Novel insights on imaging sex-hormone-dependent tumourigenesis in vivo.

Sex hormones modulate proliferation, apoptosis, migration, metastasis and angiogenesis in cancer cells influencing tumourigenesis from the early hyperplastic growth till the end-stage metastasis. Although decades of studies have detailed these effects at the level of molecular pathways, where and when these actions are needed for the growth and progression of hormone-dependent neoplasia is poorly elucidated. Investigation of the hormone influences in carcinogenesis in the spatio-temporal dimension is expected to unravel critical steps in tumour progression and in the onset of resistance to hormone therapies. Non-invasive in vivo imaging represents a powerful tool to follow in time hormone signalling in the whole body during tumour development. This review summarizes the tools currently available to follow hormone action in living organisms.