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: However , one or more additional genes may yet be found that explain some proportion of hereditary breast cancer . .
### Output Text:
However , one or more additional genes may yet be found that explain some proportion of <span class="disease">hereditary breast cancer</span> . . 