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: Five families ( 22 % ) provided evidence against linkage to both BRCA1 and BRCA2 .
### Output Text:
Five families ( 22 % ) provided evidence against linkage to both BRCA1 and BRCA2 . 