STAT3 and AL amyloidosis: Interestingly, formononetin was found to inhibit the constitutive activation of the signal transducer and transcriptional activator 3 (STAT3) (tyrosine residues 705 and 727) and STAT5 (tyrosine residues 694 and 699) in multiple myeloma cells, which was associated with the suppression of upstream kinases.