DHRS9, also known as SDR9C4, is a gene encoding a retinol-metabolizing enzyme. It is involved in multiple biological pathways. For example, it mediates the conversion of retinol into retinoic acid, and its enzyme activity is related to the metabolism of lipid mediator oxylipins, playing a role in inflammation and immune response [5,6].

In atherosclerosis, DHRS9 is upregulated in macrophages of atherosclerotic lesions, and its pro-atherogenic effect is mediated by the immune mechanism, suggesting it could be a novel target for atherosclerosis management [1]. In pancreatic cancer, DHRS9 is overexpressed, and high expression is correlated with poor prognosis, potentially affecting the oncological process through the MAPK/ERK pathway [2]. In contrast, in colorectal cancer and oral squamous cell carcinoma, decreased DHRS9 expression is associated with tumor progression and poor prognosis [3,4]. Mice deficient in DHRS9 protein show reduced oxidative activity of microsomal membranes from certain tissues towards specific oxylipins, indicating its role in oxylipin metabolism in vivo [6].

In conclusion, DHRS9 is involved in retinol metabolism and oxylipin metabolism, with its expression and function being closely related to various diseases such as atherosclerosis, pancreatic cancer, colorectal cancer, and oral squamous cell carcinoma. The study of DHRS9-deficient mouse models has provided insights into its role in oxylipin metabolism and disease-related processes, facilitating a better understanding of disease mechanisms and potential therapeutic targets.