RACK1 and gastric cancer: EPHB3 (Ephrin type‐B receptor 3) is one of EPH transmembrane tyrosine kinase receptors (TKRs) and has a critical function in tumour progression or regression in various cancers, such as colorectal cancer,31, 32, 33 non‐small‐cell lung cancer34, 35 and gastric cancer.36, 37, 38 In non‐small‐cell lung cancer, Li et al34 show that EPHB3 suppresses cancer cell metastasis via a PP2A/RACK1/Akt signalling complex. In contrast, Ji et al35 demonstrate that EPHB3 is overexpressed in this cancer and promotes tumour metastasis by enhancing cell survival and migration