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: Cardiotoxicity that was thought to be related to CYA occurred in 1 / 32 ( 3 % ) of patients in Group 1 and in 13 / 52 ( 25 % ) patients in Group 2 ( P less than 0 . 025 ) .
### Output Text:
Cardiotoxicity that was thought to be related to <span class="chemical">CYA</span> occurred in 1 / 32 ( 3 % ) of patients in Group 1 and in 13 / 52 ( 25 % ) patients in Group 2 ( P less than 0 . 025 ) . 