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

Proliferation, apoptosis and their regulatory protein expression in colorectal adenomas and serrated lesions

BACKGROUND

Adenomas and serrated lesions represent heterogeneous sets of early precursors in the colorectum with varying malignant potential. They are often distinguished by their histopathologic differences, but little is known about potential differences in regulation of epithelial proliferation and apoptosis.

METHODS

We conducted a protein expression analysis using tissue microarrays of 625 colorectal adenomas and 142 serrated lesions to determine potential differences in regulation of epithelial proliferation and apoptosis. We quantitated proliferation with Ki-67; apoptosis with activated caspase-3 (CASP3); up- and down-regulators of proliferation with cyclin D1, p16INK2, and p21Cip1; and apoptosis regulators with BAX, BCL2, and survivin. Linear mixed effects models and circos diagrams were used to determine relationships among expression and lesion characteristics.

RESULTS

Adenomas had a significantly higher CASP-3 labeling index (LI) than serrated lesions, resulting in a lower net growth ratio (Ki-67 LI/activated CASP-3 LI, p-value<0.0001). Cyclin D1 LI, p16 LI and p21 LI were lower in adenomas compared to serrated lesions, while expression of both BCL2 and BAX were higher (p <0.001). Among adenomas, cyclin D1 LI and p16 LI levels increased with greater villous component, and the highest BAX expression was detected in adenomas larger than 2 cm (both p<0.0001). Right-sided adenomas had higher CASP3 LI than left colorectal adenomas (p = 0.008). Significant differences in cyclin D1 LI, p21 LI and survivin LI were also observed across histopathologic subtypes of serrated lesions.

CONCLUSIONS

Our findings demonstrate different patterns of regulatory protein expression in adenomas than serrated lesions, especially involving apoptosis. ClinicalTrials.gov Identifier: NCT00272324.

Prevalence of proliferating CD8+ cells in normal lymphatic tissues, inflammation and cancer

CD8⁺ cytotoxic T-lymphocytes are essential components of the anti-tumor immunity. To better understand the expansion of CD8⁺ T-cells we used multiplex fluorescence immunohistochemistry to study Ki67⁺CD8⁺ cells in normal lymphoid tissues, selected inflammatory diseases and cancers in 41 large sections/ microenvironment tissue microarrays (TMAs) as well as 765 samples in a conventional TMA format. The evaluation of more than 20 different compartments of normal lymphoid tissues revealed that the percentage of proliferating (ki67⁺) CD8⁺ cells did commonly not exceed 3%. In inflammations, the percentage of Ki67⁺CD8⁺ cells was more variable and higher compared to normal tissues. In cancers, the percentage of Ki67⁺CD8⁺ cells was higher in the tumor center than at the invasive margin. In the tumor center of 765 colorectal cancers, the density of Ki67⁺CD8⁺ cells and the percentage of proliferating CD8⁺ cytotoxic T-cells was significantly associated with microsatellite instability (p<0.0001), pT (p<0.0002) and pN category (p<0.0098). In summary, these data show that the percentage of Ki67⁺CD8⁺ cells is usually at a baseline proliferation rate below 3% in healthy secondary lymphoid organs. This rate is often markedly higher in inflammatory and neoplastic diseases compared to normal tissues. The striking link with unfavorable tumor features in colorectal cancer suggest a potential clinical utility of assessing the percentage of Ki67⁺CD8⁺ cells to predict patients outcome.

Correlation study of GAPDH, Bcl-2, and Bax protein immunoexpression in patients with colorectal adenocarcinoma

Introduction

Colorectal cancer (CRC) is the third and second most commonly diagnosed cancer worldwide in males and females, respectively. Despite prominent progress in diagnosis and treatment, the recurrence rates are still high. A tumour hypoxic environment leads to an increase in glycolytic metabolism. The crucial intermediate component of glycolysis, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), could play a significant role in cancer progression. An increased level of GAPDH has been described in oncogene-induced transformation and anti-apoptotic function. In other studies, GAPDH has been involved in apoptosis induction.

Aim

We examined colorectal adenocarcinoma samples to assess the immunoexpression of GAPDH protein. We also evaluated the correlation between the expression of GAPDH protein and apoptotic parameters including expression of Bcl2 and Bax.

Material and methods

Paraffin sections were incubated for 60 min with primary antibody against GAPDH, Bcl-2, and Bax.

Results

Results of our study have shown that GAPDH expression in colorectal cancer is upregulated. We revealed significant positive correlation between expression of this protein and grade and size of tumour, and regional lymph node involvement. In the case of apoptosis-associated proteins, e.g. Bcl-2 and Bax, we found negative correlations between expression of these proteins and grade and size of tumour, lymphovascular invasion, and regional lymph node involvement. Finally, we demonstrated that GAPDH up-regulation is connected with down-regulation in Bcl-2 and Bax.

Conclusions

Up-regulation of GAPDH protein and down-regulation of Bcl-2 and Bax may result in increased of cancer.

BCL2 Expression and its Correlation with Neuroendocrine Differentiation in Colon Carcinomas

Aims and background

In this study we investigated the association between BCL2 expression and neuroendocrine differentiation in tubular adenomas and colon carcinomas. We also evaluated the prognostic significance of BCL2 expression and neuroendocrine differentiation in the carcinoma group.

Methods

Forty-eight colon carcinomas and twelve tubular adenomas were stained immunohistochemically with BCL2 and chromogranin A (CgA). Staining patterns were scored semiquantitatively and correlated with tumor type, tumor grade, Dukes stage, and survival time.

Results

BCL2 expression was detected in 7 of 12 (58.3%) adenomas and 37 of 48 (77.0%) carcinomas. In normal mucosa we observed positive staining only in the basal portions of the crypts. However, diffuse positivity was observed in the adenomas and carcinomas. Carcinomas had significantly higher BCL2 scores than the normal group, but we did not observe any significant differences either between the adenoma and carcinoma group or between the adenoma and normal group. BCL2 scores were higher in stage B than in stage C tumors, and in adenocarcinomas than in mucinous carcinomas. CgA positivity was observed in 24 of 48 (50%) carcinomas. It was not detected in adenomas. We did not find a significant correlation between CgA expression and any of the clinicopathological parameters.

Conclusion

On consecutive sections BCL2 and CgA positivity closely paralleled each other and a significant positive correlation was observed between CgA and BCL2 expression. These findings suggest a close association between BCL2 expression and neuroendocrine differentiation and indicate that BCL2 may be involved in neuroendocrine differentiation in addition to its role in protecting cells from apoptosis.

A High Ki67/BCL2 Index Could Predict Lower Disease-Free and Overall Survival in Intestinal-Type Gastric Cancer

BACKGROUND

The heterogeneity of gastric cancer makes the identification of potential prognostic indicators particularly important. The Ki67 and BCL2 proteins are known prognostic markers for different types of cancer. Ki67 is associated with cell proliferation, whereas BCL2 has antiproliferative roles. A combined marker based on these opposite functions might provide improved prognostic information in gastric cancer.

METHOD

Ki67 and BCL2 expression was assessed in 276 gastric adenocarcinoma tissue microarrays. A Ki67/BCL2 index based on the relative expression of each protein was divided into low- and high-risk groups using receiver operating characteristic curves.

RESULTS

A high Ki67/BCL2 index significantly correlated with advanced stage, recurrence, intestinal type, high histologic grade, and lymphatic and perineural invasion (all p < 0.05). Univariate and multivariate analyses revealed a significant relationship between disease-free or overall survival and the Ki67/BCL2 index in intestinal-type gastric cancer (all p < 0.05).

CONCLUSIONS

A combined marker using Ki67 and BCL2 could be a useful indicator for predicting survival in patients with intestinal-type gastric cancer.

Ki-67 Expression in CRC Lymph Node Metastasis Does Not Predict Survival

Colorectal cancer is one of the most common malignancies and a leading cause of cancer death worldwide. Molecular markers may improve clinicopathologic staging and provide a basis to guide novel therapeutic strategies which target specific tumour-associated molecules according to individual tumour biology; however, so far, no ideal molecular marker has been found to predict disease progression. We tested Ki-67 proliferation marker in primary and lymph node metastasis of CRC. We observed a statistical significant difference between the positive rates of neoplastic cells positively stained by Ki-67 in both sites, with remarkable increased number of Ki-67 positive cells in primary tumor cells compared to cancer cells that invaded lymph nodes. We can speculate that the metastatic CRC in lymph node can be more resistant to the drugs that target cellular division.

Highly Expressed Genes in Rapidly Proliferating Tumor Cells as New Targets for Colorectal Cancer Treatment

PURPOSE

The clinical management of colorectal cancer patients has significantly improved because of the identification of novel therapeutic targets such as EGFR and VEGF. Because rapid tumor proliferation is associated with poor patient prognosis, here we characterized the transcriptional signature of rapidly proliferating colorectal cancer cells in an attempt to identify novel candidate therapeutic targets.

EXPERIMENTAL DESIGN

The doubling time of 52 colorectal cancer cell lines was determined and genome-wide expression profiling of a subset of these lines was assessed by microarray analysis. We then investigated the potential of genes highly expressed in cancer cells with faster growth as new therapeutic targets.

RESULTS

Faster proliferation rates were associated with microsatellite instability and poorly differentiated histology. The expression of 1,290 genes was significantly correlated with the growth rates of colorectal cancer cells. These included genes involved in cell cycle, RNA processing/splicing, and protein transport. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and protoporphyrinogen oxidase (PPOX) were shown to have higher expression in faster growing cell lines and primary tumors. Pharmacologic or siRNA-based inhibition of GAPDH or PPOX reduced the growth of colon cancer cells in vitro. Moreover, using a mouse xenograft model, we show that treatment with the specific PPOX inhibitor acifluorfen significantly reduced the growth of three of the seven (42.8%) colon cancer lines investigated.

CONCLUSIONS

We have characterized at the transcriptomic level the differences between colorectal cancer cells that vary in their growth rates, and identified novel candidate chemotherapeutic targets for the treatment of colorectal cancer.

Cantharidin inhibits cell proliferation and promotes apoptosis in tongue squamous cell carcinoma through suppression of miR-214 and regulation of p53 and Bcl-2/Bax

Cantharidin, a type of terpenoid, is a chemical compount secreted by the blister beetle or Mylabris phelarata pallas of the Meloidae family. Cantharidin is known to have good antitumor activity. The present study aimed to investigate the anticancer effect of cantharidin and its possible underlying mechanism using tongue squamous cell carcinoma (TSCC) TCA8113 cells. TCA8113 cells were treated with various concentrations of cantharidin, and the cell viability and cytotoxicity were assessed using MTT and LDH assays, respectively. Flow cytometry was conducted to examine cell apoptosis and colorimetric protease assay was performed to analyze caspase-9/3 activities in TCA8113 cells. qPCR and western blot analysis were used to investigate microRNA-214 (miR-214) expression, as well as the expression of p53, Bcl-2 and Bax proteins in TCA8113 cells. miR-214 and anti-miR-214 were transfected with mimics to examine whether miR-214 expression regulated the anticancer effect of cantharidin on TCA8113 cells and p53, Bcl-2 and Bax protein expression. The anticancer effect of cantharidin significantly inhibited cell proliferation and increased cytotoxicity of TSCC Tca8113 cells in a dose- and time-dependent manner. In addition, cantharidin induced cell apoptosis and activated caspase-9/3 activities of TSCC Tca8113 cells. Cantharidin markedly weakened miR-214 expression level, activated p53 protein expression, and suppressed the Bcl-2/Bax signaling pathway in Tca8113 cells. Downregulation of miR-214 increased p53 protein expression and decreased the Bcl-2/Bax signaling pathway of TSCC Tca8113 cells. However, the overexpression of miR-214 reduced the anticancer effect of cantharidin on the proliferation and apoptosis of TSCC Tca8113 cells, inhibited p53 protein expression, and increased the Bcl-2/Bax signaling pathway. The results suggested that cantharidin is a potential anticancer drug that can be used to regulate the proliferation and apoptosis of human TSCC Tca8113 cells. Additionally, its mechanism may partially be associated with the downregulation of miR-214, upregulation of p53 protein expression and suppression of the Bcl-2/Bax signaling pathway.

Bcl2 and Ki67 refine prognostication in luminal breast cancers

Combined B-cell lymphoma 2 (Bcl2) and Ki67 expression for breast cancer prognostication has been proposed recently. However, the combinatorial relationship with patient outcome, clinico-pathologic features, and various biomarkers has not been fully explored. Bcl2 and Ki67 expression were examined in a large cohort of breast cancers. Differential Bcl2 and Ki67 combinatorial analysis, particularly in luminal cancers, were evaluated with respect to the clinico-pathologic features, biomarkers profile and outcome. Combined Bcl2/Ki67 phenotypes classified by Bcl2 and Ki67 cutoffs showed a better correlation with outcome. Multivariate analysis revealed this to be an independent prognostic factor in luminal cancers. Both Ki67 and Bcl2 contributed to the prognostic implications of different subgroups defined by Bcl2/Ki67 combination phenotypes with clinico-pathologic features and biomarkers profile. Ki67low/Bcl2high cases showed better DFS (HR = 2.17, P = 0.015) and OS (HR = 3.217, P = 0.015) compared to Ki67high/Bcl2low cases. Interestingly, Ki67low/Bcl2high cases also showed better outcome than other phenotypes in grade 2 cancers (log-rank = 4.844, P = 0.028) and TNM stage 2 cancers (log-rank = 8.161, P = 0.004). This classification by Bcl2/Ki67 combination phenotypes, together with PR expression, can also refine luminal A cancers prognostication. Not all PR low luminal A cases had poorer outcome compared to the PR high luminal A cases; poor prognosis was only limited to those with also low Bcl2 (log-rank = 23.568, P < 0.001 compared to PR high Bcl2 high cases). The combined Ki67/Bcl2 phenotyping was useful in luminal cancers prognostication. It also refined prognostication in intermediate groups (grade 2 and stage 2 cancers) of luminal cancers; and aided in further classification of luminal A cancers.

Expression of apoptotic proteins in human colorectal cancer and metastatic lymph nodes

PURPOSE

The aim of this study was to determine the expression of Bak, Bax, Bcl-2, Bcl-xl and procaspase-3 proteins in colorectal tumor and regional lymph nodes, as well as to investigate the correlation between them and with clinicopathologic parameters.

METHODS

Expression of the examined proteins was evaluated by immunohistochemical study.

RESULTS

No significant correlation was revealed between Bcl-2, Bcl-xl, Bak, Bax and procaspase-3 expressions and age, gender, location or size of primary tumor and grade in the main tumor mass or in lymph nodes. Additionally, the only association we found was between Bak protein in primary tumor and in adjacent metastatic lymph nodes.

CONCLUSION

Bcl-2 protein seems to exert substantial effects prevention of apoptosis in pT3 CRC with positive lymph node involvement, while lower expressions of Bcl-xl proteins suggest that it does not play a significant part in the inhibition of apoptosis.

Expression of E-cadherin and KRAS mutation may serve as biomarkers of cetuximab-based therapy in metastatic colorectal cancer

Cetuximab (Cmab), a chimeric monoclonal antibody for targeting the epidermal growth factor receptor, has become one of the standard treatments for metastatic colorectal cancer (mCRC). However, only a small proportion of patients respond to Cmab, and it has been reported that KRAS mutation is a negative biomarker of response to Cmab therapy. The aim of this study was to detect additional biomarkers of response to Cmab therapy in patients with mCRC. We evaluated the effects of Cmab therapy in 36 patients with mCRC according to the Response Evaluation Criteria in Solid Tumors, and classified patients who achieved complete response, partial response or stable disease as responders, and patients who achieved progressive disease as non-responders. We retrospectively examined the difference between the two groups using KRAS analysis and immunohistochemistry to determine the expression of E-cadherin, p53 and Ki67. Nineteen patients were responders, while 17 patients were non-responders. KRAS status and expression of E-cadherin were significantly correlated with the effect of Cmab therapy. Moreover, the expression of E-cadherin was significantly correlated with the effect of Cmab therapy in KRAS wild-type patients. In KRAS mutant-type patients, the expression of E-cadherin did not significantly correlate with the effect of Cmab therapy, but all responders with KRAS mutant-type tumors expressed E-cadherin. Our results indicate that the expression of E-cadherin detected by immunohistochemistry may be a positive predictor of Cmab-based therapy in mCRC, and that a combination of E-cadherin immunohistochemistry and KRAS analysis may be a more sensitive biomarker than KRAS analysis alone.

Matrix metalloproteinase-9 functions as a tumor suppressor in colitis-associated cancer

There is a well-documented association of matrix metalloproteinase-9 (MMP-9) and receptor Notch-1 overexpression in colon cancer. We recently showed that MMP-9 is also upregulated in colitis, where it modulates tissue damage and goblet cell differentiation via proteolytic cleavage of Notch-1. In this study, we investigated whether MMP-9 is critical for colitis-associated colon cancer (CAC). Mice that are wild type (WT) or MMP-9 nullizygous (MMP-9(-/-)) were used for in vivo studies and the human enterocyte cell line Caco2-BBE was used for in vitro studies. CAC was induced in mice using an established carcinogenesis protocol that involves exposure to azoxymethane followed by treatment with dextran sodium sulfate. MMP-9(-/-) mice exhibited increased susceptibility to CAC relative to WT mice. Elevations in tumor multiplicity, size, and mortality were associated with increased proliferation and decreased apoptosis. Tumors formed in MMP-9(-/-) mice exhibited expression of p21(WAF1/Cip1) and increased expression of beta-catenin relative to WT mice. In vitro studies of MMP-9 overexpression showed increased Notch-1 activation with a reciprocal decrease in beta-catenin. Notch and beta-catenin/Wnt signaling have crucial roles in determining differentiation and carcinogenesis in gut epithelia. Despite being a mediator of proinflammatory responses in colitis, MMP-9 plays a protective role and acts as a tumor suppressor in CAC by modulating Notch-1 activation, thereby resulting in activation of p21(WAF1/Cip1) and suppression of beta-catenin.

Transforming growth factor beta 1 and metalloproteinase-9 overexpression in colorectal cancer (CC) and adenoma

BACKGROUND AND AIMS

Although the role of transforming growth factor beta (TGFbeta) 1 and metalloproteinase-9 (MMP-9) is well documented in colorectal cancer (CC), there is a little evidence supporting its role in early carcinogenesis. The aim of the study was to determine the pattern of immunohistochemical expression of TGFbeta1, MMP-9, and Ki-67 in CC and adenomatous polyps.

PATIENT/METHODS

The study group comprised 50 patients with colorectal polyps and 33 patients with CC. Endoscopically removed polyps and CC biopsies had been evaluated with histopatologic examination and immunohistochemistry. The biopsies from 30 healthy objects served as a control group. For all antibodies labeling indices (LI) had been calculated.

RESULTS

Among 62 adenomas, 33 high-grade dysplasia (HGD) and 29 low-grade dysplasia (LGD) had been detected. Mean TGFbeta1, MMP-9, and Ki-67 LI in CC were significantly higher (p < 0.01, 0.01, and 0.01, respectively) than in HGD polyps. Mean TGFbeta1, MMP-9, and Ki-67 LI in HGD polyps were significantly higher than in LGD polyps (p < 0.01, 0.01, and 0.01, respectively). There had been no statistical difference in TGFbeta1, MMP-9, and Ki-67 LI between LGD and the control group (p > 0.05, 0.05, and 0.05, respectively). There was a positive correlation between TGFbeta1 and MMP-9 (r = 0.898), Ki-67 and MMP-9 (r = 0.938), and TGFbeta1 and Ki-67 (r = 0.913). We did not observe any correlation between TGFbeta1, MMP-9, Ki-67 LI and the clinical parameters evaluated.

CONCLUSION

The increased expression of TGFbeta1, MMP-9 observed in colorectal adenomas seems to be related to the grade of dysplasia. We assume that overexpression of TGFbeta1, MMP-9 represent an early event in colorectal carcinogenesis and may possibly have the prognostic value.

Novel anticancer agent, benzyldihydroxyoctenone, isolated from Streptomyces sp. causes G1 cell cycle arrest and induces apoptosis of HeLa cells

In the course of screening for anticancer agents, a novel active compound, F3-2-5, was isolated from culture broth of Streptomyces sp., KACC91015. Its structure was identified using nuclear magnetic resonance, mass spectrometry, and molecular modeling experiments, and confirmed by total synthesis. The growth of various human cancer cell lines was inhibited in a dose-dependent manner by 0.06-0.48 mM F3-2-5 over 24 h. Its IC(50) values were estimated at 37 microM on HeLa, 72 microM on A549, and 190 microM on HT-29 cells. However, F3-2-5 had no antiproliferative effect on normal lymphocytes and normal fibroblasts used as controls. Moreover, it affected cell cycle regulation and caused apoptosis of the HeLa cells; chromatin condensation and DNA fragmentation were observed in cells exposed to 80 microM F3-2-5. Western blot analysis revealed that F3-2-5 inhibited phosphorylation of retinoblastoma protein (pRb) and reduced expression of cyclin-dependent kinase-4 and -6, and cyclin D1 and E, while levels of p53 and p21(WAF1/CIP1) increased. Taken together, these findings show that F3-2-5 inhibits proliferation of HeLa cells by inducing G(1) phase arrest as a consequence of inhibition of pRb phosphorylation following up-regulation of p21(WAF1/CIP1) and p53. Furthermore, apoptosis in HeLa cells treated with F3-2-5 was associated with an increase in Bax and p53, leading to release of cytochrome c, activation of caspase-3, and -8, and cleavage of poly (ADP-ribose) polymerase.

NF-kappaB and apoptosis in colorectal tumourigenesis

BACKGROUND

Nuclear factor-kappaB (NF-kappaB) may play an important role in colorectal tumourigenesis, controlling cell cycle and apoptosis gene expression. In addition, imbalances between cell proliferation and cell death are thought to underlie neoplastic development. The aims of this study were to investigate apoptosis and expression of several apoptosis-related proteins, and to determine correlations with colorectal tumour progression.

MATERIALS AND METHODS

Apoptosis was evaluated by the TUNEL assay in 48 patient samples, including adenomas, adenocarcinomas and adjacent normal mucosas. Immunohistochemistry was performed for Bcl-2 and NF-kappaB. Expression levels of p53, Bax and IkappaB proteins were determined by immunoblotting. Cultured human colon cancer cells were used to evaluate NF-kappaB expression and nuclear translocation by immunocytochemistry and immunoblotting.

RESULTS

Apoptosis and NF-kappaB immunoreactivity were significantly higher in tumour tissue compared with normal mucosa (P < 0.01), increasing in association with histological tumour progression (P < 0.01). Bcl-2 was consistently higher in normal mucosa (P < 0.01) and inversely correlated with the percentage of apoptosis (P < 0.01). Phosphorylated p53 and Bax levels were similar in tumour tissue and normal mucosa; however, the NF-kappaB inhibitor, IkappaB, tended to decrease in tumours. In vitro, nuclear translocation of NF-kappaB was greater in proliferative than in resting phases of colon cancer cells.

CONCLUSIONS

NF-kappaB expression and apoptosis are increased from adenoma to poorly differentiated adenocarcinoma tissues. Apoptosis is correlated with suppression of Bcl-2 expression, but appears to proceed through a p53- and Bax-independent pathway. Activation of NF-kappaB may play an important role in colorectal tumour progression.

NF-kappaB and apoptosis in colorectal tumourigenesis

BACKGROUND

Nuclear factor-kappaB (NF-kappaB) may play an important role in colorectal tumourigenesis, controlling cell cycle and apoptosis gene expression. In addition, imbalances between cell proliferation and cell death are thought to underlie neoplastic development. The aims of this study were to investigate apoptosis and expression of several apoptosis-related proteins, and to determine correlations with colorectal tumour progression.

MATERIALS AND METHODS

Apoptosis was evaluated by the TUNEL assay in 48 patient samples, including adenomas, adenocarcinomas and adjacent normal mucosas. Immunohistochemistry was performed for Bcl-2 and NF-kappaB. Expression levels of p53, Bax and IkappaB proteins were determined by immunoblotting. Cultured human colon cancer cells were used to evaluate NF-kappaB expression and nuclear translocation by immunocytochemistry and immunoblotting.

RESULTS

Apoptosis and NF-kappaB immunoreactivity were significantly higher in tumour tissue compared with normal mucosa (P < 0.01), increasing in association with histological tumour progression (P < 0.01). Bcl-2 was consistently higher in normal mucosa (P < 0.01) and inversely correlated with the percentage of apoptosis (P < 0.01). Phosphorylated p53 and Bax levels were similar in tumour tissue and normal mucosa; however, the NF-kappaB inhibitor, IkappaB, tended to decrease in tumours. In vitro, nuclear translocation of NF-kappaB was greater in proliferative than in resting phases of colon cancer cells.

CONCLUSIONS

NF-kappaB expression and apoptosis are increased from adenoma to poorly differentiated adenocarcinoma tissues. Apoptosis is correlated with suppression of Bcl-2 expression, but appears to proceed through a p53- and Bax-independent pathway. Activation of NF-kappaB may play an important role in colorectal tumour progression.

Apoptotic and cell cycle regulatory markers in uterine leiomyosarcoma

OBJECTIVES

The primary aim of this study was to investigate the expression of apoptotic and cell cycle regulators p53, p21, p27, bax, and bcl-2 in uterine leiomyosarcoma in order to identify molecular pathways that possibly could be important in the development of leiomyosarcoma. A secondary aim was to examine if the apoptotic and cell cycle regulatory protein expression profile of uterine leiomyosarcoma is potentially useful for clinical prognostic purposes.

METHODS

A tissue microarray representing 36 uterine leiomyosarcomas and 19 uterine leiomyomas was created with 3 representative cores from each tumor. Immunohistochemical staining was performed for bcl-2, bax, p21, p27, and p53 using standard techniques. Staining was scored 0-12 for each marker, 0-3 being negative and 4-12 positive. Outcome analyses were performed only for leiomyosarcomas. First recurrence was determined from the time of initial diagnosis. Survival was determined from the time of initial diagnosis to last follow-up.

RESULTS

Associations were found between disease type (leiomyosarcoma vs. leiomyoma) and the positivity status of p21 (43% vs. 0%, P < 0.001), p53 (54% vs. 0%, P < 0.001), and bax (34% vs. 94%, P < 0.001). bcl-2-positive leiomyosarcoma was associated with a longer time to recurrence (P = 0.02) in a univariate analysis. In a multivariate analysis, tumor stage was the only independent significant prognostic factor (P = 0.002).

CONCLUSION

The significant differential expression of apoptotic and cell cycle regulatory proteins in uterine leiomyosarcoma as compared to benign smooth muscle tumors suggests that pathways involving these proteins may be important in the development of malignant disease and, therefore, could be potential targets for molecular therapies.

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.

Using a combination of cytochrome P450 1B1 and beta-catenin for early diagnosis and prevention of colorectal cancer

BACKGROUND

Although fecal occult blood test and invasive endoscopic examination are common used to detect colorectal adenomas and cancers, non-invasive and specific biomarkers are still under investigation. The objective is to evaluate the biomarker CYP1B1 alone or in combination with aryl hydrocarbon receptor (AhR), nuclear beta-catenin, p53 or bcl-2 for early diagnosis and prevention of colorectal cancer.

METHODS

These biomarkers were analyzed semi-quantified across 231 colonic tissues including 97 adenocarcinomas, 85 adenomas and 49 non-neoplastic colons using immunohistochemistry. In order to differentiate non-neoplastic colons from colorectal neoplasms (adenoma and carcinoma), the values for CYP1B1, AhR, nuclear beta-catenin, p53 and bcl-2 expressions were subjected to discrimination analysis, then the cross-validation, sensitivity and specificity of these models were calculated.

RESULTS

Expressions of CYP1B1, p53, nuclear beta-catenin and bcl-2 were significantly associated with colorectal carcinogenesis (p<0.01 for the trend test). The overexpression rates for CYP1B1, p53, nuclear beta-catenin and bcl-2 were significantly higher in the adenoma and carcinoma groups than in the non-neoplastic colon group (p<0.05). The discrimination models showed that a combination of two biomarkers was better than a single biomarker, and provided specificity ranging from 39% to 100% and sensitivity ranging from 43% to 82% for colorectal carcinoma.

CONCLUSIONS

The increase in expression of CYP1B1 occurred not only in colorectal carcinoma and but also in adenoma. Moreover, a screening panel of CYP1B1 in combination with nuclear beta-catenin was the most suitable marker pair to screen for colorectal carcinoma based on this study.

Clinical significance of Ki-67 proliferation index in disease progression and prognosis of patients with resected colorectal carcinoma

BACKGROUND

The prognostic role of proliferation markers in patients with colorectal neoplasia is inconclusive. The aim of this study was to evaluate proliferation markers in patients with colorectal carcinoma, to relate these to standard clinicopathological findings and to investigate their potential role in the prediction of long-term survival.

METHODS

Archived formalin-fixed, paraffin-embedded tissue samples from a cohort of 106 patients who underwent curative resection for colorectal carcinoma were analysed to determine a Ki-67 (MIB-1)-derived proliferation index (PI) using a double immunostaining technique. The relationship between PI and standard clinicopathological variables was assessed and its association with long-term survival evaluated.

RESULTS

A significant association was found between PI and tumour (T) status (P = 0.001), lymph node (N) involvement (P = 0.0098), the presence of distant metastases (P < 0.010) and advanced stage of disease (P < 0.001). On multivariate analysis, PI was shown to be an independent prognostic factor for long-term survival (hazard ratio 2.1 (95 per cent confidence interval 1.1 to 4.1); P = 0.032).

CONCLUSION

Cell proliferation is significantly associated with tumour progression and may be used to identify patients with a predicted adverse outcome after resection of colorectal carcinoma.

Expression of Cyclooxygenase-2 and Bcl-2 in human gastric adenomas

BACKGROUND

Cyclooxygenase (COX)-2 is the rate-limiting enzyme in prostaglandin synthesis. An increased expression has been implicated in the development and progression of human gastric cancers and colorectal adenomas and cancers. This study aimed to determine the involvement and association of COX-2 and Bcl-2 in precancerous gastric adenomas.

METHODS

Seventy-nine gastric polyps were obtained by endoscopic mucosal resection or polypectomy from January, 2000 to July, 2003. Immunohistochemical expression of COX-2 and Bcl-2 was observed, and their relationships with various clinicopathological factors were analyzed.

RESULTS

Histologically, 13 hyperplastic polyps and 66 tubular adenomas, of which 17 showed high-grade dysplasia, were observed. Increased COX-2 expression was observed in low-grade and high-grade tubular adenomas compared to hyperplastic polyps (p=0.004 and p=0.001, respectively). COX-2 expression was significantly higher in larger (>1 cm) compared with smaller (<1 cm) tubular adenomas (o=0.034), but no relation was observed in hyperplastic polyps. While Bcl-2 expression differed significantly according to histology, increased Bcl-2 expression was observed especially in COX-2 positive low-grade tubular adenomas.

CONCLUSION

COX-2 expression increased in a size-dependent manner in tubular adenomas, suggesting a role in polyp growth. The increased expression of Bcl-2 in tubular adenomas, especially in COX-2 positive tubular adenomas, suggests that COX-2 action may be related to Bcl-2 expression.

Isoliquiritigenin induces apoptosis and cell cycle arrest through p53-dependent pathway in Hep G2 cells

Isoliquiritigenin (ISL) is a natural pigment with the simple chalcone structure 4,2',4'-trihydroxychalcone. In this study, we report ISL induced inhibition in the proliferation of human hepatoma cells (Hep G2) for the first time. The cell proliferation inhibition achieved by ISL treatment resulted in a G2/M-phase arrest and programmed cell death. ISL treatment was found to result in the upregulation of p53, p21/WAF1, Fas/APO-1 receptor, Fas ligand, Bax and NOXA, but not in Bad. To elevate the role of p53 in these functions, we generated Hep G2 cells that express the dominant negative p53, which blocks the transcriptional activity of p53. The enhancement of p21/WAF1, Fas/APO-1, Bax and NOXA were decreased in Hep G2 cells that lack functional p53. Furthermore, Hep G2 cells were significantly more resistant to ISL when the activity of p53 was blocked. These results demonstrated that ISL-inducible p53 plays a key apoptotic role, and may do so by regulating the expression of specific target molecules that promotes efficient apoptotic cell death following G2/M-cell cycle arrest.

Paradoxes of Non-Trivial Gene Networks: How Cancer-Causing Mutations Can Appear to Be Cancer-Protective

Abnormalities of gene structure or expression are commonly found in cancers, where they are used as prognostic markers, predicting the likely severity of disease or chances of response to therapy. An odds ratio (OR) of <1 indicates that a marker's presence is correlated with better outcome. An OR of <1 is also often taken to mean that the gene concerned has a protective effect in the mechanism of cancer. I show that this is not necessarily so. Modeling of the genes involved in the causation of cancer as a network of weak, failure-prone elements shows that "cancer-causing" genes (i.e., genes whose abnormality is causal in driving cancer) can nevertheless appear as "protective" markers in later stage cancers. This implies that results suggesting that well-known oncogenes have an OR of <1 are quite valid, and that predicting a "protective" role from an apparently protective prognostic value is not valid. I identify mdm-2 and bax as candidates for genes with an apparently protective role through this mechanism.

BCL-2 translation is mediated via internal ribosome entry during cell stress

The cellular response to stress involves a rapid inhibition of cap-dependent translation via multiple mechanisms, yet some translation persists. This residual translation may include proteins critical to the cellular stress response. BCL-2 is a key inhibitor of intrinsic apoptotic signaling. Its primary transcript contains a 1.45-kb 5'-untranslated region (UTR) including 10 upstream AUGs that may restrict translation initiation via cap-dependent ribosome scanning. Thus, we hypothesized that this 5'-UTR may contain an internal ribosome entry site (IRES) that facilitates BCL-2 translation, particularly during cell stress. Here we show that the BCL-2 5'-UTR demonstrated IRES activity both when translated in vitro and also when m(7)G-capped and polyadenylated mRNA was transiently transfected into 293T cells. The activity of this IRES in unstressed cells was approximately 6% the strength of the hepatitis C virus IRES but was induced 3-6-fold in a dose-dependent manner following short term treatment with either etoposide or sodium arsenite. Thus, the IRES-mediated translation of BCL-2 may enable the cell to replenish levels of this critical protein during cell stress, when cap-dependent translation is repressed, thereby maintaining the balance between pro- and anti-apoptotic BCL-2 family members in the cell and preventing unwarranted induction of apoptosis.

Immunohistochemical evaluation of tissue-specific proteolytic enzymes in adenomas containing foci of early carcinoma: correlations with cathepsin D expression and other malignant features

BACKGROUND

Cathepsin D (CD) is an aspartyl lysosomal protease, and the prognostic value of CD expression has been studied in a variety of tumors, however, its role in early adenocarcinomas remains unclear.

AIM OF THE STUDY

We evaluated the expression of CD in a series of colorectal adenomas with severe dysplasia containing foci of early carcinoma and compared the results to several histopathological and immunohistochemical features.

METHODS

Adenomas were obtained by endoscopic polypectomy from 33 patients. Twenty-four of the 33 adenomas contained well-differentiated adenocarcinomas and nine adenomas contained moderately differentiated adenocarcinomas.

RESULTS

Positive CD expressions were observed in 25% of well-differentiated adenocarcinomas and in 66.7% of moderately differentiated adenocarcinomas (p < 0.05). Of the 12 adenocarcinomas with positive CD expression, four had positive CD expression in their adenomas (p < 0.01), 6 showed positive Ki-67 expression in their adenomas (NS), and 10 had positive p53 expression in their adenomas (p < 0.05). No significant association was seen between the level of CD expression and adenoma size.

CONCLUSIONS

The expression of CD in adenocarcinoma correlated significantly with differentiation, and with the levels of CD and p53 expression in the adenomas of the polyp.

Identification of genes regulating colorectal carcinogenesis by using the algorithm for diagnosing malignant state method

We studied the expression profiles of various stages of colorectal tumors (adenoma (AD), seven samples; carcinoma (CA), 16 samples) by using cDNA microarrays and developed ADMS (algorithm for diagnosing malignant state) method, selecting 335 clones characteristic of CA state. We, then, applied ADMS to 12 additional samples (five from primary lesions with metastasis and seven metastases); all 16 CAs and 12 metastatic tumors were diagnosed correctly as cancerous states. Although three of the seven ADs were diagnosed as "cancerous," the large size of two of these tumors suggested their potential malignancy. Our strategy for selecting clones characteristic of the malignant state is widely applicable to diagnosis and for predicting the stage of progression during multistep carcinogenesis. Of the 335 clones we selected, 135 were known genes. Included in the 135 genes were tumor suppressor and growth factor-related genes and were consistent with the literature. ADMS is a reliable means for identifying genes useful for the diagnosis of cancer.