SPINK1 and pancreatic ductal adenocarcinoma: Single-cell clustering demonstrates that SPINK1-high malignant cells dominate the OSCC ecosystem, consistent with previous reports that malignant ductal cells in primary pancreatic ductal adenocarcinoma (PDAC) exhibit specific immunometabolic activities through single-cell sequencing, and SPINK1 also serves as a prognostic marker for PDAC (39).