Core Viewpoint - The article discusses the significance of Total Neoadjuvant Therapy (TNT) in the treatment of locally advanced rectal cancer (LARC) and highlights the need for a deeper understanding of the immune remodeling mechanisms involved in its efficacy [3][6]. Group 1: Treatment Strategies and Mechanisms - LARC accounts for over one-third of both incidence and mortality in colorectal cancer, which is the third most common and the second deadliest cancer globally [3]. - Recommended treatment strategies for LARC include TNT or neoadjuvant chemotherapy (nCT), with additional options like radiotherapy for cases with poor response [3]. - The immune remodeling mechanisms behind the efficacy of TNT remain unclear, necessitating further research into the tumor microenvironment (TME) changes induced by this therapy [6]. Group 2: Research Findings - A study published in Cancer Cell reveals that TNT significantly remodels the immune microenvironment in LARC, with CD8+ T cells and endothelial cells interacting as a potential key factor for clinical efficacy [4][10]. - The research utilized single-cell RNA sequencing and spatial transcriptomics to analyze pre- and post-treatment samples, showing that TNT is associated with a reduction in regulatory T cells (Treg) and an increase in IFNG+ CD8+ effector memory T cells, which may enhance complete response rates [6][7]. - The abundance of tumor-infiltrating CD8+ T cells post-TNT correlates with the enrichment of ACKR1+ endothelial cell subpopulations, which are activated by IFNγ released from CD8+ T cells, enhancing their antigen-presenting capabilities [6][7][10]. Group 3: Implications for Clinical Practice - The study provides new insights into optimizing clinical treatment strategies for rectal cancer by elucidating the complex mechanisms of immune response during neoadjuvant therapy [4][10]. - The findings suggest that the quantity of IFNG+ CD8+ T cells and peripheral blood IFNG signaling could serve as markers for response to TNT [8].

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].