CHEK1 and cancer: We found that Nutlin 3b, an isomer of the well-known Nutlin 3a, efficiently interferes with PGAM1-Chk1 binding in cancers and SnCs, similar to Nutlin 3a, whereas Nutlin-3b was less effective (~150-fold) at inhibiting the p53-Mdm2 interaction than Nutlin 3a.24 Both Nutiln 3b and 3a induce apoptosis in SnCs.