Cancer can mean:
- Cancer, the group of malignant diseases
- Cancer (constellation), the constellation
- Cancer (astrology), the astrological sign
- Tropic of Cancer, a major circle of latitude
- Cancer (genus), a genus of crab
- Cancer (band), a British death metal band
- "Cancer", a song by Joe Jackson on his 1982 album Night and Day.
- "Cancer", a song by Filter on their 1999 album Title of Record.
- "Cancer", a song by My Chemical Romance on their 2006 album The Black Parade.
- Cancer (mobile suit), a mecha in the Gundam Wing anime.
- Cancer (comics), a Marvel Comics character
See also:
- Cancer on the Presidency, a recorded conversation between U.S. President Richard M. Nixon, his lawyer John Dean, and White House Chief of Staff H.R. Haldeman discussing the Watergate scandal
- 55 Cancri, a star system 40 light years away from Earth in which NASA has recently discovered five planets
