PTGDS and head and neck squamous cell carcinoma: There were two fibroblastic clusters (X7 and X9) expressing CAF associated genes (COL11A1, COL12A1, MMP11, INHBA, THBS2, COL10A1, COL8A1, FN1) and ASC associated genes (APOD, C7, PTGDS), respectively (S4 Table), which confirmed the presence of these two populations in HNSCC.