IRF2 and neuroblastoma: Flow cytometry and Western blotting of NB cell lines revealed that the 3 cell lines expressing higher levels of cell surface MHC-I (SH-EP, SK-N-AS and SK-N-SH) also expressed higher levels of IRF1 and IRF2, whereas the 5 cell lines expressing lower levels of cell surface MHC-I displayed lower levels of IRF1 and IRF2 (Figs. 1A, 1B and S1).