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: BACKGROUND To define the incidence of BRCA1 mutations among patients seen in clinics that evaluate the risk of breast cancer , we analyzed DNA samples from women seen in this setting and constructed probability tables to provide estimates of the likelihood of finding a BRCA1 mutation in individual families .
### Output Text:
BACKGROUND To define the incidence of BRCA1 mutations among patients seen in clinics that evaluate the risk of <span class="disease">breast cancer</span> , we analyzed DNA samples from women seen in this setting and constructed probability tables to provide estimates of the likelihood of finding a BRCA1 mutation in individual families . 