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: The pattern of hereditary cancer in 14 ( 61 % ) of the 23 families studied was attributed to BRCA1 by a combination of linkage and mutation analyses .
### Output Text:
The pattern of <span class="disease">hereditary cancer</span> in 14 ( 61 % ) of the 23 families studied was attributed to BRCA1 by a combination of linkage and mutation analyses . 