A mutation in the Speckle-type POZ protein (SPOP), a tumor-suppressor protein, can lead to the formation of many solid tumors, including prostate, gastric and colorectal cancers.137,138 SPOP functions as a substrate adaptor of a cullin3-RING ubiquitin ligase to promote the degradation of its substrates via the ubiquitin-proteasome system.139–142 The substrates of SPOP are various proto-oncogenic proteins, such as androgen receptor and death-domain-associated protein.143–145 The accumulation of these proteins can oncogenically transform sensitive cell types. Here, SPOP is linked to colorectal cancer.