PRL and growth hormone-producing pituitary gland adenoma: In our cohort of PitNETs, as well as within NF-PitNET or somatotrophinoma subgroups, we did not find significant correlations between serum prolactin levels and microvessel density or vessel morphology parameters, although prolactin has recognised angiogenic properties [45, 46], and previous studies showed that prolactinomas may have higher microvessel density compared to other PitNET types [11, 13, 17] which could be, at least in part, due to prolactin hypersecretion.