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: Microscopic evaluation revealed that treatment with DOX alone induced significant cardiac damage in comparison to the saline control group ( P < 0 . 001 ) .
### Output Text:
Microscopic evaluation revealed that treatment with <span class="chemical">DOX</span> alone induced significant cardiac damage in comparison to the saline control group ( P < 0 . 001 ) . 