The Sun represents your will and purpose, your sense of vitality, and your evolving higher Self. In Cancer it is Cardinal-Water and rules the stomach and breasts.
Cancerians are nurturing and protective of others. Your ruling planet is the Moon, and your emotions can to be effected by its constant pull. You are also likely to be security-conscious and highly value your home life.
You may appear passive, and tend to rely on your feelings to make decisions. You are likely more subtle, than direct, and are likely to reflect the moods of those around you, as energetically you can be very sensitive.
You may be involved with the past in some way, because the sign of Cancer, the sign of nurturing, protecting and sustaining, is strongly tied to the past, and the principle of Karma.
You may tend to collect the residue of past experience and hold onto it, allowing it to color present activities and lead you to instinctual action. Practicing conscious awareness of your thoughts, feelings, actions and reactions will serve you well for your spiritual growth.
Rather than allowing yourself to be driven by your changing moods, you benefit from shedding the light of conscious reason on your habitual patterns and focusing on your true goals.