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: 2 , a region proposed to contain tumor suppressor gene ( s ) , is mutated at high frequency in human breast cancer .
### Output Text:
2 , a region proposed to contain <span class="disease">tumor</span> suppressor gene ( s ) , is mutated at high frequency in human <span class="disease">breast cancer</span> . 