In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: The cardiotoxicity of conventional anthracycline therapy highlights a need to search for methods that are highly sensitive and capable of predicting cardiac dysfunction .
### Output Text:
The cardiotoxicity of conventional <span class="chemical">anthracycline</span> therapy highlights a need to search for methods that are highly sensitive and capable of predicting cardiac dysfunction . 