What is a lump in the breast before menstruation?

Breast cancer

is a benign breast tumor,

usually related to genetic, endocrine and other factors. In most cases, it does

not cause pain, but sometimes it may lead to breast pain and hard lumps.

3,

breast cancer

is a malignant tumor originating from breast tissue, the cause is unclear, may be genetic, environmental, endocrine and other factors, will lead to abnormal lumps in the breast, some patients feel sore.