 "DCC" was initially cloned out of the region and put forth as a putative tumour suppressor gene, though nothing was known about its function at the time.The "DCC" gene was examined for the genetic changes found with most other tumour suppressor genes, but it was found to have a comparatively low frequency of somatic mutation.Several years later "DCC" was shown to encode a transmembrane receptor protein that mediated the effects of netrin-1 on axon outgrowth.