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: In addition , mRNA levels of sterol 12alpha - hydroxylase and lithocholate 6beta - hydroxylase were increased by bile diversion and suppressed by EE .
### Output Text:
In addition , mRNA levels of <span class="chemical">sterol</span> 12alpha - hydroxylase and lithocholate 6beta - hydroxylase were increased by bile diversion and suppressed by <span class="chemical">EE</span> . 