Tumor suppressors: recessive mutations that lead to cancer.

Several lines of evidence point to the involvement of recessive mutations in the predisposition to, and hence initiation of, cancer in vivo. Analyses of the genetic behavior of transformed cells suggest that at least one way to explain these events is to invoke loci which suppress the tumorous phenotype and which are inactivated by mutation. These suppressors are the subject of much speculation, but whether or not they are ultimately determined to be the regulators of differentiation antigens, growth factors, or proto-oncogenes, it is certain that the investigation of such loci will allow yet another glimpse at the inner mysteries of organismal development.