Final answer:
Alpha-fetoprotein (AFP) is a tumor marker that may be used for liver cancer. Elevated levels of AFP in the blood can indicate the presence of liver cancer.
Step-by-step explanation:
A tumor marker that may be used for liver cancer is AFP (alpha-fetoprotein). AFP is a protein that is normally produced by the developing fetus, but it can also be produced by certain types of cancer cells, including liver cancer. Blood tests can detect elevated levels of AFP, which can indicate the presence of liver cancer.