The flowers associated with Cancer are the water lily and the magnolia (depicted).

The Cancer glyph may represent the breasts as a symbol of the nurturing qualities of the sign.

The ruling planet of the sign of Cancer is the Moon, depicted here.

The Moon represents our deepest personal needs, our basic habits and reactions, our emotions, and our unconscious. Where the Sun acts, the Moon reacts. The Moon is both our inner child and our inner mother. It is responsive, receptive, and reflective. The Moon represents our spontaneous and instinctual reactions. The Moon is a mediator between the inner world and the outer world.

Cancer's element is WATER. There are three water signs: Cancer, Scorpio, and Pisces.

Water signs are fluid, emotional, and intuitive.

The crab is Cancer's symbol.

A crab is able to walk or run sideways. Similarly, Cancer natives can sometimes "move about" in life, in a figurative sense, in an indirect manner. The crab's body is covered by a carapace (shell). Cancer natives are self-protective and sensitive and often retreat into themselves when hurt. Crabs are able to resist changes in the environment, thereby protecting themselves from hostile elements in various habitats. Similarly, Cancer natives are thought to avoid too much change and to be on the defensive. Crabs have "complex behavior patterns." The inner world of Cancer natives is thought to be rather complex. Some crabs "conceal themselves by decorating their bodies with plants and animals." Cancer natives tend to try to blend in with their environments, preferring not to make a big splash in life.

Cancer's mode is Cardinal. There are four Cardinal signs: Aries, Cancer, Libra, and Capricorn.

Cardinal signs want action! They correspond to the beginning of each of the four seasons.

The planetary ruler of Cancer is the Moon, and the symbol or glyph of the Moon is depicted here.

The Moon's glyph resembles the Moon itself when it is a crescent shape. The crescent shows reception, and the Moon is a lens that focuses the light of the Sun.

This is a depiction of the constellation of Cancer.

The metal associated with Cancer is elegant silver.

Cancer is related to the Pearl. Pearls symbolize integrity, loyalty, wisdom, and calm -- traits also associated with the sign.

Cancer is related to the colors Violet, Silver, and White (although not technically a color). 

Cancer is the fourth sign and the house related to Cancer is the fourth house. The fourth house is shaded in the chart wheel depicted here.

The fourth house is associated with our psychological foundations and roots, family, home life, instinctive behavior, the mother or the more "maternal" parent/caregiver, ancestry, our connection with our past, our sense of security, domestic life, real estate, and more.

The cusp of the fourth house is a special angle called the IC (Immum Coeli) and is also called the nadir.

The fourth house is an angular house. Its natural sign ruler is Cancer and its natural planetary ruler is the Moon.