RSPO1 and colorectal carcinoma: Additionally, alteration of the Rspo2 gene is linked to CRC in a transposon-based genetic screening in mice (72).Consistent with the elevated expression of Rspo genes observed in human tumors, a 20-fold increase in Rspo2 messenger RNA expression in a mouse tumor carrying a transposon insertion near the Rspo2 transcription start site was detected relative to adjacent normal tissue.