carcinogen vs substance

carcinogen and substance both are nouns.

Word	Noun	Adjective	Verb	Adverb
carcinogen	Yes	No	No	No
substance	Yes	No	No	No

As nouns, substance is a hypernym of carcinogen; that is, substance is a word with a broader meaning than carcinogen:

carcinogen (noun)	substance (noun)
any substance that produces cancer	the real physical matter of which a person or thing consists
	a particular kind or species of matter with uniform properties
	the property of holding together and retaining its shape
	the idea that is intended
	the choicest or most essential or most vital part of some idea or experience
	content communicating a message; what something is about
	considerable capital (wealth or income)
	material of a particular kind or constitution