USP8 and neoplasm: Altogether, our data demonstrate that, although USP8 mutations are associated with an increased SSTR5 expression, P720R USP8 represents the sole mutation that could be used as a marker to predict a favorable antisecretory response to pasireotide treatment in tumor corticotroph cells since other USP8 mutations have been shown to induce resistance to pasireotide antisecretory and anti-proliferative effects.