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 homologies suggest that PTEN may suppress tumor cell growth by antagonizing protein tyrosine kinases and may regulate tumor cell invasion and metastasis through interactions at focal adhesions . .
### Output Text:
These homologies suggest that PTEN may suppress <span class="disease">tumor</span> cell growth by antagonizing protein tyrosine kinases and may regulate <span class="disease">tumor</span> cell invasion and <span class="disease">metastasis</span> through interactions at focal adhesions . . 