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: Cases of endometrial cancer diagnosed after breast cancer ( n = 135 ) and 467 controls matched for age , year of diagnosis of breast cancer and hospital and survival time with an intact uterus were included .
### Output Text:
Cases of endometrial cancer diagnosed after breast cancer ( n = 135 ) and 467 controls matched for age , year of diagnosis of breast cancer and hospital and survival time with an intact uterus were included . 