Pathobiology of the neutrophil-intestinal epithelial cell interaction: Role in carcinogenesis

The role of chronic inflammation, acting as an independent factor, on the onset of gastrointestinal carcinogenesis is now well accepted. However, even if there is an increase in the number of elements directly involving polymorphonuclear leukocytes (PMNL), as a major actor in digestive carcinogenesis, the different cellular and molecular events occurring in this process are still not completely understood. The transepithelial migration of PMNL, which is the ultimate step of the afflux of PMNL into the digestive mucosa, is a complex phenomenon involving sequential interaction of molecules expressed both on PMNL and on digestive epithelial cells. Chronic inflammatory areas rich in PMNL [so-called (chronic active inflammation)] and iterative transepithelial migration of PMNL certainly evoke intracellular signals, which lead toward progressive transformation of epithelia. Among these different signals, the mutagenic effect of reactive oxygen species and nitrates, the activation of the nuclear factor-κB pathway, and the modulation of expression of certain microRNA are key actors. Following the initiation of carcinogenesis, PMNL are involved in the progression and invasion of digestive carcinomas, with which they interact. It is noteworthy that different subpopulations of PMNL, which can have some opposite effects on tumor growth, in association with different levels of transforming growth factor-β and with the number of CD8 positive T lymphocytes, could be present during the development of digestive carcinoma. Other factors that involve PMNL, such as massive elastase release, and the production of angiogenic factors, can participate in the progression of neoplastic cells through tissues. PMNL may play a major role in the onset of metastases, since they allow the tumor cells to cross the endothelial barrier and to migrate into the blood stream. Finally, PMNL play a role, alone or in association with other cell parameters, in the initiation, promotion, progression and dissemination of digestive carcinomas. This review focuses on the main currently accepted cellular and molecular mechanisms that involve PMNL as key actors in digestive carcinogenesis.

Nitric oxide and cancer

Nitric oxide (NO) is a lipophilic, highly diffusible and short-lived physiological messenger which regulates a variety of important physiological responses including vasodilation, respiration, cell migration, immune response and apoptosis. NO is synthesized by three differentially gene-encoded NO synthase (NOS) in mammals: neuronal NOS (nNOS or NOS-1), inducible NOS (iNOS or NOS-2) and endothelial NOS (eNOS or NOS-3). All isoforms of NOS catalyze the reaction of L-arginine, NADPH and oxygen to NO, L-citrulline and NADP. NO may exert its cellular action by cGMP-dependent as well as by cGMP-independent pathways including postranslational modifications in cysteine (S-nitrosylation or S-nitrosation) and tyrosine (nitration) residues, mixed disulfide formation (S-nitrosoglutathione or GSNO) or promoting further oxidation protein stages which have been related to altered protein function and gene transcription, genotoxic lesions, alteration of cell-cycle check points, apoptosis and DNA repair. NO sensitizes tumor cells to chemotherapeutic compounds. The expression of NOS-2 and NOS-3 has been found to be increased in a variety of human cancers. The multiple actions of NO in the tumor environment is related to heterogeneous cell responses with particular attention in the regulation of the stress response mediated by the hypoxia inducible factor-1 and p53 generally leading to growth arrest, apoptosis or adaptation.

Association of Caveolin-1 polymorphisms with colorectal cancer susceptibility in Taiwan

AIM: To investigate the association of Caveolin-1 (Cav-1) polymorphisms with colorectal cancer (CRC) risk in a central Taiwanese population.

METHODS: Three hundred and sixty-two patients with colorectal cancer and the same number of recruited age- and gender-matched healthy controls were genotyped. And only those matches with all single nucleotide polymorphisms data (case/control = 362/362) were selected for final analyzing.

RESULTS: There were significant differences between CRC and control groups in the distributions of their genotypes (P = 1.6 × 10^-12 and 3.0 × 10^-4) and allelic frequencies (P = 2.3 × 10^-13 and 4.0 × 10^-5) in the Cav-1 G14713A (rs3807987) and T29107A (rs7804372) polymorphisms respectively. As for the haplotype analysis, those who had GG/AT or GG/AA at Cav-1 G14713A/T29107A showed a 0.68-fold (95% CI: 0.48-0.98) decreased risk of CRC compared to those with GG/TT, while those of any other combinations were of increased risk. There were joint effects of Cav-1 G14713A and T29107A genotype with smoking status on individual CRC susceptibility.

CONCLUSION: This is the first report providing evidence of Cav-1 being involved in CRC and it may be novel useful genomic markers for early detection of CRC.

MicroRNAs and lung cancer: Biology and applications in diagnosis and prognosis

MicroRNAs are tiny non-coding RNA molecules which play important roles in the epigenetic control of cellular processes by preventing the translation of proteins from messenger RNAs (mRNAs). A single microRNA can target different mRNAs, and an mRNA can be targeted by multiple microRNAs. Such complex interplays underlie many molecular pathways in cells, and specific roles for many microRNAs in physiological as well as pathological phenomena have been identified. Changes in expression of microRNAs have been associated with a wide variety of disease conditions, and microRNA-based biomarkers are being developed for the identification and monitoring of such states. This review provides a general overview of the current state of knowledge about the biology of microRNAs, and specific information about microRNAs with regard to the diagnosis and prognosis of lung cancer.

Role of loss of o⁶-methylguanine dna methyltransferase (MGMT) expression in non-small cell lung carcinomas (NSCLCs): with reference to the relationship with p53 overexpression

PURPOSE

Functional inactivation of the O⁶-methylguanine-DNA methyltransferase (MGMT) gene has been demonstrated as loss of MGMT protein and suggested that it plays an important role in primary human neoplasia, including lung cancer. It has also been reported to be associated with the G : C-->A : T transition mutation in the p53 gene of lung cancer. The aims of this study were to investigate the role of MGMT expression loss and its prognostic significance in non-small cell lung carcinomas (NSCLCs), and its correlation with p53 overexpression as well as influence on patient survival.

MATERIALS AND METHODS

112 surgically resected NSCLC specimens were reviewed by medical records for their clinicopathologic variables. Their tissue microarray blocks were immunostained with anti-human MGMT and p53 primary antibodies. Correlation between MGMT loss and the clinicopathologic prognostic factors, including p53 overexpression and the single or combined actions of MGMT loss and p53 overexpression on patient survival were statistically analyzed by SPSS15.0.

RESULTS

Reduced or absent MGMT expression was found in 48 of 112 NSCLCs (43%), and significantly associated with nodal metastasis and squamous or undifferentiated cell types. Loss of MGMT expression was correlated with p53 overexpression in adenocarcinomas, but not in overall NSCLCs. Its solitary or combined actions with p53 overexpression did not have influence on patient survival.

CONCLUSION

Loss of MGMT expression is a relatively common event in NSCLCs and significantly associated with nodal metastasis and p53 overexpression, suggesting that it may play a major role in pulmonary carcinogenesis, and also in disease progression of NSCLCs.

Cell origin and premalignant lesions of gastric signet-ring cell carcinoma: a histopathologic study

AIM: To investigate the cell origin and premalignant lesions of gastric signet-ring cell carcinoma (SRCC).

METHODS: A total of 42 cases of early gastric SRCC were included in this study. The histological morphology of gastric SRCC was observed. Differentiation markers MUC5AC and MUC6 were labeled by immunohistochemical double-staining of gastric SRCC tissue. The expression of Ki-67 and gastrointestinal stem/progenitor cell marker musashi-1 in SRCC was detected by immunohistochemistry. Additionally, the immunophenotype of gastric glands adjacent to carcinoma was also detected.

RESULTS: Early gastric SRCC was characterized by a two-layered structure consisting of superficial layer and basal layer. The superficial layer contained typical large signet-ring cells that possessed abundant cytoplasm, whereas the basal layer was composed of small-sized primitive cancer cells with a high nucleus/cytoplasm ratio. Cells in the basal layer shared common morphologic features and a similar anatomic location with those in the proliferative zone of gastric glands. These cells were negative for both MUC5AC and MUC6, or merely exhibited a weak MUC5AC expression. Compared with the superficial layer, the percentages of Ki-67- and musashi-1-positive cells were significantly higher in the basal layer (t = 31.0 and 22.8, respectively, both P < 0.01). Cells in the basal layer could differentiate into typical signet-ring cells, which resembles the differentiation process of proliferitive zone cells into gastric pit cells. Dysplasia of the proliferative zone of gastric glands adjacent to SRCC was noted, and dysplastic cells in the proliferative zone were phenotypically consistent with cancer cells in the basal layer.

CONCLUSION: Gastric SRCC may originate from MUC5AC-/lowMUC6- pre-pit cells in the proliferative zone of gastric glands. Dysplasia of the proliferative zone may represent the premalignant lesions of gastric SRCC.

Simultaneous occurrence of a hepatocellular carcinoma and a hepatic non-Hodgkin's lymphoma infiltration

To investigate the simultaneous occurrence of hepatocellular carcinoma and non-Hodgkin's lymphoma, we report the case of a 70 year old patient with a primary diagnosis of non-Hodgkin's lymphoma in 2002. In a routine follow up investigation of his chronic lymphocytic leukemia a newly detected mass in the Couinaud's segments 2 and 3 was found. No hepatitis C virus or hepatitis B virus infection or cirrhosis was evident. After laparoscopic segmentectomy the histological examination revealed a hepatocellular carcinoma. While the relation between liver parenchyma damages and hepatocellular carcinoma or non-Hodgkin's lymphoma is well known, only a few publications have focused on the coexistence of hepatocellular carcinoma and non-Hodgkin's lymphoma. With this case we demonstrate the coexistence of these diseases without having a predamaged liver parenchyma.

Peroxisome proliferator activated receptor-γ and the ubiquitin-proteasome system in colorectal cancer

Peroxisome proliferator activated receptor-γ (PPARγ), a transcription factor of the nuclear receptor superfamily plays a significant role in colorectal cancer pathogenesis. In most experimental systems PPARγ activation has tumor suppressing effects in the colon. PPARγ is regulated at multiple levels by the ubiquitin-proteasome system (UPS). At a first level, UPS regulates PPARγ transcription. This regulation involves both PPARγ transcription specific factors and the general transcription machinery. At a second level UPS regulates PPARγ and its co-factors themselves, as PPARγ and many co-factors are proteasome substrates. At a third level of regulation, transduction pathways working in parallel but also having interrelations with PPARγ are regulated by the UPS, creating a network of regulation in the colorectal carcinogenesis-related pathways that are under UPS control. Activation of PPARγ transcription by direct pharmacologic activators and by stabilization of its molecule by proteasome inhibitors could be strategies to be exploited in colorectal cancer treatment.

Connection between inflammation and carcinogenesis in gastrointestinal tract: Focus on TGF-β signaling

Inflammation is a primary defense process against various extracellular stimuli, such as viruses, pathogens, foods, and environmental pollutants. When cells respond to stimuli for short periods of time, it results in acute or physiological inflammation. However, if the stimulation is sustained for longer time or a pathological state occurs, it is known as chronic or pathological inflammation. Several studies have shown that tumorigenesis in the gastrointestinal (GI) tract is closely associated with chronic inflammation, for which abnormal cellular alterations that accompany chronic inflammation such as oxidative stresses, gene mutations, epigenetic changes, and inflammatory cytokines, are shared with carcinogenic processes, which forms a critical cross-link between chronic inflammation and carcinogenesis. Transforming growth factor (TGF)-β is a multi-potent cytokine that plays an important role in regulation of cell growth, apoptosis and differentiation. Most importantly, TGF-β is a strong anti-inflammatory cytokine that regulates the development of effector cells. TGF-β has a suppressive effect on carcinogenesis under normal conditions by inhibiting abnormal cell growth, but on the other hand, many GI cancers originate from uncontrolled cell growth and differentiation by genetic loss of TGF-β signaling molecules or perturbation of TGF-β adaptors. Once a tumor has developed, TGF-β exerts a promoting effect on the tumor itself and stromal cells to enhance cell growth, alter the responsiveness of tumor cells to stimulate invasion and metastasis, and inhibited immune surveillance. Therefore, novel development of therapeutic agents to inhibit TGF-β-induced progression of tumor and to retain its growth inhibitory activities, in addition to anti-inflammatory actions, could be useful in oncology. In this review, we discuss the role of TGF-β in inflammation and carcinogenesis of the GI tract related to abnormal TGF-β signaling.

Modifier-concept of colorectal carcinogenesis: Lipidomics as a technical tool in pathway analysis

In the modifier concept of intestinal carcinogenesis, lipids have been established as important variables and one focus is given to long-chain fatty acids. Increased consumption of long-chain fatty acids is in discussion to modify the development of colorectal carcinoma in humans. Saturated long-chain fatty acids, in particular, are assumed to promote carcinogenesis, whereas polyunsaturated forms are likely to act in the opposite way. At present, the molecular mechanisms behind these effects are not well understood. Recently, it has been demonstrated by lipidomics and associated molecular techniques, that activation and metabolic channeling of long-chain fatty acids are important mechanisms to modify colorectal carcinogenesis. In this Editorial, an overview about the present concept of long-chain fatty acids and its derivatives in colorectal carcinogenesis as well as technical algorithms in lipid analysis is given.

Oral administration of the anti-proliferative substance taurolidine has no impact on dextran sulfate sodium induced colitis-associated carcinogenesis in mice

Background:

New chemopreventive strategies for ulcerative colitis (UC)-associated dysplasia and cancer have to be evaluated. Taurolidine (TRD) has anti-inflammatory, anti-proliferative and anti-neoplastic properties with almost absent toxicity. The aim of the study was to determine whether TRD decreases dysplasia in the well-characterized Dextran Sulfate Sodium – Azoxymethane (DSS-AOM) animal model for UC-associated carcinogenesis.

Material and Methods:

The DSS-AOM model of carcinogenesis was induced in female inbred C57BL/6 mice. Half of the mice were treated with TRD, the other served as control. After 100 days macroscopic, histological and immunhistochemical (β-Catenin, E-Cadherin, SOX9, Ki-67, Cyclin-D1) examination of the colon was performed.

Results:

Incidence, multiplicity, grading and growth pattern of adenomas did not differ significantly between TRD and control group. In all animals, inflammatory changes were absent. Immunhistochemistry revealed increased expression of Ki-67, β-catenin, SOX9 and Cyclin-D1 in adenomas compared to normal mucosa – without significant difference between TRD and control treatment.

Conclusion:

Oral administration of TRD has no impact on DSS-induced colitis-associated carcinogenesis. However, SOX9 and Cyclin-D1 representing key members of the Wnt pathway have not yet been described in the DSS-AOM model of carcinogenesis – underlining the importance of this oncogenic pathway in this setting.

Expression pattern of the class I homeobox genes in ovarian carcinoma

OBJECTIVE

Although some sporadic reports reveal the link between the homeobox (HOX) genes and ovarian carcinoma, there is no comprehensive analysis of the expression pattern of the class I homeobox genes in ovarian carcinoma that determines the candidate genes involved in ovarian carcinogenesis.

METHODS

The different patterns of expression of 36 HOX genes were analyzed, including 4 ovarian cancer cell lines and 4 normal ovarian tissues. Using a reverse transcription-polymerase chain reaction (RT-PCR) and quantification analysis, the specific gene that showed a significantly higher expression in ovarian cancer cell lines than in normal ovaries was selected, and western blot analysis was performed adding 7 ovarian cancer tissue specimens. Finally, immunohistochemical and immunocytochemical analyses were performed to compare the pattern of expression of the specific HOX gene between ovarian cancer tissue and normal ovaries.

RESULTS

Among 36 genes, 11 genes had a different level of mRNA expression between the cancer cell lines and the normal ovarian tissues. Of the 11 genes, only HOXB4 had a significantly higher level of expression in ovarian cancer cell lines than in normal ovaries (p=0.029). Based on western blot, immunohistochemical, and immunocytochemical analyses, HOXB4 was expressed exclusively in the ovarian cancer cell lines or cancer tissue specimens, but not in the normal ovaries.

CONCLUSION

We suggest HOXB4 may be a novel candidate gene involved in ovarian carcinogenesis.

Carcinogenesis and chemoprevention of biliary tract cancer in pancreaticobiliary maljunction

Pancreaticobiliary maljunction (PBM) is a high risk factor for biliary tract cancer. In PBM, since the pancreatic duct and bile duct converge outside the duodenal wall beyond the influence of the sphincter of Oddi, pancreatic juice and bile are constantly mixed, producing a variety of harmful substances. Because of this, the biliary mucosa is repeatedly damaged and repaired, which causes an acceleration of cell proliferative activity and multiple gene mutations. Histological changes such as hyperplasia, metaplasia, and dysplasia ultimately result in a high incidence of carcinogenesis. In a nationwide survey by the Japanese Study Group on PBM, coexisting biliary tract cancer was detected in 278 of the 1627 registered cases of PBM (17.1%). Of these cases, in those with dilatation of the extrahepatic bile duct, cancer was often detected not only in the gallbladder but also in the bile ducts. More than 90% of cancer cases without dilatation of the extrahepatic bile duct develop in the gallbladder. Standard treatment for PBM is a cholecystectomy and resection of the extrahepatic bile duct. However, cholecystectomy alone is performed at nearly half of institutions in Japan. Conversely, reports of carcinogenesis in the remnant bile duct or pancreas after diversion surgery are steadily increasing. One of the causes for this is believed to be an accumulation of gene mutations which were present before surgery. Anticancer drugs are ineffective in preventing such carcinogenesis following surgery, thus the postoperative administration of chemopreventive agents may be necessary.

DNA polymorphism and risk of esophageal squamous cell carcinoma in a population of North Xinjiang, China

AIM: To investigate the role of metabolic enzyme and DNA repair genes in susceptibility of esophageal squamous cell carcinoma (ESCC).

METHODS: A case-control study was designed with 454 samples from 128 ESCC patients and 326 gender, age and ethnicity-matched control subjects. Genotypes of 69 single nucleotide polymorphisms (SNPs) of metabolic enzyme (aldehyde dehydrogenase-2, ALDH2; alcohol dehydrogenase-1 B, ADHB1; Cytochrome P450 2A6, CYP2A6) and DNA repair capacity genes (excision repair cross complementing group 1, ERCC1; O⁶-methylguanine DNA methyltransferase, MGMT; xeroderma pigmentosum group A, XPA; xeroderma pigmentosum group A, XPD) were determined by the Sequenom MassARRAY system, and results were analyzed using unconditional logistic regression adjusted for age, gender.

RESULTS: There was no association between the variation in the ERCC1, XPA, ADHB1 genes and ESCC risk. Increased risk of ESCC was suggested in ALDH2 for frequency of presence C allele of SNP [Rs886205: 1.626 (1.158-2.284)], XPD for C allele [Rs50872: 1.482 (1.058-2.074)], and MGMT for A allele [Rs11016897: 1.666 (1.245-2.228)]. Five variants of MGMT were associated with a protective effect on ESCC carcinogenesis, including C allele [Rs7069143: 0.698 (0.518-0.939)], C allele [Rs3793909: 0.653 (0.429-0.995)], A allele [Rs12771882: 0.719 (0.524-0.986)], C allele [Rs551491: 0.707 (0.529-0.945)], and A allele [Rs7071825: 0.618 (0.506-0.910)]. At the genotype level, increased risk of ESCC carcinogenesis was found in homozygous carriers of the ALDH2 Rs886205 [CC vs TT, odds ratios (OR): 3.116, 95% CI: 1.179-8.234], MGMT Rs11016879 (AA vs GG, OR: 3.112, 95% CI: 1.565-6.181), Rs12771882 (AA vs GG, OR: 2.442, 95% CI: 1.204-4.595), and heterozygotes carriers of the ALDH2 Rs886205 (CT vs TT, OR: 3.930, 95% CI: 1.470-10.504), MGMT Rs11016879 (AG vs GG, OR: 3.933, 95% CI: 2.216-6.982) and Rs7075748 (CT vs CC, OR: 1.949, 95% CI: 1.134-3.350), respectively. Three variants were associated with a protective effect on ESCC carcinogenesis, carriers of the MGMT Rs11016878 (AG vs AA, OR: 0.388, 95% CI: 0.180-0.836), Rs7069143(CT vs CC, OR: 0.478, 95% CI: 0.303-0.754) and Rs7071825 (GG vs AA, OR: 0.493, 95% CI: 0.266-0.915). Increased risk of ESCC metastasis was indicated in MGMT for frequency of presence C allele [Rs7068306: 2.204 (1.244-3.906)], A allele [Rs10734088: 1.968 (1.111-3.484)] and C allele [Rs4751115: 2.178 (1.251-3.791)]. Two variants in frequency of presence C allele of CYP2A6 [Rs8192720: 0.290 (0.099-0.855)] and A allele of MGMT [Rs2053139: 0.511 (0.289-0.903)] were associated with a protective effect on ESCC progression. Increased risk of ESCC metastasis was found in heterozygote carriers of the MGMT Rs7068306 (CG vs CC, OR: 4.706, 95% CI: 1.872-11.833).

CONCLUSION: Polymorphic variation in ALDH2, XPD and MGMT genes may be of importance for ESCC susceptibility. Polymorphic variation in CYP2A6 and MGMT are associated with ESCC metastasis.

Possibility of differentiation and malignant transformation of bone marrow stromal cells in the liver of mice

AIM: To evaluate the possibility of differentiation and malignant transformation of bone marrow stromal cells (BMSCs) in a mouse model of chemical hepatocarcinogenesis.

METHODS: BMSCs were harvested from male BALB/c mice, cultured and transplanted into the liver of female syngeneic BALB/c mice via the portal vein. Diethylnitrosamine was administered to mice for six months to induce hepatocarcinogenesis. Six months later, liver samples were taken and used to evaluate the expression of placental form of glutathione-S-transferase, α-fetoprotein and cytokeratin 19 by immunohistochemistry. Y chromosome-positive hepatocytes were detected by fluorescence in situ hybridization (FISH).

RESULTS: BMSCs were shown to differentiate into hepatocyte-like phenotypes after hepatocyte growth factor treatment in vitro. Twenty-six percent of recipient mice survived and developed multiple hepatocellular carcinomas (HCCs). Immunohistochemically, HCCs expressed placental form of glutathione-S-transferase and α-fetoprotein, but did not express cytokeratin 19. Y chromosome-positive hepatocytes were detected by FISH in the liver of mice that were treated with diethylnitrosamine after BMSC transplantation while no such hepatocytes were identified in the liver of mice that were not treated with diethylnitrosamine. No hepatocellular carcinoma cells positive for Y chromosome marker were detected.

CONCLUSION: Transplanted BMSCs can differentiate into hepatocytes but have low malignant potential in the mouse model of chemical hepatocarcinogenesis.

Tobacco interventions and anaesthesia- a review

SUMMARY

Tobacco use is the leading preventable agent of death in the world. It is manufactured on a large scale in India and has a huge international market also. Death toll from tobacco use is on the rise. Use of tobacco is also increasing esp. in developing countries, in teenagers & in women, despite government, WHO and intervention by other statutory bodies. Prolonged use of tobacco or its products, as smoke or chew, endows significant risk of developing various diseases. With advances in surgical and anaethesia techniques & prolonged life expectancy, anaesthetist will be faced with management of these patients. Tobacco consumption affects every major organ system of the body; esp. lung, heart and blood vessels. Perioperative smoking cessation can significantly reduce the risk of postoperative complications & duration of hospital stay. Anaesthetist can play an important role in motivating these patients to quit smoking preoperatively by providing brief counselling and nicotine replacement therapy in reluctant quitters. More of concern is the effect of passive smoking (second & third hand smoke) on non smokers. This is a review of tobacco & its products, their health consequences, diseases caused, anaesthetic considerations & their role in helping these patients quit smoking Preventing nicotine addiction and improving smoking cessation strategies should be the priority and despite these being only partially successful, strong measures at all levels should be continued & enforced.

Molecular Aspects of Melanoma

Melanoma is the most serious type of skin cancer. Unfortunately, treatment has progressed little and advanced melanoma has appalling survival rates. A goal of molecular analysis is to fully describe the alterations that underpin melanoma's clinical phenotype so that diagnosis can be more accurate, outcome can be predicted with greater confidence, and treatment that is tailored to the patient can be given. This article describes the handful of "signature" changes that are known to occur, describes how some recent studies have shed light on changes beyond this signature, and finally discusses the impact of molecular pathology for practicing histopathologists.

Methylation of PTCH1a gene in a subset of gastric cancers

AIM: To establish if PTCH1a transcriptional regulation region (TRR) is methylated in gastric cancer and its influence in gastric tumorigenesis.

METHODS: The CpG islands in PTCH1a TRR were analyzed by Methyl Primer Express v1.0 software. The region from -643 to -355 bp (the transcription initiation site of PTCH1a was designated as 0) that contained 19 CpG sites was chosen for bisulfite-sequencing PCR (BSP) and methylation-specific PCR (MSP) detection. The gastric cancer cell line AGS was treated with 5-aza-2’-deoxycytidine (5-Aza-dC; 1 μmol/L) for 3 d. Alterations in PTCH1a TRR methylation in treated AGS cells was measured through BSP clone sequences, and their PTCH1 expression was measured by quantitative RT-PCR. The cell cycle and apoptosis were observed with flow cytometry through propidium iodide (PI) staining or annexin V/PI double staining. The prevalence of PTCH1a TRR methylation was investigated in 170 gastric cancer tissue samples and the adjacent normal tissues by MSP. The correlation of PTCH1a TRR methylation with PTCH1 expression or with patients’ clinical features was analyzed.

RESULTS: Methylation of PTCH1a TRR was observed in AGS cells and a subset of gastric cancer tissues (32%, 55/170), while no methylation amplification products were observed in any normal tissues by MSP. The methylation of PTCH1a TRR was correlated negatively with PTCH1 expression (Spearman’s r = -0.380, P = 0.000). However, methylation of PTCH1a TRR was not related to the gastric cancer patients’ clinical features, such as sex, age of onset, clinical stage, lymph node metastasis or histological grade. The methylation of PTCH1a TRR in AGS cells was almost converted to non-methylation after 5-Aza-dC treatment, which increased PTCH1 expression (5.3 ± 2.5 times; n = 3) and apoptosis rate (3.0 ± 0.26 times; P < 0.05; n = 3).

CONCLUSION: Methylation of PTCH1a TRR is present in a subset of gastric cancers and correlated negatively with PTCH1 expression. This may be an early event in gastric tumorigenesis and a new treatment target.

Expression of C-Reactive Protein in Rectal Cancer

BACKGROUND

The possible involvement of inflammation on colorectal carcinogenesis has potential prognostic, preventive and therapeutic implications. We investigated immunohistochemically whether C-reactive protein is expressed in human primary rectal adenocarcinoma and assessed its relationship with clinicopathological findings.

METHODS

Ninety-one rectal cancer samples and 22 normal control samples were immunohistochemically analysed.

RESULTS

Cell accumulation of C-reactive protein was observed in 65 (71%) out of 91 patients with rectal adenocarcinoma and in all 22 control cases (p < 0.01). No significant difference was observed regarding to clinicopathological features or survival rates, but a linear correlation between the positivity proportion of C-reactive protein and Dukes-Turnbull stage (p = 0.005) was observed.

CONCLUSIONS

These data suggest that C-reactive protein might play a role in rectal carcinogenesis, but seems not to affect prognosis. Additional studies are warranted in larger population samples.

Midkine translocated to nucleoli and involved in carcinogenesis

Midkine (MK) is a heparin-binding growth factor with its gene first identified in embryonal carcinoma cells at early stages of retinoic acid-induced differentiation. MK is frequently and highly expressed in a variety of human carcinomas. Furthermore, the blood MK level is frequently elevated with advance of human carcinomas, decreased after surgical removal of the tumors. Thus, it is expected to become a promising marker for evaluating the progress of carcinomas. There is mounting evidence that MK plays a significant role in carcinogenesis-related activities, such as proliferation, migration, anti-apoptosis, mitogenesis, transforming, and angiogenesis. In addition, siRNA and anti-sense oligonucleotides for MK have yielded great effects in anti-tumor activities. Therefore, MK appears to be a potential candidate molecular target of therapy for human carcinomas. In this paper, we review MK targeting at nucleoli in different tumor cells and its role in carcinogenesis to deepen our understanding of the mechanism of MK involved in carcinogenesis.

Transient and etiology-related transcription regulation in cirrhosis prior to hepatocellular carcinoma occurrence

AIM: To search for transcription dysregulation that could (1) differentiate hepatocellular carcinoma (HCC)-free from HCC-related cirrhosis (2) differentiate HCC-free cirrhosis related to HCV from that related to alcohol intake.

METHODS: Using microarray analysis, we compared transcript levels in HCC-free cirrhosis (alcoholism: 7; hepatitis C: 7), HCC-associated cirrhosis (alcoholism: 10; hepatitis C: 10) and eight control livers. The identified transcripts were validated by qRT-PCR in an independent cohort of 45 samples (20 HCC-free cirrhosis; 15 HCC-associated cirrhosis and 10 control livers). We also confirmed our results by immunohistochemistry.

RESULTS: In HCC-free livers, we identified 70 transcripts which differentiated between alcoholic-related cirrhosis, HCV-related cirrhosis and control livers. They mainly corresponded to down-regulation. Dysregulation of Signal Transduction and Activator of Transcription-3 (STAT-3) was found along with related changes in STAT-3 targets which occurred in an etiology-dependent fashion in HCC-free cirrhosis. In contrast, in HCC, such transcription dysregulations were not observed.

CONCLUSION: We report that transcriptional dysregulations exist in HCC-free cirrhosis, are transiently observed prior to detectable HCC onset and may be appear like markers from cirrhosis to HCC transition.

Azoxymethane-induced rat aberrant crypt foci: Relevance in studying chemoprevention of colon cancer

The pathogenesis of colon cancer involves sequential and multistep progression of epithelial cells initiated to a cancerous state with defined precancerous intermediaries. Aberrant crypt foci (ACF) represent the earliest identifiable intermediate precancerous lesions during colon carcinogenesis in both laboratory animals and humans. ACF are easily induced by colon-specific carcinogens in rodents and can be used to learn more about the process of colon carcinogenesis. For over two decades, since its first discovery, azoxymethane (AOM)-induced rodent ACF have served as surrogate biomarkers in the screening of various anticarcinogens and carcinogens. Several dietary constituents and phytochemicals have been tested for their colon cancer chemopreventive efficacy using the ACF system. There has been substantial effort in defining and refining ACF in terms of understanding their molecular make-up, and extensive research in this field is currently in progress. In chemoprevention studies, AOM-induced rat ACF have been very successful as biomarkers, and have provided several standardized analyses of data. There have been several studies that have reported that ACF data do not correlate to actual colon tumor outcome, however, and hence there has been an ambiguity about their role as biomarkers. The scope of this mini-review is to provide valuable insights and limitations of AOM-induced rat ACF as biomarkers in colon cancer chemoprevention studies. The role of the dynamics and biological heterogeneity of ACF is critical in understanding them as biomarkers in chemoprevention studies.

Role of cycloxygenase-2 in ulcerative colitis

Cycloxygenase-2 (COX-2) plays an important role in the development and prognosis of ulcerative colitis. First, it may initiate inflammatory process. Many studies show that expression of COX-2 is significantly increased in the lesion of ulcerative colitis. During regenerative phase, inhibition of COX-2 may hinder the healing process, and thereafter exacerbate symptoms. COX-2-induced regeneration is monitored under delicate systems. If the balance of this system is disturbed by unknown factors, dysplasia or even carcinoma may develop.

Advances in hepatitis C virus core protein

Hepatitis C virus (HCV), a blood-borne virus, is one of the leading causes responsible for chronic hepatitis, liver cirrhosis and even hepatocellular carcinoma. At present precise mechanism of HCV infection has not been known yet, and no effective treatment and vaccination against HCV are available. However, recent findings show that apart from the function of viral partial package as the nucleocapsid protein, HCV core protein also participates in modulating cell apoptosis, lipid metabolism, transcription and antigen presentation, and has a close relationship with interferon resistance. HCV core protein has intense trans-activation effect and its interaction with the host protein accounts for persistent infection and hepatocellular tumorigenesis. Further cognition and analysis of molecular features of HCV core protein is of significance to elucidate persist HBV infection, mechanism underlying tumorigenesis induced by HCV, as well as impact of HCV on hepatic steatosis and interferon resistance.

MUC1 and colorectal cancer pathophysiology considerations

Several lines of evidence point towards a biological role of mucin and particularly MUC1 in colorectal cancer. A positive correlation was described between mucin secretion, proliferation, invasiveness, metastasis and bad prognosis. But, the role of MUC1 in cancer progression is still controversial and somewhat confusing. While Mukherjee and colleagues developed MUC1-specific immune therapy in a CRC model, Lillehoj and co-investigators showed recently that MUC1 inhibits cell proliferation by a β-catenin-dependent mechanism. In carcinoma cells the polarization of MUC1 is lost and the protein is over expressed at high levels over the entire cell surface. A competitive interaction between MUC1 and E-cadherin, through β-catenin binding, disrupts E-cadherin-mediated cell-cell interactions at sites of MUC1 expression. In addition, the complex of MUC1-β-catenin enters the nucleus and activates T-cell factor/leukocyte enhancing factor 1 transcription factors and activates gene expression. This mechanism may be similar to that just described for DCC and UNC5H, which induced apoptosis when not engaged with their ligand netrin, but mediate signals for proliferation, differentiation or migration when ligand bound.

Tumor suppressor and hepatocellular carcinoma

A few signaling pathways are driving the growth of hepatocellular carcinoma. Each of these pathways possesses negative regulators. These enzymes, which normally suppress unchecked cell proliferation, are circumvented in the oncogenic process, either the over-activity of oncogenes is sufficient to annihilate the activity of tumor suppressors or tumor suppressors have been rendered ineffective. The loss of several key tumor suppressors has been described in hepatocellular carcinoma. Here, we systematically review the evidence implicating tumor suppressors in the development of hepatocellular carcinoma.

Genetic alterations in pancreatic cancer

The diagnosis of pancreatic cancer is devastating for patients and their relatives as the incidence rate is approximately the same as mortality rate. Only a small percentage, which ranges from 0.4% to 4% of patients who have been given this diagnosis, will be alive at five years. At the time of diagnosis, 80% of pancreatic cancer patients have unresectable or metastatic disease. Moreover, the therapeutic alternatives offered by chemotherapy or radiotherapy are few, if not zero. For all these reasons, there is an imperative need of analyzing and understanding the primitive lesions that lead to invasive pancreatic adenocarcinoma. Molecular pathology of these lesions is the key of our understanding of the mechanisms underlying the development of this cancer and will probably help us in earlier diagnosis and better therapeutic results. This review focuses on medical research on pancreatic cancer models and the underlying genetic alterations.

Head and Neck Squamous Cell Cancer: Biology (II) and Translational Methods

The essential steps implicated in carcinogenesis are acquisition of autonomous proliferative signaling; inhibition of growth inhibitory signals; evasion of apoptosis; immortalization; angiogenesis; tissue invasion and metastasis. A considerable progress in understanding the process of carcinogenesis has further stimulated the high throughput translational methods and systems biology approach to revolutionize this field of cancer biology. The era of molecular targeted therapy has dawned and would soon replace the more 'toxic' classical 'broad-spectrum' cancer chemotherapy. This review summarises the steps of carcinogenesis and the concepts involved in translational methods, systems-biology and molecular targeted therapy.

Correlations of Helicobacter pylori infection with the expression of basic fibroblast growth factor and fibroblast growth factor receptor-2 in gastric mucosa and their significances

AIM: To study the expression of basic fibroblast growth factor (bFGF) and fibroblast growth factor receptor-2 (FGFR-2) in gastric mucosal epithelia with H. pylori infection and their significances in the carcinogenesis of stomach cancer.

METHODS: A total of 30 patients with chronic superficial gastritis (CGS), 29 with intestinal metaplasia (IM), 31 with dysplasia (Dys) and 55 with gastric cancer (GC) were included in this study. The expression of bFGF and FGFR-2 were assessed by immunohistochemistry (SP method). Rapid urease test and histological examination with Warthin-Starry were used to determine the status of H. pylori infection.

RESULTS: The expression of bFGF and FGFR-2 in CSG patients were significantly lower than those in the other patients (IM: χ² = 4.002, P < 0.05; χ² = 4.163, P < 0.05; Dys: χ² = 15.779, P = 0.000; χ² = 15.949, P = 0.000; GC: χ² = 24.110, P = 0.000; χ² = 18.736, P = 0.000). The expression of bFGF and FGFR-2 in IM patients were significantly lower than those in Dys and GC patients (Dys: χ² = 4.258, P < 0.05; χ² = 4.212, P < 0.05; GC: χ² = 7.786, P < 0.01; χ² = 4.687, P < 0.05). But there was no significant difference between Dys and GC patients. The positive rates of bFGF and FGFR-2 expression were significantly higher in H. pylori-infected IM and Dys patients than those in the patients without H. pylori infection (IM: χ² = 10.076, P < 0.01; χ² = 7.535, P < 0.01; Dys: χ² = 11.501, P < 0.01; χ² = 8.330, P < 0.01). The positive rates of bFGF and FGFR-2 expression in H. pylori-infected Dys patients were significantly higher than those in GC group (bFGF: χ² = 4.201, P < 0.05; FGFR-2: χ² = 3.982, P < 0.05), while no significant difference was found between GC and IM patients. The expression of bFGF in Dys and IM patients without H. pylori infection were significantly lower than that in GC patients (Dys: χ² = 5.736, P < 0.05; IM: χ² = 17.113, P = 0.000), and FGFR-2 expression in H. pylori-negative IM patients was significant lower than that in GC patients (χ² = 11.091, P < 0.05). No significant difference was found between H. pylori-negative Dys and GC patients.

CONCLUSION: H. pylori may induce over-expression of bFGF and FGFR-2 in gastric mucosal epithelia, which may play a vital role in the carcinogenesis of stomach cancer.

pRB expression in esophageal mucosa of individuals at high risk for squamous cell carcinoma of the esophagus

AIM: To investigate the pRb expression in a large group of patients with history of chronic exposure to the main risk factors for development of squamous cell carcinoma of the esophagus.

METHODS: One hundred and seventy asympto-matic individuals at high risk for esophageal squamous cell carcinoma (consumption of more than 80 g of ethanol and 10 cigarettes/d for at least 10 years) underwent upper gastrointestinal endoscopy with biopsies of the esophageal mucosa. As a control group, specimens of esophageal mucosa obtained from 20 healthy subjects were also studied. Immunohistochemical assessment of the tissues was performed using a monoclonal antibody anti-pRB protein.

RESULTS: Absence of the pRB staining, indicating loss of RB function, was observed in 33 (19.4%) of the individuals at risk for esophageal cancer, but in none of the healthy controls (P < 0.02). Loss of pRb expression increased in a stepwise fashion according to the severity of the histological findings (P < 0.005): normal mucosa (11/97 or 11.3%), chronic esophagitis (17/60 or 28.3%), low-grade dysplasia (3/10 or 30%), high-grade dysplasia 1/2 or 50%) and squamous cell carcinoma (1/1 or 100%).

CONCLUSION: Our findings suggest that abnormal expression of the pRB protein may be implicated in the process of esophageal carcinogenesis. Additional studies are warranted to define the role of the pRB protein as a biomarker for development of esophageal squamous cell carcinoma in individuals at high risk for this malignancy.

Emerging therapies in gastrointestinal cancers

Members of the receptor tyrosine kinase family, that include EGFR, ErbB-2/HER-2, ErbB-3/HER-3 and ErbB-4/HER-4, are frequently implicated in experimental models of epithelial cell neoplasia as well as in human cancers. Therefore, interference with the activation of these growth factor receptors represents a promising strategy for development of novel and selective anticancer therapies. Indeed, a number of inhibitors that target either EGFR or HER-2, with the exception of a few that target both; have been developed for treatment of epithelial cancers. Since most solid tumors express different ErbB receptors and/or their ligands, identification of inhibitor(s), targeting multiple EGFR family members may provide a therapeutic benefit to a broader patient population. Here we describe the significance of an ErbB family of receptors in epithelial cancers, and summarize different available therapeutics targeting these receptors. It also emphasizes the need to develop pan-ErbB inhibitors and discusses EGF-Receptor Related Protein, a recently isolated negative regulator of EGFR as a potential pan-ErbB therapeutic for a wide variety of epithelial cancers.

Methylation in esophageal carcinogenesis

Genetic abnormalities of proto-oncogenes and tumor suppressor genes have been demonstrated to be changes that are frequently involved in esophageal cancer pathogenesis. However, hypermethylation of CpG islands, an epigenetic event, is coming more and more into focus in carcinogenesis of the esophagus. Recent studies have proved that promoter hypermethylation of tumor suppressor genes is frequently observed in esophageal carcinomas and seems to play an important role in the pathogenesis of this tumor type. In this review, we will discuss current research on genes that are hypermethylated in human esophageal cancer and precancerous lesions of the esophagus. We will also discuss the potential use of hypermethylated genes as targets for detection, prognosis and treatment of esophageal cancer.

Expression and significance of cyclooxygenase-2 and basic fibroblast growth factor in colorectal carcinoma and adenoma

AIM: To investigate the mechanism of cyclooxygenase-2 (COX-2), basic fibroblast growth factor (BFGF) in the carcinogenesis of colorectal carcinoma and adenoma.

METHODS: Intestinal biopsy specimens were collected from patients with colorectal carcinoma (n = 49), adenoma (n = 25), and normal mucosa (n = 20), and the expression of COX-2 and BFGF were detected by immunohistochemical staining (SP method).

RESULTS: The positive rates of COX-2, BFGF expression were 59.2%, 69.3% in colorectal carcinoma, and 52.0%, 56.0% in adenoma, respectively. COX-2 and BFGF expression were not detected in normal intestinal mucosa. The positive rates of COX-2 and BFGF expression were not significantly difference between colorectal carcinoma and adenoma (P > 0.05). The expression of COX-2 and BFGF were not significantly correlated with the gender, age, tumor size, tumor location, and cell differentiation, but had marked correlations with Dukes stages (stage C, D vs A, B: 81.5% vs 54.5%, P < 0.05) and lymph node metastasis (metastasis vs non-metastasis: 81.5% vs 54.5%, P < 0.05). Furthermore, there were significant correlations between COX-2 and BFGF expression (r = 0.349, P < 0.05).

CONCLUSION: Excessive expression of COX-2 and BFGF may play a synergic role in the carcinogenesis and development of colorectal carcinoma and adenoma.

Expression of cyclooxygenase-2 is associated with p53 accumulation in premalignant and malignant gallbladder lesions

AIM: To examine the relationship between cyclooxygenase-2 (COX-2) overexpression and p53 accumulation in gallbladder carcinoma and its precursor lesions.

METHODS: Sixty-eight gallbladder tissue samples comprising 14 cases of normal gallblader epithelium, 27 cases of dysplasia (11 low-grade dysplasia and 16 high-grade dysplasia) and 27 adenocarcinomas were evaluated by immunohistochemistry for COX-2 expression and p53 accumulation. The relationship among COX-2 expression, p53 accumulation and clinicopathological characteristics was analysed.

RESULTS: COX-2 was expressed in 14.3% of normal gallbladder epithelium, 70.3% of dysplastic epitehlium, and 59.2% of adenocarcinomas. When divided into low- and high-grade dysplasia, COX-2 was positive in 5 (45.4%) cases of low-grade and 14 (87.5%) of high-grade dysplasia (P = 0.019). Accumulation of p53 was detected in 5 (31.2%) cases of high-grade dysplasia and in 13 (48.1%) of carcinomas. No p53 accumulation was found in normal epithelium or low-grade dysplasia. COX-2 overexpression was observed in 17 of 18 (94.4%) cases with p53-accumulation in comparison with 20 (40.0%) out of 50 cases without p53 accumulation (P < 0.001).

CONCLUSION: The significant differences in COX-2 expression among normal epithelium, low-grade dysplasia and high-grade dysplasia suggest that overexpression of COX-2 enzyme is an early event in gallbladder carcinogenensis. Furthermore, since accumulation of p53 correlates with COX-2 expression, COX-2 overexpression observed in gallbladder high-grade dysplasia and carcinoma might be partly due to the dysfunction of p53.

Latest insights into the effects of Helicobacter pylori infection on gastric carcinogenesis

There appears to be the strong association between Helicobacter pylori (H pylori) and gastric cancer. We reviewed the latest evidences about the effects of H pylori infection on gastric carcinogenesis, classified into epidemiology, dynamics of gastric mucosal changes, DNA damages, virulence factors, host factors, and source of gastric malignancy. Through the considerable progress made in research into virulence factors resulting from differences between H pylori strains, such as cagA positivity, as well as into host factors, such as gene polymorphisms, a diverse spectrum of H pylori-associated diseases, including gastric cancer, is beginning to lend itself to elucidation. The impact of the novel hypothesis advanced by Houghton et al proposing bone-marrow derived stem cells (BMDC) as a potential source of gastric malignancy on evolving research remains to be seen with interest. Further progress in research into H pylori eradication as a viable prophylaxis of gastric cancer, as well as into the mechanisms of gastric carcinogenesis, is to be eagerly awaited for the current year and beyond.

Expression of Axin protein correlates with genesis and metastasis of gastric carcinoma

AIM: To investigate the relationship between Axin protein expression and genesis and metastasis of gastric carcinoma.

METHODS: A total of 46 patients with gastric carcinoma underwent surgical resection were included in this study. The expression of Axin protein was detected by immunohistochemical techniques (SABC) in paraffin-embedded samples prepared from gastric carcinoma tissues and normal stomach tissues far from the tumor. In addition, the positive rate of Axin expression was calculated and its corrrelation with the pathological characteristics of gastric carcinoma was analyzed.

RESULTS: In normal stomach tissues, Axin protein expression was strongly positive and intensified in basal cells. Axin was also expressed in tissues from gastric carcinoma and normal stomach mucosa far from the tumor with a positive rate of 62.0% and 91.3%, respectively. There was a significant difference between them (P < 0.01). Axin protein expression was significantly correlated with clinical TNM classification (TNM Ⅰ, Ⅱ vs Ⅲ, Ⅳ: 78.6% vs 56.3%, P = 0.035) and lymphatic metastasis (without vs with: 85.7% vs 53.1%, P = 0.034). The expression of Axin protein was not markedly correlated with the age and gender of patients, tumor size, biological features and serosa invasion (P > 0.05).

CONCLUSION: The expression of Axin protein is down-regulated in gastric carcinoma, which correlates with the genesis and metastasis of the disease.

Causal role of Helicobacter pylori infection in gastric cancer: An Asian enigma

Helicobacter pylori (H pylori) has been etiologically linked to gastric cancer. H pylori infection is more frequent in less developed Asian countries like India, Bangladesh, Pakistan, and Thailand and is acquired at early age than in more developed Asian countries like Japan and China. Frequency of gastric cancer, however, is very low in India, Bangladesh, Pakistan and Thailand compared to that in Japan and China. Similar enigma has been reported from Africa as compared to the West. Seroprevalence of H pylori infection in adult populations of India, Bangladesh, Pakistan and Thailand varies from 55% to 92%. In contrast, seroprevalence of H pylori in Chinese and Japanese adults is 44% and 55%, respectively. Annual incidence rate of gastric cancer in India, Bangladesh, and Thailand is 10.6, 1.3, 7.1 per 100 000 populations, respectively; in contrast, that in China and Japan is 32-59 and 80-115 per 100 000 populations, respectively. Several studies from India failed to show higher frequency of H pylori infection in patients with gastric cancer than controls. Available evidences did not support difference in H pylori strains as an explanation for this enigma. Despite established etiological role of H pylori, situation is somewhat enigmatic in Asian countries because in countries with higher frequency of infection, there is lower rate of gastric cancer. Host’s genetic make-up and dietary and environmental factors might explain this enigma. Studies are urgently needed to solve this issue.

Cyclooxygenase-2 and epithelial growth factor receptor up-regulation during progression of Barrett’s esophagus to adenocarcinoma

AIM: To investigate the expression of cyclooxygenase-2 (COX-2) and epithelial growth factor receptor (EGFR) throughout the progression of Barrett’s esophagus (BE).

METHODS: COX-2 and EGFR protein expressions were detected by using immunohistochemical method. A detailed cytomorphological changes were determined. Areas of COX-2 and EGFR expression were quantified by using computer Imaging System.

RESULTS: The expressions of both COX-2 and EGFR increased along with the progression from BE to esophagus adenocarcinoma (EAC). A positive correlation was found between COX-2 expression and EGFR expression.

CONCLUSION: COX-2 and EGFR may be cooperative in the stepwise progression from BE to EAC, thereby leading to carcinogenesis.

Lipid peroxidation and antioxidant status in colorectal cancer

AIM: Reactive oxygen species (ROS) can induce carcinogenesis via DNA injury. Both enzymatic and non-enzymatic parameters participate in cell protection against harmful influence of oxidative stress. The aim of the present study was to assess the levels of final lipid peroxidation products like malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE) in primary colorectal cancer. Moreover, we analysed the activity of main antioxidative enzymes, superoxide dismutase (Cu, Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GSSRG-R) and the level of non-enzymatic antioxidants (glutathione, vitamins C and E).

METHODS: Investigations were conducted in 81 primary colorectal cancers. As a control, the same amount of sample was collected from macroscopically unchanged colon regions of the most distant location to the cancer. Homogenisation of specimens provided 10% homogenates for our evaluations. Activity of antioxidant enzymes and level of glutathione were determined by spectrophotometry. HPLC revealed levels of vitamins C and E and served as a method to detect terminal products of lipid peroxidation in colorectal cancer.

RESULTS: Our studies demonstrated a statistically significant increase in the level of lipid peroxidation products (MDA-Adc.muc.-2.65±0.48 nmol/g, Adc.G3-2.15±0.44 nmol/g, clinical IV stage 4.04±0.47 nmol/g, P<0.001 and 4-HNE-Adc.muc. -0.44±0.07 nmol/g, Adc.G3-0.44±0.10 nmol/g, clinical IV stage 0.52±0.11 nmol/g, P<0.001) as well as increase of Cu,Zn-SOD (Adc.muc.-363±72 U/g, Adc.G3-318±48 U/g, clinical IV stage 421±58 U/g, P<0.001), GSH-Px (Adc.muc. -2143±623 U/g, Adc.G3-2005±591 U/g, clinical IV stage 2467±368 U/g, P<0.001) and GSSG-R (Adc.muc.-880±194 U/g, Adc.G3-795±228 U/g, clinical IV stage 951±243 U/g, P<0.001) in primary tumour comparison with normal colon (MDA-1.39±0.15 nmol/g, HNE-0.29±0.03 nmol/g, Cu, Zn-SOD-117±25 U/g, GSH-Px-1723±189 U/g, GSSG-R-625±112 U/g) especially in mucinous and G3-grade adenocarcinomas as well as clinical IV stage of colorectal cancer. We also observed a decrease of CAT activity (Adc.muc. -40±14 U/g, clinical IV stage 33±18 U/g vs 84±17 U/g, P<0.001) as well as a decreased level of reduced glutathione (clinical IV stage 150±48 nmol/g vs 167±15 nmol/g, P<0.05) and vitamins C and E (vit. C-clinical IV stage 325±92 nmol/g vs 513±64 nmol/g, P<0.001; vit. E-clinical IV stage 13.3±10.3 nmol/g vs 37.5±5.2 nmol/g).

CONCLUSION: Colorectal carcinogenesis is associated with serious oxidative stress and confirms that gradual advancement of oxidative-antioxidative disorders is followed by progression of colorectal cancer.