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: Paclitaxel ( Taxol ; Bristol - Myers Squibb Company , Princeton , NJ ) has demonstrated significant antineoplastic activity against different tumor types , notably ovarian and breast carcinoma .
### Output Text:
<span class="chemical">Paclitaxel</span> ( <span class="chemical">Taxol</span> ; Bristol - Myers Squibb Company , Princeton , NJ ) has demonstrated significant antineoplastic activity against different tumor types , notably ovarian and breast carcinoma . 