Although both apCAFs in PDAC and apCAFs in certain solid tumor types such as HNSCC, CC, NPC, and RCC express MHC class II molecules like CD74, the potential transformation paths and enriched signaling pathways of these 2 apCAFs types greatly differ, possibly accounting for the pro-tumor effects of apCAFs in PDAC and the association of apCAFs with anti-tumor effects in certain solid tumor types like HNSCC, CC, NPC, and RCC. The gene discussed is CD74; the disease is head and neck squamous cell carcinoma.