It has been suggested that PC-1 and p53 participate in an autofeedback pathway which functions to tightly regulate their expression, and aberrant expression of either protein leads to impaired development.

He flies much about from place to place; now at Potsdam, now at Berlin, at Charlottenburg, Reinsberg; nothing loath to run whither business calls him, and appear in public: the gazetteer world, as we noticed, which has been hitherto a most mute world, breaks out here and there into a kind of husky jubilation over the great things he is daily doing, and rejoices in the prospect of having a Philosopher King;[…]

{{quote-journal|en|year=2015|date=|author=Maryam Saidy-Sarjoubi, Davoud Kamani|title=Moving Fractional Branes with Background Fields: Interaction and Tachyon Condensation|journal=arXiv|url=http://arxiv.org/abs/1508.02084|doi=|volume=|issue=|pages=

It has been used in medicine from time immemorial; but until recently its use was nothing more than a species of mere unscience, shadowed in mystery.