A more severe hematologic disease (MM stage IIIB, MM associated with amyloidosis, higher serum free λ light chain and β2M levels), kidney condition (baseline eGFR, preexisting–CKD, and ACEI or ARB therapy), and more frequent ASCT complications (mucositis grade 3 or 4) were significantly associated with AKI in univariate analysis. This evidence concerns the gene B2M and mucositis.