a mutagen refers to a substance that can increase the chances of DNA mutations.
a carcinogen is a known substance that increases the chances of cancer development.
while a carcinogen can usually be considered a mutagen,
not all mutagens can be considered a carcinogen due to the lack of correlation to cancer.
the differences between the two were discussed in lecture Gene Expression III.
please refer to slide 21 of lecture 17. Gene Expression III.