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: None of these tumours showed abnormal migration patterns .
### Output Text:
None of these <span class="disease">tumours</span> showed abnormal migration patterns . 