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: Two - dimensional speckle tracking echocardiography combined with high - sensitive cardiac troponin T in early detection and prediction of cardiotoxicity during epirubicine - based chemotherapy .
### Output Text:
Two - dimensional speckle tracking echocardiography combined with high - sensitive cardiac troponin T in early detection and prediction of cardiotoxicity during <span class="chemical">epirubicine</span> - based chemotherapy . 