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: The renal function of 74 children with malignant mesenchymal tumors in complete remission and who have received the same ifosfamide chemotherapy protocol ( International Society of Pediatric Oncology Malignant Mesenchymal Tumor Study 84 [ SIOP MMT 84 ] ) were studied 1 year after the completion of treatment .
### Output Text:
The renal function of 74 children with malignant mesenchymal tumors in complete remission and who have received the same <span class="chemical">ifosfamide</span> chemotherapy protocol ( International Society of Pediatric Oncology Malignant Mesenchymal Tumor Study 84 [ SIOP MMT 84 ] ) were studied 1 year after the completion of treatment . 