BIG3 (brefeldin A-inhibited guanine nucleotide-exchange protein 3) is exclusively overexpressed in the majority of breast cancers8, 9, and it interacts with the tumour suppressor PHB2 (prohibitin 2) in the cytoplasm, thereby inhibiting E2-dependent translocation to the nucleus and plasma membrane. The gene discussed is PHB2; the disease is neoplasm.