PTPRR and colonic neoplasm: Further investigation is also needed to determine the functional relevance of the PTPRR downregulation we documented in colorectal tumors, but one interesting possibility is that this change represents a mechanism for early establishment in colon tumor cells of "epigenetic sensitization" to the activation of oncogenic signalling (reviewed in [39,40]), in this case, through the RAS/RAF/MAPK/ERK pathway.