Reappearance of embryonal antigens in planarian regenerates.

A transient and apparently orderly re-expression of embryonal antigens in planarian regenerates has been demonstrated. This finding seems to corroborate the hypothesis that regeneration in planarians is based on a recapitulation of mechanisms that operate the embryogenesis of these animals, andgives some support to the concept of cancer as a misprogrammed regeneration when contemplated against the background of facts pointed out in the literature.