Interference of the expression of ERK1,ERK2,and c-Fos in breast cancer by soybean isoflavones and its significance

Objective:To investigate the effects of soybean isoflavones on the expressions of extracellular signal regulated kinase 1/2(ERK1/2) and c-Fos in breast cancer of MMTV-erbB-2 transgenic mice and its significance.Methods:One hundred 3-week old healthy MMTV-erbB-2 transgenic female mice were divided into four groups: early intervention group,advanced intervention group,whole-course intervention group and control group.The incidence rate and the latent period of breast cancer were observed.The expression of ERK1,ERK2 and c-Fos proteins in normal breast tissues and breast cancer tissues were determined using immunohistochemical(SP) method.The statistical difference was analyzed.Results:The incidence rates were 48%,28%,20%,and 92% for early intervention group,advanced intervention group,whole-course intervention group,and control group,respectively.The latent periods were(47.67±9.25) weeks,(47.29±14.13) weeks,(51.8±6.69) weeks,and(49.91±8.07)weeks,respectively.Compared with the control group,the incidence rates were decreased in the other three groups(P0.01).The incidence rate of whole-course intervention group was lower than that in early intervention group(P0.05).There was no statistical difference in the incidence rate between early intervention group and advanced intervention group(P0.05) and between advanced intervention group and whole-course intervention group(P0.05).There was no significant difference in the latent period of breast cancer among the four groups(P0.05).And the tumor diameter had no significant difference among the four groups(P0.05).The positive rates of ERK1,ERK2 and c-Fos in breast cancer tissue were 71.6%,68.7%,and 61.2%,respectively,while the positive rates of these proteins in normal breast tissues were 27.7%,19.1%,and 12.8%,respectively(P0.01).Compared with the control group,the positive rates of these proteins in breast cancer tissues were decreased in intervention group,advanced intervention group,and whole-course intervention group.But the difference was not significant(P0.05).Conclusion:Soybean isoflavones have a preventive effect against the tumorigenesis of breast cancer of MMTV-erbB-2 transgenic mice.Mitogen-activated protein kinase(MAPK) signaling transduction pathway may play an important role in the initiation and progression of breast cancer.