A Pan-Cancer Analysis of FAT Atypical Cadherin 4 (FAT4) in Human Tumors

Objective: We performed a pan-cancer analysis to explore the potential molecular mechanisms of FAT4 in 33 different tumors. Methods: : In this study, we selected 33 types of cancer based on the datasets of TCGA (the cancer genome atlas). We analyzed the expression of FAT4 in tumor and paracancer tissues. Meanwhile, we analyzed the expression levels of FAT4 in tissues from tumors of different stages. Kaplan-Meier survival analysis, immune infiltration analysis and FAT4-related gene enrichment analysis were performed. Results: : FAT4 expression in most tumor tissues was lower than in corresponding control tissues. FAT4 expression was different in different stages of bladder cancer (BLCA), kidney clear cell carcinoma (KIRC) and breast cancer (BRCA). In addition, the expression level of FAT4 in different types of tumors has an important impact on the prognosis of patients. We observed a statistically positive correlation between cancer-associated fibroblasts and FAT4 expression in most tumors. Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated that the role of FAT4 in the pathogenesis of cancer may be related to human papillomavirus infection, Hippo signaling pathway, PI3K−Akt signaling pathway. Gene Ontology (GO) enrichment analysis further showed that most of these genes were related to the pathways or cell biology, such as peptidyl−tyrosine phosphorylation, cell junction assembly, protein tyrosine kinase activity, etc. Conclusion: This pan-cancer analysis showed that FAT4 expression was statistically correlated with clinical stages, clinical prognosis, immune infiltration, and FAT4-related gene enrichment analysis, which aided in understanding the role of FAT4 in tumorigenesis from the perspective of clinical tumor samples.