Breast cancer occurs when the cells lining the breast ducts or lobules grow abnormally and out of control. A tumour can form in the ducts or lobules of the breast.
Women and men can both get breast cancer, although it is rare in men. Men's symptoms are similar to women's.
Breast cancer is the most common cancer in Victorian women. About 3,690 women are diagnosed each year. Breast cancer is rare in men with about 28 diagnosed in Victoria each year.
Although it can occur at any age, breast cancer is more common in older women. The average age at diagnosis is 60. About one-quarter of women who are diagnosed are younger than 50 years of age.
More than $12.5 million has been given to fund research specifically into breast cancer.
In addition, more than $16.2 million has been spent on research projects looking into the detection and treatment of all tumour types (including breast).
Overall, Cancer Council Victoria has funded $69 million worth of lab-based research in Victorian hospitals, universities and research institutions since 2003.