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: Immunocytochemistry confirmed expression of h - SOD1 in inner ear tissues of transgenic C57BL / 6 - TgN [ SOD1 ] 3Cje mice .
### Output Text:
Immunocytochemistry confirmed expression of h - SOD1 in inner ear tissues of transgenic C57BL / 6 - TgN [ SOD1 ] 3Cje mice . 