Based on two tamoxifen-resistant PDXs, namely HBCx22 TamR and HBCx34 TamR, developed by the lab of Dr E. Marangoni from two primary hormone sensitive ERα-positive breast cancers, HBCx22 and HBCx34 [25], we assessed oestrogen non-genomic pathway activation by measuring the levels of interaction of ERα/Src and ERα/PI3K. The gene discussed is SRC; the disease is breast cancer.