Invasive Front Of Colorectal Cancer Research Articles

Systematic analysis of proteins from different signaling pathways in the tumor center and the invasive front of colorectal cancer

In colorectal cancer, the functional impact of proteins from different signaling pathways varies between tumor center and tumor front. Our objective was to identify differential protein expression profiles between the tumor center and the tumor front of colorectal cancer. Twenty proteins from different signaling pathways (epidermal growth factor receptor [EGFR], phosphorylated extracellular signal regulated kinase [pERK], receptor for hyalouronic acid mediated motility [RHAMM], Raf-1 kinase inhibitor protein [RKIP], β-catenin, E-cadherin, phosphorylated AK transforming [pAKT], p16, p21, Ki-67, B-cell Lymphoma-2 [BCL2], vascular endothelial growth factor, apoptosis protease activating factor 1 [APAF-1], mucin1 [MUC1], ephrin B2 receptor [EphB2], matrix metalloproteinase 7 [MMP7], phosphorylated mothers against decapentaplegic 2 [pSMAD2], caudal type homeobox transcription factor 2 [CDX2], Laminin5γ2, and mammalian sterile 20-like kinase 1 [MST1]) involved in colorectal cancer progression were studied immunohistochemically on 220 well-characterized patients using a multiple-punch tissue microarray including 437 and 430 samples from the tumor center and the invasive front, respectively. Mean expression between the tumor center and the tumor front varied statistically significantly for pSMAD2, pERK, Raf-1 kinase inhibitor protein, E-cadherin, pAKT, BCL2, vascular endothelial growth factor, EphB2, matrix metalloproteinase 7, CDX2, Laminin5γ2, MST1, and APAF-1. Overexpression of pAKT, BCL2, vascular endothelial growth factor, APAF-1, pERK, EphB2, Raf-1 kinase inhibitor protein, CDX2, E-cadherin, MST1 (P < .001 each), and pSMAD2 (P = .002) was more frequently observed in the tumor center, whereas matrix metalloproteinase 7 and Laminin5γ2 (P < .001 each) overexpression was associated with the invasive front. In multivariate analysis, vascular endothelial growth factor (P < .001), Raf-1 kinase inhibitor protein (P = .009), and Laminin5γ2 (P < .001) were the most relevant proteins with the multimarker phenotypes positive/positive/negative and negative/negative/positive being most discriminating between the tumor center and the tumor front. Moreover, the combination negative/negative/positive vascular endothelial growth factor/Raf-1 kinase inhibitor protein/Laminin5γ2 at the tumor front was associated with vascular/lymphatic invasion (P = .014), distant metastasis (P = .019), higher tumor grade (P < .001), and poorer survival (P = .05). Our findings show that, in colorectal cancer progression, vascular endothelial growth factor overexpression seems to play a role in the tumor center, whereas Laminin5γ2-positivity combined with Raf-1 kinase inhibitor protein loss is associated with tumor invasion at the front.

Re‐expression of CEACAM1 long cytoplasmic domain isoform is associated with invasion and migration of colorectal cancer

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is known to be downregulated at the transcriptional level in adenoma and carcinoma. Recent reports have shown that CEACAM1 is overexpressed at protein level in colorectal cancer and correlated with clinical stage. The reason why colorectal cancer cells re-expressed CEACAM1 remains unclear. The aim of our study was to clarify the implication of CEACAM1 re-expression in colorectal cancer. Immunohistochemical analyses were conducted with CEACAM1 long (CEACAM1-L) or short (CEACAM1-S) cytoplasmic domain-specific antibodies on clinical samples from 164 patients with colorectal cancer. The risk factors for metastasis and survival were calculated for clinical implication of CEACAM1 re-expression. Invasion chamber and wound healing assays were performed for the effect of CEACAM1 expression on invasion and migration of colorectal cancer cells. CEACAM1-L and CEACAM1-S stained with greater intensity at the invasion front than at the luminal surface of tumors. Differences between the long and short cytoplasmic isoform expression levels were observed at the invasion front. Multivariate analysis showed that CEACAM1-L dominance was an independent risk factor for lymph node metastasis, hematogenous metastasis and short survival. The Kaplan-Meier evaluation demonstrated that CEACAM1-L dominance was associated with shorter survival time (p < 0.0001). In the invasion chamber and wound healing assays, CEACAM1-L promoted invasion and migration. Re-expression of CEACAM1 is observed at the invasion front of colorectal cancer. CEACAM1-L dominance is associated with metastasis and shorter survival of the patients with colorectal cancer. CEACAM1-L dominance is important for colorectal cancer cells invasion and migration.

Abstract 5234: CEACAM1 expressing spheroid with a hollow beyond the invasive margin indicates the malignant potential of colorectal cancer

Abstract BACKGROUND: Spheroid with hollow (SWH) induced by Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1) and inner cells apoptosis is observed in three-dimensional (3D) in vitro culture and in an in vivo mouse model. However, it is unclear whether SWH exists in clinical cancer tissue. The aim of the current study is to address which cytoplasmic domain of CEACAM1 is responsible for SWH formation, and to elucidate the existence and the implication of SWH in colorectal cancer. METHODS: To address which cytoplasmic domain of CEACAM1 is responsible for SWH formation, 3D culture was conducted to investigate lumen formation of colorectal cancer cells (LS174T and HT29) transfected with CEACAM1-4L (long cytoplasmic isoform), -4S (short cytoplasmic isoform), or shRNA for CEACAM1. Immunohistochemical analyses were conducted with CEACAM1, CEACAM1-L (long cytoplasmic isoform) and M30 (cleaved cytokeratin 18 fragment) as an apoptosis marker on clinical samples from 164 patients with colorectal cancer. The risk factors for metastases and survival were calculated using univariate and multivariate analyses. RESULTS: In 3D culture experiment, CEACAM1-L is responsible for lumen formation of colorectal cancer cells. Knock down of CEACAM1 or over-expression of CEACAM1-4S inhibited lumen formation, indicating that modulation of CEACAM1 can control SWH structure. Immunohistochemical analyses showed that CEACAM1 expressing spheroid with hollow accompanying with central cells apoptosis shown by M30 staining existed at the invasion front of colorectal cancer tissues. All of SWH was stained by CEACAM1 and CEACAM1-L. It means that SWH at the invasion front has already acquired tumor initiating property. A multivariate analysis showed that the SWH is an independent risk factor for lymph node metastasis (p=0.004) and distant metastasis (p=0.002). The SWH was also identified to be an independent prognostic factor by a Cox proportional hazards model (p=0.020). The Kaplan-Meier evaluation for the overall survival analysis showed that SWH was significantly associated with a shorter survival (p&amp;lt;0.0001). These results suggested that CEACAM1 expressing SWH indicates metastatic and malignant phenotype. CONCLUSIONS: CEACAM1-L expressing SWH was significantly correlated with colorectal cancer metastasis and poor survival, suggesting that the SWH can be metastatic phenotype. SWH at the invasion front of colorectal cancer can be useful for diagnosis of malignancy, and morphological control of SWH by modulation of CEACAM1 may be novel therapeutic strategy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5234. doi:10.1158/1538-7445.AM2011-5234

Role of L1 cell adhesion molecule in gastric carcinoma.

56 Background: L1 cell adhesion molecule (L1) is a 200-220 kDa transmembrane glycoprotein of the immunoglobulin super family initially identified in neural cells. L1 was detected in ovarian cancer in a stage-dependent manner, was found exclusively in the invasion front of colorectal cancer, and has been considered a stem cell marker in glioma. The authors have shown that mRNA expression of L1 was a significant prognostic factor in gastric cancer (Kodera et al. Gastrointestinal Cancer Symposium 2009, abst 37). Its role in gastric cancer was further investigated. Methods: Expression of L1 was observed by immunostaining in 72 surgically resected pT4A-stage gastric cancer specimens. The association of L1 with peritoneal seeding and prognosis was elucidated. mRNA expression of L1-expressing gastric cancer cell line, KATO3, was suppressed using siRNA (KATO3 L1-). Microarray was used to indentify molecules that differ in expression between KATO3 L1- and the parental cell line. Results: L1 was scarcely stained in non-cancerous epithelial cells and intestinal metaplastic cells. L1 was detected mainly in the cell surface membrane of cancer cells in 15 of 72 specimens, more often in the intestinal type cancer. No correlation was found between L1 expression and detection of cancer cells in the peritoneal washes or development of peritoneal carcinomatosis. Nevertheless, the prognosis of L1-positive cancer was significantly inferior (p = 0.024). Prognosis was particularly poor among 6 cases where L1 was expressed in cancer cells at the invasive front (median survival time 149 days). Of 40,000 genes evaluated in the microarray, mRNA expression of 50 genes were amplified by &gt; 4-fold whereas the expression of 20 genes were attenuated to less than 1/4. Of these, expression of DYRK1A that induces apoptosis in conjunction with p53 was markedly suppressed to less than 1/8. Suppression of DYRK1A in the KATO3 L1- in comparison with the parental cell line was confirmed by RT-PCR. Conclusions: L1 affects prognosis of gastric cancer, particularly when it is expressed in cancer cells at the invasion front. Its role in the biology of gastric cancer has began to be elucidated. No significant financial relationships to disclose.

Prognostic Value of Nuclear β-catenin Overexpression at Invasive Front in Colorectal Cancer for Synchronous Liver Metastasis

β-catenin plays an important role in colorectal tumorigenesis. Relatively little is known about the relationship between β-catenin overexpression and liver metastasis. The purpose of this study was to investigate whether nuclear β-catenin overexpression in colorectal cancer is associated with synchronous liver metastasis. The β-catenin expression in tumor tissue from 486 patients with colorectal cancer was examined by immunohistochemistry. The relationship between nuclear β-catenin expression in colorectal cancers and liver metastatic lesions and other clinicopathological characteristics was analyzed. Univariate analysis and logistic multivariate regression analysis were adopted to discriminate risk factors of liver metastasis. Nuclear β-catenin overexpression at the invasive front of the primary tumor in patients with liver metastasis is more evident than that in patients without liver metastasis (71.5% vs. 29.3%; P<0.001). Nuclear β-catenin expression in primary tumors had a positive correlation with that in the matched metastatic lesions (r=0.499, P<0.001). Univariate and multivariate analyses indicated that overexpression of nuclear β-catenin at the invasive front in colorectal cancer correlated with liver metastasis. Overexpression of nuclear β-catenin at the invasive front in colorectal cancer is strongly associated with liver metastasis and may be a promising predictor of liver metastasis.

Expression of C4.4A at the invasive front is a novel prognostic marker for disease recurrence of colorectal cancer

Metastasis-associated gene C4.4A is a glycolipid-anchored membrane protein expressed in several human malignancies. The aim of this study was to explore the expression and clinical relevance of C4.4A in colorectal cancer. By quantitative RT-PCR, 154 colorectal cancer tissues were examined for C4.4A mRNA. We examined 132 colorectal cancer tissues by immunohistochemistry using a new polyclonal antibody that recognizes the C4.4A protein C-terminus containing the glycosylphosphatidyl-inositol anchor signaling sequence. A significant difference in 5-year overall survival was found between samples with high and low expression of C4.4A mRNA (P = 0.0005). Immunohistochemistry showed strong membranous staining of C4.4A at the invasive front of colorectal cancer tumors and at the frontier of metastatic lesions to lymph node and lung. The membranous staining with enhanced intensity at the invasive front of the primary colorectal cancer (Type A: 34/132, 25.6%) was associated with depth of invasion (P = 0.033) and venous invasion (P = 0.003), and was a significant independent prognostic factor (5-year overall survival in the entire series [n = 132; P = 0.004] and disease-free survival in stage II and III colorectal cancers [n = 82; P = 0.003]). Moreover, Type A C4.4A expression was linked to shorter liver metastasis-free survival rate, lung metastasis-free survival rate, or hematogenous metastasis-free survival (P = 0.0279, P = 0.0061, and P = 0.0006, respectively). Our data indicate that expression of the C4.4A protein at the invasive front acts as a novel prognostic marker in colorectal cancer, possibly through invasion-related mechanisms.

Nuclear factor-κB signaling and ezrin are essential for L1-mediated metastasis of colon cancer cells

Hyperactivation of beta-catenin-T-cell-factor (TCF)-regulated gene transcription is a hallmark of colorectal cancer (CRC). The cell-neural adhesion molecule L1CAM (hereafter referred to as L1) is a target of beta-catenin-TCF, exclusively expressed at the CRC invasive front in humans. L1 overexpression in CRC cells increases cell growth and motility, and promotes liver metastasis. Genes induced by L1 are also expressed in human CRC tissue but the mechanisms by which L1 confers metastasis are still unknown. We found that signaling by the nuclear factor kappaB (NF-kappaB) is essential, because inhibition of signaling by the inhibitor of kappaB super repressor (IkappaB-SR) blocked L1-mediated metastasis. Overexpression of the NF-kappaB p65 subunit was sufficient to increase CRC cell proliferation, motility and metastasis. Binding of the L1 cytodomain to ezrin - a cytoskeleton-crosslinking protein - is necessary for metastasis because when binding to L1 was interrupted or ezrin gene expression was suppressed with specific shRNA, metastasis did not occur. L1 and ezrin bound to and mediated the phosphorylation of IkappaB. We also observed a complex containing IkappaB, L1 and ezrin in the juxtamembrane region of CRC cells. Furthermore, we found that L1, ezrin and phosphorylated p65 are co-expressed at the invasive front in human CRC tissue, indicating that L1-mediated activation of NF-kappaB signaling involving ezrin is a major route of CRC progression.

Clinicopathologic Significances of EGFR Expression at Invasive Front of Colorectal Cancer

Background : Epidermal growth factor receptor (EGFR) is frequently expressed in the invasive front of colorectal cancer (CRC), but its clinicopathologic significance remains unclear. We investigated the clinical value of the EGFR expression at the invasive front of CRC. Methods : We performed an immunohistochemical analysis in order to examine the expression and distribution of EGFR in 214 cases of CRC. The EGFR status was considered positive when 1% of the tumor cells had membranous staining. Results : Overall, an EGFR expression was observed in 144 (67%) cases and it had no significant relationship with the clinicopathologic parameters. However, an EGFR expression at the invasive front was correlated with lymphatic invasion, lymph node metastasis and a high level of serum carcinoembryonic antigen (p = 0.028, p = 0.043, and p = 0.045, respectively). For the budding-positive CRCs liver metastases were found in the cases with an EGFR expression at the budding, but no liver metastasis occurred in the EGFR negative cases at the budding (p = 0.030). Conclusions : An EGFR expression at the invasive front has clinicopathologic significances in patients with CRC. An EGFR expression at tumor cell budding is a pathologic marker that suggests the high potential for liver metastasis in CRC.

CD8+ lymphocytes/ tumour-budding index: an independent prognostic factor representing a ‘pro-/anti-tumour’ approach to tumour host interaction in colorectal cancer

Background:The tumour-host interaction at the invasive front of colorectal cancer, including the epithelial–mesenchymal transition and its hallmark ‘tumour budding’, is an important area of investigation in terms of prognosis. The aim of this study was to determine the prognostic impact of a ‘pro-/anti-tumour’ approach defined by an established ‘pro-tumour’ (tumour budding) and host-related ‘anti-tumour’ factor of the adaptive immunological microenvironment (CD8+ lymphocytes).Methods:Double immunostaining for CK22/CD8 on whole tissue sections (n=279; Cohort 1) and immunohistochemistry for CD8+ using tissue microarrays (n=191; Cohort 2) was carried out. Tumour buds, CD8+ and CD8+ T-lymphocytes : tumour buds indices were evaluated per high-power field.Results:In Cohort 1, a low-CD8+/ buds index was associated with lymph node metastasis (P<0.001), vascular invasion (P=0.009), worse survival in univariate (P<0.001) and multivariable (P<0.001) analysis, and furthermore in lymph node-negative patients (P=0.002). In Cohort 2, the CD8+/ buds index was associated with T stage (P<0.001), N stage (P=0.041), vascular invasion (P=0.005) and survival in patients with TNM stage II (P=0.019), stage III (P=0.004), and adjuvantly untreated (P=0.009) and treated patients (P<0.001).Conclusion:The CD8+ lymphocyte : tumour-budding index is an independent prognostic factor in colorectal cancer and a promising approach for a future prognostic score for patients with this disease.

Invasion associated up‐regulation of nuclear factor κB target genes in colorectal cancer

: Colorectal cancer (CRC) displays intratumoral heterogeneity with less differentiated tumor cells at the invasive front (IF) than in the tumor center (TC). The authors previously observed that several genes were overexpressed at the IF of CRC with relations to inflammatory processes. Because nuclear factor kappaB (NF-kappaB), a dimeric transcription factor, is a major regulator of such processes, and because its target genes are involved in immune response, cell growth control, and cell survival, the expression of NF-kappaB target genes was investigated comparatively in CRC. : By using gene array profiling, NF-kappaB target gene expression was assessed in CRCs that expressed human mutL homolog 1 (hMLH1), hMSH2, and nuclear beta-catenin by comparing expression at the IF, in the TC, and in normal mucosa. In addition, 5 NF-kappaB target genes with high differential expression were validated by using immunohistochemistry. : The expression of NF-kappaB target genes in the TC, at the IF, and in normal mucosa was distinct; whereas, specifically at the IF, most differentially expressed NF-kappaB targets were up-regulated. Moreover, the results indicated that the expression diverged between epithelial tumor cells and inflammatory stromal cells. : Because the results demonstrated that inflammation and the activation of NF-kappaB signaling promoted CRC invasiveness, the current study provided further evidence that downstream targets of NF-kappaB signaling may be specifically relevant in invasion and progression of CRC. Finally, as has been suggested for colitis-associated cancer, the authors of this report concluded that the inhibition of NF-kappaB signaling also may be an additional option for the treatment of sporadic CRC. Cancer 2009. (c) 2009 American Cancer Society.

Prognostic significance of mast cell number and microvascular density for the survival of patients with primary colorectal cancer

The prognostic relevance of tumor-related angiogenesis and mast cell presence in colorectal cancer remains controversial. The aim of the current study was to assess the mast cell and microvessel densities (MCD and MVD) in the invasive front of colorectal cancers and to determine their prognostic relevance for survival of the patient with colorectal carcinoma. Histochemistry and immunohistochemistry were used to identify mast cells by toluidine blue (TB) histochemical staining and tryptase (Try) immunohistochemical staining and to determine the MVD in 106 biopsies from patients with 57 colonic and 49 rectal primary cancers. The MVD was assessed using CD31 as an endothelial cell marker. Significant positive correlations were found between the MVD in the 'hot spots' and MCD-Try and MCD-TB (R = 0.623 and R = 0.414, respectively, P < 0.001). The survival analyses showed that the patients with hypovascular tumor tissues had significantly longer survival than those with hypervascular tumor biopsies (P < 0.0001). Analogous significant correlation was observed for MCD-Try: patients with low MCD-Try had significantly better prognosis compared to those with high MCD (P = 0.038). In the multivariate Cox's hazard analysis of the 'hot spots' MVD was found to be an independent prognostic factor (P = 0.0007), together with the presence of invasion of lymph vessels (P = 0.017) and the presence of regional lymph node metastases (P = 0.028). We suggest that the assessment of MVD and tryptase-positive mast cells in the invasive front of the primary colorectal cancer could be a useful tool for prognosis of patients after surgical therapy.

Invasive front of colorectal cancer: Dynamic interface ofpro-/anti-tumor factors

Tumor-host interaction at the invasive front of colorectal cancer represents a critical interface encompassing a dynamic process of de-differentiation of colorectal carcinoma cells known as epithelial mesenchymal transition (EMT). EMT can be identified histologically by the presence of "tumor budding", a feature which can be highly specific for tumors showing an infiltrating tumor growth pattern. Importantly, tumor budding and tumor border configuration have generated considerable interest as additional prognostic factors and are also recognized as such by the International Union Against Cancer. Evidence seems to suggest that the presence of tumor budding or an infiltrating growth pattern is inversely correlated with the presence of immune and inflammatory responses at the invasive tumor front. In fact, several tumor-associated antigens such as CD3, CD4, CD8, CD20, Granzyme B, FOXP3 and other immunological or inflammatory cell types have been identified as potentially prognostic in patients with this disease. Evidence seems to suggest that the balance between pro-tumor (including budding and infiltrating growth pattern) and anti-tumor (immune response or certain inflammatory cell types) factors at the invasive front of colorectal cancer may be decisive in determining tumor progression and the clinical outcome of patients with colorectal cancer. On one hand, the infiltrating tumor border configuration and tumor budding promote progression and dissemination of tumor cells by penetrating the vascular and lymphatic vessels. On the other, the host attempts to fend off this attack by mounting an immune response to protect vascular and lymphatic channels from invasion by tumor buds. Whereas standard pathology reporting of breast and prostate cancer involves additional prognostic features, such as the BRE and Gleason scores, the ratio of pro- and anti-tumor factors could be a promising approach for the future development of a prognostic score for patients with colorectal cancer which could complement tumor node metastasis staging to improve the clinical management of patients with this disease.

Identification of the Molecular Mechanisms for Dedifferentiation at the Invasion Front of Colorectal Cancer by a Gene Expression Analysis

The aim of this study is to identify gene expression signatures that accompany dedifferentiation at the cancer invasion front in colorectal cancer. Two types of colorectal cancer were selected. Both types were well-differentiated adenocarcinomas at the superficial lesion. One type showed a dedifferentiated phenotype at the invasion front (type A, 13 samples); the other showed almost no dedifferentiated cancer cells at the invasion front (type B, 12 samples). Laser microdissection was combined with a cDNA microarray analysis to investigate the superficial lesions and the invasion front in colorectal cancers. Eighty-three genes were differentially expressed between types A and B in the superficial lesions, and the samples of superficial lesions were divided correctly into two clusters by these genes. Interestingly, the samples of the invasion front were also divided into the two same clusters by these genes. The text mining method selected 10 genes involved in potential mechanisms causing dedifferentiation of cancer cells at the invasion front. The potential mechanisms include the networks of transforming growth factor-beta, Wnt, and Hedgehog signals. The expression levels of 10 genes were calculated by quantitative reverse transcription-PCR and 8 genes were confirmed to be significantly differentially expressed between two types (P < 0.05). The gene expression profiles of 8 genes divided 12 test cases into two clusters with one misclassification. The molecular mechanisms constructed with 8 genes from three networks of transforming growth factor-beta, Wnt, and Hedgehog signals were found to correlate with dedifferentiation at the invasion front of colorectal cancer.

Prognostic implication of laminin-5 gamma 2 chain expression in the invasive front of colorectal cancers, disclosed by area-specific four-point tissue microarrays

The laminin-5 gamma 2 chain (LN-5γ2) is known to be a marker of invasion in several cancer types. Our purpose was to examine the prognostic significance of LN-5γ2 expression in different areas of individual colorectal cancers (CRCs) by using tissue microarrays (TMAs), and to clarify the optimal areas for prognostic assessment. Using formalin-fixed paraffin-embedded tissue blocks of pT3 primary CRCs resected from 120 patients, we constructed TMA blocks of tissue core specimens taken from the submucosal invasive front, subserosal invasive front, central area, and rolled edge of each tumor. Using these four-point TMA sets, cytoplasmic LN-5γ2 expression was immunohistochemically surveyed, and the area-specific prognostic significance of LN-5γ2 expression was evaluated. The data revealed that 35, 30, 15 and 10% of the 120 CRCs showed high-grade LN-5γ2 expression in the submucosal invasive front, subserosal invasive front, central area and rolled edge, respectively. Disease-specific survival curves for the groups with high- and low-grade LN-5γ2 in the submucosal invasive front and subserosal invasive front were different significantly or of marginal difference (respective 5-year survival rates: 54 and 78% for submucosal invasive front (P=0.030) and 58 and 75% for subserosal invasive front (P=0.055)). Multivariate analysis revealed that the grades of LN-5γ2 expression in submucosal invasive front (hazard ratio=2.0, P=0.047) and subserosal invasive front (hazard ratio=2.9, P=0.0033) were independent prognostic factors. In contrast, the grades of LN-5γ2 expression in the central area and rolled edge did not have a significant impact on patient prognosis. Analysis using area-specific four-point TMAs clearly demonstrated that LN-5γ2 expression in the invasive front largely influences the degree of clinical aggressiveness of CRC and its tendency to metastasize.

Beta-catenin activates a coordinated expression of the proinvasive factors laminin-5 gamma2 chain and MT1-MMP in colorectal carcinomas.

In colorectal carcinomas, loss-of-function mutations of the adenomatous polyposis coli (APC) tumor suppressor gene lead to a nuclear accumulation of the oncogenic transcriptional activator beta-catenin, predominantly at the invasive front within the tumor host interface. Various identified genes activated by beta-catenin are associated with tumor invasion. One prerequisite for malignant tumor invasion is the ability of tumor cells to migrate. We recently described the gamma2 chain of laminin as another beta-catenin target gene. Fragments of the laminin gamma2 chain, resulting from cleavage by the membrane type 1 matrix metalloproteinase (MT1-MMP), are strong inducers of epithelial cell migration. We here show a coordinated expression of nuclear beta-catenin, its target gene and MT1-MMP substrate laminin gamma2 chain, as well as MT1-MMP in tumor cells at invasive regions of colorectal carcinomas. We further demonstrate that MT1-MMP expression is regulated by beta-catenin/TCF through a TCF binding site in its promoter. These results suggest that nuclear beta-catenin activates the coordinated expression of the interacting proinvasive proteins laminin gamma2 chain and MT1-MMP, thereby leading to a promigratory activity at the invasive front of colorectal cancers. This further supports an important role of beta-catenin for invasion and metastasis of colorectal carcinomas.

Prognostic significance of tumor-induced angiogenesis in colorectal carcinoma

Tumor-induced angiogenesis is a central pathogenic step in the process of tumor growth, invasion and metastasis. The aim of this study was to analyze the quantitative expression of angiogenesis in colorectal carcinoma and to determine if and how angiogenesis correlates with other clinicopathologic factors and prognosis. This study included 40 patients who underwent curative resection of colorectal cancer at the Department of Surgery of the Senta General Hospital with complete 5 years follow-up or till death. Microvessels were identified immunohistochemically, using monoclonal CD31 antibodies. The microvessel count was assessed by means of stereology with test grid M42, as well as vascular surface density in the stromal volume at the invasive front of colorectal cancer. Tumor-induced angiogenesis count of colorectal carcinomas statistically significantly correlated with stage of disease and histologic tumor grade. There was no significant correlation between intratumoral microvessel density and sex and age of patients, localization and histologic tumor type. Five-year survival rate in patients with hypervascular colorectal tumors was statistically significantly lower than in patients with hypovascular tumors. Thus, microvessel density in colorectal cancer is an independent prognostic factor, but its significance is less than the importance concerning stage of disease and histologic grade of tumor. Intratumoral microvessel density quantification in histologic specimens of colorectal carcinoma reflects the biological malignant potential of tumors and may be a useful additional predictive marker. Assessment of intratumoral microvessel count might be used for determining the pathologic stage when adjuvant therapy is concerned. Microvessel density in tumor specimens is valuable in stratifying patients in planning appropriate adjuvant and antiangiogenic therapy after surgery.

The prognostic significance of type IV collagen expression in colorectal carcinomas

BACKGROUND: Breakdown of basement membrane is believed to be an essential step for tumor invasion and metastasis. The interaction between tumor cells and extracellular matrix can also result in induction of basement membrane synthesis by tumor and stromal cells. The aim of this study was to investigate distribution patterns of type IV collagen expression at the basement membrane in the tumor tissue of colorectal carcinomas by immunohistochemical staining. The degree of expression of type IV collagen correlated with classical clinicopathologic prognostic factors and their potential relationship with patients' prognosis. PATIENTS AND METHODS: This study included 40 patients who underwent curative resection of colorectal cancer at the Department of Surgery in the General Hospital Senta with complete follow-up for 5 years or until death. The identification of basement membrane was performed immunohistochemically using monoclonal antibodies to collagen IV. The basement membrane synthesis at the invasive front of colorectal cancer was semiquantitatively assessed as mild, moderate or severe. RESULTS: The deposition of basement membrane type of collagen IV had a statistically significant correlation with the stage of disease and histological grade of tumor with tendency of lesser synthesis of basement membrane in the advanced stage of disease and poorer histological grade of tumor. There were no significant correlations between intratumoral basement membrane synthesis and sex and age of patients, and localization and histological type of tumor. Five-year survival rates in patients with mild synthesis of basement membrane in colorectal tumor were significantly lower than in patients with severe expression of basement membrane. The basement membrane synthesis in colorectal cancer was a prognostic factor with significance behind stage of disease and histological grade of tumor by univariate Cox hazard-model. Multivariate Cox analysis verified that explicit synthesis of basement membrane showed a trend toward better prognosis, but it was not statistically significant. CONCLUSION Immunohistochemical staining for type IV collagen is an important additional technique with prognostic value.