Hormones as biomarkers: practical guide to utilizing luminex technologies for biomarker research

Hormones are chemical messengers produced in one part of the body and released into the blood to trigger or regulate particular functions of the body in another part. Hormone actions vary widely, but can include stimulation or inhibition of growth, induction or suppression of apoptosis, activation or inhibition of the immune system, regulating metabolism, and preparation for a new activity or phase of life. There is a growing interest in the role that hormones may play in the development and progression of various cancers. Recent research suggests that hormone levels may explain differences in risk for some of the most commonly diagnosed cancers, including breast, ovarian, and others; however, additional studies utilizing novel hormone measurement technologies are needed to investigate the roles of common hormones in cancer. Increasing our understanding of the role of hormones and other biomarkers in the etiology and the course of different cancers has a great potential to facilitate the development of new treatment modalities. This chapter provides an overview on multiplexing xMAP technology by Luminex (Austin, TX) that can be used for simultaneous analysis of several biologic markers, e.g., hormones. The xMAP immunoassay technology combines the principle of a sandwich ELISA with the fluorescent-bead-based technology allowing individual and multiplex analysis of up to 100 different analytes in a single microtiter well. Serum assay described in the methods section is performed in 96-well microplate format according to the protocol provided by LINCO Research, Inc. (St. Louis, MO). Human Pituitary LINCOplex Kit is utilized for simultaneous quantification of six pituitary hormones in serum, plasma, tissue lysate, and culture supernatant samples: Prolactin, FSH, LH, TSH, GH, and ACTH.