Distinct prognostic values of YAP1 in gastric cancer

A literature review of recent advances in gastric cancer treatment: exploring the cross-talk between targeted therapies

BACKGROUND

Gastric cancer (GC) ranks fourth in global mortality rates and fifth in prevalence, making it one of the most common cancers worldwide. Recent clinical studies have highlighted the potential of immunotherapies as a promising approach to treating GC. This study aims to shed light on the most impactful therapeutic strategies in the context of GC immunotherapy, highlighting both established and emerging approaches.

MAIN BODY

This review examines over 160 clinical studies conducted globally, focusing on the effectiveness of various immunotherapy modalities, including cancer vaccines, adoptive cell therapy, immune checkpoint inhibitors (ICIs), and monoclonal antibodies (mAbs). A comprehensive search of peer-reviewed literature was performed using databases such as Web of Science, PubMed, and Scopus. The selection criteria included peer-reviewed articles published primarily within the last 10 years, with a focus on studies that provided insights into targeted therapies and their mechanisms of action, clinical efficacy, and safety profiles. The findings indicate that these immunotherapy strategies can enhance treatment outcomes for GC, aligning with current treatment guidelines. ICIs like pembrolizumab and nivolumab have shown significant survival benefits in specific GC subgroups. Cancer vaccines and CAR-T cell therapies demonstrate potential, while mAbs targeting HER2 and VEGFR pathways enhance outcomes in combination regimens. We discuss the latest advancements and challenges in targeted therapy and immunotherapy for GC. Given the evolving nature of this field, this research emphasizes significant evidence-based therapies and those currently under evaluation rather than providing an exhaustive overview. Challenges include resistance mechanisms, immunosuppressive tumor environments, and inconsistent results from combination therapies. Biomarker-driven approaches and further research into emerging modalities like CAR-T cells and cancer vaccines are critical for optimizing treatments.

CONCLUSIONS

Immunotherapy is reshaping GC management by improving survival and quality of life. Ongoing research and clinical evaluations are crucial for refining personalized and effective therapies.

Mechanisms of cellular crosstalk in the gastric tumor microenvironment are mediated by YAP1 and STAT3

Deregulation of the Hippo pathway is a driver for cancer progression and treatment resistance. In the context of gastric cancer, YAP1 is a biomarker for poor patient prognosis. Although genomic tumor profiling provides information of Hippo pathway activation, the present study demonstrates that inhibition of Yap1 activity has anti-tumor effects in gastric tumors driven by oncogenic mutations and inflammatory cytokines. We show that Yap1 is a key regulator of cell metabolism, proliferation, and immune responses in normal and neoplastic gastric epithelium. We propose that the Hippo pathway is targetable across gastric cancer subtypes and its therapeutic benefits are likely to be mediated by both cancer cell-intrinsic and -extrinsic mechanisms.

Long non-coding RNA SNHG1/microRNA-195-5p/Yes-associated protein axis affects the proliferation and metastasis of gastric cancer via the Hippo signaling pathway

Long non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) has been found to be highly expressed in gastric cancer (GC). However, the study for exploring the effects of SNHG1 and microRNA (miR)-195-5p on GC is limited. This research commits to unravel the regulatory effects of SNHG1, miRNA-195-5p, and Yes-associated protein 1 (YAP1) on GC. SNHG1, miR-195-5p and YAP1 levels in GC tissues and GC cells were detected. The GC cells were treated with various constructs altering SNHG1 or miR-195-5p expression to determine the biological activities of GC cell in vitro. The effect of SNHG1 inhibition on subcutaneous tumorigenesis of GC cells in a nude mouse model in vivo was detected. The binding relation among SNHG1, miR-195-5p, and YAP1 was validated. SNHG1 and YAP1 levels were elevated and miR-195-5p level was reduced in GC. Reduction of SNHG1 or elevation of miR-195-5p retarded GC cell biological activity in vitro. Downregulated SNHG1 suppressed tumor growth in vivo. SNHG1 bound to miR-195-5p, and miR-195-5p directly targeted YAP1. The downregulated SNHG1 hinders the biological behaviors of GC cells via the modulation of the miR-195-5p/YAP1 axis.

LncRNA DLGAP1-AS2 overexpression associates with gastric tumorigenesis: a promising diagnostic and therapeutic target

BACKGROUND

Aberrant expression of long noncoding RNAs (lncRNAs) is associated with the progression of human cancers, including gastric cancer (GC). The function of lncRNA DLGAP1-AS2, as a promising oncogene, has been identified in several human cancers. Therefore, this study was aimed to explore the association of DLGAP1-AS2 with gastric tumorigenesis, as well.

METHODS AND RESULTS

The expression level of DLGAP1-AS2 was initially pre-evaluated in GC datasets from Gene Expression Omnibus (GEO). Moreover, qRT-PCR experiment was performed on 25 GC and 25 adjacent normal tissue samples. The Cancer Genome Atlas (TCGA) data were also analyzed for further validation. Consistent with data obtained from GEO datasets, qRT-PCR results revealed that DLGAP1-AS2 was significantly (p < 0.0032) upregulated in GC specimens compared to normal samples, which was additionally confirmed using TCGA analysis (p < 0.0001). DLGAP1-AS2 expression level was also correlated with age (p = 0.0008), lymphatic and vascular invasion (p = 0.0415) in internal samples as well as poor survival of GC patients (p = 0.00074) in GEO datasets. Also, Gene Ontology analysis illustrated that DLGAP1-AS2 may be involved in the cellular process, including hippo signaling, regulated by YAP1, as its valid downstream target, in GC samples. Moreover, ROC curve analysis showed the high accuracy of the DLGAP1-AS2 expression pattern as a diagnostic biomarker for GC.

CONCLUSION

Our findings indicated that DLGAP1-AS2 might display oncogenic properties through gastric tumorigenesis and could be suggested as a therapeutic, diagnostic, and prognostic target.

m6A Methyltransferase 3 Promotes the Proliferation and Migration of Gastric Cancer Cells through the m6A Modification of YAP1

Gastric cancer is the most common gastrointestinal tumor with an increasing incidence. Furthermore, advanced gastric cancer is more common, but the mechanism underlying the proliferation and metastasis of gastric cancer has not been thoroughly explored. N6-methyladenosine (m6A) methyltransferase 3 (METTL3) may be involved in the proliferation and metastasis of gastric cancer. Therefore, Yes-associated protein 1 (YAP1) in the Hippo pathway was selected as the target, and the relationship between METTL3 and the proliferation and metastasis of gastric cancer was proved through a series of experiments. This research showed that the expression of m6A and METTL3 was upregulated in human gastric cancer tissues and gastric cancer cell lines. After lentiviral transfection, METTL3 silencing in AGS (human gastric adenocarcinoma cell line AGS) and MKN-45 (human gastric cancer cell line MKN-45) gastric cancer cell lines directly inhibited the proliferation, aggressiveness, and migration of gastric cancer cells. Mechanically, the inhibition of the YAP1-TEAD signaling pathway by peptide 17 reduces m6A methylation and the total mRNA level of YAP1. It also eliminates the promoting effect of METTL3 on the proliferation and migration of gastric cancer cells. In turn, the overexpression of YAP1 eliminates the inhibitory effect of METTL3 silencing on the proliferation, migration, and invasion of gastric cancer cells. This article proved that m6A methyltransferase METTL3 promoted the proliferation and migration of gastric cancer cells through the m6A modification of YAP1.

Gene Regulation Network of Prognostic Biomarker YAP1 in Human Cancers: An Integrated Bioinformatics Study

Background: Yes-associated protein 1 (YAP1) is the main downstream effector of the Hippo signaling pathway, which is involved in tumorigenesis. This study aimed to comprehensively understand the prognostic performances of YAP1 expression and its potential mechanism in pan-cancers by mining databases.

Methods: The YAP1 expression was evaluated by the Oncomine database and GEPIA tool. The clinical significance of YAP1 expression was analyzed by the UALCAN, GEPIA, and DriverDBv3 database. Then, the co-expressed genes with YAP1 were screened by the LinkedOmics, and annotated by the Metascape and DAVID database. Additionally, by the MitoMiner 4.0 v tool, the YAP1 co-expressed genes were screened to obtain the YAP1-associated mitochondrial genes that were further enriched by DAVID and analyzed by MCODE for the hub genes.

Results: YAP1 was differentially expressed in human cancers. Higher YAP1 expression was significantly associated with poorer overall survival and disease-free survival in adrenocortical carcinoma (ACC), brain Lower Grade Glioma (LGG), and pancreatic adenocarcinoma (PAAD). The LinkedOmics analysis revealed 923 co-expressed genes with YAP1 in adrenocortical carcinoma, LGG and PAAD. The 923 genes mainly participated in mitochondrial functions including mitochondrial gene expression and mitochondrial respiratory chain complex I assembly. Of the 923 genes, 112 mitochondrial genes were identified by MitoMiner 4.0 v and significantly enriched in oxidative phosphorylation. The MCODE analysis identified three hub genes including CHCHD1, IDH3G and NDUFAF5.

Conclusion: Our findings showed that the YAP1 overexpression could be a biomarker for poor prognosis in ACC, LGG and PAAD. Specifically, the YAP1 co-expression genes were mainly involved in the regulation of mitochondrial function especially in oxidative phosphorylation. Thus, our findings provided evidence of the carcinogenesis of YAP1 in human cancers and new insights into the mechanisms underlying the role of YAP1 in mitochondrial dysregulation.

A methylation-based mRNA signature predicts survival in patients with gastric cancer

Background

Evidence suggests that altered DNA methylation plays a causative role in the occurrence, progression and prognosis of gastric cancer (GC). Thus, methylated-differentially expressed genes (MDEGs) could potentially serve as biomarkers and therapeutic targets in GC.

Methods

Four genomics profiling datasets were used to identify MDEGs. Gene Ontology enrichment and Kyoto Encyclopaedia of Genes and Genomes pathway enrichment analysis were used to explore the biological roles of MDEGs in GC. Univariate Cox and LASSO analysis were used to identify survival-related MDEGs and to construct a MDEGs-based signature. The prognostic performance was evaluated in two independent cohorts.

Results

We identified a total of 255 MDEGs, including 192 hypermethylation-low expression and 63 Hypomethylation-high expression genes. The univariate Cox regression analysis showed that 83 MDEGs were associated with overall survival. Further we constructed an eight-MDEGs signature that was independent predictive of prognosis in the training cohort. By applying the eight-MDEGs signature, patients in the training cohort could be categorized into high-risk or low-risk subgroup with significantly different overall survival (HR = 2.62, 95% CI 1.71–4.02, P < 0.0001). The prognostic value of the eight-MDEGs signature was confirmed in another independent GEO cohort (HR = 1.35, 95% CI 1.03–1.78, P = 0.0302) and TCGA-GC cohort (HR = 1.85, 95% CI 1.16–2.94, P = 0.0084). Multivariate cox regression analysis proved the eight-MDEGs signature was an independent prognostic factor for GC.

Conclusion

We have thus established an innovative eight-MDEGs signature that is predictive of overall survival and could be a potentially useful guide for personalized treatment of GC patients.

TAZ Controls Helicobacter pylori-Induced Epithelial-Mesenchymal Transition and Cancer Stem Cell-Like Invasive and Tumorigenic Properties

Helicobacter pylori infection, the main risk factor for gastric cancer (GC), leads to an epithelial–mesenchymal transition (EMT) of gastric epithelium contributing to gastric cancer stem cell (CSC) emergence. The Hippo pathway effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ binding motif (TAZ) control cancer initiation and progression in many cancers including GC. Here, we investigated the role of TAZ in the early steps of H. pylori-mediated gastric carcinogenesis. TAZ implication in EMT, invasion, and CSC-related tumorigenic properties were evaluated in three gastric epithelial cell lines infected by H. pylori. We showed that H. pylori infection increased TAZ nuclear expression and transcriptional enhancer TEA domain (TEAD) transcription factors transcriptional activity. Nuclear TAZ and zinc finger E-box-binding homeobox 1 (ZEB1) were co-overexpressed in cells harboring a mesenchymal phenotype in vitro, and in areas of regenerative hyperplasia in gastric mucosa of H. pylori-infected patients and experimentally infected mice, as well as at the invasive front of gastric carcinoma. TAZ silencing reduced ZEB1 expression and EMT phenotype, and strongly inhibited invasion and tumorsphere formation induced by H. pylori. In conclusion, TAZ activation in response to H. pylori infection contributes to H. pylori-induced EMT, invasion, and CSC-like tumorigenic properties. TAZ overexpression in H. pylori-induced pre-neoplastic lesions and in GC could therefore constitute a biomarker of early transformation in gastric carcinogenesis.

miR-205 Promotes Apoptosis of Cervical Cancer Cells and Enhances Drug Sensitivity of Cisplatin by Inhibiting YAP1

Objective: Elevated expression of Yes-associated protein (YAP1) involves in the pathogenesis of cervical cancer. Bioinformatics analysis showed a targeting relationship between miR-205 and the 3'-UTR of YAP1. In this study, we aim to explore the role of miR-205 in the proliferation, apoptosis, or cisplatin (CDDP) resistance of cervical cancer cells. Patients and Methods: The dual luciferase reporter gene assay verified the relationship between miR-205 and YAP1. The CDDP-resistant cell line Hela/CDDP cells were cultured in vitro and divided into miR-NC group, miR-205 mimic group, and miR-205 inhibitor group followed by analysis of the expression of miR-205 and YAP1 mRNA by quantitative real-time polymerase chain reaction (qRT-PCR), and YAP1 protein level by western blot. Results: There was a targeted relationship between miR-205 and YAP1 mRNA. Compared with cervical cell line HCerEpiC cells, miR-205 expression was significantly decreased and YAP1 mRNA and protein expression was significantly increased in Hela cells (p < 0.01). Compared with miR-NC group, YAP1 protein expression in HeLa/CDDP cells was significantly decreased, cell apoptosis was increased, and proliferation was inhibited in miR-205 mimic-transfected Hela/CDDP cells (p < 0.01). Opposite results were obtained in miR-205 inhibitor-transfected Hela/CDDP cells. Conclusions: The expression of miR-205 is related to the CDDP resistance of cervical cancer cells. Increasing the expression of miR-205 can downregulate the expression of YAP1, inhibit the proliferation and promote apoptosis of cervical cancer cells, and enhance the sensitivity to CDDP.

Claudin-6 is a single prognostic marker and functions as a tumor-promoting gene in a subgroup of intestinal type gastric cancer

BACKGROUND

We aimed to identify novel tumor-promoting drivers highly expressed in gastric cancer (GC) that contribute to worsened prognosis in affected patients.

METHODS

Genes whose expression was increased and correlated with worse prognosis in GC were screened using datasets from the Cancer Genome Atlas and Gene Expression Omnibus. We examined Claudin-6 (CLDN6) immunoreactivity in GC tissues and the effect of CLDN6 on cellular functions in GC cell lines. The mechanisms underlying GC-promoting function of CLDN6 were also investigated.

RESULTS

CLDN6 was identified as a gene overexpressed in GC tumors as compared with adjacent non-tumorous tissues and whose increased expression was positively correlated with worse overall survival of GC patients, particularly those with Lauren's intestinal type GC, in data from multiple publicly available datasets. Additionally, membranous CLDN6 immunoreactivity detected in intestinal type GC tumors was correlated with worse overall survival. In CLDN6-expressing GC cells, silencing of CLDN6 inhibited cell proliferation and migration/invasion abilities, possibly via suppressing transcription of YAP1 and its downstream transcriptional targets at least in part.

CONCLUSIONS

This study identified CLDN6 as a GC-promoting gene, suggesting that CLDN6 to be a possible single prognostic marker and promising therapeutic target for a subset of GC patients.

The Hippo Kinase LATS2 Controls Helicobacter pylori-Induced Epithelial-Mesenchymal Transition and Intestinal Metaplasia in Gastric Mucosa

BACKGROUND & AIMS

Gastric carcinoma is related mostly to CagA+-Helicobacter pylori infection, which disrupts the gastric mucosa turnover and elicits an epithelial-mesenchymal transition (EMT) and preneoplastic transdifferentiation. The tumor suppressor Hippo pathway controls stem cell homeostasis; its core, constituted by the large tumor suppressor 2 (LATS2) kinase and its substrate Yes-associated protein 1 (YAP1), was investigated in this context.

METHODS

Hippo, EMT, and intestinal metaplasia marker expression were investigated by transcriptomic and immunostaining analyses in human gastric AGS and MKN74 and nongastric immortalized RPE1 and HMLE epithelial cell lines challenged by H pylori, and on gastric tissues of infected patients and mice. LATS2 and YAP1 were silenced using small interfering RNAs. A transcriptional enhanced associated domain (TEAD) reporter assay was used. Cell proliferation and invasion were evaluated.

RESULTS

LATS2 and YAP1 appear co-overexpressed in the infected mucosa, especially in gastritis and intestinal metaplasia. H pylori via CagA stimulates LATS2 and YAP1 in a coordinated biphasic pattern, characterized by an early transient YAP1 nuclear accumulation and stimulated YAP1/TEAD transcription, followed by nuclear LATS2 up-regulation leading to YAP1 phosphorylation and targeting for degradation. LATS2 and YAP1 reciprocally positively regulate each other's expression. Loss-of-function experiments showed that LATS2 restricts H pylori-induced EMT marker expression, invasion, and intestinal metaplasia, supporting a role of LATS2 in maintaining the epithelial phenotype of gastric cells and constraining H pylori-induced preneoplastic changes.

CONCLUSIONS

H pylori infection engages a number of signaling cascades that alienate mucosa homeostasis, including the Hippo LATS2/YAP1/TEAD pathway. In the host-pathogen conflict, which generates an inflammatory environment and perturbations of the epithelial turnover and differentiation, Hippo signaling appears as a protective pathway, limiting the loss of gastric epithelial cell identity that precedes gastric carcinoma development.

Activating Hippo Pathway via Rassf1 by Ursolic Acid Suppresses the Tumorigenesis of Gastric Cancer

The Hippo pathway is often dysregulated in many carcinomas, which results in various stages of tumor progression. Ursolic acid (UA), a natural compound that exists in many herbal plants, is known to obstruct cancer progression and exerts anti-carcinogenic effect on a number of human cancers. In this study, we aimed to examine the biological mechanisms of action of UA through the Hippo pathway in gastric cancer cells. MTT assay showed a decreased viability of gastric cancer cells after treatment with UA. Following treatment with UA, colony numbers and the sizes of gastric cancer cells were significantly diminished and apoptosis was observed in SNU484 and SNU638 cells. The invasion and migration rates of gastric cancer cells were suppressed by UA in a dose-dependent manner. To further determine the gene expression patterns that are related to the effects of UA, a microarray analysis was performed. Gene ontology analysis revealed that several genes, such as the Hippo pathway upstream target gene, ras association domain family (RASSF1), and its downstream target genes (MST1, MST2, and LATS1) were significantly upregulated by UA, while the expression of YAP1 gene, together with oncogenes (FOXM1, KRAS, and BATF), were significantly decreased. Similar to the gene expression profiling results, the protein levels of RASSF1, MST1, MST2, LATS1, and p-YAP were increased, whereas those of CTGF were decreased by UA in gastric cancer cells. The p-YAP expression induced in gastric cancer cells by UA was reversed with RASSF1 silencing. In addition, the protein levels in the Hippo pathway were increased in the UA-treated xenograft tumor tissues as compared with that in the control tumor tissues; thus, UA significantly inhibited the tumorigenesis of gastric cancer in vivo in xenograft animals. Collectively, UA diminishes the proliferation and metastasis of gastric cancer via the regulation of Hippo pathway through Rassf1, which suggests that UA can be used as a potential chemopreventive and therapeutic agent for gastric cancer.

Mechanotransduction and Cytoskeleton Remodeling Shaping YAP1 in Gastric Tumorigenesis

The essential role of Hippo signaling pathway in cancer development has been elucidated by recent studies. In the gastrointestinal tissues, deregulation of the Hippo pathway is one of the most important driving events for tumorigenesis. It is widely known that Yes-associated protein 1 (YAP1) and WW domain that contain transcription regulator 1 (TAZ), two transcriptional co-activators with a PDZ-binding motif, function as critical effectors negatively regulated by the Hippo pathway. Previous studies indicate the involvement of YAP1/TAZ in mechanotransduction by crosstalking with the extracellular matrix (ECM) and the F-actin cytoskeleton associated signaling network. In gastric cancer (GC), YAP1/TAZ functions as an oncogene and transcriptionally promotes tumor formation by cooperating with TEAD transcription factors. Apart from the classic role of Hippo-YAP1 cascade, in this review, we summarize the current investigations to highlight the prominent role of YAP1/TAZ as a mechanical sensor and responder under mechanical stress and address its potential prognostic and therapeutic value in GC.

miR-424-5p Regulates Hepatoma Cell Proliferation and Apoptosis

OBJECTIVE

Yes-associated protein (Yes-associated protein 1 [YAP1]) is an important oncogene that is related to the pathogenesis and progression of liver cancer. It was found that miR-424-5p expression was significantly decreased in liver cancer tissues, revealing its anticancer effect. Bioinformatic analysis demonstrated the targeted relationship between miR-424-5p and the 3' untranslated region of YAP1. This study investigated the role of miR-424-5p in regulating YAP1 expression and affecting hepatoma cell proliferation and apoptosis.

MATERIALS AND METHODS

Tumors and normal liver tissues adjacent to tumors were collected from patients to detect the expression of miR-424-5p and YAP1. A dual-luciferase reporter gene assay was adopted to explore the targeted regulation between miR-424-5p and YAP1. Liver cancer HCCLM3 and MHCC97-L cells and normal liver HL-7702 cells were cultured in vitro to compare expression levels of miR-424-5p and YAP1. HCCLM3 and MHCC97-L cells were divided into the miR-NC group and miR-424-5p mimic group. Cell apoptosis was detected by flow cytometry. Cell proliferation was determined by EdU staining.

RESULTS

Compared with normal liver tissue, miR-424-5p expression was significantly decreased, while YAP1 mRNA and protein levels were obviously upregulated in liver cancer tissues, which were related to the clinical stage. A negative correlation was found between miR-424-5p and YAP1 mRNA levels in liver cancer tissues. Dual-luciferase reporter gene assay confirmed the targeted relationship between miR-424-5p and YAP1. miR-424-5p expression in HCCLM3 and MHCC97-L cells decreased compared with L20 cells, which correlated with malignancy. YAP1 level in HCCLM3 and MHCC97-L cells was significantly enhanced, which correlated with malignancy. miR-424-5p mimic transfection significantly downregulated YAP1 expression in HCCLM3 and MHCC97-L cells, resulting in enhanced apoptosis and attenuated cell proliferation.

CONCLUSIONS

Decreased miR-424-5p expression and increased YAP1 expression are found in patients with liver cancer. Increased miR-424-5p can inhibit YAP1 expression, attenuate hepatoma cell proliferation, and induce cell apoptosis.

Plasticity of differentiated cells in wound repair and tumorigenesis, part II: skin and intestine

Recent studies have identified and begun to characterize the roles of regenerative cellular plasticity in many organs. In Part I of our two-part Review, we discussed how cells reprogram following injury to the stomach and pancreas. We introduced the concept of a conserved cellular program, much like those governing division and death, which may allow mature cells to become regenerative. This program, paligenosis, is likely necessary to help organs repair the numerous injuries they face over the lifetime of an organism; however, we also postulated that rounds of paligenosis and redifferentiation may allow long-lived cells to accumulate and store oncogenic mutations, and could thereby contribute to tumorigenesis. We have termed the model wherein differentiated cells can store mutations and then unmask them upon cell cycle re-entry the ‘cyclical hit’ model of tumorigenesis. In the present Review (Part II), we discuss these concepts, and cell plasticity as a whole, in the skin and intestine. Although differentiation and repair are arguably more thoroughly studied in skin and intestine than in stomach and pancreas, it is less clear how mature skin and intestinal cells contribute to tumorigenesis. Moreover, we conclude our Review by discussing plasticity in all four organs, and look for conserved mechanisms and concepts that might help advance our knowledge of tumor formation and advance the development of therapies for treating or preventing cancers that might be shared across multiple organs.

Summary: This final installment of a two-part Review discusses how cycles of dedifferentiation and redifferentiation can promote tumorigenesis in the skin and intestine, showing how plasticity in these continuously renewing tissues might contribute to tumorigenesis.

Plasticity of differentiated cells in wound repair and tumorigenesis, part I: stomach and pancreas

For the last century or so, the mature, differentiated cells throughout the body have been regarded as largely inert with respect to their regenerative potential, yet recent research shows that they can become progenitor-like and re-enter the cell cycle. Indeed, we recently proposed that mature cells can become regenerative via a conserved set of molecular mechanisms ('paligenosis'), suggesting that a program for regeneration exists alongside programs for death (apoptosis) and division (mitosis). In two Reviews describing how emerging concepts of cellular plasticity are changing how the field views regeneration and tumorigenesis, we present the commonalities in the molecular and cellular features of plasticity at homeostasis and in response to injury in multiple organs. Here, in part 1, we discuss these advances in the stomach and pancreas. Understanding the extent of cell plasticity and uncovering its underlying mechanisms may help us refine important theories about the origin and progression of cancer, such as the cancer stem cell model, as well as the multi-hit model of tumorigenesis. Ultimately, we hope that the new concepts and perspectives on inherent cellular programs for regeneration and plasticity may open novel avenues for treating or preventing cancers.