ABSTRACT: Tetraspanins (TSPANs) are a class of four-transmembrane segmented proteins. The precise functions of TSPANs and their roles in pan-cancer are unclear. In this work, we analyzed TSPAN1, TSPAN10, TSPAN11, TSPAN12, TSPAN13, TSPAN14, TSPAN15, TSPAN16, TSPAN17, TSPAN18, TSPAN18-AS1, TSPAN19, TSPAN2, TSPAN3, TSPAN31, TSPAN32, TSPAN33, TSPAN4, TSPAN5, TSPAN6, TSPAN7, TSPAN8, TSPAN9, TSPAN9-IT1 (24 TSPAN family genes) in relation to tumor characteristics from 11,057 TCGA samples across 33 cancer types. On 24 TSPAN family genes, multidimensional studies were conducted, including gene differential expression, immunological subtype analysis, clinical analysis, stemness indices analysis, drug sensitivity analysis, alteration analysis, and multi-omics validation (including ATAC-seq validation, single-c