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: Two cases of severe delayed neurologic toxicity related to the administration of intrathecal ( IT ) combination chemotherapy including thiotepa ( TSPA ) are presented .
### Output Text:
Two cases of severe delayed neurologic toxicity related to the administration of intrathecal ( IT ) combination chemotherapy including <span class="chemical">thiotepa</span> ( <span class="chemical">TSPA</span> ) are presented . 