SDF4 and nasopharyngeal carcinoma: Instead, relying on the stimulation of RAB1B, LINC00173 could facilitate the extracellular secretion of proliferation‐associated 2G4 (PA2G4) and stromal cell‐derived factor 4 (SDF4; also known as 45‐kDa calcium‐binding protein) proteins, and knockdown of these proteins could reverse the NPC aggressive phenotype induced by LINC00173 overexpression.