Abnormal expression of Nek2 and β-catenin in breast carcinoma: clinicopathological correlations
ABSTRACT NIMA-related kinase 2 (Nek2) and β-catenin are important centrosome regulatory factors. The aim of this study was to detect the possible disparity in their expression among normal breast tissue, invasive ductal carcinoma (IDC), concomitant ductal carcinoma in situ (DCIS), and pure DCIS, and to explore its correlation with clinicopathological factors.
We used immunohistochemistry to detect protein expression of Nek2 and β-catenin in breast cancer tissues from 60 cases of pure DCIS, 348 cases of IDC and 137 cases of concomitant DCIS with that in normal breast tissues from the same 137 concomitant DCIS patients as controls. As compared with normal tissue, expression of Nek2 and β-catenin in the cytoplasm was significantly increased in IDC and DCIS (P < 0.05), and variation in expression was also observed in different grades of IDC (P < 0.01). Also, cytoplasmic expression of Nek2 and and of β-catenin were correlated with each other in IDC and DCIS (P < 0.01). In addition, they were both related to Ki67 immunoreactivity (P < 0.05). Furthermore, our study also revealed a correlation between their expression and some clinicopathological factors. We found that Nek2 cytoplasmic expression was associated with grade and tumour size (P < 0.01) in IDC, whereas β-catenin cytomembrane expression showed significant variation with grades, TNM stages, lymphoid node status, oestrogen receptor status, and molecular subtype (P < 0.05); a difference in expression was also observed between IDC and DCIS (P < 0.05). Also, β-catenin cytoplasmic expression was associated with TNM stage (P < 0.05). Expression of Nek2 at the mRNA level was detected in 50 pairs of breast cancer specimens and matched normal tissues by reverse transcriptase polymerase chain reaction, and the result showed increased expression in IDC.
This study suggests that abnormal expression of Nek2 and β-catenin might be one of the mechanisms of tumorigenesis, especially of abnormal tumour proliferation. They may represent new potential targets for therapeutic intervention.
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ABSTRACT: It is a challenging task to distinguish between benign and malignant lesions in patients with biliary strictures. Here we analyze whether determination of target gene mRNA levels in intraductal brush cytology specimens may be used to improve the diagnosis of bile duct carcinoma. Brush cytology specimens from 119 patients with biliary strictures (malignant: n = 72; benign: n = 47) were analyzed in a retrospective cohort study. mRNA of IGF-II mRNA-binding protein 3 (IGF2BP3), homeobox B7 (HOXB7), Forkhead box M1 (FOXM1), kinesin family member 2C (KIF2C) and serine/threonine kinase NEK2 was determined by semi-quantitative RT-PCR using the ΔCt method. IGF2BP3 (p<0.0001), HOXB7 (p<0.0001), and NEK2 (p<0.0001) mRNA expression levels were significantly increased in patients with cholangiocarcinoma or pancreatic cancer. Median ΔCt values differed by 3.5 cycles (IGF2BP3), 2.8 cycles (HOXB7) and 1.3 cycles (NEK2) corresponding to 11-fold, 7-fold and 2.5-fold increased mRNA levels in malignant versus benign samples. Sensitivity to detect biliary cancer was 76.4% for IGF2BP3 (80.9% specificity); 72.2% for HOXB7 (78.7% specificity) and 65.3% for NEK2 (72.3% specificity), whereas routine cytology reached only 43.1% sensitivity (85.4% specificity). Diagnostic precision was further improved, when all three molecular markers were assessed in combination (77.8% sensitivity, 87.2% specificity) and achieved 87.5% sensitivity and 87.2% specificity when molecular markers were combined with routine cytology. Our data suggest that measuring IGF2BP3, HOXB7 and NEK2 mRNA levels by RT-PCR in addition to cytology has the potential to improve detection of malignant biliary disorders from brush cytology specimens.PLoS ONE 08/2012; 7(8):e42141. DOI:10.1371/journal.pone.0042141 · 3.53 Impact Factor
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ABSTRACT: About 50% of all malignant peripheral nerve sheath tumors (MPNSTs) arise as neurofibromatosis type 1 associated lesions. In those patients malignant peripheral nerve sheath tumors are thought to arise through malignant transformation of a preexisting plexiform neurofibroma. The molecular changes associated with this transformation are still poorly understood. We sought to test the hypothesis that dysregulation of expression of kinases contributes to this malignant transformation. We analyzed expression of all 519 kinase genes in the human genome using the nanostring nCounter system. Twelve cases of malignant peripheral nerve sheath tumor arising in a background of preexisting plexiform neurofibroma were included. Both components were separately sampled. Statistical analysis compared global changes in expression levels as well as changes observed in the pairwise comparison of samples taken from the same surgical specimen. Immunohistochemical studies were performed on tissue array slides to confirm expression of selected proteins. The expression pattern of kinase genes can separate malignant peripheral nerve sheath tumors and preexisting plexiform neurofibromas. The majority of kinase genes is downregulated rather than overexpressed with malignant transformation. The patterns of expression changes are complex without simple recurring alteration. Pathway analysis demonstrates that differentially expressed kinases are enriched for kinases involved in the direct regulation of mitosis, and several of these show increased expression in malignant peripheral nerve sheath tumors. Immunohistochemical studies for the mitotic regulators BUB1B, PBK and NEK2 confirm higher expression levels at the protein level. These results suggest that the malignant transformation of plexiform neurofibroma is associated with distinct changes in the expression of kinase genes. The patterns of these changes are complex and heterogeneous. There is no single unifying alteration. Kinases involved in mitotic regulation are particularly enriched in the pool of differentially expressed kinases. Some of these are overexpressed and are therefore possible targets for kinase inhibitors.Modern Pathology advance online publication, 1 February 2013; doi:10.1038/modpathol.2012.242.Modern Pathology 02/2013; 26. DOI:10.1038/modpathol.2012.242 · 6.36 Impact Factor
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ABSTRACT: Beta-catenin is a multifunctional protein with critical roles in cell-cell adhesion, Wnt-signaling and the centrosome cycle. Whereas the roles of β-catenin in cell-cell adhesion and Wnt-signaling have been studied extensively, the mechanism(s) involving β-catenin in centrosome functions are poorly understood. β-Catenin localizes to centrosomes and promotes mitotic progression. NIMA-related protein kinase 2 (Nek2), which stimulates centrosome separation, binds to and phosphorylates β-catenin. β-Catenin interacting proteins involved in Wnt signaling such as adenomatous polyposis coli, Axin, and GSK3β, are also localized at centrosomes and play roles in promoting mitotic progression. Additionally, proteins associated with cell-cell adhesion sites, such as dynein, regulate mitotic spindle positioning. These roles of proteins at the cell cortex and Wnt signaling that involve β-catenin indicate a cross-talk between different sub-cellular sites in the cell at mitosis, and that different pools of β-catenin may co-ordinate centrosome functions and cell cycle progression.BioEssays 06/2013; · 4.84 Impact Factor