The developed protocol for the assay of hPRL is suitable for the assessment of PRL in tissues of patients with benign and malignant serous ovarian tumors.A higher incidence of prolactin was obtained in malignant than in benign serous ovarian tumors in tissues and sera.The kinetic studies of 125I-anti hPRL antibody with hPRL in premenopausal and postmenopausal patients with benign and malignant serous ovarian tumors showed that the binding reaction is a temperature and time dependent process. The results indicate that the reaction fits pseude-first order kinetic.The results obtained from the thermodynamics studies on the association of 125I-anti hPRL antibody with hPRL in benign and malignant serous ovarian tumors were spontaneously occurred and the binding reactions were entropically driven.The spectroscopic studies revealed that each of (125I-anti hPRL antibody/PRL) complex and 125I-anti hPRL antibody has a characteristic spectrum.