However, after she completes a full-term pregnancy, 70% of a woman's breast lobules
have become mature, cancer-resistant Type 3 lobules.
C, Negative p16 staining in paired, benign breast lobules. D, Positive PELP1 staining in TNBC.
Morphologic features of the lung tumor (A through C); with TTF-1 staining (D); with ER staining at low power (E) and high power (F); and with napsin A staining of the tumor (G) and in residual, benign breast lobules (H) (hematoxylin-eosin, original magnifications 320 [A], x40 [B], and x100 [C]; original magnification x40 [D]; original magnifications x40 [E] and x100 [F]; original magnification x100 [G and H]).
After giving birth, breast lobules
switch to a secretory phenotype and ductules are found to be dilated.
Interestingly, CCCTCbinding factor (CTCF) and Dipeptidase 1 (DPEP1), both candidate tumor-suppressor genes, were found to have decreased expression in LCIS versus normal breast lobules
. (50) Both genes are found on chromosome 16q.
That is because by the end of a 40-week pregnancy, 85% of a woman's breast lobules
have become mature, cancer-resistant lobules known as Type 4 lobules.
Although abundant normal breast lobules
were present around the tumors, no histologic lactational change was noted.