In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: In relatively healthy women , combined continuous HT significantly increased the risk of venous thromboembolism or coronary event ( after one year ' s use ) , stroke ( after 3 years ) , breast cancer ( after 5 years ) and gallbladder disease .
### Output Text:
In relatively healthy women , combined continuous HT significantly increased the risk of venous thromboembolism or coronary event ( after one year ' s use ) , stroke ( after 3 years ) , breast cancer ( after 5 years ) and gallbladder disease . 