Figure 2.

Pivotal intracellular signalling cascades involved in endocrine resistance and site of action for selected targeted anticancer drugs. AMPK=adenosine monophosphate-activated protein kinase; AR=androgen receptor; CDK4/6=cyclin-dependent kinase 4/6; E2=oestradiol; E2F=E2F transcription factors; ERα=oestrogen receptor-α; HDAC=histone deacetylase; HER2=human epidermal growth factor receptor-2; IGFR=insulin like growth factor receptor; P=phosphate; Rb=retinoblastoma protein; MEK=mitogen-activated ERK-activating kinase; mTOR=mammalian target of rapamycin; SERD=selective oestrogen receptor downregulator.