ERBB2 and neoplasm: This would suggest that the association of the parameters with the tumour stage is rather complex: no association of ErbB2-IR per se with the tumour stage; a negative association for AR-IR (i.e. where a lower AR-IR is associated with a higher tumour stage); a positive association for the rate of cell proliferation as measured by the Ki-67 index; and a positive influence whereby a high AR-IR and a high ErbB2 are associated with a higher tumour stage.