TP53 and neoplasm: Many studies have sought to identify markers of aggressive PitNET behaviour; however, only few aggressiveness markers are recognised, including radiological invasion (into the cavernous/sphenoid sinus or bone erosion), the proliferation markers Ki-67, mitotic count and p53 staining, as well as some histotypes such as sparsely granulated somatotroph tumours, null-cell or Crooke’s tumours [1,36,37,38,39].