Mutagen is a mutagen, not necessarily a carcinogen.

Abstract

A largely unspoken but underlying assumption that has been made by authors throughout these proceedings is that processes involved in antimutagenesis are related to anticarcinogenesis, a corollary of the somatic mutation theory of carcinogenesis. It is generally known that most carcinogens are mutagens, but certainly not all chemicals that are mutagenic in short-term in vitro mutagenicity tests are carcinogens. Reasons that contribute to this lack of concordance are discussed later.