Growth kinetics of colorectal adenoma-carcinoma sequence: an immunohistochemical study of proliferating cell nuclear antigen expression

Molecular interplay between EIF4 family and circular RNAs in cancer: Mechanisms and therapeutics

The eukaryotic translation initiation factor 4 (EIF4) family is a major contributor to the recruitment of mRNAs to ribosomes during the initial translation stage in eukaryotes, whose dysregulation either allows for cancer transformation or prevents disordered cancerous cell growth. Circular RNAs (circRNAs), which exhibit distinctive structures and are widely expressed in eukaryotes, are anticipated to be a clinical diagnostic biomarker for cancer therapy. There is considerable evidence that EIF4s can influence the biogenesis, transport, and function of circRNAs and, in turn, circRNAs can control the expressions of EIF4s through certain molecular pathways. Herein, we primarily review the emerging studies of the EIF4 family and pinpoint the roles of dysregulated EIF4s in cancer. We also evaluate the patterns of intricate interactions between circRNAs and EIF4s and discuss the potential utility of circRNA-based therapeutics targeting EIF4s in clinical cancer research.

Green Synthesized Gold and Silver Nanoparticles Increased Oxidative Stress and Induced Cell Death in Colorectal Adenocarcinoma Cells

The research investigated the effect of gold (Au-CM) and silver nanoparticles (Ag-CM) phytoreduced with Cornus mas fruit extract (CM) on a human colorectal adenocarcinoma (DLD-1) cell line. The impact of nanoparticles on the viability of DLD-1 tumor cells and normal cells was evaluated. Oxidative stress and cell death mechanisms (annexin/propidium iodide analysis, caspase-3 and caspase-8 levels, p53, BCL-2, BAX, NFkB expressions) as well as proliferation markers (Ki-67, PCNA and MAPK) were evaluated in tumor cells. The nanoparticles were characterized using UV-Vis spectroscopy and transmission electron microscopy (TEM) and by measuring zeta potential, hydrodynamic diameter and polydispersity index (PDI). Energy dispersive X-ray (EDX) and X-ray powder diffraction (XRD) analyses were also performed. The nanoparticles induced apoptosis and necrosis of DLD-1 cells and reduced cell proliferation, especially Ag-CM, while on normal cells, both nanoparticles maintained their viability up to 80%. Ag-CM and Au-CM increased the expressions of p53 and NFkB in parallel with the downregulation of BCL-2 protein and induced the activation of caspase-8, suggesting the involvement of apoptosis in cell death. Lipid peroxidation triggered by Ag-CM was correlated with tumor cell necrosis rate. Both nanoparticles obtained with phytocompounds from the CM extract protected normal cells and induced the death of DLD-1 tumor cells, especially by apoptosis.

Reduction in Gastrointestinal Cancers in Cirrhotic Patients Receiving Rifaximin vs Lactulose Only Therapy for Hepatic Encephalopathy

Background Rifaximin and/or lactulose therapy is widely used in cirrhotic patients for the prevention and treatment of hepatic encephalopathy. The incidence of gastrointestinal cancers in these patients on lactulose, rifaximin, and/or combination therapy is unknown. We investigated the possible effect of lactulose and rifaximin on cancer risk in patients with cirrhosis using the MarketScan database. Methods A retrospective cohort study was conducted using the Truven Health MarketScan Commercial Claims databases from 2007-2017. An index date was defined for each participant as the earliest date of cirrhosis diagnosis. A baseline period for each participant was defined as the 12 months prior to the first medication date while the study follow-up period represented the period from the initiation of the medication to its cessation. ANOVA was used to compare all continuous measures of age and duration of medication. Wald Chi-square tests were performed to test the associations between the study groups. Results A total of 12,409 patients were included in our study. The rifaximin only cohort had the greatest reduction in risk of developing colon cancer, esophageal cancer, and stomach cancer compared to the other groups. Rifaximin reduced the risk of colon cancer and esophageal cancer by 59.42% and 70.37%, respectively, compared to patients taking lactulose only. Patients in the lactulose plus rifaximin cohort had the highest rate of development of pancreatic cancer (lactulose plus rifaximin vs rifaximin only vs lactulose only, 0.45% vs 0.24% vs 0.21%; P < 0.0001) and liver and intrahepatic bile duct cancers (11.73% vs 5.84% vs 5.49%; P < 0.0001). Conclusion Colon, esophageal, and gastric cancers had a marked incidence reduction in the rifaximin only cohort compared to the other cohorts studied.

Cell-cycle and apoptosis related and proteomics-based signaling pathways of human hepatoma Huh-7 cells treated by three currently used multi-RTK inhibitors

Sorafenib, lenvatinib and regorafenib, the multi-RTK inhibitors with potent anti-angiogenesis effects, are currently therapeutic drugs generally recommended for the patients with advanced hepatocellular carcinoma (HCC). To date, however, there have been no published studies on the mechanism underling differential effects of the three drugs on HCC cell proliferation, and the proteomic analysis in HCC cell lines treated by regorafenib or lenvatinib. The present study for the first time performed a direct comparison of the cell cycle arrest and apoptosis induction in the Huh-7 cells caused by sorafenib, regorafenib and lenvatinib at respective IC₅₀ using flow cytometry technique, as well as their pharmacological interventions for influencing whole cell proteomics using tandem mass tag-based peptide-labeling coupled with the nLC-HRMS technique. Sorafenib, regorafenib and lenvatinib at respective IC₅₀ drove the remaining surviving Huh-7 cells into a G₀/G₁ arrest, but lenvatinib and regorafenib were much more effective than sorafenib. Lenvatinib produced a much stronger induction of Huh-7 cells into early apoptosis than sorafenib and regorafenib, while necrotic cell proportion induced by regorafenib was 2.4 times as large as that by lenvatinib. The proteomic study revealed 419 proteins downregulated commonly by the three drugs at respective IC₅₀. KEGG pathway analysis of the downregulated proteins indicated the ranking of top six signaling pathways including the spliceosome, DNA replication, cell cycle, mRNA surveillance, P53 and nucleotide excision repair involved in 33 proteins, all of which were directly related to their pharmacological effects on cell cycle and cell apoptosis. Notably, lenvatinib and regorafenib downregulated the proteins of PCNA, Cyclin B1, BCL-xL, TSP1, BUD31, SF3A1 and Mad2 much more strongly than sorafenib. Moreover, most of the proteins in the P53 signaling pathway were downregulated with lenvatinib and regorafenib by more than 36% at least. In conclusion, lenvatinib and regorafenib have much stronger potency against Huh-7 cell proliferation than sorafenib because of their more potent effects on cell cycle arrest and apoptosis induction. The underling mechanism may be at least due to the 33 downregulated proteins centralizing the signal pathways of cell cycle, p53 and DNA synthesis based on the present proteomics study.

The HIV reverse transcriptase Inhibitor Tenofovir suppressed DMH/HFD-induced colorectal cancer in Wistar rats

Colon rectal cancer (CRC) is the second commonest malignancy in developed countries and a significant cause of mortality. Tenofovir reportedly reduces the risk of hepatocellular carcinoma and interferes with cell cycle and cell proliferation. The current study investigated the potential antitumor effect of tenofovir against experimentally induced CRC. CRC was induced by 1,2-dimethylhydrazine (DMH, 20 mg/kg, once a week) and high-fat diet (HFD) in Wistar rats. Rats received tenofovir at a dose of 25 or 50 mg/kg (i.p.) for 24 weeks. Tenofovir-25 failed to significantly decrease the total number of dysplasia, adenoma and adenocarcinoma and to improve histopathological changes; however, tenofovir-50 resulted in no tumors seen in the colon lumen and a significant decrease in the total number of dysplasia and no adenoma or adenocarcinoma observed compared to DMH/HFD group. Tenofovir-25 failed to attenuate DMH/HFD-induced cell proliferation, whereas tenofovir-50 significantly decreased cell proliferation revealed by the decreased PCNA expression. Tenofovir-25 also failed to attenuate DMH/HFD-induced oxidative stress, whereas tenofovir-50 significantly attenuated oxidative stress as indicated by the decreased MDA concentration and SOD activity along with the increased GSH concentrations. Moreover, tenofovir-50 decreased Bcl-2 and cyclin D1 expressions in colon tissues compared with DMH/HFD group. Tenofovir-50 also significantly decreased INF-ɤ concentration in colon tissues. These findings suggest that the high dose of tenofovir (50 mg/kg) has antitumor potential against DMH/HFD-induced CRC, which might be mediated through the inhibition of cell proliferation, oxidative stress, and inflammation.

Application of Molecular Nanoprobes in the Analysis of Differentially Expressed Genes and Prognostic Models of Primary Hepatocellular Carcinoma

Analyzing hub genes related to tumorigenesis based on biological big data has recently become a hotspot in biomedicine. Nanoprobes, nanobodies and theranostic molecules targeting hub genes delivered by nanocarriers have been widely applied in tumor theranostics. Hepatocellular carcinoma (HCC) is one of the most common cancers, with a poor prognosis and high mortality. Identifying hub genes according to the gene expression levels and constructing prognostic signatures related to the onset and outcome of HCC will be of great significance. In this study, the expression profiles of HCC and normal tissue were obtained from the GEO database and analyzed by GEO₂R to identify DEGs. GO terms and KEGG pathways were enriched in DAVID software. The STRING database was consulted to find protein-protein interactions between proteins encoded by the DEGs, which were visualized by Cytoscape. Then, overall survival associated with the hub genes was calculated by the Kaplan-Meier plotter online tool, and verification of the results was carried out on TCGA samples and their corresponding clinical information. A total of 603 DEGs were obtained, of which 479 were upregulated and 124 were downregulated. PPI networks including 603 DEGs and 18 clusters were constructed, of which 7 clusters with MCODE score ≥3 and nodes ≥5 were selected. The 5 genes with the highest degrees of connectivity were identified as hub genes, and a prognostic model was constructed. The expression and prognostic potential of this model was validated on TCGA clinical data. In conclusion, a five-gene signature (TOP2A, PCNA, AURKA, CDC20, CCNB2) overexpressed inHCC was identified, and a prognostic model was constructed. This gene signature may act as a prognostic model for HCC and provide potential targets of nanotechnology.

Circ_cse1l Inhibits Colorectal Cancer Proliferation by Binding to eIF4A3

Background

Circular RNAs (circRNAs) are involved in the growth of many tumors. However, the expression and possible role of circ_cse1l (hsa_circ_0060745) in colorectal cancer (CRC) are unclear. The present study was designed to explore the role of circ_cse1l in CRC.

Material/Methods

The levels of circ_cse1l expression in cancer tissues and serum samples of 50 patients with CRC and in control subjects were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). CCK-8, colony formation, transwell and wound healing assays were performed to assess the functions of circ_cse1l in CRC cell lines after overexpression. The relationship between circ_cse1l and eIF4A3 during cell proliferation was analyzed by western blotting and RNA-binding protein immunoprecipitation (RIP).

Results

qRT-PCR assays showed that the levels of expression of circ_cse1l were lower in CRC cell lines and in tissue and serum samples from patients with CRC than in control samples. The expression of circ_cse11 in CRC tissues had clinical significance, as its level of expression was inversely associated with the depth of tumor invasion. Overexpression of circ_cse1l in HT29 and HCT116 cells markedly reduced cell proliferation and metastasis. Western blotting showed that circ_cse1l overexpression dowregulated the expression of PCNA protein. RIP results demonstrated that circ_cse1l inhibited the proliferation of CRC cells by binding to eIF4A3.

Conclusions

The expression of circ_cse1l is downregulated in CRC. Furthermore, circ_cse1l downregulated PCNA expression by binding to eIF4A3, inhibiting the proliferation of CRC cells.

MiR-34b inhibits the proliferation and promotes apoptosis in colon cancer cells by targeting Wnt/β-catenin signaling pathway

Colon cancer is one of the leading cause of cancer deaths that is severely threatening human health. Several microRNAs (miRNAs) have been found to be associated with the tumor genesis of colon cancer. The present study determined the expression of miR-34b in patients with colon cancer and studied the molecular mechanism of miR-34b in the proliferation and apoptosis of human colon cancer Caco-2 cells in vitro. In colon cancer patients, the expression of miR-34b was decreased in tumor tissues when compared with the adjacent non-tumor tissues. Furthermore, overexpression of miR-34b inhibited proliferation, migration and invasion, while promoted apoptosis in colon cancer cells. The online bioinformatics sites predicted possible regulatory genes of miR-34b and luciferase reporter assay verify that β-catenin was a direct target of miR-34b. Furthermore, miR-34b overexpression significantly decreased the expression of genes associated with Wnt/β-catenin signaling pathway. In conclusion, our results suggest that miR-34b may inhibit migration and invasion of human colon cancer cells by regulating Wnt/β-catenin signaling and miR-34b may be a key target for the treatment and diagnosis of colon cancer.

High expression of meningioma 1 is correlated with reduced survival rates in colorectal cancer patients

The identification of prognostic markers for colorectal cancer (CRC) has important clinical implications. However, the association between meningioma 1 (MN1) expression and clinical outcomes of CRC has not been fully investigated. The aim of this study was to investigate the expression of MN1 in the clinical context of CRC. We first used immunohistochemistry (IHC) staining to examine and compare MN1 expression between multiple human cancer tissues and normal tissues. Initial screening revealed that the expression of MN1 proteins was significantly higher in tumor tissues of the breast, colon, and liver than in normal tissues. In further testing conducted on 59 paired CRC samples, we observed that the expression of MN1 in CRC tissue samples was significantly higher than in adjacent normal tissues. Moreover, high MN1 expression was not significantly associated with clinicopathological characteristics. Kaplan-Meier survival analysis revealed that high expression of MN1 mRNA or MN1 protein was significantly associated with poor CRC prognosis. Furthermore, univariate Cox analysis revealed that a high MN1 score was significantly associated with prognostic factors. Multivariate Cox analysis further indicated that gender, histologic grade, tumor-node-metastasis (TNM) stage, and a high MN1 score were independent factors of overall CRC survival rates. Finally, MN1 and PCNA protein levels were positively correlated, which suggests that MN1 may be involved in the cell proliferation process during CRC formation. Our results, which confirm those of other studies, indicate that (1) high levels of MN1 expression contribute to poor CRC prognosis and (2) MN1 can serve as a novel potential biomarker in predicting the prognosis of CRC patients.

Chemopreventive efficacy zingerone (4-[4-hydroxy-3-methylphenyl] butan-2-one) in experimental colon carcinogenesis in Wistar rats

Colorectal cancer is one of the most common cancers worldwide. Development of naturally occurring inexpensive and safe alternatives can be effective in suppressing colon related proliferations. Zingerone (4-[4-hydroxy-3-methylphenyl] butan-2-one), a polyphenolic alkanone of ginger, has massive pharmacological properties and thus can be used as promising candidate against various ailments. In the current study, we aimed at demonstrating the protective effect of zingerone against experimental colon carcinogenesis and elucidating its possible mechanism by studying inflammatory and Nrf-2 signaling cascade. Four groups of animals (I-IV) were made with six animals each. Group I (control) was given normal saline orally. Group II was given 1,2-dimethylhydrazine (DMH) at the dose rate of 20 mg/kg body weight. Group III and IV were treated with DMH at the dose rate of 20 mg/kg body weight and also received oral treatment of zingerone at a dose rate of 50 and 100 mg/kg body weight, respectively, for first 5 weeks and animals were euthanized after 16 weeks. Our results reveal that DMH treated rats exhibited elevated ROS and MDA levels, increased activity of cytochrome P450 2E1 and serum marker enzyme carcinoembreyonic antigen (CEA), increased no of aberrant crypts of foci (ACF), and elevated expression of inflammatory and proliferative proteins. Nrf-2 was downregulated by DMH treatment. Treatment with zingerone to DMH treated rats, resulted in alterations in the activity of the cytochrome P450 2E1 and CEA. In addition, immunostaining of NF-kB-p65, COX-2, iNOS, and PCNA, Ki-67 was suppressed by zingerone. Furthermore, zingerone administration also attenuated the level of IL-6 and TNF-α and it also helps in preserving mucous layer. Thus, zingerone could be considered as a good chemopreventive agent in experimental model of colon carcinogenesis. Further studies are required to study other pathways involved in colon carcinogenesis and their modulation buy zingerone.

Villous Gastrointestinal Tumors: Multimodality Imaging with Histopathologic Correlation

Villous lesions are advanced adenomas that manifest most commonly in the colon; however, they can develop throughout the gastrointestinal tract. The duodenum is the most common small-bowel site of these lesions. Although in most cases these are isolated lesions that occur sporadically, patients with certain specific colorectal cancer syndromes, including familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, may develop multiple advanced adenomas. Villous lesions are important because although they are histologically benign, they may harbor dysplasia and have potential for malignancy. These characteristics make them a primary target for colorectal cancer screening with optical and virtual colonoscopy. However, these lesions can also be symptomatic and detected at diagnostic imaging when patients present for examination. They have characteristic features at a variety of imaging examinations, including barium fluoroscopy, CT, MRI, and endoscopic US. It is important for radiologists to be aware of these lesions, their potential morphologies, and their typical appearances at multimodality imaging. Although villous tumors can be detected at imaging and confirmed with biopsy, owing to limitations in identifying dysplasia and foci of malignancy with the above modalities alone and the potential for malignancy, referral for surgical resection of these lesions ultimately is required. ^©RSNA, 2018.

Prognostic significance of high YY1AP1 and PCNA expression in colon adenocarcinoma

To investigate the relationship between YY1AP1 and various clinicopathological features of colon adenocarcinoma (COAD), we conducted immunohistochemical (IHC) analyses of human tissue microarrays. We found that YY1AP1 protein expression was significantly higher in tumor tissue of the colon and liver, and was significantly lower in tumor tissue of the kidney. An analysis that employed the SurvExpress database indicated that increased expression of YY1AP1 mRNA was significantly associated with the overall survival of COAD patients. To clarify the validity of YY1AP1 or PCNA as determined by the IHC analysis was performed on 59 paired samples from COAD and adjacent normal tissue. Statistically significant differences of immunoreactivity for YY1AP1 or PCNA protein expression was observed between COAD tissue and adjacent normal tissue. High protein expression levels of YY1AP1 and PCNA were also found to be significantly correlated with M-class and distant metastasis. We also determined that YY1AP1 was correlated with PCNA expression in COAD samples, and Kaplan-Meier survival curves indicated that YY1AP1 protein expression was significantly associated with poor survival. Finally, a univariate analysis demonstrated that YY1AP1 protein expression was related to YY1AP1 score, and multivariate analysis revealed that the YY1AP1 protein expression level was an independent risk factor of overall COAD survival. Taken together, our findings indicate that YY1AP1 expression plays an important role in the tumorigenesis and progression of COAD and could serve as a clinical prognostic indicator for COAD.

Rifaximin, a non-absorbable antibiotic, inhibits the release of pro-angiogenic mediators in colon cancer cells through a pregnane X receptor-dependent pathway

Activation of intestinal human pregnane X receptor (PXR) has recently been proposed as a promising strategy for the chemoprevention of inflammation-induced colon cancer. The present study was aimed at evaluating the effect of rifaximin, a non-absorbable antibiotic, in inhibiting angiogenesis in a model of human colorectal epithelium and investigating the role of PXR in its mechanism of action. Caco-2 cells were treated with rifaximin (0.1, 1.0 and 10.0 µM) in the presence or absence of ketoconazole (10 µM) and assessed for cell proliferation, migration and expression of proliferating cell nuclear antigen (PCNA). The release of vascular endothelial growth factor (VEGF) and nitric oxide (NO), expression of Akt, mechanistic target of rapamycin (mTOR), p38 mitogen activated protein kinases (MAPK), nuclear factor κB (NF-κB) and metalloproteinase-2 and -9 (MMP-2 and -9) were also evaluated. Treatment with rifaximin 0.1, 1.0 and 10.0 µM caused significant and concentration-dependent reduction of cell proliferation, cell migration and PCNA expression in the Caco-2 cells vs. untreated cells. Treatment downregulated VEGF secretion, NO release, VEGFR-2 expression, MMP-2 and MMP-9 expression vs. untreated cells. Rifaximin treatment also resulted in a concentration-dependent decrease in the phosphorylation of Akt, mTOR, p38MAPK and inhibition of hypoxia-inducible factor 1-α (HIF-1α), p70S6K and NF-κB. Ketoconazole (PXR antagonist) treatment inhibited these effects. These findings demonstrated that rifaximin causes PXR-mediated inhibition of angiogenic factors in Caco-2 cell line and may be a promising anticancer tool.

Improved innate immune responses by Frondanol A5, a sea cucumber extract, prevent intestinal tumorigenesis

Sea cucumbers are a source of antibacterial, anti-inflammatory, and anticancer compounds. We show that sea cucumber extract Frondanol A5 is capable of enhancing innate immune responses and inhibiting intestinal tumors in APC(Min/+) mice. APC(Min/+) mice were fed semi-purified diets containing 0, 250, or 500 ppm FrondanolA5 for 14 weeks before we assessed intestinal tumor inhibition. Dietary Frondanol A5 suppressed small intestinal polyp sizes and formation up to 30% (P < 0.02) in males and up to 50% (P < 0.01) in females. Importantly, 250 and 500 ppm Frondanol A5 diet suppressed colon tumor multiplicities by 65% (P < 0.007) and 75% (P < 0.0001), compared with untreated male APC(Min/+) mice. In female APC(Min/+) mice, both dose levels of Frondanol A5 suppressed colon tumor multiplicities up to 80% (P < 0.0001). Isolated peritoneal macrophages from treated mice showed increased phagocytosis efficiency (control 24% vs. treated 50%; P < 0.01) and an increase in GILT mRNA expression, indicating increased innate immune responses by these cells in treated animals. Similarly, we observed an increase in GILT expression in treated tumors, compared with untreated tumors. Furthermore, an increase in G-CSF cytokine, a decrease in inflammatory cytokines and marker 5-LOX, its regulator FLAP, proliferation (PCNA), and angiogenesis (VEGF) markers were observed in treatment groups. These data suggest that Frondanol A5 decreased inflammatory angiogenic molecules and increased GILT expression and macrophage phagocytosis. These decreases may have improved the innate immune systems of the treated mice, thus aiding in inhibition of intestinal tumor formation. These results suggest that Frondanol A5 exhibits significant chemopreventive potential against intestinal tumorigenesis.

Immunohistochemical expression of PCNA and CD34 in colorectal adenomas and carcinomas using specified automated cellular image analysis system: a clinicopathologic study

BACKGROUND/AIM

To evaluate the immunohistochemical expression of proliferating cell nuclear antigen (PCNA) and CD34 in colorectal adenomas and carcinomas, and to correlate this expression with different clinicopathologic parameters.

MATERIALS AND METHODS

The study was retrospectively designed. A total of 86 tissue samples, including 33 paraffin blocks from patients with colorectal adenomas, 33 paraffin blocks from patients with colorectal adenocarcinomas, and a control group of 20 samples of nontumerous colonic tissue, were included in the study. From each block, 3 sections of 5 μm thickness were taken, 1 section was stained with hematoxylin and eosin (H and E) and the other 2 sections were stained immunohistochemically for PCNA and CD34. Scoring of the immunohistochemical staining was performed using a specified automated cellular image analysis system (Digimizer).

RESULTS

PCNA expression was significantly increased in a sequence of normal mucosa-adenoma-carcinoma. It was significantly higher in adenomas ≥ 1 cm and those with severe dysplasia, and it showed a significant positive correlation with grade and lymph node involvement in colorectal carcinoma. CD34 showed significantly higher expression in carcinoma than adenoma and in adenoma than in the control group. CD34 expression showed a significant correlation with adenomas carrying severe dysplasia and large-sized adenomas (≥1 cm). It was significantly correlated with tumor grade, lymphovascular invasion, and lymph node involvement in colorectal carcinoma.

CONCLUSION

PCNA plays an important role in colorectal neoplastic progression and can be utilized as ancillary marker for the risk of malignant transformation in colorectal adenomas as it correlates with high grade dysplasia and size. Intratumoral quantification of the mean (A and N) of CD34 in colorectal carcinoma reflects the grade of tumors and can predict lymph node involvement and lymphovascular invasion, to make a useful additional prognostic factor.

Identification of HLA-A*0201-restricted cytotoxic T lymphocyte epitope from proliferating cell nuclear antigen

Peptide-based immunotherapy strategies appear promising as an approach to successfully induce an antitumor immune response and prolong survival in patients with various cancers. Protein antigens and their specific epitopes are formulation targets for anti-tumor vaccines. Bioinformatical approaches to predict major histocompatibility complex binding peptides can facilitate the resource-consuming effort of T cell epitope identification. Proliferating cell nuclear antigen including Ki-67 and PCNA, associated with the proliferation process of the cell, seems to be an attractive new target for tumor-specific immunotherapy. In this study, we predicted seven HLA-A*0201-restricted CTL candidate epitope of Ki-67 and eight epitope of PCNA by computer algorithm SYFPEITHI, BIMAS, and IEDB_ANN. Subsequently, biological functions of these peptides were tested by experiments in vitro. We found Ki-67((280-288)) (LQGETQLLV) had the strongest binding-affinity with HLA-A*0201. Further study revealed that Ki-67((280-288)) increased the frequency of IFN-γ-producing T cells compared to a negative peptide. Because Ki-67 was broadly expressed in most advanced malignant tumors, indicating a potential anti-tumor application in the future.

Proliferating cell nuclear antigen as a prognostic factor after total mesorectal excision of stage II-III rectal cancer

BACKGROUND

Proliferating cell nuclear antigen (PCNA) is an auxiliary protein of DNA polymerase delta that is tightly associated with sites of DNA replication; whether PCNA is a definite prognostic factor remains controversial. This study determined the clinicopathological factors associated with the long-term oncological outcome after radical resection of stage II-III rectal cancer, focusing on PCNA.

METHODS

We retrospectively reviewed 135 consecutive patients who underwent curative surgery for stage II-III rectal cancer between August 2001 and April 2004. Prognostic factors including immunohistochemical PCNA expression and the clinical outcome were evaluated.

RESULTS

The PCNA index correlated with lymph node metastasis (P = 0.010). A multivariate analysis identified two independent factors that significantly affected both disease-free and overall survival: lymph node metastasis and PCNA index. With a median follow-up period of 60 months (range 8-87 months), both 5-year disease-free and overall survival of the low PCNA group were significantly higher than those of the high PCNA group (71.8% versus 32.0%, P < 0.001; 83.9% versus 50.0%, P < 0.001, respectively).

CONCLUSION

For patients undergoing curative resection for rectal cancer, pathological N stage and high PCNA expression can provide valuable prognostic information about survival. This study suggests that the PCNA index may be used as an independent prognostic factor in stage II-III rectal cancer patients.

Oncocytic adenocarcinoma of the rectum arising on a villous adenoma with oncocytic features

Rectal adenocarcinoma with diffuse oncocytic features is a very rare lesion, having been reported only once in the English literature. We describe a case of oncocytic adenocarcinoma of the rectum, associated with a villous adenoma, arising on a 66-year-old man. On histological examination, the adenocarcinoma was composed of neoplastic glands lined by a strongly eosinophilic, granular epithelium that deeply infiltrated the rectal wall. Some basophilic calcifications were present in the gland lumina. Superficially, a villous adenoma with high-grade dysplasia was evident; adenomatous cells showed focal eosinophilic changes, consisting of a large granular cytoplasm, an oval atypical nucleus, and a prominent nucleolus. Immunohistochemically, neoplastic glands reacted strongly with antimitochondria antibody, carcinoembryonic antigen, cytokeratin 20, p53, and CDX2. Molecular alterations observed in oncocytic changes and their significance with regards to neoplastic transformation are briefly discussed.

Immunohistochemical expression of bcl-2 and p53 oncoproteins: correlation with Ki67 proliferation index and prognostic histopathologic parameters in colorectal neoplasia

The bcl-2 oncogene plays an important role in carcinogenesis by inhibiting cell death (apoptosis). It was initially discovered in follicular B cell lymphoma with t(14,18) and subsequently found in other malignant and premalignant lesions. Alteration of the normal controls of cell proliferation is also a significant factor in the multistep process of tumorigenesis. The proliferative activity of a given lesion is commonly evaluated by MIB 1, a monoclonal antibody to Ki67 proliferation antigen. Mutation of the p53 gene is considered the most common genetic aberration in colorectal cancer. Immunohistochemical (IHC) staining expression of bcl-2, Ki67, and p53 was retrospectively investigated in a series of 52 colorectal carcinomas and 56 adenomas. The aim of the study was twofold: (i) to investigate any correlation between MIB 1, p53, and bcl-2 immunostaining expression in colonic adenomas and carcinomas and (ii) to identify any relation between these markers and several histopathologic parameters including tumor size, pathologic stage, lymph node metastasis, angiolymphatic invasion, tumor grade, and differentiation in colon carcinomas. bcl-2 was consistently higher in adenomas than in carcinomas. There were 44 of 56 (78.6%) adenomas and 27 of 52 (51.9%) carcinomas positive for bcl-2 (P = 0.004). The mean Ki67 labeling index (LI) was 30.05 +/- 7.6 and 38.12 +/- 11.01 in adenomas and carcinomas, respectively (P = 0.0001). p53 was significantly higher in carcinomas (35 of 52 [67.3%]) than in adenomas (18 of 56 [32.1%]) (P = 0.0004). Expression of bcl-2 in carcinoma was associated with a lower p53 levels and lower mean Ki67 LI and with favorable histopathologic parameters. Higher p53 and Ki67 values were associated with prognostically poor histopathologic features (differentiation and Duke's stage). We conclude that, in contrast to p53 and Ki67, bcl-2 oncoprotein expression is probably an early step in the process of colon carcinogenesis, and its expression may be associated with favorable pathologic parameters. Furthermore, an inverse relation exists between p53 and Ki67, and bcl-2 IHC expression in colonic neoplasia. Evaluation of bcl-2, p53, and Ki67 IHC expression in colonic carcinoma may be of value in predicting the clinical course in these patients.

Natural history of ampullary adenoma in familial adenomatous polyposis: reconfirmation of benign nature during extended surveillance

OBJECTIVE

Surgical or endoscopic papillectomy may be one of the therapeutic strategies for patients with familial adenomatous polyposis (FAP). To determine whether prophylactic papillectomy is necessary for FAP, we investigated the natural history of the ampullary adenoma in FAP.

METHODS

Eighteen subjects with FAP were surveyed by duodenoscopy with biopsy for >10 yr. Endoscopic appearance, histological findings, and immunohistochemical stainings for Ki-67 of ampulla were compared between initial and final endoscopic examinations.

RESULTS

The endoscopic grade in the ampulla remained unchanged in 16 subjects, whereas in two subjects an increase in the endoscopic grade was noted. In two subjects adenoma developed from an endoscopically and histologically normal ampulla. The histological grade of dysplasia increased in three of 12 subjects who initially had adenoma. The labeling index for Ki-67 was not different between initial and final examinations.

CONCLUSIONS

These data suggest that most ampullary adenoma of patients with FAP is static and that aggressive endoscopic or surgical removal is unnecessary for the adenoma.

Correlation of bcl-2 oncoprotein immunohistochemical expression with proliferation index and histopathologic parameters in colorectal neoplasia

Thebcl-2oncogene plays an important role in carcinogenesis by inhibiting cell death (apoptosis). It was initially discovered in follicular B cell lymphoma with t(14,18), and subsequently found in other malignant and premalignant lesions. Alteration of the normal controls of cell proliferation is also a significant factor in the multistep process of tumorigenesis. The proliferative activity of a given lesion is commonly valuated by MIB1, a monoclonal antibody to Ki67 proliferation antigen. Immuno-histochemical (IHC) staining expression of bcl-2 and Ki67 was retrospectively investigated in a series of 52 colorectal carcinomas and 56 adenomas according to the avidin-biotin-complex method. The aim of the study was twofold: 1) to investigate any correlation between MIB1 and bcl-2 immunostaining expression in colonic adenomas and carcinomas, 2) to identify any relationship between either marker and several histopathologic parameters including tumor size, pathologic stage, lymph node metastasis, angio-lymphatic invasion, tumor grade and differentiation in colon carcinomas. Bcl-2 was consistently higher in adenomas than in carcinomas. There were 44/56 (78.6%) adenomas, and 27/52 (51.9%) carcinomas positive for bcl-2 (p=0.004). The mean Ki67 labeling index (LI) was 30.05+/-7.6 and 38.12+/-11.01 in adenomas and carcinomas, respectively (p=0.0001). Expression of bcl-2 in carcinoma was significantly associated with a lower mean Ki67 LI and with favorable histopathologic parameters. We conclude that bcl-2 oncoprotein expression is probably an early step in the process of colon carcinogenesis, and its expression may be associated with a favorable clinical course. Furthermore, an inverse relationship exists between bcl-2 and Ki67 in colonic neoplasia. Evaluation of bcl-2 and Ki67 IHC expression in colonic carcinoma should be performed prospectively to determine if their expression is of value in predicting the clinical course in these patients.

Depressed adenoma of the duodenum in patients with familial adenomatous polyposis: endoscopic and immunohistochemical features

BACKGROUND

Depressed neoplastic lesions of the colorectum have been specified in patients with familial adenomatous polyposis (FAP). The aim of this study was to characterize endoscopic, histologic, and immunohistochemical features of depressed adenoma of the duodenum in patients with FAP.

METHODS

Duodenoscopy was performed on 25 patients with FAP, and the neoplastic nonampullary lesions were classified as polypoid or depressed adenomas. The grade of dysplasia, the proliferative activity determined by Ki-67 labeling index (LI), and the grade of p53 expression were compared between polypoid and depressed neoplasia.

RESULTS

Ten subjects had depressed nonampullary adenoma, whereas polypoid adenoma was found in the remaining 15 subjects. Moderate dysplasia was more frequent in depressed adenoma than in polypoid adenoma (70% vs. 27%, P = 0.04). Whereas p53 expression was not different between the two adenoma groups, the LI was significantly higher in depressed adenoma than in polypoid adenoma (59.7 +/- 9.5 vs. 47.5 +/- 10.7, P < 0.01).

CONCLUSIONS

Depressed adenoma of the duodenum is a distinctive phenotype of duodenal neoplasm in patients with FAP. The high proliferative activity of depressed adenoma suggests that there may be a need to survey FAP patients with such lesions intensively.

Cell kinetics, p53 and bcl-2 expression, and c-Ki-ras mutations in flat-elevated tubulovillous adenomas and adenocarcinomas of the colorectum: comparison with polypoid lesions

BACKGROUND

Flat(-elevated) tubulovillous adenomas and adenocarcinomas of the colorectum constitute a specific type of neoplasm with superficial spreading growth. To establish their characteristics, a comparative investigation of a series of tumors was performed.

METHODS

A total of 56 flat tubulovillous tumors (39 adenomas, 17 invasive carcinomas) and 154 polypoid tubular or villous tumors (77 adenomas, 77 invasive carcinomas) were comparatively assessed for cell kinetics and molecular alterations.

RESULTS

Ki-67 labeling and p53 expression for both types of tumors increased along with degree of dysplasia or invasion, whereas bcl-2 expression showed an inverse decrease. However, apoptotic activity was invariably low in the flat tubulovillous tumors, as compared with the polypoid tumors, in which increase was apparent with tumor progression. The flat tubulovillous tumors also showed a higher frequency of c-Ki-ras mutations (92.9%) than the polypoid tubular tumors (40.0%).

CONCLUSIONS

The flat tubulovillous tumor can be considered a distinct entity, with characteristics different from the polypoid counterpart.

EGF, TGF-alpha, and EGF-R in human colorectal adenocarcinoma

The over-expression of epidermal growth factor receptor (EGF-R), EGF and transforming growth factor alpha (TGFalpha) could be a mechanism for colorectal tumor cells to escape normal growth controls. Our aims were: (i) to evaluate EGF, TGFalpha, and EGF-R concentrations in neoplastic tissue and surrounding mucosa from 40 patients with colorectal adenocarcinoma, and (ii) to assess the expression of these growth factors and their receptor in relation to the tumor site. EGF, TGFalpha, and EGF-R were detected in either colorectal neoplastic tissue or surrounding mucosa. Significantly increased levels of EGF and EGF-R were present in neoplastic samples compared to surrounding mucosa. Furthermore, a significant increase in TGFalpha and in EGF levels was observed in the left-sided surrounding mucosa and left-sided neoplastic tissue, respectively. EGF-R stimulation by its ligands may play an important role in colorectal neoplastic tissue. Moreover, the higher content of growth factors in the left-side than the right-side colon suggests different growth properties in the proximal and distal colon.

Phenotypic and genotypic characteristics of aberrant crypt foci in human colorectal mucosa

Aberrant crypt foci (ACF) in colorectal mucosa are proposed to be the earliest morphological lesion in the development of neoplasia, but their characteristics remain controversial. We therefore studied the epithelial phenotype and genotype of ACF from patients with familial adenomatous polyposis (FAP) and of sporadic ACF by evaluating glycoprotein markers associated with neoplasia (lectins Dolichus biflorus agglutinin and peanut agglutinin; monoclonal antibody CA 19-9 against sialyl Lewis-a blood group substance), expression of proliferating cell nuclear antigen, and ras proto-oncogene mutations. The utility of the markers was established by comparing adenomas and hyperplastic polyps. Most FAP ACF resembled adenomas and were found to differ from sporadic ACF in their high frequency of dysplasia, staining with Dolichus biflorus agglutinin, expression of sialyl Lewis-a, proliferation in the epithelium of upper crypts, and low frequency of ras gene mutations (P = .04 to < .0000001). By contrast, sporadic ACF and a subset of FAP ACF had phenotypic characteristics resembling hyperplastic polyps but usually had ras mutations, which were inversely related to dysplasia (P = .00009). Our findings suggest that "aberrant crypt focus" is a generic term analogous to "polyp" and requires further histopathologic, phenotypic, or genotypic classification into dysplastic and heteroplastic (hetero = other, plasia = form) types. Dysplastic ACF represent potential precursors to colorectal adenomas and adenocarcinomas, but heteroplastic ACF appear to be associated, rather than precursor, lesions.

Expression of vascular endothelial growth factor in normal liver and hepatocellular carcinoma: an immunohistochemical study

Angiogenesis is of vital importance during the development and progression of solid tumors. To examine the role of vascular endothelial growth factor (VEGF) in hepatocarcinogenesis, we evaluated the expression of peptide in normal human liver (n = 6) and in 36 cases of hepatocellular carcinoma (HCC). Immunoreactivity for VEGF was present in the extracellular matrix of the portal tracts in the normal and nontumor part of liver, but not in hepatocytes and bile duct epithelium. For HCC, variable amounts of VEGF were expressed in 13 cases (36.1%) of tumor cells. Using a logistic regression model, expression of VEGF was significantly associated with a higher proliferative index (P = .01) and sonographic portal vein thrombosis (P = .05). However, VEGF expression did not correlate with a biochemical liver profile, alpha-fetoprotein levels, histological grading, gender, or clinical stage of cirrhosis (P > 0.1, respectively). Log-rank test showed that evaluation of VEGF did not provide more prognostic information (P > .5) than that from tumor volume and portal vein thrombosis (P < .01, respectively). In addition, VEGF was always present in the fibrovascular stroma or pericellular matrix of HCC, although no strong relationship was observed with the expression of VEGF in tumor cells (P > .5). Our data suggested that expression of VEGF may characterize a progression toward higher proliferation in hepatocarcinogenesis in vivo. The relevance of VEGF existing in the extracellular matrix of the normal liver and HCC remains to be clarified.