Prss27, also known as marapsin or pancreasin, is a serine protease. It belongs to the family of tryptases and is inserted into plasma membranes via glycosylphosphatidylinositol (GPI) anchors in mice [3]. Human and mouse Prss27 are preferentially expressed by stratified squamous epithelia [4].

In esophageal squamous cell carcinoma (ESCC) patients with preoperative treatment, Prss27 expression in resected tumor samples is a predictor of poor prognosis. Also, conversion of Prss27 expression from positive in biopsy samples to negative in resected tumor samples is a predictor of good prognosis, suggesting its potential as an effective tool for decision-making regarding adjuvant treatment in ESCC patients [1]. In a study on children with overweight/obesity, Prss27 was among the proteins differentially expressed between fit and unfit children, though statistical significance disappeared after FDR correction, indicating its possible involvement in biological processes related to cardiorespiratory fitness such as neurogenesis, immune/inflammatory response [2]. In breast cancer, Prss27 has prognostic significance and was confirmed as an oncogene through in-vitro experiments, suggesting it may be a promising prognostic biomarker and tumor therapeutic target [5]. Prss27-null mice develop normally in barrier conditions and are fertile without overt epithelial defects, indicating that marapsin does not play critical, non-redundant roles in development, reproduction, or epithelial differentiation [4].

In conclusion, Prss27 is a serine protease with tissue-specific expression. Its role in cancer prognosis, especially in ESCC and breast cancer, has been highlighted. The Prss27-null mouse model has provided insights into its non-essential role in normal development and epithelial differentiation, while also suggesting its potential as a biomarker and therapeutic target in cancer.