TMUB1 expression is associated with the prognosis of colon cancer and immune cell infiltration.Background
 TMUB1 is a transmembrane protein involved in biological signaling and plays an important role in the stability and transcription of P53.  However, its role in tumor remains unknown.


 Using R language, the expression level of 33 cancer spectrum TMUB1 was analyzed by the public database TCGA, GEO and HPA, the differential expressed gene (DEG) screening and protein interaction (PPI) network was constructed, and the differential genes of TMUB1 in colon cancer were identified.  The relevant signaling pathways were identified by gene functional annotation and enrichment analysis.  The ssGSEA algorithm in GSVA were used for immune infiltration analysis.  The Kaplan-Meier analysis, univariate and multivariate Cox regression analysis, nomogram and calibration map analysis were constructed to evaluate the correlation between TMUB1 expression and clinical prognosis.  The expression levels of TMUB1 in intestinal cancer cell lines as well as in 10 intestinal cancer tissues were verified by qPCR experiments.


 Results
 Through the bioinformatics analysis of multiple databases and preliminary experimental studies, we found that the expression of TMUB1 was significantly increased in colon cancer tumors, and was correlated with the clinical N stage, pathological grade, lymphatic metastasis and BMI of colon cancer.  TMUB1 may be involved in the regulation of the malignant progression of colon cancer.  Meanwhile, patients with high expression of TMUB1 mRNA had worse OS and DSS, and TMUB1 expression was an independent prognostic factor for OS and DSS.  It was further found that highly expressed TMUB1 tissues showed low levels of immune infiltration and stromal infiltration.


 We reported the expression level of TMUB1 in colon cancer and analyzed its potential prognostic value in colon cancer through the bioinformatics analysis and preliminary experimental studies.  The high expression of TMUB1 is a negative prognostic factor for colon cancer patients.  TMUB1 may be a potential target for colon cancer.
R
Using R language, the expression level of 33 cancer spectrum TMUB1 was analyzed by the public database TCGA, GEO and HPA, the differential expressed gene (DEG) screening and protein interaction (PPI) network was constructed, and the differential genes of TMUB1 in colon cancer were identified. 
TCGA
Using R language, the expression level of 33 cancer spectrum TMUB1 was analyzed by the public database TCGA, GEO and HPA, the differential expressed gene (DEG) screening and protein interaction (PPI) network was constructed, and the differential genes of TMUB1 in colon cancer were identified. 
GEO
Using R language, the expression level of 33 cancer spectrum TMUB1 was analyzed by the public database TCGA, GEO and HPA, the differential expressed gene (DEG) screening and protein interaction (PPI) network was constructed, and the differential genes of TMUB1 in colon cancer were identified. 
HPA
Using R language, the expression level of 33 cancer spectrum TMUB1 was analyzed by the public database TCGA, GEO and HPA, the differential expressed gene (DEG) screening and protein interaction (PPI) network was constructed, and the differential genes of TMUB1 in colon cancer were identified. 
PPI
The ssGSEA algorithm in GSVA were used for immune infiltration analysis. 
GSVA