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: In conclusion , the increased or sustained expression of ENaC subunits combined with increased apical targeting in the DCT2 , connecting tubule , and collecting duct are likely to play a role in the sodium retention associated with PAN - induced nephrotic syndrome .
### Output Text:
In conclusion , the increased or sustained expression of ENaC subunits combined with increased apical targeting in the DCT2 , connecting tubule , and collecting duct are likely to play a role in the <span class="chemical">sodium</span> retention associated with <span class="chemical">PAN</span> - induced nephrotic syndrome . 