Invasive mucinous carcinoma of breast is usually caused by genetic factors, long-term indiscriminate use of sex hormones, unhealthy dietary habits and other factors. Invasive mucinous carcinoma of breast belongs to a rare type of breast cancer, and the patients are usually older, the tumor develops slowly and the metastasis occurs late, which leads to better prognosis of the patients. Patients with invasive mucinous carcinoma of breast have large tumor size and irregular shape. 1. Genetic factor: genetic factor is the high risk factor of this disease, if there is a patient with breast cancer disease among first-degree relatives, then the risk of incidence will be 2 to 3 times of that of ordinary people. 2. Long-term indiscriminate use of sex hormones: if a person takes sex hormone-containing drugs or injects sex hormone-containing drugs for a long period of time, it will also increase the risk of breast cancer to a certain extent. 3. Unhealthy dietary habits: Long-term unhealthy dietary habits, such as eating greasy, spicy and stimulating foods, will also increase the risk of breast cancer to a certain extent. Therefore, once breast disease is detected, it is necessary to seek medical treatment in time.