MAPK3 and plasma cell myeloma: Another study showed that Cks1 shRNA mediated knockdown leads to decrease in ERK1/2, MEK and STAT phosphorylation in multiple myeloma cell lines KMS28PE, OCI-MY5 and XG-1 whereas forced overexpression of Cks1 activates ERK1/2 and STAT phosphorylation in the later two cell lines [21].