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: Thus the most common polymorphisms of the BRCA1 gene do not make a significant contribution to breast or ovarian cancer risk .
### Output Text:
Thus the most common polymorphisms of the BRCA1 gene do not make a significant contribution to <span class="disease">breast or ovarian cancer</span> risk . 