FIGURE 2.

mTORC1 is active in keratoacanthomas. (A) Schematic representation of the PI3K/mTOR pathway showing that activation of S6 (phospho-S6 or pS6) results from mTORC1 complex activation, whereas phosphorylation of AKT at Ser 473 (pAKT^Ser473) results from a feedback loop triggered mTORC2 complex activation. A negative feedback loop causes repression of pAKT activation when mTORC2 is suppressed. (B) Representative microphotograph of immunostaining for pS6 and pAKT^Ser473 in keratoacanthomas. Note that tumor cells are positive for pS6 in the cytoplasm (IHC-200×; insert 400×).