Western blot analysis of treated tumor replicates demonstrated that MEKi treatment decreased both p-ERK and p-S6 ribosomal protein, a marker of increased translation and a downstream target of MAPK signaling, only in BCM-2277, whereas diminished p-ERK but not p-S6 was observed in HBCx1 (Figure 1E). This evidence concerns the gene RPS6 and neoplasm.