Immunohistochemical expression of cyclin D1 in invasive breast carcinoma and its correlation with clinicopathological parameters

The overexpression of cyclin D1 is a positive prognostic factor in advanced-stage breast carcinoma cases

OBJECTIVE

Cyclin D1 (CDDN1) is a protein required for mitotic cell cycle progression through the G1 phase, as well as a regulatory component of the cyclin-dependent kinases CDK4 and CDK6. In this study, we wanted to evaluate the relationship between CDDN1 expression and clinicopathological features in breast cancer (BC) cases and whether CDDN1 could be used as a prognostic biomarker for BC cases.

METHODS

A total of 70 cases, 30 cases each with limited and advanced-stage BC, and as the control group, 10 healthy breast tissue, without a cancer diagnosis, with examined for benign reasons (mammoplasty, breast reduction surgery, etc.) were included in this study. The pathological specimens from the cases were stained, immunohistochemically, and categorized as a "low" (L) group or a "high" (H) group for CDDN1 expression. The cases' clinicopathological features and survival rates were evaluated statistically, within a 95% of confidence interval, p<0.05, retrospectively.

RESULTS

The median follow-up period of the cases was 48.00 (range, 6-150) months. CDDN1 expression was significantly higher in advanced-stage BC cases than in normal breast tissue and limited-stage BC cases. The median overall survival (OS) was 96 months (CI 95%: 67.74-117.59) in the H-CDDN1 group, compared to the L-CDDN1 group not reached, but there was no relation (p>0.05). CDDN1 overexpression was more prominent in low-grade advanced BC cases (p=0.004). The median OS of advanced-stage BC cases with Grade 1 was significantly longer than those with other grades (p=0.04).

CONCLUSION

Our results suggest that CDDN1 expression can be used as a potentially appropriate positive prognostic biomarker for advanced-stage BC cases.

Targeting Cell Death Mechanism Specifically in Triple Negative Breast Cancer Cell Lines

Triple negative breast cancer (TNBC) is currently associated with a lack of treatment options. Arsenic derivatives have shown antitumoral activity both in vitro and in vivo; however, their mode of action is not completely understood. In this work we evaluate the response to arsenate of the double positive MCF-7 breast cancer cell line as well as of two different TNBC cell lines, Hs578T and MDA-MB-231. Multimodal experiments were conducted to this end, using functional assays and microarrays. Arsenate was found to induce cytoskeletal alteration, autophagy and apoptosis in TNBC cells, and moderate effects in MCF-7 cells. Gene expression analysis showed that the TNBC cell lines’ response to arsenate was more prominent in the G2M checkpoint, autophagy and apoptosis compared to the Human Mammary Epithelial Cells (HMEC) and MCF-7 cell lines. We confirmed the downregulation of anti-apoptotic genes (MCL1, BCL2, TGFβ1 and CCND1) by qRT-PCR, and on the protein level, for TGFβ2, by ELISA. Insight into the mode of action of arsenate in TNBC cell lines it is provided, and we concluded that TNBC and non-TNBC cell lines reacted differently to arsenate treatment in this particular experimental setup. We suggest the future research of arsenate as a treatment strategy against TNBC.

Oncogenic and Tumor Suppressive Components of the Cell Cycle in Breast Cancer Progression and Prognosis

Cancer, a disease of inappropriate cell proliferation, is strongly interconnected with the cell cycle. All cancers consist of an abnormal accumulation of neoplastic cells, which are propagated toward uncontrolled cell division and proliferation in response to mitogenic signals. Mitogenic stimuli include genetic and epigenetic changes in cell cycle regulatory genes and other genes which regulate the cell cycle. This suggests that multiple, distinct pathways of genetic alterations lead to cancer development. Products of both oncogenes (including cyclin-dependent kinase (CDKs) and cyclins) and tumor suppressor genes (including cyclin-dependent kinase inhibitors) regulate cell cycle machinery and promote or suppress cell cycle progression, respectively. The identification of cyclins and CDKs help to explain and understand the molecular mechanisms of cell cycle machinery. During breast cancer tumorigenesis, cyclins A, B, C, D1, and E; cyclin-dependent kinase (CDKs); and CDK-inhibitor proteins p16, p21, p27, and p53 are known to play significant roles in cell cycle control and are tightly regulated in normal breast epithelial cells. Following mitogenic stimuli, these components are deregulated, which promotes neoplastic transformation of breast epithelial cells. Multiple studies implicate the roles of both types of components-oncogenic CDKs and cyclins, along with tumor-suppressing cyclin-dependent inhibitors-in breast cancer initiation and progression. Numerous clinical studies have confirmed that there is a prognostic significance for screening for these described components, regarding patient outcomes and their responses to therapy. The aim of this review article is to summarize the roles of oncogenic and tumor-suppressive components of the cell cycle in breast cancer progression and prognosis.