Metallothionein protein and minichromosome maintenance protein-2 expression in adrenocortical tumors.

AIM: Some resected adrenal-confined adrenocortical carcinomas metastasize and others not. The present study was designed to evaluate the expression of metallothionein protein (MT) and minichromosome maintenance protein-2 (MCM2) in adrenocortical carcinomas and adrenocortical adenomas, and to test the correlation between this and adrenocortical carcinoma aggressiveness. MATERIALS AND METHODS: The study comprised 14 patients operated on for adrenocortical carcinoma, 15 operated on for adrenocortical adenoma and 2 with normal adrenals. Hematoxylin-eosin staining was used for histological evaluation under light microscopy, and sequential sections were used for MCM2 and MT staining. RESULTS: In normal adrenals, positive staining was weak for MT and zero for MCM2. Rates of positive staining for MT and MCM2 were significantly higher in adrenocortical carcinomas than in adrenocortical adenomas (P=0.008 and P<0.001, respectively). In adrenocortical carcinomas, a significant positive correlation was found between MCM2 staining and Weiss revisited score (P=0.022) but not for Weiss score, and a significant positive correlation was found between MCM2 and mitotic rate on histology (P=0.033). MCM2 but not MT staining was also shown to correlate significantly with stage IV carcinoma (P=0.008 and P=0.165, respectively). CONCLUSION: MCM2 and MT are overexpressed in adrenocortical carcinoma, and MCM2 expression correlates significantly with metastatic disease.

Proteomic Analysis and NIR-II Imaging of MCM2 Protein in Hepatocellular Carcinoma.

Targeted therapy of hepatocellular carcinoma (HCC) is essential for improved therapies. Therefore, identification of key targets specifically to HCC is an urgent requirement. Herein, an iTRAQ quantitative proteomic approach was employed to identify differentially expressed proteins in HCC tumor tissues. Of the upregulated tumor-related proteins, minichromosome maintenance 2 (MCM2), a DNA replication licensing factor, was one of the most significantly altered proteins, and its overexpression was confirmed using tissue microarray. Clinicopathological analysis of multiple cohorts of HCC patients indicated that overexpression of MCM2 was validated in 89.8% tumor tissues and strongly correlated with clinical stage. Furthermore, siRNA-mediated repression of MCM2 expression resulted in significant suppression of the HepG2 cell cycle and proliferation through the cyclin D-dependent kinases (CDKs) 2/7 pathway. Finally, the first small molecule-based MCM2-targeted NIR-II probe CH1055-MCM2 was concisely generated and subsequently evaluated in mice bearing HepG2 xenografts. The excellent imaging properties such as good tumor uptake and high tumor contrast and specificity were achieved in the small animal models. This analytical strategy can determine novel accessible targets of HCC useful for imaging and therapy.

MCM2 expression in serrated polyps demonstrates aberrant cellular proliferation.

In normal colonic epithelium, the proliferative zone is limited to the lower half of the colonic crypt. Evaluating the changes in the colonic epithelial proliferation can be useful in understanding pathophysiology of various diseases. Our aim was to investigate the proliferative compartment of serrated polyps (SPs) using MCM2, a protein involved in DNA replication, and assess for changes along the SP spectrum. Immunohistochemistry was performed on serrated polyps (16 microvesicular-type hyperplastic polyps (HP), 58 sessile serrated adenomas (SSA), 7 SSAs with dysplasia) and 6 sections of normal colon using anti-MCM2 antibody. Multiple sections of normal colon showed the following pattern for MCM2 and Ki-67 staining: positive nuclear staining of the lower half of the colonic crypts and/or slightly expanded to the lower two-thirds of the crypt. By MCM2, SPs show expansion of the proliferative compartments; 81.3% of HPs and 100% of SSAs showed some degree of full crypt MCM2 staining. SSAs with dysplasia showed consistent diffuse polyp staining. Aberrant staining in adjacent normal mucosa was also seen in SSAs with dysplasia and in a subset of non-dysplastic SSAs. By using MCM2, we show that serrated polyps exhibit changes in proliferation during progression along the pathway. HPs and SSAs show a similar highly proliferative profile. Aberrant proliferative cell staining patterns in adjacent normal colonic mucosa as seen in SSAs with dysplasia and a subset of SSAs suggest a field effect phenomenon. This indicates that changes in the colonic micro-environment may promote adenoma morphogenesis and predisposition to malignancy.

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.

Systematic cytological evaluation and immunocytochemistry of minichromosome maintenance protein 2 and p53 significantly improve cytological diagnosis of pancreaticobiliary adenocarcinoma.

Endoscopic retrograde cholangiopancreatography (ERCP) brushing cytology often cannot distinguish adenocarcinoma from reactive epithelial changes. We attempted to improve the diagnostic sensitivity of ERCP using the following methods: systematic cytological evaluation, immunocytochemical examination of minichromosome maintenance proteins (MCM) 2 and p53, and a combination of these methods. ERCP specimens from 53 patients (13 benign and 40 malignant cases) were studied. First, we reclassified the cases into three categories according to the systematic cytological evaluation: negative, suspicious, and positive. Secondly, immunocytochemistry was performed for MCM 2 and p53. The cut-off values were set at 25% labeling index (LI) for MCM 2 and 10% LI for p53, respectively. We evaluated the sensitivity, specificity, and diagnostic accuracy. The sensitivity of the systematic cytological evaluation alone did not improve significantly, compared with the original screening examination (77% vs. 68%). The sensitivity of immunocytochemistry for MCM 2 and p53 was 90% (P < 0.05) and 68%, respectively. Applying only the suspicious or positive categories, the sensitivity improved significantly to 93% for the combination of systematic cytological evaluation and immunocytochemistry for MCM 2 and p53 (P < 0.01). In conclusion, the combination of morphology and immunocytochemistry for MCM 2 and p53 may help to overcome the diagnostic cytological difficulties of pancreaticobiliary adenocarcinoma.

Prognostic significance of MCM 2 and Ki-67 in neuroblastic tumors in children.

INTRODUCTION: Neuroblastic tumors can be characterized by three features: spontaneous regression, maturation and aggressive proliferation. The most common and routinely used method of assessing tumor cell proliferation is to determine the Ki-67 index in the tumor tissue. Despite numerous studies, neuroblastoma biology is not fully understood, which makes treatment results unsatisfactory. MCM 2 is a potential prognostic factor in the neuroblastoma group. MATERIAL/METHODS: The study is based on retrospective analysis of 35 patients treated for neuroblastic tumors in the Department of Pediatric Surgery and Oncology of the Medical University of Lodz, during the period 2001-2011. The material comprised tissues of 16 tumors excised during the operation and 19 biopsy specimens. Immunohistochemical examinations were performed with immunoperoxidase using mouse monoclonal anti-MCM 2 and anti-Ki-67 antibodies. RESULTS: We observed that MCM 2 expression ranged from 2% to 98% and the Ki-67 index ranged from 0 to 95%. There was a statistically significant correlation between expression of MCM 2 and the value of the Ki-67 index and a correlation close to statistical significance between expression of MCM 2 and unfavorable histopathology. There was no statistical relationship between expression of MCM 2 and age over 1 year and N-myc amplification. DISCUSSION: The presented research shows that MCM 2 may have prognostic significance in neuroblastic pediatric tumors and as a potential prognostic factor could be the starting point of new individualized therapy.

Minichromosome maintenance-2 (MCM2) expression differentiates oral squamous cell carcinoma from pre-cancerous lesions.

BACKGROUND: Proteins necessary for DNA replication and normal regulation for the cell cycle include minichromosome maintenance-2 (Mcm-2). Overexpression of this protein in several premalignant and malignant lesions has been observed. In this study, the diagnostic value of Mcm-2 expression in distinguishing histologically-proven normal oral mucosa (NOM), oral benign keratosis (OBK), oral epithelial dysplasia (OED), and oral squamous cell carcinoma (OSCC) was investigated. MATERIALS AND METHODS: In this descriptive analytical study, 73 archived specimens of oral tissues, including 20 OBK, 20 OED, 20 OSCC, and 13 NOM cases were selected. The means of labeling indices (LIs) of Mcm-2 expression by immunohistochemistry in each category of lesions were calculated. The data was analyzed by one-way ANOVA, discriminant analysis, and Fisher's exact tests. RESULTS: The means of labeling indices (LIs) of Mcm-2 expression show statistically significant difference between the four studied groups (P<0.001). Mcm-2 had overexpression and higher positivity in OSCCs. A cut-off point of 67% was determined in order to distinguish OSCC from precancerous lesions. CONCLUSION: The findings indicated that Mcm-2 could be a useful marker for early detection of oral SCC and dysplasia. Also, due to the overexpression of this marker in OSCC, there exists the possibility of application of Mcm-2 for molecular target therapy in these patients.

Diagnostic value of MCM2 immunocytochemical staining in cervical lesions and its relationship with HPV infection.

Cervical cancer remains the fourth most common cause of cancer-related deaths in women worldwide, and human papillomavirus infection represents the most important risk factor for the development of cervical cancer. Minichromosome maintenance protein-2 has been previously identified by DNA microarray and transcriptional profiling as genes that is overexpressed in cervical carcinomas. 183 cases were enrolled and tested with thin prep liquid-based cytology test. The expressions of human papillomavirus were detected and minichromosome maintenance protein-2 immuncytochemical test was performed on liquid-based pap smears from the samples. Those results were compared with the cervical histopathology results. The positive expression rates of minichromosome maintenance protein-2 and high-risk type human papillomavirus increased with the severity of cervical lesions. The expression level of MCM2 was positively correlated with high-risk types of human papillomavirus. In cervical carcinoma and precancerous lesions, minichromosome maintenance protein-2 was overexpressed and positively correlated with the high risk types of human papillomavirus. As minichromosome maintenance protein-2 immuncytochemical detection was better than genotyping of human papillomavirus, minichromosome maintenance protein-2 may serve as a useful marker in the screening of cervical carcinoma and precancerous lesions and improve the diagnosis of atypical squamous cell of undetermined significance. The joint application can improve the sensitivity and specificity of diagnosis.

Immunohistochemical expression of MCM2 in nonmelanoma epithelial skin cancers.

Cutaneous basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) represent 45.5% and 37.02%, respectively, of total malignant skin cancer according to the latest registry of Egyptian National Cancer Institute. Minichromosome maintenance (MCM) proteins are essential replication initiation factors. The current study examined the immunohistochemical expression of MCM2 in normal skin (10 cases), some proliferative skin lesions (6 psoriasis, 2 keratoacanthoma, and 2 seborrheic keratosis), and nonmelanoma epithelial skin cancers (20 BCC and 21 SCC). MCM2 was expressed in basal layer of normal epidermis and upregulated in proliferative skin lesions and nonmelanoma epithelial skin cancers without significant differences between the latter groups (P > 0.05). Mean and median values of MCM2 percentage of expression in BCC were higher than that of SCC (P = 0.004). MCM2 promotes proliferative capacity of the cells manifested by its expression in basal layer of epidermis, hyperproliferative skin lesions, and malignant cutaneous tumors. Proliferative capacity of BCC may be higher than SCC and this does not necessarily reflect aggressive behavior.

MCM2/TOP2A (ProExC) immunohistochemistry as a predictive marker in head and neck mucosal biopsies.

Mucosal biopsies from the head and neck are often small and poorly oriented, which impedes diagnostic interpretation, especially in patients with a history of cancer, being monitored for recurrence. A cocktail of antibodies targeted against DNA topoisomerase IIA and mini-chromosome maintenance protein 2 (MCM2/TOP2A, ProExC), markers of aberrant S-phase induction, have been used with success as a diagnostic adjunct in the evaluation of squamous dysplasia of the uterine cervix. We tested the utility in head and neck biopsies to see if ProExC could be used to discriminate reactive/inflammatory from true pre-neoplasia. Sixty-four archival biopsies were selected from patients who presented to the surgeon with an indication for biopsy to "rule out" dysplasia. Histologically, all biopsies showed nonspecific atypia that was difficult to discriminate from dysplasia. Twenty-three of the patients progressed to squamous carcinoma and the rest remained benign over five years follow-up. Cases stained with ProExC by IHC methods showed a significant pattern of expression (p=0.026). The staining was greatest in patients without a history of prior head and neck cancer but was not significant. Our results show that ProExC, used in conjunction with the H&E slide, can enhance the predictive power of a mucosal biopsy in a cohort of patients.

Markers of cell division cycle in glioblastoma: significance in prediction of treatment response and patient prognosis.

OBJECTIVE: To investigate whether expression of regulatory components of the cell division cycle can be used independently to predict survival and response to adjuvant therapy in glioblastomas. METHOD: A tissue micro-array, constructed using glioblastomas (n = 66), was stained using antibodies against minichromosome maintenance protein-2 (Mcm-2), expressed throughout the cell-division cycle; geminin, a protein that prevents re-initiation of DNA replication; and cyclin A, an S-phase cyclin. A semi-quantitative labelling index (LI) was calculated using an average of 18 high-power fields (hpf) in three replicate cores. The patients were divided into two groups: Group 1 (n = 50) underwent surgery and radiotherapy with 24 patients receiving temozolomide, and Group 2 (n = 16) received surgical treatment only. RESULTS: The LIs (median +/- IQR) for Group 1 were as follows: Mcm-2, 36.7% (22.9%-51.8%); geminin, 7.8% (5.8%-10.5%); and cyclin A, 4.2% (2.4%-6.9%). Elevated LIs, higher than the median, for geminin and cyclin A correlated with prolonged survival when the tumours received adjuvant therapy (Kaplan-Meier curves, p = 0.0046 and p = 0.0063 for geminin and cyclin A, respectively). Linear regression analysis revealed positive correlations with survival for Mcm-2 (p = 0.0376), geminin (p = 0.0006) and cyclin A (p = 0.004). In Group 2, there was no relationship between the patient survival and the LI for any marker. CONCLUSIONS: Geminin and cyclin A, each show potential as independent prognostic markers in glioblastomas receiving adjuvant therapy. This may reflect the fact that both geminin and cyclin A estimate proliferating tumour cell subpopulations sensitive to radio/chemotherapy. These markers could provide valuable prognostic information, even in small biopsies, especially if combined with O(6)MGMT expression and 1p;19q deletion status.