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: CONCLUSIONS : The expression of Fas ligand in the myocardium , as identified in HIV - positive patients , might increase the susceptibility to HAART - induced cardiomyopathy due to activation of apoptotic pathways , resulting in cardiac dilation and dysfunction .
### Output Text:
CONCLUSIONS : The expression of Fas ligand in the myocardium , as identified in HIV - positive patients , might increase the susceptibility to HAART - induced cardiomyopathy due to activation of apoptotic pathways , resulting in cardiac dilation and dysfunction . 