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: Together the data suggest that the MSH3 gene encodes a product that functions in repair of some but not all pre - mutational intermediates , its mutation in tumours can result in genomic instability and , as in yeast , MSH3 and MSH6 are partially redundant for mismatch repair . .
### Output Text:
Together the data suggest that the MSH3 gene encodes a product that functions in repair of some but not all pre - mutational intermediates , its mutation in <span class="disease">tumours</span> can result in genomic instability and , as in yeast , MSH3 and MSH6 are partially redundant for mismatch repair . . 