Long Non-Coding RNA HOTAIR Modulates KLF12 to Regulate Gastric Cancer Progression via PI3K/ATK Signaling Pathway by Sponging miR-618

Inhibiting miR-618 Promotes Keratinocytes Proliferation and Migration to Enhance Wound Healing in Mice

The delay in wound healing caused by chronic wounds or pathological scars is a pressing issue in clinical practice, imposing significant economic and psychological burdens on patients. In particular, with the aging of the population and the increasing incidence of diseases such as diabetes, impaired wound healing is one of the growing health problems. MicroRNA (miRNA) plays a crucial role in wound healing and regulates various biological processes. Our results show that miR-618 was significantly upregulated during the inflammatory phase of wound healing.Subsequently, miR-618 promotes the secretion of pro-inflammatory cytokines and regulates the proliferation and migration of keratinocytes. Mechanistically, miR-618 binds to the target gene-Atp11b and inhibits the PI3K-Akt signaling pathway, inhibiting the epithelial-mesenchymal transition (EMT) of keratinocytes. In addition, the PI3K-Akt signaling pathway induces the enrichment of nuclear miR-618, and miR-618 binds to the promoter of Lin7a to regulate gene transcription. Intradermal injection of miR-618 antagomir around full-thickness wounds in peridermal mice effectively accelerates wound closure compared to control. In conclusion, miR-618 antagomir can be a potential therapeutic agent for wound healing.

MALAT1 binds to miR-188-3p to regulate ALOX5 activity in the lung inflammatory response of neonatal bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) causes high morbidity and mortality in infants, but no effective preventive or therapeutic agents have been developed to combat BPD. In this study, we assessed the expression of MALAT1 and ALOX5 in peripheral blood mononuclear cells from BPD neonates, hyperoxia-induced rat models and lung epithelial cell lines. Interestingly, we found upregulated expression of MALAT1 and ALOX5 in the experimental groups, along with upregulated expression of proinflammatory cytokines. According to bioinformatics prediction, MALAT1 and ALOX5 simultaneously bind to miR-188-3p, which was downregulated in the experimental groups above. Silencing MALAT1 or ALOX5 and overexpressing miR-188-3p inhibited apoptosis and promoted the proliferation of hyperoxia-treated A549 cells. Suppressing MALAT1 or overexpressing miR-188-3p increased the expression levels of miR-188-3p but decreased the expression levels of ALOX5. Moreover, RNA immunoprecipitation (RIP) and luciferase assays showed that MALAT1 directly targeted miR-188-3p to regulate ALOX5 expression in BPD neonates. Collectively, our study demonstrates that MALAT1 regulates ALOX5 expression by binding to miR-188-3p, providing novel insights into potential therapeutics for BPD treatment.

RNF7 Facilitated the Tumorigenesis of Pancreatic Cancer by Activating PI3K/Akt Signaling Pathway

RING finger protein-7 (RNF7) functions as a positive regulator in the progression of multiple malignancies. However, the underlying mechanism by which RNF7 contributes to pancreatic cancer (PC) is lacking. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to test the level of RNF7expression in PC cell lines and tissues. The role of RNF7 in PC tumorigenesis was analyzed by Cell Counting Kit-8 (CCK-8). 5-Ethynyl-20-deoxyuridine (EdU), wound-healing/Transwell assays, as well as a subcutaneous tumorigenesis model were constructed to assess the role of RNF7 in PC cells. The association between RNF7 and PI3K/Akt signaling were assessed by western blot and further confirmed by rescue experiments. The PC patients with upregulated expression of RNF7 had poor survival. Overexpression of RNF7 significantly facilitated PC proliferative and migrative and invasive properties in vitro and vivo; however, knockdown of RNF7exhibited the opposite results. Mechanistically, RNF7 promoted PANC-1 and SW1990 cell growth through impacting the activation of the PI3K/Akt signaling pathway. Our data demonstrated that RNF7 promoted PC tumorigenesis via activating the PI3K/Akt signaling pathway and might be regarded as one of the potential therapies to PC.

HOX cluster-embedded lncRNAs and epithelial-mesenchymal transition in cancer: Molecular mechanisms and therapeutic opportunities

Although there has been substantial improvement in the treatment modalities, cancer remains the major cause of fatality worldwide. Metastasis, recurrence, and resistance to oncological therapies are the leading causes of cancer mortality. Epithelial-mesenchymal transition (EMT) is a complex biological process that allows cancer cells to undergo morphological transformation into a mesenchymal phenotype to acquire invasive potential. It encompasses reversible and dynamic ontogenesis by neoplastic cells during metastatic dissemination. Hence, understanding the molecular landscape of EMT is imperative to identify a reliable clinical biomarker to combat metastatic spread. Accumulating evidence reveals the role of HOX (homeobox) cluster-embedded long non-coding RNAs (lncRNAs) in EMT and cancer metastasis. They play a crucial role in the induction of EMT, modulating diverse biological targets. The present review emphasizes the involvement of HOX cluster-embedded lncRNAs in EMT as a molecular sponge, chromatin remodeler, signaling regulator, and immune system modulator. Furthermore, the molecular mechanisms behind therapy resistance and the potential use of novel drugs targeting HOX cluster-embedded lncRNAs in the clinical management of distant metastasis will be discussed.

Long non-coding RNAs (lncRNAs); roles in tumorigenesis and potentials as biomarkers in cancer diagnosis

New research has indicated that long non-coding RNAs (lncRNAs) play critical roles in a broad range of biological processes, including the pathogenesis of many complex human diseases, including cancer. The detailed regulation mechanisms of many lncRNAs in cancer initiation and progression have yet to be discovered, even though a few of lncRNAs' functions in cancer have been characterized. In the present study, we summarize recent advances in the mechanisms and functions of lncRNAs in cancer. We focused on the roles of newly-identified lncRNAs as oncogenes and tumor suppressors, as well as the potential pathways these molecules could play. The paper also discusses their potential uses as biomarkers for the diagnosis and prognosis of cancer.

Inconsistency in the expression pattern of a five-lncRNA signature as a potential diagnostic biomarker for gastric cancer patients in bioinformatics and in vitro

Objectives

Due to diagnosis of gastric cancer in advanced stages as well as its poor prognosis, finding biomarkers is essential. In this study, using the TCGA RNAseq data of gastric cancer patients, we evaluated the diagnostic value of lncRNAs that had differential expression.

Materials and Methods

We evaluated P-value, FDR, and log fold change for whole transcripts. Next, by comparison of the RNAseq gene names with the total known lncRNA names, we identified differential expressed lncRNAs. Following this, specificity and sensitivity for lncRNAs coming from the previous step were calculated. For more confirmation, we predicted target genes and performed GO and KEGG signaling pathway analysis. In the end, we examined reliability and consistency of expression of this signature in three gastric cancer cell lines and one of them in twenty tumors and tumor-adjacent normal tissue samples using qRT-PCR.

Results

Five lncRNAs had proper sensitivity and specificity and had target genes involved in cancer-related signaling pathways; however, they showed different expression patterns in TCGA data and in vitro.

Conclusion

The results of our study demonstrated that the five-lncRNAs PART1, UCA1, DIRC3, HOTAIR, and HOXA11AS require more investigation to be confirmed as diagnostic biomarkers in gastric cancer.

Designing strategies of small-molecule compounds for modulating non-coding RNAs in cancer therapy

Non-coding RNAs (ncRNAs) have been defined as a class of RNA molecules transcribed from the genome but not encoding proteins, such as microRNAs, long non-coding RNAs, Circular RNAs, and Piwi-interacting RNAs. Accumulating evidence has recently been revealing that ncRNAs become potential druggable targets for regulation of several small-molecule compounds, based on their complex spatial structures and biological functions in cancer therapy. Thus, in this review, we focus on summarizing some new emerging designing strategies, such as high-throughput screening approach, small-molecule microarray approach, structure-based designing approach, phenotypic screening approach, fragment-based designing approach, and pharmacological validation approach. Based on the above-mentioned approaches, a series of representative small-molecule compounds, including Bisphenol-A, Mitoxantrone and Enoxacin have been demonstrated to modulate or selectively target ncRNAs in different types of human cancers. Collectively, these inspiring findings would provide a clue on developing more novel avenues for pharmacological modulations of ncRNAs with small-molecule drugs for future cancer therapeutics.

Circ-RNF111 aggravates the malignancy of gastric cancer through miR-876-3p-dependent regulation of KLF12

Background

The aberrant expression of circular RNAs (circRNAs) plays vital roles in the advancement of human cancers, including gastric cancer (GC). In this study, the functions of circRNA ring finger protein 111 (circ-RNF111) in GC were investigated.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed for the levels of circ-RNF111, microRNA-876-3p (miR-876-3p) and krueppel-like factor 12 (KLF12) mRNA. RNase R assay was conducted for the feature of circ-RNF111. Cell Counting Kit-8 (CCK-8) assay, colony formation assay, wound-healing assay, and transwell assay were applied for cell viability, colony formation, migration, and invasion, respectively. Flow cytometry analysis was used to analyze cell apoptosis and cell cycle process. The glycolysis level was examined using specific commercial kits. Western blot assay was carried out to measure the protein levels of hexokinase 2 (HK-2) and KLF12. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to verify the combination between miR-876-3p and circ-RNF111 or KLF12. Murine xenograft model was constructed for the role of circ-RNF111 in vivo. Immunohistochemistry (IHC) was used for KLF12 level.

Results

Circ-RNF111 was higher expressed in GC tissues and cells than normal tissues and cells. Silencing of circ-RNF111 restrained cell viability, colony formation, migration, invasion, cell cycle process and glycolysis and induced apoptosis in GC cells in vitro. Circ-RNF111 positively regulated KLF12 expression via absorbing miR-876-3p. MiR-876-3p downregulation reversed the impacts of circ-RNF111 silencing on GC cell malignant phenotypes. MiR-876-3p overexpression repressed GC cell growth, metastasis and glycolysis, inhibited apoptosis and arrested cell cycle, while KLF12 elevation weakened the effects. Besides, circ-RNF111 knockdown inhibited tumor growth in vivo.

Conclusion

Circ-RNF111 knockdown relieved the development of GC by regulating miR-876-3p/KLF12 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02373-5.

Roles of ncRNAs as ceRNAs in Gastric Cancer

Although ignored in the past, with the recent deepening of research, significant progress has been made in the field of non-coding RNAs (ncRNAs). Accumulating evidence has revealed that microRNA (miRNA) response elements regulate RNA. Long ncRNAs, circular RNAs, pseudogenes, miRNAs, and messenger RNAs (mRNAs) form a competitive endogenous RNA (ceRNA) network that plays an essential role in cancer and cardiovascular, neurodegenerative, and autoimmune diseases. Gastric cancer (GC) is one of the most common cancers, with a high degree of malignancy. Considerable progress has been made in understanding the molecular mechanism and treatment of GC, but GC’s mortality rate is still high. Studies have shown a complex ceRNA crosstalk mechanism in GC. lncRNAs, circRNAs, and pseudogenes can interact with miRNAs to affect mRNA transcription. The study of the involvement of ceRNA in GC could improve our understanding of GC and lead to the identification of potential effective therapeutic targets. The research strategy for ceRNA is mainly to screen the different miRNAs, lncRNAs, circRNAs, pseudogenes, and mRNAs in each sample through microarray or sequencing technology, predict the ceRNA regulatory network, and, finally, conduct functional research on ceRNA. In this review, we briefly discuss the proposal and development of the ceRNA hypothesis and the biological function and principle of ceRNAs in GC, and briefly introduce the role of ncRNAs in the GC’s ceRNA network.

A high level of KLF12 causes folic acid-resistant neural tube defects by activating the Shh signalling pathway in mice

Although adequate periconceptional folic acid (FA) supplementation has reduced the occurrence of pregnancies affected by neural tube defects (NTDs), the mechanisms underlying FA-resistant NTDs are poorly understood, and thus NTDs still remain a global public health concern. A high level of Krüppel-like factor 12 (KLF12) exerts deleterious effects on heath in most cases, but evidence for its roles in development has not been published. We observed KLF12-overexpressing mice showed disturbed neural tube development. KLF12-overexpressing foetuses died in utero at approximately 10.5 days post coitus, with 100% presenting cranial NTDs. Neither FA nor formate promoted normal neural tube closure in mutant foetuses. The RNA-seq results showed that a high level of KLF12 caused NTDs in mice via overactivating the sonic hedgehog (Shh) signalling pathway, leading to the upregulation of patched 1, GLI-Krüppel family member GLI1, hedgehog-interacting protein, etc., while FA metabolism-related enzymes did not express differently. PF-5274857, an antagonist of the Shh signalling pathway, significantly promoted dorsolateral hinge point formation and partially rescued the NTDs. The regulatory hierarchy between a high level of KLF12 and FA-resistant NTDs might provide new insights into the diagnosis and treatment of unexplained NTDs in the future.

LncRNA FGD5-AS1 promotes the malignant phenotypes of ovarian cancer cells via targeting miR-142-5p

Long non-coding RNAs (lncRNAs) have been reported to participate in regulating gene expression and are related to tumor progression. FGD5 antisense RNA 1 (FGD5-AS1) facilitates the progression of various tumors. However, the expression and function of FGD5-AS1 in ovarian cancer (OC) and its mechanism of action are not yet clear. Real-time polymerase chain reaction (RT-PCR) was employed to explore the expression levels of FGD5-AS1 and miR-142-5p in OC. The relationship between the expression of FGD5-AS1 and clinicopathological indicators of OC patients was analyzed by χ² test. CCK-8 assay, BrdU assay, and Transwell assay were carried out to detect cell proliferation, migration, as well as invasion, respectively. Subcutaneous tumorigenesis experiment and lung metastasis model were used to examine the biological effects of FGD5-AS1 in OC in vivo. Dual luciferase reporter gene assay or RIP experiment was employed to explore the targeting relationship between FGD5-AS1 and miR-142-5p, as well as miR-142-5p and PD-L1 3'UTR. First, we found that FGD5-AS1 was markedly up-regulated in OC. Moreover, its high expression level was associated with positive local lymph node metastasis and higher T stage in OC patients. Gain-of-function and loss-of-function assays demonstrated that FGD5-AS1 facilitated the proliferation, migration, as well as invasion of OC cells. Mechanistically, it was revealed that FGD5-AS1 targeted miR-142-5p to repress its expression and function. Furthermore, miR-142-5p has a binding site for 3' UTR of PD-L1, and FGD5-AS1 could positively regulate PD-L1 expression via repressing miR-142-5p. The present study reports that FGD5-AS1/miR-142-5p/PD-L1 axis is involved in regulating OC progression.

Depletion of Circular RNA circ_CORO1C Suppresses Gastric Cancer Development by Modulating miR-138-5p/KLF12 Axis

Background

Gastric cancer (GC) is a common and deadly malignancy in the world. CircRNAs have emerged as important regulators in human diseases, including GC. In this work, we intended to explore the role of circ_CORO1C in GC progression and potential mechanism.

Methods

Quantitative real-time PCR (qRT-PCR) or Western blot assay was performed to examine the expression of circRNA coronin-like actin-binding protein 1C (circ_CORO1C), microRNA (miR)-138-5p and Krueppel-like factor 12 (KLF12) in clinical samples and cells. Cell colony formation ability and viability were measured by colony formation assay and methyl thiazolyl tetrazolium (MTT) assay, respectively. Expression of cell proliferation and epithelia-mesenchymal transition (EMT) biomarker was detected by Western blot analysis. And cell metastasis, including migration and invasion, and apoptosis were analyzed via Transwell assay and flow cytometry, respectively. Target relationship among circ_CORO1C, miR-138-5p and KLF12 was validated by dual-luciferase reporter assay. The in vivo role of circ_CORO1C was investigated by tumor xenograft assay.

Results

Circ_CORO1C and KLF12 were upregulated, while miR-138-5p was downregulated in GC tissues and cells. Circ_CORO1C knockdown suppressed colony formation ability, viability, migration, invasion and EMT in GC cells, while promoted cell apoptosis in vitro. Circ_CORO1C targeted miR-138-5p, the inhibition of which could attenuate silenced circ_CORO1C-induced inhibitory effects on GC progression. MiR-138-5p repressed the aggressive malignant behaviors of GC cells by directly targeting KLF12. Circ_CORO1C deficiency inhibited GC tumor growth in vivo.

Conclusion

Depletion of circ_CORO1C suppressed GC progression by regulating miR-138-5p/KLF12 axis, offering a potential molecular target for GC therapy.

HOTAIR lncRNA promotes epithelial-mesenchymal transition by redistributing LSD1 at regulatory chromatin regions

Epithelial‐to‐mesenchymal transition (EMT) describes the loss of epithelial traits and gain of mesenchymal traits by normal cells during development and by neoplastic cells during cancer metastasis. The long noncoding RNA HOTAIR triggers EMT, in part by serving as a scaffold for PRC2 and thus promoting repressive histone H3K27 methylation. In addition to PRC2, HOTAIR interacts with the LSD1 lysine demethylase, an epigenetic regulator of cell fate during development and differentiation, but little is known about the role of LSD1 in HOTAIR function during EMT. Here, we show that HOTAIR requires its LSD1‐interacting domain, but not its PRC2‐interacting domain, to promote the migration of epithelial cells. This activity is suppressed by LSD1 overexpression. LSD1‐HOTAIR interactions induce partial reprogramming of the epithelial transcriptome altering LSD1 distribution at promoter and enhancer regions. Thus, we uncover an unexpected role of HOTAIR in EMT as an LSD1 decommissioning factor, counteracting its activity in the control of epithelial identity.

Downregulation of Circ_0071589 Suppresses Cisplatin Resistance in Colorectal Cancer by Regulating the MiR-526b-3p/KLF12 Axis

BACKGROUND

Chemoresistance is one key factor for the failure of cisplatin (CDDP)-based therapy in colorectal cancer (CRC). Although circular RNAs (circRNAs) are associated with chemoresistance development, the role and mechanism of hsa_circ_0071589 (circ_0071589) in the development of CDDP resistance in CRC remain unclear.

METHODS

CDDP-resistant and sensitive CRC samples were collected. CDDP-resistant HCT116/CDDP and LOVO/CDDP cells were established. The levels of circ_0071589, microRNA (miR)-526b-3p and Krüppel-like factor 12 (KLF12) were detected via quantitative reverse transcription polymerase chain reaction, Western blot or immunohistochemistry. Cell viability, proliferation, cycle process, apoptosis, migration and invasion were examined via Cell Counting Kit-8, flow cytometry, transwell assay and Western blot. The association between miR-526b-3p and circ_0071589 or KLF12 was predicted by starBase, and explored via dual-luciferase reporter assay and RNA immunoprecipitation. The effect of circ_0071589 on CDDP resistance in CRC in vivo was investigated using a xenograft model.

RESULTS

Circ_0071589 level was upregulated in CDDP-resistant CRC tissue samples and cell lines. Circ_0071589 knockdown inhibited CDDP resistance, proliferation, migration and invasion, and promoted apoptosis in CDDP-resistant CRC cells. Circ_0071589 was a sponge for miR-526b-3p. MiR-526b-3p knockdown reversed the role of circ_0071589 inhibition in CDDP resistance. MiR-526b-3p suppressed CDDP resistance by directly targeting KLF12. Circ_0071589 regulated KLF12 expression through modulating miR-526b-3p. Circ_0071589 knockdown aggravated CDDP-induced reduction of xenograft tumor growth by upregulating miR-526b-3p and decreasing KLF12.

CONCLUSION

Knockdown of circ_0071589 repressed CDDP resistance in CDDP-resistant CRC cells by regulating the miR-526b-3p/KLF12 axis.

Long Non-coding RNAs in Gammaherpesvirus Infections: Their Roles in Tumorigenic Mechanisms

Long non-coding RNAs (lncRNAs) regulate gene expression at the epigenetic, transcriptional, or posttranscriptional level by interacting with protein, DNA, and RNA. Emerging evidence suggests that various lncRNAs are abnormally expressed and play indispensable roles in virus-triggered cancers. Besides, a growing number of studies have shown that virus-encoded lncRNAs participate in tumorigenesis. However, the functions of most lncRNAs in tumors caused by oncogenic viruses and their underlying mechanisms remain largely unknown. In this review, we summarize current findings regarding lncRNAs involved in cancers caused by Epstein–Barr virus (EBV) and Kaposi’s sarcoma herpesvirus (KSHV). Additionally, we discuss the contribution of lncRNAs to tumor occurrence, development, invasion, and metastasis; the roles of lncRNAs in key signaling pathways and their potential as biomarkers and therapeutic targets for tumor diagnostics and treatment.

Roles of the HOX Proteins in Cancer Invasion and Metastasis

Invasion and metastasis correspond to the foremost cause of cancer-related death, and the molecular networks behind these two processes are extremely complex and dependent on the intra- and extracellular conditions along with the prime of the premetastatic niche. Currently, several studies suggest an association between the levels of HOX genes expression and cancer cell invasion and metastasis, which favour the formation of novel tumour masses. The deregulation of HOX genes by HMGA2/TET1 signalling and the regulatory effect of noncoding RNAs generated by the HOX loci can also promote invasion and metastasis, interfering with the expression of HOX genes or other genes relevant to these processes. In this review, we present five molecular mechanisms of HOX deregulation by which the HOX clusters products may affect invasion and metastatic processes in solid tumours.

HOX transcript antisense RNA: An oncogenic lncRNA in diverse malignancies

HOX transcript antisense RNA (HOTAIR) is a transcript produced from the antisense strand of the HOXC gene cluster and influencing expression of genes from the HOXD locus. HOTAIR has prominent roles in different aspects of carcinogenic process from cancer initiation to metastasis. A number of in vitro, in vivo and human investigations have confirmed the oncogenic impacts of HOTAIR. The diagnostic power of HOTAIR in distinguishing cancer status from healthy status has been optimal in gastric cancer, pancreatic adenocarcinoma and colorectal cancer. The most important achievement in this regard has been provided by studies that verified diagnostic value of this lncRNA in the serum samples, potentiating its application in non-invasive diagnosis of cancer. Moreover, HOTAIR has a crucial role in determination of response of cancer cells to therapeutic modalities. The current review aims to explain the outlines of these studies to emphasize its potential as a biomarker and therapeutic target for these conditions.

PI3K/AKT/mTOR signaling in gastric cancer: Epigenetics and beyond

PI3K/AKT/mTOR pathway is one of the most important signaling pathways involved in normal cellular processes. Its aberrant activation modulates autophagy, epithelial-mesenchymal transition, apoptosis, chemoresistance, and metastasis in many human cancers. Emerging evidence demonstrates that some infections as well as epigenetic regulatory mechanisms can control PI3K/AKT/mTOR signaling pathway. In this review, we focused on the role of this pathway in gastric cancer development, prognosis, and metastasis, with an emphasis on epigenetic alterations including DNA methylation, histone modifications, and post-transcriptional modulations through non-coding RNAs fluctuations as well as H. pylori and Epstein-Barr virus infections. Finally, we reviewed different molecular targets and therapeutic agents in clinical trials as a potential strategy for gastric cancer treatment through the PI3K/AKT/mTOR pathway.

Long non-coding RNAs as potential markers for occurrence, progression, and prognosis of gastric cancer

In recent years, more and more attention has been paid to the relationship between long non-coding RNAs (lncRNAs) and tumor. Abnormal expression of lncRNAs plays an oncogenic or tumor-suppressing role in gastric cancer (GC) by participating in the biological behaviors of GC cells, such as proliferation, invasion, and migration. By summarizing the relevant literature, this paper discusses the research status, detection technology, and mechanism of action of lncRNAs in GC, as well as their potential as markers for occurrence, progression, prognosis, and drug resistance of GC. It is expected that lncRNAs can play an important role in early detection, early treatment, and effective improvement of chemotherapy resistance of GC to achieve personalized precise treatment of this malignancy.

MAP Kinases Pathways in Gastric Cancer

Gastric cancer (GC) is turning out today to be one of the most important welfare issues for both Asian and European countries. Indeed, while the vast majority of the disease burden is located in China and in Pacific and East Asia, GC in European countries still account for about 100,000 deaths per year. With this review article, we aim to focus the attention on one of the most complex cellular pathways involved in GC proliferation, invasion, migration, and metastasis: the MAP kinases. Such large kinases family is to date constantly studied, since their discovery more than 30 years ago, due to the important role that it plays in the regulation of physiological and pathological processes. Interactions with other cellular proteins as well as miRNAs and lncRNAs may modulate their expression influencing the cellular biological features. Here, we summarize the most important and recent studies involving MAPK in GC. At the same time, we need to underly that, differently from cancers arising from other tissues, where MAPK pathways seems to be a gold target for anticancer therapies, GC seems to be unique in any aspect. Our aim is to review the current knowledge in MAPK pathways alterations leading to GC, including H. pylori MAPK-triggering to derail from gastric normal epithelium to GC and to encourage researches involved in MAPK signal transduction, that seems to definitely sustain GC development.