Minichromosome maintenance protein 2 is a reliable proliferative marker in breast carcinoma

The Correlation between Proliferative Immunohistochemical Markers and Papillary Thyroid Carcinoma Aggressiveness

Background and Objectives: Papillary thyroid carcinoma (PTC) is one of the most common malignancies of the endocrine system. In order to improve the ability to predict tumor behavior, several studies have been conducted to search for surrogate prognostic immunohistochemical tumor markers. Objective: To evaluate the correlation between the intensity of different immunohistochemical marker staining in PTC and the risk for extrathyroidal extension and metastases. Materials and Methods: The study comprised patients who underwent hemi- or total thyroidectomy. Thyroid tissues were immunohistochemically stained for different tumor proliferative markers: Minichromosome maintenance proteins 2 (MCM2), Ki-67 labeling index, E-Cadherin, Neuropilin-1 and Metallothionein. The correlation between the intensity of each marker staining and the final diagnosis (benign neoplasm and PTC) and the correlation between the intensity of each staining and tumor extrathyroidal extension and metastases were evaluated. Results: The study included 66 patients. Staining for Metallothionein, E-Cadherin and MCM2 significantly differed between benign neoplasm (n = 22) and thyroid-confined PTC (n = 21) (p = 0.002, 0.004 and 0.005, respectively), between benign neoplasm and PTC with extrathyroidal extension (n = 11) (p = 0.001, 0.006 and 0.01, respectively), and between benign neoplasm and PTC with metastases (n = 12) (p = 0.01, <0.001 and 0.037, respectively). No staining correlated with extrathyroidal extension. The intensity of E-Cadherin staining was significantly lower in PTC with metastases than thyroid confined PTC and PTC with extrathyroidal extension (p = 0.028 and 0.021, respectively). Conclusions: Immunohistochemical staining for Metallothionein, E-Cadherin and MCM2 significantly distinguished between benign thyroid tumor and PTC. E-Cadherin staining significantly and inversely correlated with the presence of metastases.

Fluoro-Chromogenic Labelling for Detection of MCM2 to Assess Proliferation Activity in HER2-amplified Breast Carcinomas

Minichromosome Maintenance Protein 2 (MCM2) is critical in initiating DNA replication during the cell division process. As expressed intensively in all phases of the active cell cycle, MCM2 has been proposed as a novel biomarker to determine cellular proliferation. We aimed at clarifying the prevalence and clinical significance of MCM2 in HER2-amplified breast cancer subtype. MCM2 expression was studied in 142 primary HER2-amplified breast carcinomas by applying a novel fluoro-chromogenic immunohistochemistry and tailored digital image analysis to determine labelling index (MCM2-LI). The presence of MCM2 was detected with HRP-conjugated polymer and visualized with 3, 3'-diaminobenzidine tetrahydrochloride, in cytokeratin (CK)-positive and Cy2-IgG-labelled breast cancer cells of epithelial origin. Stained slides were digitized by scanning sequentially under bright field (for MCM2) and fluorescence (for CK) illumination. Multilayer JPEG2000 images were analyzed with ImmunoRatio 2.5 (accessory in SlideVantage 1.2 software) utilizing its bright field and fluorescence image-blending mode to display MCM2-CK dual-positive cells. MCM2-LI was retrospectively compared with histopathologic characteristics and patients' clinical outcome. MCM2 protein-expressing cells (median MCM2-LI, 63.5%) were more frequent than those of Ki67 (median Ki67 labelling index, 33%). Significant correlations were found between high MCM2-LI, high Ki67 labelling index, negative hormone receptor (ER, PR) statuses, high grade of malignancy, and high cyclin E expression. MCM2-LI was not shown to be predictive of disease recurrence during the median follow-up of 5.3 years but was shown to be useful to distinguish aggressive-type HER2-amplified breast carcinomas with high malignancy grade and hormone receptor negativity. The fluoro-chromogenic double-labelling immunohistochemistry accompanied with digital image analysis provides an accurate carcinoma-specific determination of MCM2-LI on a single tumor section.

MCM2: An alternative to Ki-67 for measuring breast cancer cell proliferation

Breast cancer is a heterogeneous disease comprising a diversity of tumor subtypes that manifest themselves in a wide variety of clinical, pathological, and molecular features. One important subset, luminal breast cancers, comprises two clinically distinct subtypes luminal A and B each of them endowed with its own genetic program of differentiation and proliferation. Luminal breast cancers were operationally defined as follows: Luminal A: ER+, PR+, HER2-, Ki-67<14% and Luminal B: ER+ and/or PR+, HER2-,Ki-67≥14% or, alternatively ER+ and/or PR+, HER2+, any Ki-67. There is currently a need for a clinically robust and validated immunohistochemical assay that can help distinguish between luminal A and B breast cancer. MCM2 is a family member of the minichromosome maintenance protein complex whose role in DNA replication and cell proliferation is firmly established. As MCM2 appears to be an attractive alternative to Ki-67, we sought to study the expression of MCM2 and Ki-67 in different histological grades and molecular subtypes of breast cancer focusing primarily on ER-positive tumors. MCM2 and Ki-67 mRNA expression were studied using in silico analysis of available DNA microarray and RNA-sequencing data of human breast cancer. We next used immunohistochemistry to evaluate protein expression of MCM2 and Ki-67 on tissue microarrays of invasive breast carcinoma. We found that MCM2 and Ki-67 are highly expressed in breast tumors of high histological grades, comprising clinically aggressive tumors such as triple-negative, HER2-positive and luminal B subtypes. MCM2 expression was detected at higher levels than that of Ki-67 in normal breast tissues and in breast cancers. The bimodal distribution of MCM2 scores in ER+/HER2- breast tumors led to the identification of two distinct subgroups with different relapse-free survival rates. In conclusion, MCM2 expression can help sorting out two clinically important subsets of luminal breast cancer whose treatment and clinical outcomes are likely to diverge.

MCM2 and TIP30 are prognostic markers in squamous cell/adenosquamous carcinoma and adenocarcinoma of the gallbladder

The clinicopathological and biological characteristics of squamous cell/adenosquamous carcinoma (SC/ASC) of the gallbladder remain to be fully elucidated, due to the fact that it is a rare gallbladder cancer subtype. In the current study, the expression of minichromosome maintenance complex component 2 (MCM2) and HIV‑1 tat interactive protein 2 (TIP30) was measured in 46 cases of SC/ASC and 80 adenocarcinomas (AC) using immunohistochemistry. Positive MCM2 and negative TIP30 expression were significantly associated with large tumor size, high TNM stage, invasion, lymph node metastasis and lack of surgical curability in SC/ASC and AC. Positive MCM2 and negative TIP30 expression were significantly associated with poor differentiation in AC, whereas only MCM2 was correlated with differentiation in SC/ASC. Univariate Kaplan‑Meier analysis demonstrated that positive MCM2 and negative TIP30 expression, the degree of differentiation, tumor size, TNM stage, invasion, lymph node metastasis and surgical curability were significantly associated with post‑operative survival in patients with SC/ASC and AC. Multivariate Cox regression analysis demonstrated that positive MCM2 and negative TIP30 expression, the degree of differentiation, tumor size, TNM stage, invasion, lymph node metastasis and lack of surgical curability were also independent predictors of poor prognosis in patients with SC/ASC and AC. These data suggest that positive MCM2 and negative TIP30 expression are closely correlated with the clinical, pathological and biological parameters, in addition to poor prognosis in patients with gallbladder cancer.

Long noncoding RNA FTX inhibits hepatocellular carcinoma proliferation and metastasis by binding MCM2 and miR-374a

It has long been known that males are more susceptible than females to hepatocellular carcinoma (HCC), but the reason remains elusive. In this study, we investigated the expression and function of the long noncoding RNA FTX (lnc-FTX), an X-inactive-specific transcript (XIST) regulator transcribed from the X chromosome inactivation center, in both HCC and HCC gender disparity. lnc-FTX is expressed at higher levels in female livers than in male livers and is significantly downregulated in HCC tissues compared with normal liver tissues. Patients with higher lnc-FTX expression exhibited longer survival, suggesting that lnc-FTX is a useful prognostic factor for HCC patients. lnc-FTX inhibits HCC cell growth and metastasis both in vitro and in vivo. Mechanistically, lnc-FTX represses Wnt/β-catenin signaling activity by competitively sponging miR-374a and inhibits HCC cell epithelial-mesenchymal transition and invasion. In addition, lnc-FTX binds to the DNA replication licensing factor MCM2, thereby impeding DNA replication and inhibiting proliferation in HCC cells. In conclusion, these findings suggest that lnc-FTX may act as a tumor suppressor in HCC through physically binding miR-374a and MCM2. It may also be one of the reasons for HCC gender disparity and may potentially contribute to HCC treatment.

Hippocampal proliferation is increased in presymptomatic Parkinson's disease and due to microglia

Besides dopamine-deficiency related motor symptoms, nonmotor symptoms, including cognitive changes occur in Parkinson's disease (PD) patients, that may relate to accumulation of α-synuclein in the hippocampus (HC). This brain region also contains stem cells that can proliferate. This is a well-regulated process that can, for example, be altered by neurodegenerative conditions. In contrast to proliferation in the substantia nigra and subventricular zone, little is known about the HC in PD. In addition, glial cells contribute to neurodegenerative processes and may proliferate in response to PD pathology. In the present study, we questioned whether microglial cells proliferate in the HC of established PD patients versus control subjects or incidental Lewy body disease (iLBD) cases as a prodromal state of PD. To this end, proliferation was assessed using the immunocytochemical marker minichromosome maintenance protein 2 (MCM2). Colocalization with Iba1 was performed to determine microglial proliferation. MCM2-positive cells were present in the HC of controls and were significantly increased in the presymptomatic iLBD cases, but not in established PD patients. Microglia represented the majority of the proliferating cells in the HC. This suggests an early microglial response to developing PD pathology in the HC and further indicates that neuroinflammatory processes play an important role in the development of PD pathology.

Novel molecular markers of malignancy in histologically normal and benign breast

To detect the molecular changes of malignancy in histologically normal breast (HNB) tissues, we recently developed a novel 117-gene-malignancy-signature. Here we report validation of our leading malignancy-risk-genes, topoisomerase-2-alpha (TOP2A), minichromosome-maintenance-protein-2 (MCM2) and “budding-uninhibited-by-benzimidazoles-1-homolog-beta” (BUB1B) at the protein level. Using our 117-gene malignancy-signature, we classified 18 fresh-frozen HNB tissues from 18 adult female breast cancer patients into HNB-tissues with low-grade (HNB-LGMA; N = 9) and high-grade molecular abnormality (HNB-HGMA; N = 9). Archival sections of additional HNB tissues from these patients, and invasive ductal carcinoma (IDC) tissues from six other patients were immunostained for these biomarkers. TOP2A/MCM2 expression was assessed as staining index (%) and BUB1B expression as H-scores (0–300). Increasing TOP2A, MCM2, and BUB1B protein expression from HNB-LGMA to HNB-HGMA tissues to IDCs validated our microarray-based molecular classification of HNB tissues by immunohistochemistry. We also demonstrated an increasing expression of TOP2A protein on an independent test set of HNB/benign/reductionmammoplasties, atypical-ductal-hyperplasia with and without synchronous breast cancer, DCIS and IDC tissues using a custom tissue microarray (TMA). In conclusion, TOP2A, MCM2, and BUB1B proteins are potential molecular biomarkers of malignancy in histologically normal and benign breast tissues. Larger-scale clinical validation studies are needed to further evaluate the clinical utility of these molecular biomarkers.

Breast cancer biomarker discovery in the functional genomic age: a systematic review of 42 gene expression signatures

In this review we provide a systematic analysis of transcriptomic signatures derived from 42 breast cancer gene expression studies, in an effort to identify the most relevant breast cancer biomarkers using a meta-analysis method. Meta-data revealed a set of 117 genes that were the most commonly affected ranging from 12% to 36% of overlap among breast cancer gene expression studies. Data mining analysis of transcripts and protein-protein interactions of these commonly modulated genes indicate three functional modules significantly affected among signatures, one module related with the response to steroid hormone stimulus, and two modules related to the cell cycle. Analysis of a publicly available gene expression data showed that the obtained meta-signature is capable of predicting overall survival (P < 0.0001) and relapse-free survival (P < 0.0001) in patients with early-stage breast carcinomas. In addition, the identified meta-signature improves breast cancer patient stratification independently of traditional prognostic factors in a multivariate Cox proportional-hazards analysis.

Decreased numbers of progenitor cells but no response to antidepressant drugs in the hippocampus of elderly depressed patients

Imaging studies have consistently documented hippocampal volume reductions in depression. Although depressive disorders are traditionally considered to have a neurochemical basis, recent studies suggest that impairments of structural plasticity contribute to the volume reductions and the related cognitive changes. This might result from repeated periods of stress that are a wellknown risk factor for depression. Adult neurogenesis is a prominent example of neuroplasticity that in rodents, is reduced by stress but stimulated by antidepressant drugs. Although reductions in neurogenesis have been proposed to contribute to the etiology of depression, only two studies have so far examined hippocampal cytogenesis in depression, but this was in a limited number of subjects with considerable interindividual variation, and these studies came to different conclusions. We therefore collected hippocampal tissue of 10 elderly control subject and 10 well-matched depressed patients that were highly comparable in terms of age, sex, pH-CSF and postmortem delay, and tested whether the numbers of MCM2-positive progenitors and PH3-positive proliferating cells were altered by depression or antidepressant treatment. A significant reduction was found in MCM2-, but not PH3-immunopositive cells in depression. Although this result is consistent with the concept that structural plasticity is decreased in depression, we could not confirm that antidepressant drugs had a stimulatory effect on these cells. This discrepancy may relate to anatomical differences, in medication, to neurogenesis-independent mechanisms of antidepressant action, or the age of the patients that was higher than in previous studies. Whether the reduction is a cause or consequence of depression awaits to be determined.

Lithium chloride treatment induces epithelial cell proliferation in xenografted human endometrium

BACKGROUND

In mouse endometrium, glycogen synthase kinase-3beta (GSK3beta) is a key enzyme controlling nuclear localization of cyclin D1. We developed a functional model of xenografted human endometrium to test whether similar mechanisms are operative in the human by using Lithium chloride (LiCl), an inhibitor of GSK3beta.

METHODS

Human endometrial samples were obtained from normal volunteers, then implanted under the kidney capsule of nude mice, and treated with estradiol-17beta (E2) or LiCl. Xenografts were assessed for protein expression of MKI-67, mini-chromosome maintenance protein-2, estrogen receptor (ER), progesterone receptor (PR) and cyclin D1.

RESULTS

Both E2 and LiCl induced a robust proliferative response in the epithelium. Only lithium treatment produced clear nuclear localization of cyclin D1 consistent with the proliferative response observed. Regenerated endometrium had detectable ER and PR expression.

CONCLUSION

Xenografted human endometrium provides a dynamic model of uterine biology. Administration of LiCl in the absence of E2 induced epithelial proliferation, supporting the hypothesis that human and murine endometrial proliferation may share key regulatory pathways. These data suggest a possible link between the increased menstrual disturbances in women with affective disorders taking lithium and the consequent potential for the development of endometrial proliferative disorder.