We further used real-time quantitative PCR to examine the mRNA expression of two NF-κB downstream genes, TNF-αand IL-6, using samples from Fig. 3A. Results show that IGF2 increases TNFα (Fig. 3G left panel) and IL-6 (Fig. 3G right panel) mRNA expression in HD cells, suggesting IGF2 activates NF-κB pathway in HD cells. Here, TNF is linked to Huntington disease.