GSK3B and neoplasm: This crosstalk from MAPKs to β-catenin appears to be mediated through the phosphorylation of GSK3β and potentially by the ERK-mediated activation of the ribosomal proteins p70 S6 (officially known as RPS6KB2) and p90 RSK (officially known as RPS6KA1), as described in a variety of tumour cells (Ding et al., 2005).