The effect of high gravidity on the carcinogenesis of mammary gland in TA2 mice.
OBJECTIVE
Spontaneous breast cancer in Tientsin Albinao 2 (TA2) mice, like human pregnancy-associated breast cancer (PABC), often occurs in pregnancy and puerperium, especially in mice with high gravidity. We hypothesized that the dysfunction of cellular immunity caused by the increase of 17beta-estradiol (E2) and progesterone (P) might be one of the reasons for carcinogenesis of mammary gland.


METHODS
We investigated the T lymphocyte subsets and the concentration of serum hormone and cytokines in cancer-bearing, pregnant or postpartum TA2 mice using flow cytometry, chemiluminescent immunoassay, and enzyme-linked immunosorbent assay (ELISA), respectively.


RESULTS
The number of T lymphocytes and the concentration of E2, P, interleukin-2 (IL-2), IL-4, and interferon-gamma (IFN-gamma) changed with the increase of pregnancy and puerperium. During four pregnancies, elevated E2 and P resulted in a decrease in the number of CD3(+), CD4(+) T lymphocytes, CD4(+)/CD8(+) ratio, and the concentration of IL-2, IL-4, and IFN-gamma. Data in the fourth pregnancy were the closest to those of cancer-bearing mice.


CONCLUSIONS
T lymphocyte subsets and concentration of IL-2, IL-4, and IFN-gamma are affected by E2 and P during multiple pregnancy and delivery to some degree, which may contribute to the genesis of spontaneous breast cancer in TA2 mice.
Department of Pathology, Tianjin Cancer Institute and Hospital, Tianjin Medical University, He Xi District, China.
Xuan
X
Wang
Chun
C
Huang
Baocun
B
Sun
Yanjun
Y
Gu
Yanfen
Y
Cui
Xiulan
X
Zhao
Yan
Y
Li
Shiwu
S
Zhang
D000818:Animals; D001943:Breast Neoplasms / Q000097:blood / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D005260:Female; D020073:Gravidity; D007371:Interferon-gamma / Q000097:blood / Q000276:immunology; D007376:Interleukin-2 / Q000097:blood / Q000276:immunology; D015847:Interleukin-4 / Q000097:blood / Q000276:immunology; D051379:Mice; D011247:Pregnancy; D013601:T-Lymphocytes / Q000276:immunology
D007376:Interleukin-2; D015847:Interleukin-4; D007371:Interferon-gamma