A better understanding of the molecular mechanisms involved in regulating tumor microenvironment is essential in order to develop new therapies which are effective for prostate cancer. In this context, one of the molecular axes of high impact in determining the properties of the microenvironment associated with prostatic carcinoma involves galectins, making it imperative to understand all molecular processes in which these lectins are involved. This project challenges the assumption that galectins, besides exerting an extracellular role promoting a tolerogenic microenvironment, may mediate additional regulatory roles arising from their intracellular properties in responding lymphocytes. It would be the combination of all of these functional properties which determine whole galectins’ roles as regulator of the profile of the immune response induced by tumors. This project is developed in the context of an international collaboration, will allow a better understanding of the paradigms by which galectins regulate tumor progression in their complex microenvironment associated. The long term goal of this project is to generate basic findings that may be transferable to the clinical setting, where new procedures may impact on survival of patients with prostate cancer.