STAT-5 and STAT-6 in Breast Cancer: Potential Crosstalk With Estrogen and Progesterone Receptors Can Affect Cell Proliferation and Metastasis

BACKGROUND: Signal transducers and activators of transcription 5a and 6 (STAT5a and STAT6) play a critical role in tumorigenesis of mammary glands. Based on previous studies, the breast cancer is largely dependent on hormone receptors. Consequently, it is very interesting to decipher the relationship between the STAT5a and STAT6 expression and the molecular distribution of estrogen receptors (ERs) and progesterone receptors (PRs) in mammary tumors. METHODS: Our study analyzed the expression of STAT5a and STAT6, ERα, ERβ and PR in 40 breast tumor tissues using quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, the Ki-67 and HER2 status were detected using immunohistochemistry. RESULTS: STAT5a and STAT6 were retained in the majority of the cases studied. Increasing of STAT5a and STAT6 is significantly associated with ERs and PR. The coexpression of both STAT5a and STAT6 with ERs and PR is associated with high tumor grades. Moreover, the coexpression of STAT5a and STAT6 with ERα and PR is associated with a high proliferation index. In addition, (STAT6 + ERβ+) and (STAT6 + PR+) breast cancer subgroups are associated with lymph node infiltration (P = 0.001 and P = 0.03, respectively). CONCLUSIONS: Our study results provide an interaction between STAT5a and STAT6 with ERs and PR inducing cell proliferation. Coexpression of STAT5a and STAT6 with ERs and PR can predict sensibility to hormonal therapy.