Longitudinal and vertical studies on prostatic cancer have confirmed that many forms of oestrogen therapy have a profound effect on the levels of several acute phase reactant proteins (APRP). This action overrides any response of the APRPs to a rising tumour load. However, serum C-Reactive protein and albumin levels appear to be independent of oestrogen control and their respective rise and fall is associated with tumour progression even when the patient is saturated with oestrogens.