In the sentence extracted from biomedical literature, identify all the disease entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="disease"> to denote a disease.

### Input Text: Thus , gene - specific mechanisms were selected to overexpress PAX3 - FKHR and PAX7 - FKHR in alveolar rhabdomyosarcoma , presumably due to differences in regulation between the wild - type loci .
### Output Text:
Thus , gene - specific mechanisms were selected to overexpress PAX3 - FKHR and PAX7 - FKHR in <span class="disease">alveolar rhabdomyosarcoma</span> , presumably due to differences in regulation between the wild - type loci . 