Combination of PD184352 and PI103 [(5 μmol/l)/(1 μmol/l)] led to strongly enhanced cell death in most cell lines tested (mean survival 24·5 ± 21·4%; P = 0·025, compared to single‐agent PI103 treatment). Again, RAS‐mutated MM cell lines all belonged to the sensitive subgroup in that they were either already strongly sensitive to PI103 treatment alone or showed big declines in survival upon application of the drug combination...