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: p75NTR expression in rat urinary bladder sensory neurons and spinal cord with cyclophosphamide - induced cystitis .
### Output Text:
p75NTR expression in rat urinary bladder sensory neurons and spinal cord with <span class="chemical">cyclophosphamide</span> - induced cystitis . 