We examined associations between common germline genetic variation in 13 genes involved in cell cycle control (CCND1, CCND2, CCND3, CCNE1, CDK2 [p33], CDK4, CDK6, CDKN1A [p21, Cip1], CDKN1B [p27, Kip1], CDKN2A [p16], CDKN2B [p15], CDKN2C [p18], and CDKN2D [p19]) and survival among women diagnosed with invasive breast cancer participating in the SEARCH (Studies of Epidemiology and Risk factors in Cancer Heredity) breast cancer study.
Although the exact biological mechanism remains to be explored, our findings suggest possible involvement of CDKN1A and CDKN1B variants in the etiology of breast cancer.
Furthermore, the antiproliferative effect of silencing FLOT2 on breast cancer cells was associated with upregulation of cyclin-dependent kinase (CDK) inhibitors p21Cip1 and p27Kip1.
Meanwhile, the up-regulated expression of LAPTM4B together with the down-regulated expression of p27kip1 could classified a group of breast cancer patients with poor prognosis, consequently considered as a potentially prognostic marker and candidate target for therapeutic intervention of triple-negative breast cancer.
The correlation between nuclear p27(KIP1) expression and estrogen (ER) and progesterone (PR) hormone receptor status was analyzed in 122 human T1N0M0 (68 T1a/b, 54 T1c) breast cancer specimens.
Additional studies are required to determine why some breast cancer cells express relatively high levels of p27(Kip1) despite its known role as an inhibitor of cell cycle progression.
High p27Kip1 expression was an independent predictor of responsiveness to hormonal therapy and thus may be useful for the selection of premenopausal women with early-stage hormone receptor-positive breast cancer for adjuvant combination endocrine therapy.
Previously, immunochemical analysis of a series of breast cancer cell lines demonstrated a correlation between the expression of p27(Kip1) and the breast cancer susceptibility gene BRCA1.
Moreover, we demonstrated that the anti-proliferative effect of silencing Sam68 on breast cancer cells was associated with up-regulation of cyclin-dependent kinase inhibitor p21(Cip1) and p27(Kip1), enhanced transactivation of FOXO factors, and attenuation of Akt/GSK-3β signalling.
Thus, cytoplasmic relocalization of p27(kip1), secondary to Akt-mediated phosphorylation, is a novel mechanism whereby the growth inhibitory properties of p27(kip1) are functionally inactivated and the proliferation of breast cancer cells is sustained.
Downregulation of the cyclin-dependent kinase inhibitor p27kip1 might correlate with poor disease-free and overall survival in inflammatory breast cancer.
The negative effects of cyclin G2 on cell cycle and cell proliferation, which occur without altering p27(Kip1) levels, may contribute to the ability of trastuzumab to inhibit breast cancer cell growth.
In epithelial cells of normal and benign breast disease, expression of p27Kip1 was well preserved while its expression markedly decreased in breast cancer (45 of 68).
We investigated the effect of the transfected p21 (Waf1) -p27 (Kip1) gene on centrosome duplication, cell proliferation, and apoptosis of MCF-7, a breast cancer cell line.
The purpose is to evaluate expression levels of Jun activation domain-binding protein 1 (JAB1) in breast cancer tissue and adjacent normal tissue, to determine whether JAB1 expression is associated with p27(Kip1) expression in invasive breast carcinomas, and to evaluate the prognostic significance of JAB1 and p27(Kip1) in node-negative breast cancer.
We have demonstrated by immunohistochemistry that p27Kip1 protein levels are reduced in primary breast cancers and that this is associated with tumor progression in both in situ and invasive lesions.
Through pharmacologic approaches, we demonstrated that SRC and PKC negatively regulated expression of the cell-cycle inhibitor protein p27KIP1, and are necessary for CCL2-induced breast cancer cell proliferation.