Comparative Expression Analysis of TP53 Tumor Suppressor and MDM2 Oncogene in Colorectal Adenocarcinoma.

Background/Aim: The tumor protein 53 (TP53) tumor suppressor protein (17p13.1) acts as a significant regulator for the cell cycle normal function. The gene is frequently mutated in colorectal adenocarcinoma (CRC) patients and is associated to poor prognosis and low response rates to chemo-targeted therapy. Our purpose was to correlate TP53 expression with Mouse Double Minute 2 Homolog (MDM2), a proto-oncogene (12q14.3) and a major negative regulator in the TP53-MDM2 auto-regulatory pathway. Materials and Methods: A total of forty (n=40) colorectal adenocarcinoma (CRC) cases were included in this study. An immunohistochemistry-based assay was implemented by using anti-TP53 and anti-MDM2 antibodies in the corresponding tissue sections. Additionally, a digital image analysis assay was implemented for objectively measuring TP53/MDM2 immunostaining intensity levels. Results: TP53 protein overexpression was detected in 27/40 (67.5%), whereas MDM2 overexpression in 28/40 (70%) cases. Interestingly, in 21/40 (52.5%) cases, a combined TP53/MDM2 co-expression was detected, whereas in 6/40 (15%), a combined loss of expression was identified (overall co-expression: p=0.119). p53 overexpression was significantly correlated to grade of the examined cases (p=0.001), whereas MDM2 to stage and max diameter of the malignancies (p=0.001 and 0.024, respectively). Conclusion: TP53/MDM2 over expression is a frequent and significant genetic event in CRCs associated with an aggressive biological behavior, as a result of increased dedifferentiation grade and advanced stage/elevated tumor volume, respectively. MDM2 oncogene overactivation combined with mutated and overexpressed TP53 is observed in sub-groups of patients leading to specific gene/protein signatures - targets for personalized chemotherapeutic approaches.

PTEN Deregulation Mechanisms in Salivary Gland Carcinomas.

Among the tumour suppressor genes that affect critically cell functions and homeostasis, phosphatase and tensin homolog deleted in chromosome 10 (PTEN- gene locus: 10q21) regulates the PI3K/Akt/mTOR signalling pathway. PTEN is deleted, mutated or epigenetically hyper-methylated in a variety of human solid malignancies. Salivary gland carcinomas (SGCs) belong to the head and neck carcinomas (HNCs) super category of solid malignancies. Histo-pathologically, they demonstrate a significant diversity due to a variety of distinct and mixed subtypes. Genetically, they are characterized by a broad spectrum of gene and chromosomal imbalances. Referring specifically to suppressor genes, PTEN deregulation plays a critical role in signaling transduction in the corresponding SGC pre- and malignant epithelia modifying the response rates to potential targeted therapeutic strategies. In the current review, we explored the role of PTEN deregulation mechanisms that are involved in the onset and progression of SGCs.

Impact of Amplified Oncogenes on Salivary Gland Carcinomas.

In normal epithelia, proto-oncogenes regulate critical intra- or intercellular functions, including cell growth and proliferation, apoptosis, and signaling transduction from the cell periphery (extracellular space) to the nucleus mediated by different pathways. Oncogenes are the mutated or amplified forms of the corresponding proto-oncogenes that are crucially involved in cell neoplastic and malignant transformation during carcinogenesis. Salivary gland carcinomas (SGCs) demonstrate a variety of histogenetic types. They are characterized by a broad spectrum of chromosomal and gene alterations. In particular, amplifications in specific genes [human epidermal growth factor receptor 2 (HER2), human epidermal growth factor receptor 4 (HER4), epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), Mouse double minute 2 homolog (MDM2), androgen receptor (AR), programmed death (ligand 1 (PD-L1), neurogenic differentiation factor 2 (NEUROD2), phosphatidylinositol 3,4,5-trisphosphate-dependent RAC exchanger 1 protein (PREX1), cyclin-dependent kinase4/6 (CDK4/6), proline-rich acidic protein 1 (PRAP1), kell antigen system (KEL), glutamate receptor subunit epsilon 2 (GRIN2D), Ewing sarcoma RNA-binding protein 1 (EWSR1), MYC proto-oncogene (MYC)] combined or not with chromosomal numerical imbalances (aneuploidy/ polysomy/monosomy) form different genetic signatures affecting the response to monoclonal antibody-based, oncologicaly targeted regimens. Different SGC histotypes demonstrate specific combinations of mutated/amplified genes that modify their clinicohistological features. In the current molecular review, we present the most important amplified oncogenes and their impact on the biological behavior of SGCS.

Calpain-mediated Mechanoptosis in Breast Adenocarcinoma.

Calpains belong to a family of important calcium-dependent cysteine proteases. They are involved in intracellular processes including cytoskeleton disorganization and substrate proteolysis. They also enhance apoptosis and cell to cell adhesion. Calpains demonstrate also a mechanosensory function in neoplastic and malignant cells due to their implication in mechanoptosis. This is a specific type of apoptotic death induced by strong external mechanical stimuli. Anti-cytoskeleton rigidity inhibition strategies based on calpain induction lead to increased apoptosis of tumor transformed cells. Elevated intracellular calcium concentration mediated by specific receptors and channels activates calpains. In the current molecular review, we explored the role of calpains in calcium-dependent signa transduction pathways in breast adenocarcinoma in conjunction with novel agents that activate their important anti-tumor functions.

DNA Mismatch Repair System Imbalances in Breast Adenocarcinoma.

DNA mismatch repair system (MMR) is considered a leading genetic mechanism in stabilizing DNA structure and maintaining its function. DNA MMR is a highly conserved system in bacteria, prokaryotic, and eukaryotic cells, and provides the highest protection to DNA by repairing micro-structural alterations. DNA MMR proteins are involved in the detection and repair of intra-nucleotide base-to-base errors inside the complementary DNA strand recognizing the recently synthesized strand from the parental template. During DNA replication, a spectrum of errors including base insertion, deletion, and miss-incorporation negatively affect the molecule's structure and its functional stability. A broad spectrum of genomic alterations such as promoter hyper methylation, mutation, and loss of heterozygosity (LOH) in MMR genes including predominantly hMLH1, hMSH2, hMSH3, hMSH6, hPMS1, and hPMS2 lead to their loss of base-to-base error repairing procedure. Microsatellite instability (MSI) refers to the DNA MMR gene alterations that are observed in a variety of malignancies of different histological origins. In the current review, we present the role of DNA MMR deficiency in breast adenocarcinoma, a leading cancer-based cause of death in females worldwide.

Epigenetic Mechanisms in Breast Adenocarcinoma: Novel DNA Methylation Patterns.

Breast adenocarcinoma is a leading cause of death in females worldwide. A broad spectrum of genetic and epigenetic alterations has been already identified and reported in millions of examined cancerous substrates, evidence of a high-level genomic heterogeneity that characterizes these malignancies. Concerning epigenetic changes and imbalances that critically affect progression and prognosis in the corresponding patients, DNA methylation, histone modifications (acetylation), micro-RNAs (miRs) alterations and chromatin re-organization represent the main mechanisms. Referring to DNA methylation, promoter hyper-hypo methylation in critical tumour suppressor and oncogenes is implicated in normal epithelia transformation to their neoplastic and finally malignant cyto-phenotypes. The current review is focused on the different methylation patterns and mechanisms detected in breast adenocarcinoma and their impact on the corresponding groups of patient response to specific chemotherapeutic regimens and life span prognosis.

P53 Suppressor Gene Tissue Microarray-based Protein Expression Analysis in Meningiomas.

BACKGROUND/AIM: Meningiomas represent the main intracranial primary central nervous system (CNS) tumour in adults worldwide. Oncogenes' over-activation combined with suppressor genes' silencing affect negatively the biological behavior of these neoplasms. This study aimed to explore the impact of p53 suppressor gene expression in meningiomas' clinic-pathological features based on a combination of sophisticated techniques. MATERIALS AND METHODS: Fifty (n=50) meningiomas were included in the study, comprising a broad spectrum of histopathological subtypes. An immunohistochemistry assay was applied on tissue microarray cores followed by digital image analysis. RESULTS: p53 protein over-expression (high staining intensity levels) was observed in 27/50 (54%) cases, whereas the rest (23/50-/46%) demonstrated moderate to low levels of the protein. p53 over-expression was statistically significantly correlated to the mitotic index of the examined cases (p-value=0.001). Interestingly, the atypical/anaplastic group of histotypes demonstrated the strongest p53 expression rates compared to the others (p-value=0.001). CONCLUSION: p53 overexpression is observed in a broad spectrum of meningiomas. High expression levels lead to an aggressive biological behavior of the malignancy (combined with increased mitotic rates), especially in atypical and anaplastic sub-types that also have a high recurrence rate.

Impact of Ubiquitination Signaling Pathway Modifications on Oral Carcinoma.

Among intra-cellular homeostasis mechanisms, ubiquitination plays a critical role in protein metabolism regulation by degrading proteins via activating a broad spectrum of ubiquitin chains. In fact, ubiquitination and sumoylation signaling pathways are characterized by increased complexity regarding the molecules and their interactions. The Ubiquitin-Proteasome System (Ub-PS) recognizes and targets a broad spectrum of protein substrates. Ubiquitin conjugation modifies each substrate protein determining its biochemical fate (degradation). A major functional activity of Ub-PS is autophagy mechanism regulation. Interestingly, Ub-PS promotes all stages of bulk autophagy (initiation, execution, and termination). Autophagy is a crucial catabolic process that provides protein degradation and for this reason the interaction with Ub-PS is crucial. Furthermore, ubiquitination controls and regulates specific types of protein targets. Ub-PS is also involved in oxidative cellular stress and DNA damage response. Additionally, the functional role of Ub-PS in ribosome machinery regulation seems to be crucial. Concerning carcinogenesis, Ub-PS is involved in malignant disease development and progression by negatively affecting the corresponding TGF-B-, MEEK/MAPK/ERK-JNK- dependent signaling pathways. In the current review article, we describe the role of Ub-PS biochemical modifications and alterations in oral squamous cell carcinoma (OSCC).

Impact of SARS-CoV-2 infection on oral carcinoma patients.

Coronavirus-related Severe Acute Respiratory Syndrome (SARS-CoV) in 2002/2003, Middle-East Respiratory Syndrome (MERS-Cov) in 2012/2013, and especially the current 2019/2020 Severe Acute Respiratory Syndrome-2 (SARS-CoV-2) tested the national health systems' endurance worldwide. In order to fight this emergency situation, a variety of pharmaceutical companies focused on the design and development of efficient vaccines that are considered necessary for providing a level of normalization in totally affected human social-economical activity worldwide. COVID-19 led to an increased uncertainty in the field of oncological patients' management disrupting the normal conditions of therapeutic and monitoring procedures. In the current article, we explored the impact of SARS-CoV-2 infection on oral carcinoma patients. We observed COVD-19 pandemic negatively affects the normality regarding early diagnosis and optimal management (surgical operation, post-operational follow up/monitoring) in HNSCC/OSCC patients. Understanding the involvement of SARS-CoV-2 in the progression of malignancies is the first critical step for targeting the virus by efficient monoclonal antibodies and vaccines.

Chromogenic in situ hybridization analysis of Epidermal Growth Factor Receptor gene/chromosome 7 numerical aberrations in hepatocellular carcinoma based on tissue microarrays.

Although Epidermal Growth Factor Receptor (EGFR) overexpression is observed frequently in hepatocellular carcinomas (HCC), specific gene deregulation mechanisms remain unknown. Our aim was to investigate the prognostic significance of the combined protein and gene/chromosome 7 numerical alterations. Using tissue microarray technology, thirty-five (n = 35) paraffin embedded histologically confirmed HCCs were cored and re-embedded in a paraffin block. Immunohistochemistry was performed for the determination of EGFR protein levels and evaluated by the performance of digital image analysis. Chromogenic in situ hybridization was also performed based on the use of EGFR gene and chromosome 7 centromeric probes, respectively. EGFR overexpression was observed in 26/35 (74.2%) cases and was correlated to the grade of the tumors and also to the history of the patients (p = 0.013, p = 0.036, respectively). Numerical alterations regarding gene and chromosome 7 were identified in 4/35 (11.4%) and 12/35 (43.2%) cases associated to the grade of the tumors (p = 0.019, p = 0.001, respectively) and to the survival rate of the patients (p = 0.037, p = 0.001, respectively). EGFR overall expression was also correlated to the gene copies (p = 0.020). EGFR gene numerical alterations -although rare- and also chromosome 7 aneuploidy maybe affect prognosis in HCC patients. To our knowledge this is the first chromogenic in situ hybridization analysis based on tissue microarrays in hepatocellular carcinoma.

EGFR alterations in pancreatic ductal adenocarcinoma: a chromogenic in situ hybridization analysis based on tissue microarrays.

BACKGROUND/AIMS: To evaluate epidermal growth factor receptor (EGFR) gene status in pancreatic ductal adenocarcinoma correlating the results to protein expression and clinicopathological features METHODOLOGY: Using tissue microarray technology (TMArrayer 100), fifty (n = 50) paraffin-embedded tissue samples of histologically-confirmed primary tumors were cored twice at a diameter of 1 mm and re-embedded into the final recipient block. Immunohistochemistry was performed by the use of anti-EGFR monoclonal antibody (31G7). Also, a chromogenic in situ hybridization protocol was applied based on the use of EGFR gene and chromosome 7 centromeric probes, respectively. RESULTS: EGFR protein overexpression was observed in 29/50 (58%) cases and correlated to stage (p = 0.001) but not to grade (p = 0.206). EGFR gene analysis identified numerical alterations in 6/50 (12%), including 2 cases characterized by low-level gene amplification and 4 by absence of one allele. Gene status was associated to tumor grade (p = 0.023) and stage (p = 0.02). Chromosome 7 analysis detected aneuploidy in 14 (28%) cases. CONCLUSIONS: A subset of pancreatic ductal adenocarcinomas (PDACs) is characterized by EGFR gene numerical alterations including sporadic cases of amplification or absence of one allele (maybe due to gene deletion or intragenic point mutation and allelic silence). Those alternative mechanisms maybe influence the efficacy of novel targeted therapeutic strategies based on monoclonal antibodies or intracellular tyrosine-kinase inhibitors in PDACs.