dedifferentiation is a mechanism whereby specialized cells regain properties of their ancestors , including , in the extreme , stemness . we found that highly - purified cardiomyocytes isolated from adult mammalian hearts dedifferentiated rapidly when cultured in mitogen - rich medium . such myocytes reentered the cell cycle and proliferated , expressing stem cell surface markers such as c - kit and early cardiac transcription factors including gata and nkx2 . 5 . these myocyte - derived cells were capable of re - differentiating into myocytes and endothelial cells . contrary to prevailing dogma , cardiomyocyte dedifferentiation yields proliferative cells expressing stem cell markers and capable of multilineage differentiation . cardiomyocyte dedifferentiation is a potential source of endogenous stem cells in the adult heart .