PEAK1 and neoplasm: Since PEAK1 KO or RA306 treatment impacts cell proliferation, migration and invasion but not apoptosis8 (Fig. 7 and Supplementary Figs. 9, 10), the effect on primary tumour growth is likely mediated via reduced proliferation while the reduced metastatic growth must be independent of primary tumour size and reflect a decreased ability to metastasise to the lung and/or reduced proliferation at this secondary site.