Inhibin A Is Downregulated during Chemotherapy in Patients with Early Breast Cancer.

Abstract

Introduction: Inhibins are dimeric glycoproteins, composed of an alpha-subunit (INH-a) and one of two possible beta-subunits (ßA or ßB), with substantial roles in human reproduction and in endocrine-responsive tumours. In breast cancer tissue, the growth factor Inhibin A is involved in cell differentiation and proliferation, thus suggesting a possible role as tumor marker. Aims of this study were to determine the serological measurement of Inhibin A (a- bA) in breast cancer patients during chemotherapy.Material and Methods: A series of 28 high risk N0 and N+ breast cancer patients who underwent standardized chemotherapy (3 x FEC and 3 x Docetaxel) followed by two years of zoledronate in the German SUCCESS trial were prospectively evaluated before chemotherapeutic treatment as well as after chemotherapy and two years after chemotherapy for the serological expression of Inhibin A. For serological analysis the ultrasensitive Inhibin A ELISA (DSL – U.S.A.) was used according to manufactures instruction. For statistical analysis the Wilcoxon rang sum test was used for paired samples. Statistical significance was assumed at p< 0.05.Results: The concentration of Inhibin A showed a significant decrease between data obtained before chemotherapy and after chemotherapy (p<0.005) and two-year follow up (p<0.001). Interestingly, there were seen no differences between the time point four weeks after chemoherapy and at two years (p=0.744).Discussion: Therefore, chemotherapy decreases significantly the Inhibin A concentration during chemotherapy. This might reflect a suppression of ovarian function and might be a marker for chemotherapy-induced amenorrhoea. Moreover, it has been suggested that Inhibin A might be a tumour marker for breast cancer, and therefore a sudden increase of its concentration might be indicative of breast cancer recurrence. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3028.