Methods of identifying a subject having an increased risk of developing anthracycline-related cardiotoxicity are provided. Such methods may include isolating a DNA sample from a biological specimen from the subject genotyping the DNA sample to determine a copy number of a variant allele that increases the risk of developing chemotherapy-induced cardiotoxicity and identifying the subject as having an increased risk of developing anthracycline-related cardiotoxicity when the copy number is at least one. In some embodiments, the methods may include optimally administering a therapeutically effective dose of a chemotherapy agent or an alternative non-cardiotoxic chemotherapeutic agent to the subject.
