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: Atm - null mice , as well as those null for p53 , develop mainly T - cell lymphomas , supporting the view that these genes have similar roles in thymocyte development .
### Output Text:
Atm - null mice , as well as those null for p53 , develop mainly <span class="disease">T - cell lymphomas</span> , supporting the view that these genes have similar roles in thymocyte development . 