RAP1B and neoplasm: The incidence of diaphragm metastasis was similar between PBS–GFP and Rap1B groups with or without DEX treatment (Supplementary Fig. 9a); however, the diaphragm-metastatic tumours were reduced in sizes in Rap1B groups with or without DEX treatment (Supplementary Fig. 9b, c), implying that the microenvironment of the diaphragm may not be suitable for Rap1B-mediated tumour growth.