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: Expression of p300 increased the cardiac level of bcl - 2 and mdm - 2 , but not that of p53 or other members of the bcl - 2 family .
### Output Text:
Expression of p300 increased the cardiac level of bcl - 2 and mdm - 2 , but not that of p53 or other members of the bcl - 2 family . 