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: These observations support a new mechanism for VHL - mediated transcriptional repression via a direct inhibitory action on Sp1 and suggest that loss of Sp1 inhibition may be important in the pathogenesis of von Hippel - Lindau disease and RCC . .
### Output Text:
These observations support a new mechanism for VHL - mediated transcriptional repression via a direct inhibitory action on Sp1 and suggest that loss of Sp1 inhibition may be important in the pathogenesis of <span class="disease">von Hippel - Lindau disease</span> and <span class="disease">RCC</span> . . 