Fig. 9.

Proposed model of increase PTHrP expression in breast cancer cells. Depicted is a proposed model of how EGFR can stimulate PTHrP expression. Our data suggests that activation of EGFR on Tyr992 is necessary for PTHrP expression. Tyr992 has been reported to be coupled to the PLC γ and the PKC pathways but we did not evaluate this. PKC will then activated the MAPK pathway and eventually activate the Ets transcription factor. The Ets protein can then activate the transcription of the PTHrP-P3 promoter