To initially address the role of Prox1 in breast cancer, we examined the publicly available data from databases such as Oncomine (www.oncomine.org, accessed on 15 December 2020) and TCGA (The Cancer Genome Atlas, www.cancergenome.nih.gov, accessed on 1 October 2021) for clinical associations between Prox1 expression and breast cancer progression. The gene discussed is PROX1; the disease is breast cancer.