LARS2 and colorectal cancer: For instance, in patients with colorectal cancer, a specific Breg subset was found to express high levels of mitochondrial leucyl-tRNA synthetase 2 (LARS2), which promoted NAD+ regeneration and enhanced TGF-β1 production, correlating with accelerated tumor growth [3].Similarly, Breg cell differentiation depends on mitochondrial electron transport chain activity and moderate levels of reactive oxygen species (ROS).