Like oncogenes, which we saw on the last page of proliferative growth signaling, there are other classes of genes that code for proteins that affect the cell cycle. These that suppress tumor growth instead of promote tumor growth (like oncogenes) are called tumor suppressor genes. Here are some common examples of these genes and their respective protein.
p53. p53 is a cell cycle checkpoint protein. It is responsible for checking the integrity of DNA before allowing the cell cycle to progress. If working normally and DNA damage is present, it will stop the cycle. When mutated, it cannot stop the cycle even if DNA damage is present.
pRB. Named after the cancer it was discovered in, retinoblastoma, pRB is a protein that is associated with the cell cycle. When normal, pRB tells the cell not to divide. When mutated, it cannot perform its function, and thus looses the ability to stop the cell from dividing.
Many cancers have a mutation in pRB. Here is a chart stating percentages of what cancer have a mutation in pRB.
From this chart, is shows that pRB mutations that cause a loss of function can contribute to lung cancer, the number one cancer killer of men and women.
Sources: https://www.slideshare.net/RiniJoseph8/proto-oncogene-to-onco-gene-cell-signaling
Topics in Cancer Biology 