RSPO1 and colonic neoplasm: Seshagiri et al. reported recurrent fusion genes involving R-spondin family members, RSOP2 and RSPO3, in 10% of colon cancers.7 However, Kloosterman et al., Shinmura et al., and our present study demonstrated that RSPO fusion genes were lowly expressed in colon cancers (0.35%, 4%, and 1.36%, respectively).8, 43 This may be due to sampling bias, bioinformatics tools, or selection bias, among other possible reasons.