29368
Porphyrins are used for photodynamic therapy for their light - absorbing properties , and some of them were approved for the treatment of certain types of cancers .
 Chemical: Porphyrins
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Porphyrins