Cancer, the Crab, is the fourth sign of the Zo­di­ac. The sun enters it on or around June 21, at the summer solstice. Can­cer belongs to the ele­ment water, its quality is cardinal and its charge is negative. Its Ruler is the moon, and Venus exalts in it. Its motto is: "I feel." In the horo­scope chart, Cancer brings a caring, affec­tionate and protecting charac­ter to planets or Houses therein.

 Those who have Cancer as their star sign are born when the sun was in Cancer, normally June 21 - July 22 (it differs slightly from year to year, be­cause of the leap years). Therefore, it is also - more correctly - called the sun sign.
     The sun in your horoscope is your natural self - what you are when you relax, when other planets in your horoscope are not active. It is your basic drive, a character you have as an ingredient - more or less evident in all you do and all you are. It is the most important point in your horoscope chart, but of course it is not the only thing that describes your personality. You need to look at all the components of your birth chart, to get a correct astrological description of your­self.
     If your sun sign is Cancer, you are an emotional being, engaging yourself in caring about others. It is the motherly sign. That is far from a submissive charac­ter. Notice that the sign's quality is cardinal, leading. The Cancer character is caring in a protective way, a tendency to control, although with good intentions. Your perspective is one of feelings, more than of thoughts, things or action. You pay attention to moods, and strive to make everybody feel good.
     A Zodiac sign does not give exactly the same influ­ence all through its 30°. Its first third has something of a cardinal quality, whatever the quality of the sign as a whole is, its second third is slightly more fixed in quality, and the last third is more mutable.
     If the sun is in the beginning of Cancer, you are very controlling and dominating, especially in an emotional way. You allow yourself to interfere, in order to make others feel better. If the sun is in the middle of Cancer, you are very protective, trying to maintain a stillness so that others don't get upset or worried. You strive for everyone to feel good. If it's at the end of Cancer, you are anxious to avoid situations that might worry others or make them feel unpleasant. In your efforts to please, you may unwillingly irritate.

The sun in the horoscope also represents your father (the mother is represented by the moon).
     If you have the sun in Cancer, your relation to your father is one of deep affection, where both of you feel very committed to each other. You are also both quite protective, sometimes in ways that lead to frustration, because you both feel that you know what's best for the other. Still, your bonds are unlikely to ever break, and you cherish each other's company, without the need to either speak or do anything in particular.

When another planet or other point of the horo­scope is in Cancer, it is also affected by the sign, get­ting some­thing of its character. Here are those points, what they stand for, and how they are affected by Cancer:

 
    Sun   basic drive - Cancer brings caring and commit­ment.
    Moon   longing - Cancer brings a need for deep relations, and makes you quite emotional, sensitive to mood swings.
    Mercury   curiosity - Cancer brings ability to voice emotions, and a sensitivity to how words affect others.
    Venus   affection - Cancer brings a capacity to play on the emotions of others, to charm, please and de­light.
    Mars   aggression - Cancer brings a will to protect and dominate, a temper and a tendency to upset others.
    Jupiter   luck - Cancer brings a sense of joy, and happiness seems near at hand.
    Saturn   duty - Cancer brings a love for the ways of the past and for the bloodline, also some angst.
    Uranus   contemplation - Cancer brings a capacity to see through others, to understand motivation and things implied.
    Neptune   fantasy - Cancer brings vivid and en­gaging dreams, and an imagination favoring the emo­tional.
    Pluto   catharsis - Cancer brings upsetting surprises and events that stir up emotions.
    Ascendant, AC   attitude - Cancer brings a pleasant way of behaving, with no fear of intimacy.
    Medium Coeli, MC   self-image - Cancer brings un­selfishness, a wish to be good unto others.

In the astrological Houses, the Zodiac signs also bring their characters, influencing the environments de­scribed by the Houses. Here are the twelve Houses, what they stand for, and how Cancer affects them:

1. Identity - Cancer makes you seem caring and committed.
2. Resources - Cancer makes you pleased with what you have.
3. Communication - Cancer makes you care about friends, but less about learning.
4. Home - Cancer makes you deeply committed to your family.
5. Pastime - Cancer makes you want to do good deeds, especially to your loved ones.
6. Work - Cancer makes you best suited to work with people, caring for them.
7. Partners - Cancer makes your relations deep and committed, with great affection.
8. Unknown - Cancer makes you trust that all is for the best, whatever lies ahead.
9. Travel - Cancer makes you want to feel like home, wherever you are.
10. Carreer - Cancer makes you quite at home in a social setting, respected for your commitment.
11. Ideals - Cancer makes you believe in doing good and caring for each other, and that's about all.
12. Shortcomings - Cancer makes your emotional life less than you want, and you might not care as much for others as you want to.

     Of course, all of the above is very general, mainly to give you an idea of how the sign works in the horo­scope. You need to study your horoscope chart care­fully, to make a nuanced and deeper interpretation.