USP9X and AL amyloidosis: Elevated USP9X expression at the translational level correlates with poor prognosis in multiple myeloma and ESCC.[52] Jing et al reported that USP9X expression is correlated with tumor progression and poor prognosis in ESCC.[53] The expression of USP9X was found to be significantly different between normal mucosa and ESCC and between LGIN and HGIN.