Grb2 can also dock with the FGFR independent of FRS2 and activate both Erk and PI3 kinase (PI3K)/Akt pathways. It is noteworthy that Akt can antagonize the Erk pathway in some contexts.

Tailoring Neoadjuvant Therapy in Human Epidermal Growth Factor Receptor 2–Positive Early Breast Cancer: Recent Advances and Strategies ...