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.
Wang
Xuan
X
Department of Pathology, Tianjin Cancer Institute and Hospital, Tianjin Medical University, He Xi District, China.
Huang
Chun
C
Sun
Baocun
B
Gu
Yanjun
Y
Cui
Yanfen
Y
Zhao
Xiulan
X
Li
Yan
Y
Zhang
Shiwu
S
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