Mesenchymal Stem Cell Transplantation Has a Regenerative Effect in Ischemic Myocardium: An Experimental Rat Model Evaluated by SPECT-CT Assessment.

Translational perspective: Ischemic heart disease remains a major medical problem with high mortality rates. Beside the great efforts devoted to research worldwide and the use of numerous experimental models, an absolute understanding of myocardial infarction and tissue loss has not yet been achieved. Furthermore, the regeneration of myocardial tissue and the improvement of myocardial activity after ischemia is one of the major areas of interest in the medical (and especially cardiovascular) community. In a novel experimental rat model, the beneficial effect of mesenchymal stem cell transplantation (MSCT) in a surgically induced ischemic myocardium was documented. From a clinical perspective, this work supports the surgical administration of MSCT in the infarcted area during coronary artery bypass surgery. AIMS: The regeneration of myocardial tissue and the improvement of myocardial activity after ischemia is one of the major areas of interest in cardiovascular research. We developed a novel experimental rat model and used it to examine the effect of mesenchymal stem cell transplantation (MSCT) on myocardial ischemia evaluated by SPECT-CT and immunohistochemistry. METHODS AND RESULTS: An open thoracotomy took place for forty adult female Wistar rats with (n = 30) or without (n = 10) surgical ligation of the left anterior descending coronary artery (LAD) in order to cause myocardial ischemia. Myocardial viability was evaluated via SPECT/CT 7 days before surgery, as well as at 7 and 14 days post-surgery. At day 0, 15 animals received homologous stem cells injected at the ischemic myocardium area. A SPECT/CT evaluation showed decreased activity of the myocardial cells in the left ventricle one week post-infarction. Regeneration of the ischemic myocardium fifteen days post-infarction was recorded only in animals subjected to stem cell transplantation. These findings were also confirmed by histology and immunohistochemical analysis, with the significantly higher expression of GATA4 and Nkx2.5. CONCLUSIONS: The positive effect of mesenchymal stem cell transplantation in the ischemic myocardium was recorded. The application of SPECT-CT allowed a clear evaluation of both the quality and quantity of the living myocardium post-infarction, leading to a new approach in the research of cardiovascular diseases. From a clinical perspective, MSCT may be beneficial when accompanied by myocardial revascularization procedures.

A Novel Experimental Rat Model for the In Vivo Assessment of Myocardial Ischemia Based on Single Photon Emission Computed Tomography.

BACKGROUND/AIM: Myocardial infarction, an acute medical situation with a high mortality rate worldwide, has been extensively studied in modern cardiovascular research, using different experimental models. However, a deep understanding of myocardial activity loss has not been fully investigated. We have developed a novel experimental rat model for noninvasive assessment of myocardial ischemia based on single photon emission computed tomography (SPECT/CT), in order to further understand and evaluate myocardial activity before and after surgical induction of myocardial ischemia. MATERIALS AND METHODS: Thirty adult female Wistar rats underwent open thoracotomy with (n=20) or without (n=10) surgical ligation of the left anterior descending coronary artery (LAD). The myocardial ischemia was confirmed with ECG and myocardial viability was evaluated via SPECT/CT at 7 days before as well as at 7 and 14 days post-surgery, after which animals were sacrificed and myocardial ischemic injury was further assessed histologically. RESULTS: All animals were evaluated with anatomical and functional criteria based on the SPECT/CT imaging results. A successful surgical technique causing ischemia and loss of myocardial function in all animals undergoing a LAD ligation was established. Furthermore, evaluation of the viable myocardium with SPECT/CT confirmed the reduction of functional myocardial cells of the left ventricle post-infarction, which was also documented histologically. CONCLUSION: Using our technique, the validity of this animal model to induce and evaluate myocardial ischemia was demonstrated. Our choice to apply SPECT-CT qualitative and quantitative evaluation of myocardial function leads to a new approach in experimentation with an anticipated significant impact in the ongoing cardiovascular laboratory research.

Low Prevalence of TERT Promoter, BRAF and RAS Mutations in Papillary Thyroid Cancer in the Greek Population.

Thyroid cancer is a common endocrine malignancy and displays a variety of histological patterns ranging from adenoma to malignant tumors. Molecular diagnostics have given significant insights into the genetic basis of thyroid tumorigenesis, known to be linked with signaling pathways affected by oxidative stress. We report for the first time a genotype study of TERT promoter combined with BRAF and RAS mutations in Papillary Thyroid Cancer (PTC) cases in the Greek population. Polymerase Chain Reaction and sequencing were used to identify TERT promoter (C228T, C250T, CC243-243TT) mutations, the BRAF (T1799A) mutation and mutations in codons 12, 13, 61 of the HRAS, KRAS and NRAS genes. The most common C228T TERT promoter mutation was identified in 2 PTC cases co-existing with the BRAF mutation. The BRAF T1799A mutation was detected in 10 PTC cases, while two different NRAS mutations in codon 61 (C181A and A182G) were found in 2 PTC cases. These mutations occur in a mutually exclusive manner. Our results indicate that despite the low frequencies, the study of the specific mutations should be encouraged because they are indicative of aggressive forms of thyroid cancer of the papillary histotype in this patient cohort, thus providing insights towards their therapeutic management.

Deregulation of p53/survivin apoptotic markers correlated to PTEN expression in pterygium neoplastic cells.

PURPOSE: Pterygium is a distinct clinicopathological entity characterized by degenerated and neoplastic-like features. Concerning its rise on normal conjunctiva epithelia, the role of specific gene deregulations including apoptotic/anti-apoptotic factors and significant suppressor genes in signaling transduction pathways is under investigation. In the current study, we co-analyzed p53, survivin and PTEN proteins in pterygia and normal conjunctiva. METHODS: Using a liquid-based cytology assay, 50 cell specimens were obtained by a smooth scraping on conjunctiva epithelia and fixed accordingly. Among them, 38 were pterygia and the remaining (n=12) normal epithelia (control group). Immunocytochemistry assays were implemented on the corresponding slides by applying ani-p53, survivin, and PTEN antibodies. Digital image analysis was performed for evaluating objectively the corresponding immunostaining intensity levels. RESULTS: The majority of the examined pterygia cases overexpressed the markers p53:22/38-57.9%, survivin:30/38-78.9%, and PTEN:25/38-65.7%. Interestingly, overall p53/PTEN co-expression was found to be statistically significant (p=0.022). CONCLUSIONS: Survivin overexpression leads to an increased anti-apoptotic activity playing a central molecular role in the pathogenesis and progression of pterygia. Furthermore, although p53 expression is observed in these lesions, its impact seems to be low compared to survivin's influence on them. Additionally, the role of PTEN in the process is potentially significant providing a suppressor balance to the p53/ survivin complex.

Experimental Hemorrhagic Shock Protocol in Swine Models: The Effects of 21-Aminosteroid on the Small Intestine.

BACKGROUND: The protective potential of lazaroids has been reported in previous studies on ischemia/reperfusion and induced hemorrhagic shock protocols. OBJECTIVES: The present study is the first experimental protocol on the effects of the antioxidant factor U-74389G on the small intestine of swine models in a hemorrhagic shock protocol and resuscitation with 3 different types of fluids. METHODS: The study included 49 Landrace breed swine that were divided into groups of 7 each. Hemorrhage was provoked 45 minutes after starting the surgical protocol (0 minutes), followed by resuscitation starting 30 minutes after haemorrhage ceased by using 3 different fluids. Three groups (Group A, resuscitation using blood; Group B, resuscitation with Ringer's lactate solution; and Group C, resuscitation with hypertonic saline solution) underwent resuscitation with fluid alone, and another 3 groups (named A', B,' and C') were administered lazaroid U-74389G in addition to fluid. Control Group S underwent all the surgical procedures without hemorrhagic shock. Vital signs, complete blood count, and biochemical markers were analyzed, and tissue samples of the small intestine were collected from all animals. Further, malondialdehyde, tumor necrosis factor-α, and levels of inflammation in the tissue sample were measured. RESULTS: In Group S-A-A' and Group S-C-C', the analysis did not show statistically significant differences in the percentage changes of histopathology, malondialdehyde, and tumor necrosis factor-α through time. In Group S-B-B', the malondialdehyde levels in the small intestine were reduced in both the B and B' groups, without lazaroid (Group B) (P = 0.038) and lazaroid (Group B') (P = 0.011), compared with Group S (control), but the group without lazaroid (Group B) had greater reduction in malondialdehyde levels than the group treated with lazaroid (Group B'). With regard to the biochemistry results, 24% reduction was observed for alkaline phosphatase (P = 0.022) in Group A' treated with lazaroid compared with that in the untreated group. Lastly, for the complete blood count parameters, a 14% reduction in white blood cells was observed in Group B', which was treated with lazaroid in all phases (P = 0.015) (absolute value = 6.23) compared with Group B (absolute value = 13.74). CONCLUSIONS: Despite few initial findings of this study suggesting that administration of lazaroid U-74389G may have some potential in attenuation of the effects of hemorrhagic shock in the small intestine of swine models, no differences remained after correction for multiple comparisons was made. Therefore, further research is required to investigate this result thoroughly.

Numerical Imbalances of Chromosome 7 in Oral Squamous Cell Carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is an aggressive neoplasm. Many chromosomal and gene alterations have been identified in OSCC, including structural and numerical changes. In this study, we implemented a molecular assay of chromosome 7 (Chr7) in order to investigate the level of its numerical instability in OSCC. MATERIALS AND METHODS: Using tissue microarray technology, 30 primary OSCCs were cored and re-embedded into one recipient block. Chromogenic in situ hybridization assay was performed based on Chr7 centromeric probedetection. RESULTS: Chr 7 numerical analysis detected polysomy (trisomy/ tetrasomy) in 4/30 (13.3%) of the examined tissue OSCC cores. Statistical significance was assessed correlating Chr7 numerical aberrations with stage (p=0.015), especially detected in cases not related to human papillomavirus (HPV) (p=0.01). CONCLUSION: Although Chr7 polysomy is a relatively rare gross genetic event in OSSC, it affects their biological behavior leading toa progressively aggressive phenotype (advanced stage). Furthermore, Chr7 polysomy is observed more frequently in non-viral (HPV) cases.

Deregulation of PTEN Expression in Laryngeal Squamous Cell Carcinoma Based on Tissue Microarray Digital Analysis.

BACKGROUND/AIM: Phosphatase and tensin homolog (PTEN) (gene locus: 10q23.3) -a tumor suppressor gene- is deleted, mutated or epigenetically hyper-methylated in a variety of malignancies. PTEN acts as a negative regulator in PI3K/AKT/mTOR signaling transduction pathway. Our aim was to investigate PTEN protein expression patterns in laryngeal squamous cell carcinomas (LSCC). MATERIALS AND METHODS: Using tissue microarray technology, fifty (n=50) primary LSCCs were cored and re-embedded into one recipient block. Immunohistochemistry and digital image analysis were implemented for evaluating protein expression levels. RESULTS: Abnormal protein expression (low to negative staining intensity values) was observed in 28/50 (56%) tissue cores. Overall PTEN expression was associated with the anatomical region of the malignancies (p=0.039), whereas a borderline correlation with the differentiation grade was also assessed (p=0.05). CONCLUSION: Aberrant expression of PTEN tumor-suppressor gene in LSCCs seems to affect their biological behavior. Well-differentiated tumors express moderate to high protein levels, an evidence of normal gene function, whereas loss of its expression correlates with a progressive tumor dedifferentiation. Additionally, loss of its expression is detected more frequently in specific anatomical regions of the larynx (glottis, predominantly, and partially supraglottis).

Topoisomerase I deregulation in laryngeal squamous cell carcinomas based on tissue microarray analysis.

PURPOSE: Topoisomerases (types: I/IIa-b/IIIa-b) represent a super-family of nucleic enzymes involved in the DNA replication, transcription, recombination, and also chromosome topological formation. Topoisomerase's I (Topo I- gene location: 20q12) aberrant expression is a frequent genetic event in a variety of solid malignancies. Topo I inhibition promotes cell death due to DNA damage and for this reason it is a target for specific targeted chemotherapy (camptothecin, topotecan, irinotecan). Our aim was to investigate the role of abnormal Topo I protein expression in laryngeal squamous cell carcinomas (LSCC) in which there are very limited data regarding the influence of the marker. METHODS: Using tissue microarray (TMA) technology, 50 formalin-fixed, paraffin-embedded primary laryngeal SCCs were cored and re-pembedded into one recipient block. Immunohistochemistry was performed using anti- Topo I antibody. Digital image analysis was also implemented for evaluating objectively the protein expression levels on the corresponding stained nuclei. RESULTS: Topo I protein overexpression (moderate to high staining intensity values) was observed in 32/50 (64%) tissue cores, whereas low expression rates were detected in 18/50 (36%) cases. Topo I overall expression was strongly associated with the differentiation grade of the examined tumors (p=0.021). No other statistical correlations were identified. CONCLUSIONS: Topo I overexpression is observed in a significant subset of LSCCs affecting the level of differentiation in them. Additional molecular studies focused on the mechanism of Topo I gene/protein deregulation (i.e. amplification, abnormal epigenetic promoter methylation, mRNA aberrant expression) are necessary discriminating the eligible patients for applying specific chemotherapeutic strategies based on anti-Topo I agents.

Chromosome 7 Multiplication in EGFR-positive Lung Carcinomas Based on Tissue Microarray Analysis.

BACKGROUND/AIM: Epidermal growth factor receptor (EGFR) over-activation is observed in significant proportions of non-small cell lung carcinomas (NSCLC). Our aim was to investigate the role of chromosome 7 multiplication with regard to its influence in EGFR expression, combined or not with gene amplification. MATERIALS AND METHODS: Using tissue microarray technology, fifty (n=50) primary NSCLCs were cored and re-embedded into the final recipient block. Immunohistochemistry (IHC) and also chromogenic in situ hybridization (CISH) were performed. RESULTS: EGFR expression at any level was detected in 40/50 (80%) cores. Over-expression was observed in 23/40 (57.5%) cases. Gene amplification was identified in 11/50 (22%) cases whereas chromosome 7 polysomy in 8/50 (16%) cases. Pure chromosome 7 multiplication alone led to low or moderate levels of expression. Overall EGFR expression was correlated with gene (p=0.001) and interestingly with chromosome 7 centromere numerical imbalances (p=0.004). CONCLUSION: EGFR expression is associated not only with amplification, but also with chromosome 7 centromere multiple copies. Chromosome 7 multiplication -due to centromere region amplification or true polysomy- is critical for applying monoclonal antibody targeted therapeutic strategies excluding the pure non-amplified cases.

Epithelial-Mesenchymal Transition in Non Small-cell Lung Cancer.

BACKGROUND/AIM: Lung cancer is the first cause of cancer related deaths in both males and females. Epithelial-mesenchymal transition (EMT) is a reversible process by which epithelial cells transform to mesenchymal stem cells by losing their cell polarity and cell-to-cell adhesion, gaining migratory and invasive properties. High levels of E-cadherin are expressed in epithelial cells, whereas mesenchymal cells express high levels of N-cadherin, fibronectin and vimentin. The aim of this study was to evaluate the correlation between E-cadherin and vimentin expression and their clinical significance in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: The immunohistochemical expression of E-cadherin, vimentin and Ki-67 was performed on tissue microarrays from NSCLC specimens obtained from 112 newly- diagnosed cases and were studied using classical pathological evaluation. Associations between E-cadherin, vimentin and Ki-67 expression, clinicopathological variables and survival were analyzed. In all cases, a value of p≤0.05 was considered significant. RESULTS: Low E-cadherin expression was significantly correlated with tumor necrosis (p=0.019). Moreover, there was a trend for correlation between high E-cadherin expression and better overall survival (hazard ratio=1.02, and 95% confidence interval=0.45-1.87, p=0.091). There was also a significant negative correlation between vimentin expression and overall survival (hazard ratio=1.13, and 95% confidence interval=0.78-1.65, p=0.026). Additionally, there was a significant negative correlation between vimentin expression and grade I tumors (p=0.031). Finally, a positive correlation trend between vimentin expression and Ki-67 was found (p=0.073). CONCLUSION: High E-cadherin and low vimentin expression correlate with better prognosis and overall survival.

Lower adenoma miss rate with FUSE vs. conventional colonoscopy with proximal retroflexion: a randomized back-to-back trial.

Background and study aims Full-spectrum colonoscopy (FSC) promises to increase adenoma detection by providing a wider field of view. The aim of this study was to compare adenoma miss rates of FSC with those of conventional colonoscopy complemented by right-colon re-examination using scope retroflexion (CC/R). Patients and methods At two tertiary endoscopy facilities, patients who were scheduled for colonoscopy for the assessment of symptoms or for colorectal cancer screening/surveillance were randomized (1:1) to undergo same-day, back-to-back colonoscopies (FSC or CC/R first), performed by one of five endoscopists who had documented adenoma detection rates > 35 %. Per-protocol data were analyzed. Results We randomized 220 patients. There were five FSC technical failures (three air pump and two left screen); therefore, 107 and 108 cases were analyzed in the FSC and CC/R index procedure arms, respectively. Withdrawal times were similar for FSC and CC/R (7.7 minutes vs. 7.6 minutes). Overall, we detected 3 cancers and 153 adenomas (FSC = 92; CC/R = 61); 81 were detected in the proximal colon, 3 of which were detected by retroflexed examination. By per-lesion analysis, FSC showed a significantly lower adenoma miss rate compared with CC/R overall (10.9 % [95 % confidence interval (CI) 3.8 to 18.1] vs. 33.7 % [95 %CI 23.4 to 44.1]) and in the proximal colon (13.9 % [95 %CI 2.6 to 25.2] vs. 42.2 % [95 %CI 27.8 to 56.7]). The advanced adenoma miss rate was lower with FSC overall (4.3 % [95 %CI - 4.0 to 12.7] vs. 25.9 % [95 %CI 9.4 to 42.5]). There were no adverse events. Conclusions FSC outperformed conventional colonoscopy with right-colon scope retroflexion in the detection of missed adenomas, both overall and in the proximal colon, even when performed by experienced endoscopists.Trial registered at ClinicalTrials.gov (NCT02117674).

E-cadherin/α-catenin deregulated co-expression in thyroid carcinoma based on tissue microarray digital image analysis.

PURPOSE: Deregulation of cell-to-cell adhesion molecules is a common and also critical genetic event in epithelial malignancies leading to an increasing metastatic potential. Among them, e-cadherin and catenins--especially α and ß--, act as oncogenes during the carcinogenetic process affecting specific signaling transduction pathways (i.e. Wnt/ b-catenin). Concerning thyroid carcinoma, decreased or loss of expression in these proteins seems to affect the biological behavior of the neoplasm increasing its aggressiveness. The aim of this study was to investigate the deregulation of e-cadherin/α-catenin complex in thyroid carcinomas. METHODS: Thirty-five paraffin-embedded tissue samples including thyroid carcinomas (N=20) and also 15 cases of benign follicular nodules were cored at 1 mm diameter and transferred to a microarray block. Immunohistochemistry (IHC) was performed using anti-e-cadherin/α-catenin antibodies. Digital image analysis was also implemented for measuring the corresponding protein expression levels. RESULTS: E-cadherin/α-catenin protein expression demonstrated a significant progressive decrease regarding benign and malignant lesions (p=0.001). Simultaneous e-cadherin/α-catenin reduced or loss of expression was observed in 10/20 (50%) cancer cases correlated to advanced stage (especially nodal metastasis) of the examined tumours (p=0.02). Concerning the histological type, combined loss of e-cadherin/α-catenin expression was predominantly associated with follicular and anaplastic histology (p=0.001). Interestingly, α-catenin protein expression pattern was significantly correlated with the grade of differentiation of the examined malignancies (p=0.01). CONCLUSIONS: Progressive loss of e-cadherin mainly and also α-catenin expression is associated with an aggressive phenotype (low differentiation, increased metastatic activity/advanced stage) in thyroid carcinomas. Based on their aberrant protein expression, novel agents have been developed for restoring their normal function.

Pathogenesis of Gastric Cancer.

Gastric cancer (GC) is the fifth most common malignancy and the third leading cause of cancer-related death worldwide. GC is a heterogeneous disease and the endpoint of a long multistep process largely influenced by Helicobacter pylori infection, genetic susceptibility, and environmental factors. In a subset of GC cases, infection with the Epstein-Barr virus (EBV) may also be involved. The development of GC is the consequence of the accumulation of multiple epi/genetic changes during the patient's lifetime that will result in oncogenic activation and/or tumor suppressor pathways' inactivation. This review will focus on the most recent updates on the characterization of the molecular phenotypes of sporadic and hereditary GC. This article will also update the most recent findings on the relationship between H. pylori infection and stem cells at the origin of GC. The understanding of the molecular genetics underlying gastric carcinogenesis is of paramount importance to identify novel potential targets for the development of screening and prognostic markers that can be clinically valuable for the management of GC patients and for the design of clinical trials.

Hemiepiphysiodeses for guided growth in children.

Lower-extremity angular deformities are among the most common non-traumatic conditions in children being referred to pediatric orthopedists. Understanding of this abnormality and knowledge of current treatment is essential for pediatricians and primary caregivers. A development in the surgical management of these problems has improved the quality of care of affected children and adolescents. Traditionally, angular deformities are treated by means of osteotomy. In patients who are skeletally immature, this major intervention can be avoided by influencing or guiding the growth of the affected physis using hemiepiphysiodesis techniques. Recently, alternative surgical techniques and implants have been described for improved control of the guided growth.

The clinical and pathological significance of RCAS1 expression as a prognostic biomarker in non-small cell lung cancer.

BACKGROUND: Lung cancer remains a major health problem due to its incidence and mortality. Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a protein that can be expressed in cancer cells and is involved in tumor cell escape from immune system surveillance. AIM: The aim of this study was to evaluate the clinical significance of immunohistochemical staining for RCAS1 in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Tissue microarrays of tumor specimens from 112 consecutive patients with newly diagnosed primary NSCLC were constructed. RCAS1 and Ki-67 immunohistochemistry were studied through computerized image analysis. Associations between RCAS1 and Ki-67 expression and clinico-pathological variables and survival were analyzed. RESULTS: RCAS1 expression was higher in grade III tumors (p=0.009), regardless of the histological type, and in adenocarcinomas with lymphovascular invasion (p=0.014). A positive correlation between RCAS1 and Ki-67 levels was observed (p=0.002). Moreover, there was an inverse correlation of overall survival with RCAS1 (hazard ratio=0.99, p<0.001) and Ki-67 (hazard ratio=1.05, p=0.003) levels. Particularly, patients with higher expression of RCAS1 or Ki-67 had a significantly shorter survival than those with lower expression. CONCLUSION: RCAS1 could be a useful immunohistochemical biomarker, indicating not only tumor aggressiveness but also a poorer prognosis for patients with NSCLC.

Impact of HPV detection in colorectal adenocarcinoma: HPV protein and chromogenic in situ hybridization analysis based on tissue microarrays.

PURPOSE: Human papillomaviruses (HPV)-mediated cervical carcinogenesis represents a well analyzed model of viral implication in epithelial malignant transformation. Concerning colorectal cancer, HPV infection seems to be a significant genetic event in squamous colon epithelia carcinogenesis, but with an unclear role in colon adenocarcinomas (CACs). In the current study, we analyzed 60 CACs based on tissue microarray (TMA) blocks. METHODS: Cancerous tissues were cored, embedded on a tissue microarray block and analyzed by immunohistochemistry (HPV IHC) and also by chromogenic in situ hybridization (HPV 16/18 DNA CISH) in repetitive serial sections for protein and DNA specific typing detection, respectively. RESULTS: Based on HPV IHC and CISH simultaneous analysis, 16 (26.6%) cases expressed HPV protein. In 7 (11.6%) cores HPV 16/18 DNA signals were detected. Overall HPV protein expression and stage of the examined cases were significantly correlated with HPV CISH results (p=0.0001, p=0.022, respectively). CONCLUSION: A subset of CACs demonstrated HPV infection associated with stage. In particular, detection of 16/18 HPV DNA types seemed to be a molecular parameter in analyzing genetically CACs, in contrast to HPV protein expression which did not offer significant and specific molecular information.

HER2/CHR 17 tissue microarray chromogenic in situ hybridization analysis in colon adenocarcinoma: multiple gene signals vs protein expression.

PURPOSE: HER2-dependent signalling pathway is deregulated in a subset of colon adenocarcinomas. Although HER2 protein expression patterns demonstrate a broad diversity in these tumors, the critical parameter for targeting the gene is the detection of gene amplification. Our aim was to investigate the correlation between HER2 protein levels and chromosome 17 (chr 17) copies. METHODS: Sixty paraffin-embedded samples of primary colon adenocarcinomas were cored at 1 mm diameter and transferred to the microarray block. Immunohistochemistry (IHC) was performed using anti-HER2 monoclonal antibody. Chromogenic in situ hybridization (CISH) was performed using HER2 gene/chromosome 17 centromeric probes. RESULTS: HER2 protein overexpression (score: 2+/3+) was observed in 20/60 (33.3%) samples. CISH analysis detected 11/60 (18.33%) amplified cases, whereas chromosome 17 aneuploidy (polysomy) was identified in 13/60 (21.66%) cases. Significant associations were detected correlating HER2 expression with grade of the tumors (p=0.03), Chr 17 with stage (p=0.01), gene copies with protein expression (p=0.008), and also Chr 17 centromere signals with overall gene signals (p=0.001). CONCLUSION: Multiple HER2 gene copies lead to different protein expression patterns (score 1+ to 3+) but pure gene amplification is only a subset of them. Identification of chromosome polysomy is a critical parameter in detecting original gene amplification in conventional one-color CISH methods.