GDF15 and AL amyloidosis: Preliminary studies suggest that growth differentiation factor-15 (GDF-15) [78], soluble suppression of tumorigenicity 2 (ST2) [79], hepatocyte growth factor [80], mid-regional pro-adrenomedullin [81], and von Willebrand factor [82] may be useful to improve risk stratification in patients with AL amyloidosis, both in conjunction or substitution to the existing Mayo staging systems but, apart GDF-15 and ST2, they remain in early stages of clinical investigation and merit further clinical evaluation.