IL21 and cancer: Expressional analysis of Th17-associated markers during H. pylori-infection and gastric cancer (GC) demonstrated a strong positive correlation between the transcription factor associated with Th17 responses, Rorγt, IL-17A and IL-21 in both H. pylori-infected tissues and cancer tissues.37 The authors posit that this correlation provides evidence supporting the notion that Th17 cell expansion may contribute to cancer development.