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: Fourteen of fifteen patient samples with known mutations were accurately diagnosed , and no false positive mutations were identified in 20 control samples .
### Output Text:
Fourteen of fifteen patient samples with known mutations were accurately diagnosed , and no false positive mutations were identified in 20 control samples . 