumor model. Phenformin also blocked epithelial-mesenchymal transition, decreased the invasive phenotype, and suppressed receptor tyrosine kinase signaling, including insulin receptor substrate 1 and IGF1R, in ErbB2-overexpressing breast cancer cells and mouse mammary tumor-derived tissues. Moreover, phenformin suppressed IGF1-stimulated proliferation, receptor tyrosine kinase signaling, and epithelial-mesenchymal transition markers in vitro. Together, our study implicates phenformin-mediated IGF1/IGF1R regulation as a potential anti-cancer mechanism and supports the development of phenformin and other biguanides as breast cancer therapeutics.

Macroscopic appearance of Type IV and giant Type III is a high risk for a poor prognosis in pathological stage II/III advanced gastric cancer with postoperative adjuvant chemotherapy

AIM

To evaluate whether a high risk macroscopic appearance (Type IV and giant Type III) is associated with a dismal prognosis after curative surgery, because its prognostic relevance remains elusive in pathological stage II/III (pStage II/III) gastric cancer.

METHODS

One hundred and seventy-two advanced gastric cancer (defined as pT2 or beyond) patients with pStage II/III who underwent curative surgery plus adjuvant S1 chemotherapy were evaluated, and the prognostic relevance of a high-risk macroscopic appearance was examined.

RESULTS

Advanced gastric cancers with a high-risk macroscopic appearance were retrospectively identified by preoperative recorded images. A high-risk macroscopic appearance showed a significantly worse relapse free survival (RFS) (35.7%) and overall survival (OS) (34%) than an average risk appearance (P = 0.0003 and P < 0.0001, respectively). A high-risk macroscopic appearance was significantly associated with the 13^th Japanese Gastric Cancer Association (JGCA) pT (P = 0.01), but not with the 13^th JGCA pN. On univariate analysis for RFS and OS, prognostic factors included 13^th JGCA pStage (P < 0.0001) and other clinicopathological factors including macroscopic appearance. A multivariate Cox proportional hazards model for univariate prognostic factors identified high-risk macroscopic appearance (P = 0.036, HR = 2.29 for RFS and P = 0.021, HR = 2.74 for OS) as an independent prognostic indicator.

CONCLUSION

A high-risk macroscopic appearance was associated with a poor prognosis, and it could be a prognostic factor independent of 13^th JGCA stage in pStage II/III advanced gastric cancer.

Key Genes in Stomach Adenocarcinoma Identified via Network Analysis of RNA-Seq Data

RNA-seq data of stomach adenocarcinoma (STAD) were analyzed to identify critical genes in STAD. Meanwhile, relevant small molecule drugs, transcription factors (TFs) and microRNAs (miRNAs) were also investigated. Gene expression data of STAD were downloaded from The Cancer Genome Atlas (TCGA). Differential analysis was performed with package edgeR. Relationships with correlation coefficient > 0.6 were retained in the gene co-expression network. Functional enrichment analysis was performed for the genes in the network with DAVID and KOBASS 2.0. Modules were identified using Cytoscape. Relevant small molecules drugs, transcription factors (TFs) and microRNAs (miRNAs) were revealed by using CMAP and WebGestalt databases. A total of 520 DEGs were identified between 285 STAD samples and 33 normal controls, including 244 up-regulated and 276 down-regulated genes. A gene co-expression network containing 53 DEGs and 338 edges was constructed, the genes of which were significantly enriched in focal adhesion, ECM-receptor interaction and vascular smooth muscle contraction pathways. Three modules were identified from the gene co-expression network and they were associated with skeletal system development, inflammatory response and positive regulation of cellular process, respectively. A total of 20 drugs, 9 TFs and 6 miRNAs were acquired that may regulate the DEGs. NFAT-COL1A1/ANXA1, HSF2-FOS, SREBP-IL1RN and miR-26-COL5A2 regulation axes may be important mechanisms for STAD.

HER3 over-expression and overall survival in gastrointestinal cancers

Published studies on the association between human epidermal factor receptor 3 (HER3) expression and overall survival (OS) in gastrointestinal cancers have yielded conflicting results. The aim of this study was to explore the association of HER3 over-expression with OS in gastrointestinal cancers. A systematic search was performed through Medline/PubMed, Embase, Science Direct and Elsevier. The summary odds ratio (OR) with 95% confidence interval (CI) was calculated to estimate the strength of the association. Overall, we observed that HER3 over-expression was associated with worse OS at five years (OR = 1.38, 95% CI: 1.04-1.82); however, HER3 over-expression was not associated with worse OS at three years (OR = 1.33, 95% CI: 0.97-1.84). The cumulative meta-analysis showed similar results. In subgroup analyses by tumor type, HER3 over-expression in gastric cancers was associated with worse OS at both three years (OR = 1.69, 95% CI: 1.28-2.25) and five years (OR = 1.74, 95% CI: 1.26-2.41). In conclusion, our results suggest that HER3 over-expression may be associated with worse overall survival in gastric cancers. Well-designed studies with a large sample size are required to further confirm our findings.

HER3, but Not HER4, Plays an Essential Role in the Clinicopathology and Prognosis of Gastric Cancer: A Meta-Analysis

Background and Aim

Human epidermal growth factor receptor (HER) family plays an important role in gastric cancer (GC), especially HER2. Too much attention has been paid to HER2; however, the functions of HER3 and HER4 overexpression in GC are always ignored. The clinicopathological and prognostic roles of HER3 and HER4 in GC are controversial. In this study, a systematic review and meta-analysis was conducted to evaluate the use of HER3 or HER4 as a predictor of clinicopathology and survival time in GC patients.

Methods

Eligible studies were searched on PubMed, Ovid, Web of Science, and Cochrane databases through multiple search strategies. Data collection and statistical analysis were carried out by the Revman 5.3 software. The Newcastle-Ottawa scale was used to assess the quality of included studies.

Results

A total of 448 studies about HER3 overexpression and GC, and 398 studies about HER4 overexpression and GC were searched. Of these, 5 eligible studies about HER3 including 1016 GC patients and 3 eligible studies about HER4 including 793 GC patients met the inclusion criteria. The results showed that HER3 and HER4 overexpression were significantly associated with depth of tumor invasion (OR = 0.44, 95%CI 0.29–0.67, P = 0.0002 and OR = 0.50, 95%CI 0.38–0.86, P = 0.007) and lymph node metastasis (OR = 0.40, 95%CI 0.20–0.77, P = 0.007 and OR = 0.57, 95%CI 0.38–0.86, P = 0.007), and HER3 overexpression reveals a tendency of later tumor node metastases (TNM) stage (OR = 0.50, 95%CI 0.22–1.15, P = 0.10) and predicts a worse survival time (RR = 0.71, 95%CI 0.61–0.84, P<0.00001), while HER4 overexpression had no correlation with TNM stage (OR = 0.60, 95%CI 0.20–1.78) and survival time (RR = 1.09, 95%CI 0.91–1.30).

Conclusions

This meta-analysis indicated that HER3 plays an essential role in the clinicopathology and prognosis of GC. However, HER4 may not be an ideal prognostic factor for GC.

Lymph node ratio as a novel and simple prognostic factor in advanced gastric cancer

TNM staging is no doubt the most critical prognostic factors, representing tumor (T)/lymph node metastasis (N)/distant metastasis (M) in gastric cancer. Lymph node ratio-based N system (Nr) has been repeatedly reported to be of prognostic relevance in advanced gastric cancer independent of stage in the multivariate analysis world-wide, and proposed as more sophisticated than N with regard to predicting accurate prognosis. As a result, proposed TNrM system may predict survival more accurately than the present TNM staging system for patients undergoing limited lymph node analysis. It could adjust stage migration when the lymph node number was used as staging factor. Although correlation of the number of metastatic lymph nodes and lymph node ratio is obvious, biological characteristics other than that could also have been reflected on. It may indicate how successful the operation of lymph node dissection was, or it may be revealing the potential of the patient's lymph node immune-reaction. Recently, high lymph node ratio is closely associated with EGFR expression in advanced gastric cancer. When efficiency of applying lymph node ratio as a biomarker is verified and confirmed in an expansive research, and when cancer causing molecules are identified, as well as the competence as a treatment target is studied, the new biomarker, namely, lymph node ratio, could find itself in a limelight in gastric cancer treatment in the future.

Pertuzumab in gastrointestinal cancer

INTRODUCTION

Human epidermal growth factor receptor 2 (HER2) and HER3 are altered in multiple tumor types, including gastrointestinal cancer. The HER2/HER3 dimer is crucial for HER2-mediated signaling in HER2-positive tumors. HER2-targeting agents, including trastuzumab, lapatinib, trastuzumab emtansine, and pertuzumab, have been approved for the treatment of HER2-positive breast cancer, with trastuzumab also approved for the treatment of HER2-positive gastric cancer. Pertuzumab, a recombinant humanized immunoglobulin (Ig) G1 monoclonal antibody targeting HER-2, binds to the dimerization domain (extracellular domain II) of HER2, which leads to blocking of ligand-induced HER2 heterodimerization. It is under investigation in gastrointestinal cancers, including HER2-positive gastric cancer.

AREA COVERED

In this review, the authors summarize the biology of HER2/HER3 and its alterations in gastrointestinal cancers. The authors focus specifically on the current status of development of pertuzumab in gastrointestinal cancers.

EXPERT OPINION

The HER2/HER3 alteration in gastrointestinal cancers is quite interesting. In HER2-positive gastric cancer, the dual blockade of HER2 and HER3 using trastuzumab and pertuzumab is being tested in an international phase III trial, the JACOB study. This strategy may benefit HER2-positive gastric cancer patients more as in the case of HER2-positive breast cancer. In other gastrointestinal cancers, including biliary tract cancer, esophageal cancer, pancreatic cancer, and colorectal cancer, there is huge room for the development of pertuzumab.

Recent advances in the molecular diagnostics of gastric cancer

Gastric cancer (GC) is the third most common cause of cancer-related death in the world, representing a major global health issue. Although the incidence of GC is declining, the outcomes for GC patients remain dismal because of the lack of effective biomarkers to detect early GC and predict both recurrence and chemosensitivity. Current tumor markers for GC, including serum carcinoembryonic antigen and carbohydrate antigen 19-9, are not ideal due to their relatively low sensitivity and specificity. Recent improvements in molecular techniques are better able to identify aberrant expression of GC-related molecules, including oncogenes, tumor suppressor genes, microRNAs and long non-coding RNAs, and DNA methylation, as novel molecular markers, although the molecular pathogenesis of GC is complicated by tumor heterogeneity. Detection of genetic and epigenetic alterations from gastric tissue or blood samples has diagnostic value in the management of GC. There are high expectations for molecular markers that can be used as new screening tools for early detection of GC as well as for patient stratification towards personalized treatment of GC through prediction of prognosis and drug-sensitivity. In this review, the studies of potential molecular biomarkers for GC that have been reported in the publicly available literature between 2012 and 2015 are reviewed and summarized, and certain highlighted papers are examined.

Expression of tumor necrosis factor α-induced protein 8 is upregulated in human gastric cancer and regulates cell proliferation, invasion and migration

Tumor necrosis factor α-induced protein 8 (TNFAIP8) has been associated with the tumorigenicity of various types of cancer, however, the expression of TNFAIP8 and its function in gastric cancer remain to be fully elucidated. Therefore, the present study examined the expression and biological function of TNFAIP8 in gastric cancer. The expression levels of TNFAIP8 were determined in 86 gastric cancer tissue samples and adjacent normal tissues using immunohistochemistry, and in four gastric cancer cell lines and GES-1 cells using reverse transcription-quantitative polymerase chain reaction. The expression of TNFAIP8 and its association with the tumor, node, metastasis (TNM) status and lymphatic metastasis of gastric cancer was evaluated. Furthermore, the functions of decreased expression levels of TNFAIP8 were analyzed in human gastric cancer cell lines. The expression of TNFAIP8 was significantly upregulated in the gastric cancer tissues and in the gastric cancer cell lines, and its expression levels were associated with the TNM staging and lymphatic metastasis. Furthermore, decreased expression of TNFAIP8 inhibited the growth, invasion and migration of gastric cancer cells. These data provided an innovative insight suggesting the downregulation of TNFAIP8 as a meaningful approach for treating human gastric cancer and other types of cancer. In addition, the expression levels of TNFAIP8 may be considered as a biomarker of gastric cancer progression.