†These authors contributed equally.
Background: Rab10 is a small GTPase protein belonging to the Ras superfamily. It is expressed and plays a role in a variety of malignant tumours. However, the expression of Rab10 and its role in breast cancer (BC) prognosis remains unclear. The aim of this study was to analyse the differential expression and prognostic value of Rab10 in BC using bioinformatics techniques and immunohistochemistry in a clinical cohort. Methods: The TIMER2, GEPIA2, and UALCAN databases were used to analyse the correlation between the differential expression of Rab10 and BC. Rab10 and BC prognosis were correlated using the Kaplan–Meier Plotter and UALCAN databases. The expression of Rab10 in BC tissues was detected using immunohistochemistry, and its correlation with the BC clinical cohort was analysed using Chi-squared tests and logistic regression analysis. Results: The expression of Rab10 mRNA identified in BC patients using TIMER2, GEPIA2, and UALCAN databases was higher than that in para-cancerous tissues. Kaplan–Meier plotter and the UALCAN database revealed that increased Rab10 expression was associated with poor prognosis in BC patients. Immunohistochemistry showed that Rab10 was expressed on cell membranes and in cytoplasm of BC tissues. In a clinical cohort, Rab10 expression correlated with histological grade, (human epidermal growth factor receptor 2) HER2 status, and molecular typing. Conclusions: Rab10 can be used as an effective clinical prognostic biomarker for BC.