The prognostic value of DAAM2 in lower grade glioma, liver cancer, and breast cancer.

PURPOSE: Dishevelled-associated activator of morphogenesis 2 (DAAM2) is a formin protein and has a potential role in the tumor metastasis. The prognostic value of DAAM2 in pan-cancer is investigated in this study.

METHODS: TCGA and GTEx database were downloaded to perform bioinformatics analysis and ROC curves. Then we explored protein-protein interaction and GO-KEGG enrichment to figure out the protein pathways associated with DAAM2 and studied DAAM2-related immune infiltration and methylation. Fifteen pairs of BRCA clinical samples were enrolled to determine the expression and distribution of DAAM2 in BRCA sections by immunohistochemistry. Finally, BRCA cells were transfected with siRNA targeting DAAM2 and subsequently subject to cell proliferation, migration, and invasion assays.

RESULTS: DAAM2 was closely related to the diagnosis and clinical characteristics of lower grade glioma (LGG), liver hepatocellular carcinoma (LIHC), and breast cancer (BRCA). Survival curve analysis demonstrated DAAM2 served as a potential prognostic indicator of LGG and LIHC (P = 0.0029 and P = 0.025, respectively). DAAM2 was mainly participated in signaling pathways mediating cytoskeleton regulation and tumor development. The correlation of DAAM2 with tumor-infiltrating immune cells (TIICs) and methylation levels was conducive to the prediction of novel biomarkers of pan-carcinoma. DAAM2 was highly expressed in BRCA tissues than that in paracancerous tissues. The proliferation, invasion, and migration of BRCA cells were inhibited by DAAM2 siRNA.

CONCLUSION: DAAM2 had a specific value in foretelling the prognosis of LGG, LIHC, and BRCA. High expression level of DAAM2 has longer survival rates in LGG and LIHC. The knockdown of DAAM2 retards the proliferation, invasion, and migration of BRCA cells. This study provides a novel sight of DAAM2 into the exploration of a potential biomarker in pan-cancer.