Behavior of CA cell
' in situ' means with in the confinement, ' ductal carcinoma in situ' means the cancer
cell are confined to inside of ducts, cells are dormant ( sleepy ) , not spreading, confined to within basement membrane of the duct .
If one area cells penetrate the membrane of the duct, and seen out side the duct means invasive, will be ready to spread, still a very early stage. Same for lobular carcinom.