You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Pharmacogenomic approaches for tailored anti-leukemic therapy in children. Several lympholytic and cytotoxic agents are used in acute lymphoblastic leukemia (ALL) polychemotherapy. Genetic variants for cellular components involved in the pharmacokinetics and pharmacodynamics of these drugs can influence the pharmacological response, and molecular characterization of these genetic variants could be helpful for the comprehension of the mechanisms of resistance or increased sensitivity. The purpose of this review is to carry out an update of recent publications on genes that might influence ALL treatment in terms of outcome and/or toxicity and to underlie the role of genetic variants, particularly single nucleotide polymorphisms (SNP), in predicting clinical response, with particular reference to the current protocol for ALL therapy used in Italy, AIEOP-BFM ALL 2009.
{"Chemical": []}