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: We describe the proportion of hereditary breast cancer explained by BRCA1 or BRCA2 in a sample of North American hereditary breast cancers and assess the evidence for additional susceptibility genes that may confer hereditary breast or ovarian cancer risk .
### Output Text:
We describe the proportion of <span class="disease">hereditary breast cancer</span> explained by BRCA1 or BRCA2 in a sample of North American <span class="disease">hereditary breast cancers</span> and assess the evidence for additional susceptibility genes that may confer <span class="disease">hereditary breast or ovarian cancer</span> risk . 