The landscape of prognostic and immunological role of myosin light chain 9 (MYL9) in human tumors

INTRODUCTION: Recent studies have shown that myosin light chain 9 (MYL9) plays a vital role in immune infiltration, tumor invasion, and metastasis; however, the prognostic and immunological role of MYL9 has not been reported. The purpose of this study was to explore the potential prognostic and immunological roles of MYL9 in human cancers by public datasets mainly including the cancer genome atlas (TCGA) and Gene expression omnibus. METHODS: The expression pattern and prognostic value of MYL9 were analyzed across multiple public datasets in different cancer. The correlations between MYL9 expression and immune infiltration among multiple cancers were analyzed by using the TIMER2.0. The MYL9‐related gene enrichment analysis was implemented by mainly using KEGG and GO datasets. RESULTS: MYL9 was lowly expressed in most cancers, such as breast cancer, lung adenocarcinoma and squamous cell carcinoma, and stomach adenocarcinoma; but it was highly expressed in several cancers, such as cholangiocarcinoma, head and neck squamous cell carcinoma, and liver hepatocellular carcinoma. Furthermore, MYL9 expression was distinctively associated with prognosis in adrenocortical carcinoma, colon adenocarcinoma, brain glioma, lung cancer, ovarian cancer, gastric cancer, breast cancer, blood cancer, and prostate cancer patients. The expressions of MYL9 were significantly associated with the infiltration of cancer‐associated fibroblasts, B cell, CD8(+)T cell, CD4(+)T cell, macrophage, neutrophil, dendritic cell in different tumors as well as immune markers. In addition, we found that the functional mechanisms of MYL9 involved muscle contraction and focal adhesion. CONCLUSION: MYL9 can serve as a prognostic signature in pan‐cancer and is associated with immune infiltration. This pan‐cancer study is the first to show a relatively comprehensive understanding of the prognostic and immunological roles of MYL9 across different cancers.