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: FANFT - induced cell proliferation in the bladder was significantly suppressed by aspirin co - administration after 4 weeks but not after 12 weeks .
### Output Text:
<span class="chemical">FANFT</span> - induced cell proliferation in the bladder was significantly suppressed by <span class="chemical">aspirin</span> co - administration after 4 weeks but not after 12 weeks . 