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: PARP inhibitors may exert protective effects against the development of severe cardiac complications associated with the DOX treatment .
### Output Text:
PARP inhibitors may exert protective effects against the development of severe cardiac complications associated with the <span class="chemical">DOX</span> treatment . 