Insights into the Prognostic Value of Small Nucleolar RNA U81 and SNORA7B in Breast Cancer

Purpose: Small nucleolar RNAs (snoRNAs) has been closely associated with tumor development. However, its prognostic role and underlying molecular mechanisms in breast cancer (BC) remain unclear. This study aimed to identify prognostic snoRNAs by analyzing sequencing data from BC and para-cancer tissues, building a risk score model to predict breast cancer prognosis, and investigating the mechanisms by which they affect BC prognosis. Patients and Methods: We analyzed the expression levels of snoRNAs between breast cancer and para-cancer tissues in the SNORic and Cancer Genome Atlas (TCGA) databases. We constructed a risk score model based on the differentially expressed snoRNAs. Receiver operating characteristic (ROC) curves and nomograms were plotted to assess the prognostic value of the risk score model. In this model, we divided breast cancer patients into high-and low-risk groups and studied each group's infiltration of immune cells. Pearson's correlation was used to identify differentially expressed mRNAs that were significantly correlated with prognostic snoRNAs. Results: Small nucleolar RNAs, C/D box 81 (U81) and H/ACA box 7 B (SNORA7B), were identified as breast cancer prognosis-associated snoRNAs, and low-U81-or high-SNORA7B-expression groups had worse survival. A risk score model based on U81 and SNORA7B expression can predict BC survival. The infiltration of multiple immune cell types was significantly different between the high-and low-risk score groups. The high-risk score group may respond better to anti-immune checkpoint therapy. Many genes are related to U81 and SNORA7B, some of which are related to cell proliferation, metastasis, and changes in the extracellular matrix. Conclusion: U81 and SNORA7B may serve as potential prognostic biomarkers of BC. Risk scoring models based on the expression of two snoRNAs can screen patients with breast cancer who can benefit from immunotherapy.