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: CYP - induced cystitis increased ( P < or = 0 . 001 ) p75 ( NTR ) expression in the superficial lateral and medial dorsal horn in L1 - L2 and L6 - S1 spinal segments .
### Output Text:
<span class="chemical">CYP</span> - induced cystitis increased ( P < or = 0 . 001 ) p75 ( NTR ) expression in the superficial lateral and medial dorsal horn in L1 - L2 and L6 - S1 spinal segments . 