In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.

[Q]: Relative expression of cholesterol transport-related proteins and inflammation markers through the induction of 7-ketosterol-mediated stress in Caco-2 cells.
[A]: cholesterol

[Q]: Loss of alpha 2-macroglobulin and epidermal growth factor surface binding induced by phenothiazines and naphthalene sulfonamides.
[A]: phenothiazines

[Q]: Diels-Alder mediated controlled release from a poly(ethylene glycol) based hydrogel.
[A]:
poly(ethylene glycol)