Comprehensive Analysis of SLC35A2 in Pan-Cancer and Validation of Its Role in Breast Cancer

PURPOSE: Elucidation of the oncogenic role of SLC35A2 in human tumors and the potential function and clinical significance in breast cancer. METHODS: Pan-cancer analysis was performed via various bioinformatics tools to explain the pathogenic role of SLC35A2. A prognostic nomogram was also developed based on the SLC35A2 expression and clinicopathological characteristics in breast cancer patients. In addition, the role of SLC35A2 was validated in breast cancer by in vivo and in vitro experiments. RESULTS: SLC35A2 expression is increased in 27 tumor types, and its high expression is substantially correlated with poor prognosis in patients with a variety of cancers. Receiver operating characteristic (ROC) curves showed that SLC35A2 expression levels could accurately distinguish most tumor tissues from normal tissues. High SLC35A2 expression was linked to increased immune infiltration in myeloid-derived suppressor cells (MDSC), as well as immune checkpoints, ferroptosis-related genes, tumor mutational burden (TMB), and microsatellite instability (MSI). SLC35A2 may be involved in tumorigenesis by regulating the glycosylation process. Furthermore, multivariate Cox analysis showed that SLC35A2 was an independent prognostic factor for breast cancer. And the nomogram model had good predictive accuracy for the prognosis of breast cancer patients. Meanwhile, cellular experiments demonstrated that knockdown of SLC35A2 could significantly inhibit the proliferation, migration and invasion of breast cancer cells, while increasing the protein level of E-cadherin and decreasing N-cadherin. A nude mouse xenograft model showed that inhibition of SLA35A2 expression could significantly inhibit tumor growth. CONCLUSION: SLC35A2 has good diagnostic and prognostic values in multiple cancers and is closely related to tumor immune infiltration. In addition, SLA35A2 as an oncogene in breast cancer may be involved in the progression of epithelial mesenchymal transition (EMT).