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 nephrotoxic action of anticancer drugs such as nitrogranulogen ( NG ) , methotrexate ( MTX ) , 5 - fluorouracil ( 5 - FU ) and cyclophosphamide ( CY ) administered alone or in combination [ MTX + 5 - FU + CY ( CMF ) ] was evaluated in experiments on Wistar rats .
### Output Text:
The nephrotoxic action of anticancer drugs such as <span class="chemical">nitrogranulogen</span> ( <span class="chemical">NG</span> ) , <span class="chemical">methotrexate</span> ( <span class="chemical">MTX</span> ) , <span class="chemical">5 - fluorouracil</span> ( <span class="chemical">5 - FU</span> ) and <span class="chemical">cyclophosphamide</span> ( <span class="chemical">CY</span> ) administered alone or in combination [ <span class="chemical">MTX</span> + <span class="chemical">5 - FU</span> + <span class="chemical">CY</span> ( CMF ) ] was evaluated in experiments on Wistar rats . 