The prognosis of patients with malignant melanoma treated with pegylated arginine deiminase (ADI-Peg) correlated with the baseline status of ASS1 expression: patients who had ASS1-negative MM and received four doses of ADI-Peg of 320 IU/m2 had a significantly longer survival (26.5 months) than patients with ASS1-positive MM (8.5 months).10 This evidence concerns the gene ASS1 and Miyoshi myopathy.