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: Analyses of markers associated with the mTOR pathway were carried out on archival tumor from a subgroup using immunohistochemistry ( IHC ) and direct mutation sequencing .
### Output Text:
Analyses of markers associated with the mTOR pathway were carried out on archival tumor from a subgroup using immunohistochemistry ( IHC ) and direct mutation sequencing . 