GAB1 and prostate carcinoma: The primary candidate for the pathway acting parallel to ERK is the PI3K‐AKT pathway.57 In accord with our results, it has been shown that the inhibition of the ERK pathway resulted in up‐regulation of PI3K activity and AKT phosphorylation in different cell lines including breast and prostate cancer.58, 59 Concordantly, ERK can impose a negative crosstalk towards PI3K‐AKT by phosphorylation of GAB1 adaptor protein and decoupling PI3K from growth factor receptors,60 by phosphorylation of upstream receptor61 or by inducing PTEN translocation to the membrane and to the close proximity of PI3K.