Prox1, short for Prospero-related homeobox 1, is a transcription factor belonging to the homeobox transcription factor family. It plays a crucial role in the development of the lymphatic system and is widely used as a lymphatic vessel marker. It is involved in various biological processes, with its expression and function being regulated by multiple pathways such as WNT/β-catenin, and is associated with numerous diseases, especially cancers [4].

In breast cancer, Prox1 is upregulated and promotes invasion and metastasis by interacting with hnRNPK to activate the WNT/β-catenin signaling, making it a potential diagnostic biomarker and therapeutic target [1]. In prostate cancer, anti-androgen therapy alleviates the transcriptional inhibition of Prox1, which then drives neuroendocrine plasticity and liver metastases [2]. In heart valve disease, conditional deletion of Prox1 from valvular endothelial cells (VECs) in Prox1ΔVEC mice leads to myxomatous degeneration of heart valves, suggesting Prox1's role in maintaining valve extracellular matrix composition [3].

In conclusion, Prox1 is essential for lymphatic system development and has a significant impact on cancer metastasis and heart valve health. The use of gene knockout (KO) and conditional knockout (CKO) mouse models, such as Prox1ΔVEC mice, has been instrumental in revealing Prox1's role in these biological processes and disease conditions, providing valuable insights for potential therapeutic strategies.