USP33 and breast carcinoma: As a Robo1‐interacting protein, our previous studies have demonstrated that USP33 regulates the expression of Robo115, 27, 28 and is required for Slit‐Robo signalling in modulating axon midline crossing22 and inhibiting cell migration in breast cancer,15 colorectal cancer27 and lung cancer.28 In this study, the results that Robo1 expression is reduced in GC prompted us to explore whether USP33 affect the Slit‐Robo signalling in GC.