MIB1 and testicular germ cell tumor: In this work we aim to assess the prognostic value of biomarkers related to proliferation (MIB-1, TEX19) and to the surrounding immune microenvironment (CXCL12, CXCR4, beta-catenin and MECA-79) in a cohort of stage I testicular germ cell tumor patients undergoing surveillance, including their impact in patient outcome, and to compare their performance to the classical histopathological variable vascular invasion.