An example of a tumor suppressor gene is-
Tumor suppressor gene
The replication of cell should be controlled to maintain a steady state.
Failure to inhibit cell replication is one of the fundamental alterations in the process of carcinogenesis.
Tumor suppressor genes are the genes whose products downregulate the cell cycle and thus apply brakes to cellular proliferation.
So, loss of function of tumor suppressor genes results in uncontrolled cell proliferation and carcinogenesis.
 Similar to an oncogene, tumor suppressor gene may be -
Cell surface receptor
 Transduction molecules
Transcription factor.
In addition,
Cell cycle inhibitors
Regulators of cellular responses to DNA damage (DNA repair regulators) 
These protein products are involved in -
Cell cycle control
Regulation of apoptosis 
DNA
myc
fos
ras
RB