Immunity：揭开p53突变的新型促癌机制

Core Viewpoint - The article discusses the role of the p53 R172H mutation in pancreatic ductal adenocarcinoma (PDAC), highlighting its contribution to creating an immunosuppressive tumor microenvironment and reducing the efficacy of immune checkpoint inhibitors (ICIs) [4][13][15]. Group 1: Background on PDAC - PDAC is a highly aggressive cancer characterized by KRAS gene activation mutations and TP53 gene alterations, with TP53 mutations leading to the loss of tumor suppressor function [2][6]. - Approximately 90% of PDAC cases have KRAS activation mutations, while around 70% exhibit changes in the TP53 tumor suppressor gene, indicating the critical role of p53 in genomic protection [7]. Group 2: Research Findings - A study published by MIT researchers reveals that the common p53 mutation, p53 R172H, occupies enhancers of immunosuppressive chemokines (e.g., Cxcl1), stimulating their expression and establishing an immunosuppressive tumor microenvironment in PDAC [3][4][11]. - The study indicates that knocking out the p53 R172H mutation enhances the efficacy of immune checkpoint inhibitors [13][15]. - Mechanistically, p53 R172H enhances Cxcl1 expression by occupying its distal enhancer, with NF-κB being a crucial cofactor for this process [12][15]. Group 3: Implications for Treatment - The findings suggest that p53 R172H promotes tumor growth by regulating cancer cell-specific gene expression programs that shape the tumor microenvironment, thereby inhibiting anti-tumor immune responses [15][16]. - In mouse models of PDAC, tumors lacking p53 R172H showed fewer T cells and higher levels of myeloid-derived suppressor cells (MDSCs), indicating a more favorable immune environment for tumor growth [15].