Yet, despite the prognostic relevance of hypoxia in ER + disease, there is a paucity of clinical imaging studies in ER + breast tumours relating functional parameters of the tumour microenvironment to histopathological evidence or other biomarkers, with only three reports comparing [18F]-FMISO-PET with HIF-1α immunohistochemistry [20] or tumour-secreted cytokine expression [19, 22]. This evidence concerns the gene HIF1A and neoplasm.