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: AIMS : Doxorubicin ( DOX ) is an effective anti - cancer therapeutic , but is associated with both acute and late - stage cardiotoxicity .
### Output Text:
AIMS : <span class="chemical">Doxorubicin</span> ( <span class="chemical">DOX</span> ) is an effective anti - cancer therapeutic , but is associated with both acute and late - stage cardiotoxicity . 