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: Doxorubicin treatment resulted in heavy proteinuria ( > 100 mg protein / mg crea ) in 15 / 44 of sgk1 ( + / + ) and 15 / 44 of sgk1 ( - / - ) mice leading to severe nephrotic syndrome with ascites , lipidemia , and hypoalbuminemia in both genotypes .
### Output Text:
<span class="chemical">Doxorubicin</span> treatment resulted in heavy proteinuria ( > 100 mg protein / mg crea ) in 15 / 44 of sgk1 ( + / + ) and 15 / 44 of sgk1 ( - / - ) mice leading to severe nephrotic syndrome with ascites , lipidemia , and hypoalbuminemia in both genotypes . 