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: We report a case of a 76 - year - old man with Waldenstrom macroglobulinaemia who suffered necrotising fasciitis without neutropenia after the combination treatment with bortezomib , high - dose dexamethasone and rituximab .
### Output Text:
We report a case of a 76 - year - old man with Waldenstrom macroglobulinaemia who suffered necrotising fasciitis without neutropenia after the combination treatment with <span class="chemical">bortezomib</span> , high - dose <span class="chemical">dexamethasone</span> and rituximab . 