RPS6KB1 and pancreatic neoplasm: REP1 knockdown in pancreatic cancer cells substantially decreased phosphorylation levels of the downstream targets p70 S6 kinase at T389 (S6K) and S6 ribosomal protein at S235/236 (S6) in spite of similar levels of total p70 S6 kinase seen in Western blotting (Figure 2A).