The clinicopathological and prognostic values of TAZ and YAP expression in gastric cancer

Background: The transcriptional co-activator with PDZ-binding motif(TAZ) and Yes-associated protein(YAP) are well-known members of the Hippo signaling pathway, which may correlated with organ development regulation and interaction between organ and tumor. At the same time, it is closely related to the occurrence and development of tumors. Methods: The purpose of this study is to explore a potential marker that is specific for gastric cancer. In our study, we designed a bioinformatics analysis of the clinicopathological features of TAZ and YAP mRNA expression in gastric cancer using Kaplan-Meier plotter, Oncomine and TCGA databases. Results: According to Kaplan-Meier plotter, the mRNA expression of TAZ and YAP are negatively related with the overall post-progression and first progression survival rates of gastric cancer patients(p0.05), even stratified by clinicopathological features(p0.05). As shown in Oncomine, TAZ and YAP mRNA expression is higher in gastric cancers than gastric tissue and gastric mucosa(p0.05). In TCGA data, univariate analysis showed that age, TNM staging, lymph node metastasis, distant metastasis was correlated with prognosis in patients with gastric cancer(p0.05). COX multivariate analysis showed that age and distant metastasis are risk factors affecting the survival of patients with gastric cancer(p0.05). Conclusion: TAZ/YAP may be employed as a good molecular market for patients and might help researchers discover a targeted inhibitor for treating gastric cancer.

protein, and then LATS1/2 kinase is activated. The activated LATS1/2 kinase phosphorylates YAP and TAZ, thereby initializing the regulation of TAZ/YAP [4]. The TAZ gene is situated on chromosomes 3q23-q24 and has a molecular weight of 43KD, including a TEAD binding domain, a WW domain, and a C-terminal PDZ binding motif. The YAP gene is situated on the 11q13 region of the chromosome and encodes a YAP protein with a molecular weight of about 65KD, which is one more WW domain, SH3 binding motif, and N-terminal proline domain hindering J than TAZ [5]. TAZ and YAP are paralogs and are very similar in topology. Their functions are similar and highly dependent on TEAD family transcription factors in transcriptional activity [6][7]. Although TAZ and YAP are similar in structure, they have some differences in function. It was found in the knockout mouse model that YAP/TAZ also has some independent costimulators. After knocking out the YAP gene, it will cause the stagnation of embryonic development, and when knocking out the TAZ gene, mice will develop defects in the kidneys and lungs [8]. These results suggest that they may regulate different physiological processes.
TAZ and YAP proteins are overexpressed in various tumors, such as breast cancer, lung cancer, oral squamous cell carcinoma, and bladder cancer [9][10][11][12]. Chen et al. found that TAZ and YAP proteins are highly expressed in non-small cell lung cancer and are significantly related to the clinical stage [13].
TAZ and YAP proteins are highly expressed in oral squamous cell carcinoma and are closely related to clinical and pathological features such as tumor differentiation and tumor volume [11]. Hao et al.
Found the expression of TAZ and YAP were significantly increased in gliomas [14]. In ovarian and colorectal cancer, TAZ mRNA expression levels are significantly elevated, indicating a poor prognosis for patients [15][16]. The experimental results of Ge et al. [17] showed that TAZ is highly expressed in gastric cancer cells, and knocking out TAZ can reverse cisplatin-resistant gastric cancer cells that have undergone epithelial-mesenchymal transition. The mRNA expression of YAP was upregulated in gastric cancer tissues, and it was positively associated with TNM staging, differentiation, age, depth of invasion and lymph node metastasis [18]. In our study, we performed a bioinformatics analysis to clarify the clinical-pathological and prognostic significances of TAZ and YAP mRNA expression in gastric cancer.

Materials And Methods 4
Kaplan-Meier plotter analysis (https://kmplot.com/analysis/) The Kaplan-Meier plotter database is a gene expression database, which integrates gene expression and clinical data simultaneously. The Kaplan-Meier plots were used to analyze the prognostic significance of specific gene, The patients cohorts was divided into high and low expression group by survival analysis plot, and the hazard ratio with 95% confidence intervals and logrank P value are calculated. The database contains more than 50000 genes, which includes four largest datasets(mRNA gene chip), respectively breast (n = 6,234), ovarian (n = 2,190), lung (n = 3,452), and gastric (n = 1,440) cancer. The system also includes mRNA RNA-seq, which contains liver cancer and pan-cancer(21 tumor types). The sources of the databases was downloaded from GEO, EGA, and TCGA. The prognostic roles of TAZ and YAP mRNA were analyzed in gastric cancer. KM plotter analyze the clinical impact of independent genes in different cancers, including Overall survival (OS) and Postprogression survival(PPS), First progression(FP). A collection of clinicopathological features, including Gender, TNM staging, Perforation, Treament, Differentiation, Lauren's classification, HER2 positivity.
Oncomine database analysis(www.oncomine.org) TAZ and YAP mRNA expression were analyzed using Oncomine, which was a large tumor gene chip database, covering 65 gene chip data sets, 4,700 gene chips and 480 million gene expression data.
The Oncomine database can be used to compare the differential expression analysis of major cancer tumor types and their respective normal tissues. It can also be used to explore various tumor subtypes and clinical and pathological-based analysis. The database can query one or more genes to visualize the results. There are two main analysis methods, including Fold change and P value. In our study, we compared the differents in TAZ and YAP mRNA between cancer and normal tissues.
TCGA database analysis(www.cancer.gov) The Cancer Genome Atlas (TCGA), which was a landmark cancer genomics program, molecularly characterized over 20,000 primary cancer and matched normal samples spanning 33 cancer types.
We downloaded gastric cancer(n = 407) sample data set from TCGA using TCGA-assembler in Rsoftware. At the same time, the median method was used to standardize the data. We organized the data, analyzed the mRNA expression of TAZ and YAP in gastric cancer, and compared it with prognostic and clinicopathological database of the gastric cancer patients. Cox's proportional hazards model was employed for univariate analysis and multivariate. Two-sided p < 0.05 was considered as statistically significant difference. SPSS 13.0 software was employed to analyze all data.

Result
The prognostic values of TAZ mRNA expression in gastric cancer According to Kaplan-Meier plotter, up-regulated TAZ mRNA expression was negative associated with Overall, Post-progression and First progression survival rates of gastric cancer patients (Fig. 1A, p < 0.05). As shown in Table I, high mRNA expression of TAZ was relationship with worse OS of gastric cancer patients, even stratified by tumor(topography) status, metastasisin status, treatment, and her2 positivity. It has the same result in male patients of stage II, stage III, stage IV, N1-3, N1, N2, N3, perforation none, poor-differentiated, diffuse type(p < 0.05). The Post-progression survival rate of the gastric cancer patients were associated with worse prognosis in patients, even stratified by gender, lymph node status, metastasisin status, lauren's classification, her2 positivity. It had the same result in patients with stage II, stage III, stage IV, T2, T3, surgery alone, other adjuvant. The First progression survival rate of the gastric cancer patients were associated with worse prognosis, even stratified into gender, treatment. It also had the same result in patients of stage II, stage III, T2, T3, M0, none-perforation, intestinal or diffuse-type, and her2 negative. According to DErrico's datasets, we found that the expression of TAZ mRNA was higher in gastric adenocarcinoma(including mixed and diffuse-type) than gastric mucosa (Fig. 1B, p < 0.05). Cho's datasets shown that TAZ mRNA expression was higher in gastric cancers than gastric tissue, even stratified into intestinal and mixedtype adenocarcinoma (Fig. 1B,

The prognostic values of YAP mRNA expression in gastric cancer
In Kaplan-Meier plotter, higher YAP mRNA expression was negative associated with Overall, Post-progression and First progression survival rates of gastric cancer patients( Fig. 2A, p < 0.05). As shown in the study, high mRNA expression of YAP was negatively related with male patients with OS, T2, T3, N1-3, N2, M0, surgery alone, diffuse-type, or Her2 negative (Table II, p < 0.05). We found that a higher YAP mRNA expression was negatively associated with Post-progression survival rates of gastric cancer patients, even stratified by gender and Her2 positivity. It was also the same result for the gastric cancer patients with stage II-IV, T2, T3, M0, surgery alone, or intestinal-type. The First progression survival rate of the gastric cancer patients were associated with worse prognosis in male, stage III-IV, T2, N1-3, N3, M0, urgery alone, intestinal-type, or Her2 negative (Table II, p < 0.05). According to Cho's, we found that the expression of YAP mRNA was higher in gastric adenocarcinoma than gastric tissue, even stratified into intestinal, diffuse and mixed-type adenocarcinoma (Fig. 2B, p < 0.05).
Chen's datasets also shown that YAP mRNA expression was higher in gastric adenocarcinoma than gastric mucosa, even stratified into intestinal, diffuse and mixed-type adenocarcinoma (Fig. 2B, p < 0.05). Wang's and Cui's datasets shown that YAP mRNA expression was higher in gastric cancer than gastric mucosa and gastric tissue (Fig. B, p < 0.05). Derrico's datasets also shown that YAP mRNA expression was higher in gastric ntestinal type adenocarcinoma than gastric mucosa (Fig. 2B,

Discussion
As a transcriptional co-activator, TAZ is highly expressed in a variety of tumors and has various carcinogenic effects. TAZ plays an important role in tumor differentiation, metastasis, growth, and maintenance of stem cell characteristics through signaling pathways such as Hippo, Wnt, and GPCR in tumors [19]. TAZ also plays an important role in regulating angiogenesis. The high expression of TAZ in gastric cancer cells may enhance the angiogenesis ability of gastric cancer by promoting the expression of β-catenin and VEGF [20,21]. TAZ is highly expressed in breast cancer, and upregulation of TAZ promotes epithelial-mesenchymal transition (EMT), invasion, migration, and proliferation of breast cancer cells [22]. High expression of TAZ was found in non-small cell lung cancer, which is closely related to poor differentiation, poor prognosis, and short survival of the patients[23, 24].
The expression of TAZ was also correlated with tumor grade, TNM stage, distant metastasis and recurrence in gastric cancer tissue [21]. According to our study, the expression of TAZ was overall negatively associated with post-progression and first progression survival. Furthermore, we also found up-regulated TAZ mRNA expression is closely related to clinical and pathological characteristics such as TNM staging, differentiation, lauren's classification.
As an oncogene, YAP interacts with TEAD to activate YAP target genes, and can promote the proliferation and Our results shown that higher TAZ/ YAP mRNA expression was associated with worse prognosis. Our study provides a novel insights into the prognostic of gastric cancer patients. TAZ/YAP may be employed as a good molecular market for patients and might help researchers discover a targeted inhibitor for treating gastric cancer.     The clinicopathological and prognostic value of YAP mRNA expression levels in gastric cancer. The relationship between YAP mRNA expression and Overall, Post-progression or First progression survival rates was analyzed according to Kaplan Meier plotter(A, p 0.05). According to Cho's, YAP mRNA expression was higher in gastric adenocarcinoma than gastric tissue, even stratified into intestinal, diffuse and mixed-type adenocarcinoma(B, p 0.05). Chen's datasets also shown that YAP mRNA expression was higher in gastric adenocarcinoma than gastric mucosa, even stratified into intestinal, diffuse and mixed-type adenocarcinoma(B, p 0.05). Wang's and Cui's datasets shown that YAP mRNA expression was higher in gastric cancer than gastric mucosa and gastric tissue(B, p 0.05). Derrico's datasets also shown that YAP mRNA expression was higher in gastric ntestinal type adenocarcinoma than gastric mucosa(B, p 0.05). HR, hazard ratio.