Latin: "Crab" In astronomy, the constellation lying between Leo and Gemini; in astrology, the fourth sign of the zodiac, governing approximately the period June 22—July It is represented as a crab or crayfisha reference to the crab in Greek mythology that pinched Heracles while he was fighting the Lernaean hydra. Heracles crushed the crab, but his enemy Hera rewarded it by placing it in the sky as a constellation.
Uncontrolled multiplication of abnormal cells.
Cancerous cells and tissues have abnormal growth rates, shapes, sizes and functioning. Cancer may progress in stages from a localized tumour confined to the site of origin to direct extension spread into nearby tissue or lymph nodes and metastasis spread to more distant sites via the blood or lymphatic system.
This malignant growth pattern distinguishes cancerous tumours from benign ones.
Cancer is also classified by grade, the extent to which cell characteristics remain specific to their tissue of origin. Both stage and grade affect the chances of survival.
Genetic factors and immune status affect susceptibility. Triggers include hormones, viruses, smoking, diet and radiation.
Cancer can begin in almost any tissue, including blood and lymph. When it metastasizes, it remains a cancer of its tissue of origin.
Early diagnosis and treatment increase the chance of cure. Treatment may include chemotherapy, surgery and radiation therapy.