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

Image analysis-derived metrics of histomorphological complexity predicts prognosis and treatment response in stage II-III colon cancer

The complexity of tumor histomorphology reflects underlying tumor biology impacting on natural course and response to treatment. This study presents a method of computer-aided analysis of tissue sections, relying on multifractal (MF) analyses, of cytokeratin-stained tumor sections which quantitatively evaluates of the morphological complexity of the tumor-stroma interface. This approach was applied to colon cancer collection, from an adjuvant treatment randomized study. Metrics obtained with the method acted as independent markers for natural course of the disease, and for benefit of adjuvant treatment. Comparative analyses demonstrated that MF metrics out-performed standard histomorphological features such as tumor grade, budding and configuration of invasive front. Notably, the MF analyses-derived "α_max" -metric constitutes the first response-predictive biomarker in stage II-III colon cancer showing significant interactions with treatment in analyses using a randomized trial-derived study population. Based on these results the method appears as an attractive and easy-to-implement tool for biomarker identification.

PD-L1 is upregulated by radiochemotherapy in rectal adenocarcinoma patients and associated with a favourable prognosis

BACKGROUND

The influence of neoadjuvant radiochemotherapy (RCT) on programmed death-ligand 1 (PD-L1) expression, a predictive marker for programmed cell death protein 1 (PD-1) inhibitor therapy, was studied on tumour and inflammatory cells in rectal adenocarcinoma patients along with its prognostic value.

METHODS

PD-L1 immunohistochemistry was performed on tissue microarrays of 103 pre-RCT biopsies and 159 post-RCT surgical specimens (central tumour, invasive front and normal tissue) of 199 patients. In 63 patients, both samples were available. Proportion and maximum intensity of PD-L1-positive (PD-L1+) cells were evaluated.

RESULTS

RCT increased the proportion of PD-L1-expressing cancer cells from 2.1% to 7.8% in the central tumour (p < 0.001) or 9.3% in the invasive front (p < 0.001). Cancer cell PD-L1 on its own could not predict prognosis. High PD-L1 expression on pre-RCT inflammatory cells (maximum intensity: p = 0.048) and post-RCT invasive front inflammatory cells (p = 0.010) correlated with improved no evidence of disease survival. In multivariate analysis, the combination of low PD-L1 in cancer and inflammatory cells was an independent negative prognostic marker for overall survival (OS) pre-RCT (Cox's proportional hazard ratio 0.438, p = 0.045) and in the invasive front post-RCT (Cox's proportional hazard ratio 0.257, p = 0.030).

CONCLUSION

Neoadjuvant RCT is associated with an increased PD-L1 expression in rectal adenocarcinoma patients, which should prompt clinical trials combining radiotherapy and PD-1/PD-L1 pathway blockade. Combined low PD-L1 expression on tumour and inflammatory cells is an independent negative prognostic marker for OS in RCT of rectal adenocarcinoma.

Accumulation of arachidonic acid-containing phosphatidylinositol at the outer edge of colorectal cancer

Accumulating evidence indicates that cancer cells show specific alterations in phospholipid metabolism that contribute to tumour progression in several types of cancer, including colorectal cancer. Questions still remain as to what lipids characterize the outer edge of cancer tissues and whether those cancer outer edge-specific lipid compositions emerge autonomously in cancer cells. Cancer tissue-originated spheroids (CTOSs) that are composed of pure primary cancer cells have been developed. In this study, we aimed to seek out the cancer cell-autonomous acquisition of cancer outer edge-characterizing lipids in colorectal cancer by analysing phospholipids in CTOSs derived from colorectal cancer patients with matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS). A signal at m/z 885.5 in negative ion mode was detected specifically at the surface regions. The signal was identified as an arachidonic acid (AA)-containing phosphatidylinositol (PI), PI(18:0/20:4), by tandem mass spectrometry analysis. Quantitative analysis revealed that the amount of PI(18:0/20:4) in the surface region of CTOSs was two-fold higher than that in the medial region. Finally, PI(18:0/20:4) was enriched at the cancer cells/stromal interface in colorectal cancer patients. These data imply a possible importance of AA-containing PI for colorectal cancer progression, and suggest cells expressing AA-containing PI as potential targets for anti-cancer therapy.

Positive surgical margins contribute to the survival paradox between patients with stage IIB/C (T4N0) and stage IIIA (T1-2N1, T1N2a) colon cancer

BACKGROUND

The underlying reasons for the survival paradox between stage IIB/C and stage IIIA colon cancer are elusive. We hypothesized that positive margins contribute to this paradox.

METHODS

We evaluated a cohort of 16,471 patients with stage IIIA and stage IIB/C colon cancer from 709,583 cases diagnosed between 2003-2012 in the National Cancer Data Base. All patients had chemotherapy, and all stage IIB/C patients had ≥12 lymph nodes retrieved. Patients with stage IIIA were subdivided further into those with <12 lymph nodes retrieved and those with ≥12 lymph nodes retrieved. Univariable and multivariable survival analyses were used.

RESULTS

The 5-year overall survival rate was 70.8% for stage IIB/C, 81.6% for stage IIIA with <12 lymph nodes, and 85.6% for stage IIIA with ≥12 lymph nodes (P < .0001). The 5-year overall survival rate was 84.3% for stage IIIA with no residual tumor, 74.8% for stage IIIA with residual tumor, 73.3% for stage IIB/C with no residual tumor, and 60.5% for stage IIB/C with residual tumor (P < .0001). Independent predictors (P < .01) of poor overall survival include stage IIB/C, advanced age, African American ethnicity, community cancer program, uninsured and Medicaid, low education level, high comorbidity index, and positive surgical margins.

CONCLUSION

Positive surgical margins may contribute to the survival paradox between stage IIB/C and stage IIIA colon cancer patients.

Epigenetic modifications in cutaneous malignant melanoma: EZH2, H3K4me2, and H3K27me3 immunohistochemical expression is enhanced at the invasion front of the tumor

Cancer stem cells and the misregulation of epigenetic modifications have been identified to possess a determinative role in carcinogenesis. The purpose of this study was to investigate the expression profile of EZH2 and H3K4me2 and H3K27me3, which constitute stem cell-like "bivalent" domains, in cutaneous malignant melanoma. A comparative analysis of their immunohistochemical expression between the invasion front (IF) and the inner tumor mass was also evaluated. Immunohistochemical methodology was performed on sections of 89 melanoma lesions from 79 patients. The 3 markers studied were identified in the cell nuclei of melanoma cells, nevus cells, and normal epidermal keratinocytes. A specific distribution pattern of H3K4me2 and H3K27me3 was found, as stronger levels were localized at the IF of the tumor (P = 0.034 and P < 0.01, respectively). In general, H3K4me2 and H3K27me3 levels were lower in metastatic with respect to primary melanoma cases (P = 0.0065 and P = 0.027, respectively). Advanced melanoma demonstrated significantly lower H3K4 immunohistochemical expression than did cases of lowest Clark level (I) (P = 0.038) or low Breslow depth (≤1 mm; P < 0.001). Furthermore, EZH2 expression in melanoma cells was higher compared with that in nevus cells (P = 0.02). A positive correlation between EZH2-H3K27me3 (P = 0.03) and H3K4me2-H3K27me3 (P < 0.01) in melanoma cells was also found. Our results suggest the possibility that combined immunohistochemical expression of EZH2, H3K4me2, and H3K27me3 might identify cancer cells with potential stem cell properties, particularly at the IF of this malignancy. This hypothesis should be further investigated, as many of the epigenetic changes are reversible via pharmacologic manipulations and new therapies, overpassing the resistance of advanced melanoma, may be developed.

Matrix metalloproteases as maestros for the dual role of LPS- and IL-10-stimulated macrophages in cancer cell behaviour

Background

The interactions established between macrophages and cancer cells are largely dependent on instructions from the tumour microenvironment. Macrophages may differentiate into populations with distinct inflammatory profiles, but knowledge on their role on cancer cell activities is still very scarce. In this work, we investigated the influence of pro-inflammatory (LPS-stimulated) and anti-inflammatory (IL-10-stimulated) macrophages on gastric and colorectal cancer cell invasion, motility/migration, angiogenesis and proteolysis, and the associated molecular mechanisms.

Methods

Following exposure of gastric and colon cancer cell lines to LPS- and IL-10-stimulated human macrophages, either by indirect contact or conditioned media, we analyzed the effect of the different macrophage populations on cancer cell invasion, migration, motility and phosphorylation status of EGFR and several interacting partners. Cancer-cell induced angiogenesis upon the influence of conditioned media from both macrophage populations was assessed using the chick embryo chorioallantoic membrane assay. MMP activities were evaluated by gelatin zymograhy.

Results

Our results show that IL-10-stimulated macrophages are more efficient in promoting in vitro cancer cell invasion and migration. In addition, soluble factors produced by these macrophages enhanced in vivo cancer cell-induced angiogenesis, as opposed to their LPS-stimulated counterparts. We further demonstrate that differences in the ability of these macrophage populations to stimulate invasion or angiogenesis cannot be explained by the EGFR-mediated signalling, since both LPS- and IL-10-stimulated macrophages similarly induce the phosphorylation of cancer cell EGFR, c-Src, Akt, ERK1/2, and p38. Interestingly, both populations exert distinct proteolytic activities, being the IL-10-stimulated macrophages the most efficient in inducing matrix metalloprotease (MMP)-2 and MMP-9 activities. Using a broad-spectrum MMP inhibitor, we demonstrated that proteolysis was essential for macrophage-mediated cancer cell invasion and angiogenesis.

Conclusions

We propose that IL-10- and LPS-stimulated macrophages distinctly modulate gastric and colorectal cancer cell behaviour, as result of distinct proteolytic profiles that impact cell invasion and angiogenesis.

A clinical model for predicting lymph node metastasis in submucosal invasive (T1) colorectal cancer

BACKGROUND

No single histopathological feature of submucosal invasive colorectal cancer (T1-CRC) can reliably predict the risk for lymph node metastasis (LNM).

AIM

The purpose of the study was to develop a prediction model of LNM in T1-CRC.

METHODS

Ninety-seven surgically resected T1-CRC at our institution were retrospectively evaluated. Morphology, localization, grading, mode of growth, presence of background adenoma, lymphoid infiltration, angiolymphatic invasion, budding, and depth of invasion were assessed. Mortality and morbidity related to surgery were also evaluated. Benefit-risk balance was assessed according to the presence of severe complications and to the presence of LNM.

RESULTS

Fourteen cases had LNM (14%). Eight patients (8%) presented severe surgical complications and there were two deaths (2 %). Infiltrative growth pattern (OR 31.91, 95% CI 2.37-428.36; p = 0.009) and the absence of lymphoid infiltrate (OR 28.75; 95% CI 2.13-388.37; p = 0.011) were the only variables independently associated with LNM in the multivariate analysis. Both variables were included in the prediction model together with sessile morphology (OR 4.88; 95% CI 0.81-29.3; p = 0.083) and poorly differentiated carcinoma (OR 11.77; 95% CI 0.77-179.83; p = 0.076). A 0-100 score was developed (infiltrative growth pattern: no = 0, yes = 33; lymphoid infiltrate: no = 29, yes = 0; sessile morphology: no = 0, yes = 15; poorly differentiated: no = 0, yes = 23). Cutoff point to indicate additional surgery was set in 35 points (i.e., 10% risk LNM). Discrimination of the prediction model was excellent (AUC 0.90; 95% CI 0.81-0.99).

CONCLUSION

Combined evaluation of infiltrative growth pattern, lymphoid infiltration, poorly differentiated carcinoma, and sessile appearance showed good performance for discriminating T1-CRC patients with LNM. The benefit-risk balance was in favor of surgery when at least two of these criteria were present.

Overexpression of SIX1 is an independent prognostic marker in stage I-III colorectal cancer

Epithelial-to-mesenchymal transition (EMT) contributes significantly to tumor progression and metastasis. The assessment of EMT-associated transcription factors could be a promising approach to identify biomarkers and potential therapeutic targets in colorectal cancer. In our study, we focused on the transcription factor "Sine oculis homeobox" (SIX) 1, which is a member of the superfamily of the homeobox genes and has been described to promote EMT in different types of tumors. Immunohistochemistry against SIX1 was performed on colorectal mucosa, adenomas, carcinomas-in situ and primary adenocarcinomas. An expression score was developed and subsequently assessed for its prognostic value in two independent cohorts. Cohort 1 consisted of 128 patients with stage I-III colorectal cancer; cohort 2 included 817 patients with stage I-III colorectal cancer who had participated in the DACHS study. HCT-116 cells were transfected with SIX1 plasmids and subjected to migration and colony formation assays. The expression of SIX1 increases gradually from mucosa to colorectal adenocarcinomas (p > 0.0001). Univariate and multivariate analyses reveal that high expression of SIX1 is associated with decreased overall survival (cohort 1: HR: 4.01, CI: 1.20-14.07, p = 0.025; cohort 2: HR: 1.43, CI: 1.014-2.02, p = 0.047). Overexpression of SIX1 induces a more mesenchymal-like phenotype in HCT-116 cells and enhances tumor migration. High expression of SIX1 is an independent prognostic marker in colorectal cancer. It might be a promising biomarker to stratify patients into different risk groups. Moreover, targeting SIX1 might be a novel therapeutic approach in patients with colorectal cancer.

Tumour border configuration in colorectal cancer: proposal for an alternative scoring system based on the percentage of infiltrating margin

AIMS

Information on tumour border configuration (TBC) in colorectal cancer (CRC) is currently not included in most pathology reports, owing to lack of reproducibility and/or established evaluation systems. The aim of this study was to investigate whether an alternative scoring system based on the percentage of the infiltrating component may represent a reliable method for assessing TBC.

METHODS AND RESULTS

Two hundred and fifteen CRCs with complete clinicopathological data were evaluated by two independent observers, both 'traditionally' by assigning the tumours into pushing/infiltrating/mixed categories, and alternatively by scoring the percentage of infiltrating margin. With the pushing/infiltrating/mixed pattern method, interobserver agreement (IOA) was moderate (κ = 0.58), whereas with the percentage of infiltrating margins method, IOA was excellent (intraclass correlation coefficient of 0.86). A higher percentage of infiltrating margin correlated with adverse features such as higher grade (P = 0.0025), higher pT (P = 0.0007), pN (P = 0.0001) and pM classification (P = 0.0063), high-grade tumour budding (P < 0.0001), lymphatic invasion (P < 0.0001), vascular invasion (P = 0.0032), and shorter survival (P = 0.0008), and was significantly associated with an increased probability of lymph node metastasis (P < 0.001).

CONCLUSIONS

Information on TBC gives additional prognostic value to pathology reports on CRC. The novel proposed scoring system, by using the percentage of infiltrating margin, outperforms the 'traditional' way of reporting TBC. Additionally, it is reproducible and simple to apply, and can therefore be easily integrated into daily diagnostic practice.

Molecular and pathogenetic aspects of tumor budding in colorectal cancer

In recent years, tumor budding in colorectal cancer has gained much attention as an indicator of lymph node metastasis, distant metastatic disease, local recurrence, worse overall and disease-free survival, and as an independent prognostic factor. Tumor buds, defined as the presence of single tumor cells or small clusters of up to five tumor cells at the peritumoral invasive front (peritumoral buds) or within the main tumor body (intratumoral buds), are thought to represent the morphological correlate of cancer cells having undergone epithelial–mesenchymal transition (EMT), an important mechanism for the progression of epithelial cancers. In contrast to their undisputed prognostic power and potential to influence clinical management, our current understanding of the biological background of tumor buds is less established. Most studies examining tumor buds have attempted to recapitulate findings of mechanistic EMT studies using immunohistochemical markers. The aim of this review is to provide a comprehensive summary of studies examining protein expression profiles of tumor buds and to illustrate the molecular pathways and crosstalk involved in their formation and maintenance.

[Isolation and identification of CD133 positive and negative cells from human lung cancer and screening of the differential genes between the positive and negative cells]

BACKGROUND AND OBJECTIVE

It has been proven that cancer stem cell existed in variety of cancer, which an significant difference of biological characteristics was observed between the cancer stem cells and non-cancer stem cells. And CD133 is considered to be cancer stem cell marker. So there may be significant differences in CD133- positive cells and CD133-negative cells. The aim of this study is to isolate CD133+ cells and CD133- cells from lung cancer cell line A549, explore their biological characteristics and screen the metastasis-related genes.

METHODS

MACS was applied to isolate CD133+ cells and CD133- cells from human lung cancer cell line A549. To observe the formation of sphere, CD133+ cells and CD133- cells were cultured in serum-free DMEM-F12 medium (containing EGF, bFGF) in vitro. The colony formatting efficiency of CD133+ cells, CD133- cells and cells without sorting was tested by colony-forming assay. The differentiation of sphere was induced by culturing in DMEM-F12 medium (containing serum). The metastasis-related genes (84 genes) of CD133+ cells and CD133- cells were detected by using DNA microarray. Immunohistochemistry was used to detect the expression of CD133 protein in Human lung cancer tissue.

RESULTS

CD133+ cells formed sphere in serum-free DMEM-F12 medium,while the CD133- cells failed to form sphere. The rates of CD133+ cell colony formation (57.1%) was significantly higher than that of CD133- cells (3.3%). Sphere (CD133+/CK7-) was induced to differentiate, and CK7 expression was found in differentiated cells. The expression levels of 19 metastasis-related genes from CD133+ cells and CD133- cells were significant different. Little CD133 positive cells which distributing around the cancer nests were found in lung cancer tissue. The expression of CD133 was not related to tumor types, cell differentiation or TNM stage.

CONCLUSIONS

CD133+ cells exhibit the characteristics of cancer stem cells. The difference of metastasis-related gene expression levels was discovered between CD133+ cells and CD133- cells. CD82 plays an important role in mechanism of tumor metastasis.
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Tumor budding is an independent prognostic factor for prediction of lymph node metastasis in oral squamous cell carcinoma

OBJECTIVE

Despite the enormous advances in diagnostic and management modalities of oral squamous cell carcinoma (OSCC), the mortality rates have remained stagnant with a 5-year survival rate of <50% challenging the available methods of prognostic assessment. Presence of tumor budding has been associated with aggressive behavior and is correlated with lymph node metastasis, recurrence, distant metastasis, and decreased survival in several cancers. However, the prognostic significance of this apparently simple to evaluate parameter is sparse in OSCC.

METHODS

A total of 75 cases of surgically excised OSCC were analyzed for tumor budding along with other clinicopathologic parameters. Tumor budding was graded as high and low intensity based on presence and absence of ≥10 or <10 budding foci in hematoxylin and eosin-stained sections. An association between the clinicopathological parameters, lymph node metastases with the budding index was examined using univariate and multivariate analyses.

RESULTS

Tumor budding was evident in 89% of cases with around 45.3% of the cases demonstrated high-intensity budding. High-intensity tumor budding was significantly associated with lymph node metastasis and depth of invasion. Multivariate analysis demonstrated that tumor budding and depth of invasion were significant independent predictors for lymph node metastasis.

CONCLUSION

Tumor budding is frequently encountered histologic marker in OSCC. High-intensity tumor budding is a strong independent prognostic factor for prediction of lymph node metastasis.

Risk assessment in early colorectal cancer: histological and molecular markers

The pathological examination of early colorectal cancer specimens, in particular 'malignant polyps', provides important prognostic information. The depth of invasion into the submucosal layer assessed according to the Haggitt (for pedunculated lesions) or Kikuchi (for nonpolypoid lesions) classification systems or by direct measurement has been associated with the risk of lymph node metastasis. Angioinvasion, in particular lymphatic invasion, budding, tumor differentiation or grade, and resection margin status have been identified as further risk factors. The combination of these parameters allows the stratification of affected individuals into low- and high-risk categories, which is pivotal for clinical management. For low-risk cancers, defined as a completely excised Haggitt level 1-3/Kikuchi sm1 tumor with no evidence of poor differentiation or angioinvasion, local excision is generally regarded as adequate treatment. Oncological surgical resection is, however, indicated for high-risk cancers, which show at least one of the following features: Haggitt level 4/Kikuchi sm3 invasion, the presence of lymphatic (or vascular) invasion, poor differentiation, or positive resection margin. The inclusion of molecular markers such as tumor suppressor genes and their products, markers involved in tumor vascularization, and markers related to tumor cell adhesion and invasion may help to refine risk stratification, but data on molecular markers are still limited in this regard.

Differential β-catenin expression levels are associated with morphological features and prognosis of colorectal cancer

β-catenin, an epithelial-mesenchymal transition (EMT)-associated marker, is key in the progression of colorectal cancer (CRC). However, the prognostic significance of β-catenin expression in patients with CRC remains controversial. In the present study, the expression of β-catenin at the tumor invasive front and the tumor center was investigated, and the correlations amongst β-catenin differential expression patterns and the clinicopathological characteristics and prognosis of CRC patients were determined. In total, 181 patients that were diagnosed with CRC (as determined by histopathological evaluation) and subjected to surgical resection at the First Hospital of China Medical University between 2000 and 2001 were examined, and CRC specimens were obtained. Immunohistochemical (IHC) staining of β-catenin was performed for each specimen. The nuclear β-catenin expression levels were identified to be significantly lower in the tumor center than at the tumor invasive front (immunoreactivity score, 0.05±0.303 versus 2.18±3.917; P<0.001). The presence of nuclear β-catenin overexpression at the tumor invasive front was found to be correlated with the tumor, node, metastasis stage (P=0.020), lymph node metastasis (P=0.016) and histological differentiation (P=0.006). Survival analysis revealed that reduced membranous expression levels and increased nuclear expression levels of β-catenin were statistically significantly associated with poor survival times. Furthermore, differential β-catenin expression levels were associated with aggressive morphological features, EMT and a poor prognosis in CRC. Therefore, IHC analysis of β-catenin is considered to be a useful marker to predict the prognosis in patients with CRC.

Invasion pattern and histologic features of tumor aggressiveness correlate with MMR protein expression, but are independent of activating KRAS and BRAF mutations in CRC

KRAS/BRAF mutation testing and mismatch repair (MMR) protein immunohistochemistry have an established role in routine diagnostic evaluation of colorectal carcinoma (CRC). However, since the exact impact of these molecular characteristics on tumor morphology and behavior is still subject to research, the aim of our study was to examine associations between molecular and morphologic features that had not been analyzed in this combination before. KRAS (codons 12, 13, and 61) and BRAF (codon 600) mutation status and MMR protein expression were analyzed in a consecutive series of 117 CRC samples using DNA pyrosequencing and immunohistochemistry. Tumor cell budding, infiltration pattern, and peritumoral lymphocytic (PTL) reaction was assessed applying established criteria. Molecular and morphological findings were correlated applying chi-square and Fisher's exact test. We found KRAS or BRAF mutations in 40 and 8 % of samples, while loss of MMR protein expression was observed in 11 %. Tumor budding was significantly associated with infiltrative growth, absence of PTLs, and blood and lymph vessel infiltration. Neither KRAS nor BRAF mutations were associated with a certain growth pattern or budding intensity of CRC, but loss of MMR protein expression was found in context with BRAF mutation, expanding growth, and presence of PTLs. Our results confirm an association between loss of MMR protein expression, presence of activating BRAF mutation, expanding growth, and PTL reaction as well as between tumor budding, infiltrative growth pattern, and tumor aggressiveness; however, there was no such association between the presence of an activating KRAS or BRAF mutation and a distinct invasion pattern or tumor aggressiveness in CRC.

Expression patterns of bone morphogenetic protein antagonists in colorectal cancer desmoplastic invasion fronts

Bone morphogenetic proteins (BMPs) are a group of growth factors with dual functions in cancer development and progression. Recently, certain tumor-promoting roles have been identified for selected antagonists/inhibitors (BMPIs) of this developmental pathway. A recent focus on the implication of BMP in colorectal cancer progression has emerged, mainly due to the presence of inactivating mutations in several members of the canonical signaling cascade. However, the detailed expression profiles of BMPIs remain largely unknown. Based on our previous work, whereby three specific BMPIs, gremlin-1 (GREM1), high-temperature requirement A3 (HTRA3) and follistatin (FST) were collectively overexpressed in desmoplastic cocultures of colorectal cancer (CRC), here, we undertook an immunohistochemical approach to describe the patterns of their expression in CRC patients. Two major characteristics described the BMPI expression signature: First, the synchronous and coordinated stromal and epithelial overexpression of individual BMPIs in desmoplastic lesions, which demonstrated that all three of them contribute to increasing levels of BMP antagonism in such areas. Second, the presence of microenvironmental polarity in the BMPI pattern of expression, which was indicated through the preferential expression of HTRA3 in the stromal, and the parallel FST/GREM1 expression in the epithelial component of the investigated sections. In addition, expression of HTRA3 in the epithelial compartment of the tumors demonstrated a significant predictive power to discriminate between tumor-budding-bearing and tumor-budding-free desmoplastic microenvironments. Together, these findings contribute to the understanding of signaling dynamics of BMP antagonism in the colorectal cancer desmoplastic invasion front.

The relationship between tumour stroma percentage, the tumour microenvironment and survival in patients with primary operable colorectal cancer

BACKGROUND

Tumour stroma percentage (TSP) has previously been reported to predict survival in patients with colorectal cancer (CRC); however, whether this is independent of other aspects of the tumour microenvironment is unknown. In the present study, the relationship between TSP, the tumour microenvironment and survival was examined in patients undergoing elective, curative CRC resection.

PATIENTS AND METHODS

Patients undergoing resection at a single centre (1997-2008) were identified from a prospective database. TSP was measured at the invasive margin and its association with cancer-specific survival (CSS) and clinicopathological characteristics examined.

RESULTS

Three hundred and thirty-one patients were included in the analysis. TSP was associated with CSS in patients with stage I-III disease [hazard ratio (HR) 1.84, 95% confidence interval (CI) 1.17-2.92, P = 0.009], independent of age, systemic inflammation, N stage, venous invasion and Klintrup-Mäkinen score. Furthermore, TSP was associated with reduced CSS in patients with node-negative disease (HR 2.14, 95% CI 1.01-4.54, P = 0.048) and those who received adjuvant chemotherapy (HR 2.83, 95% CI 1.23-6.53, P = 0.015), independent of venous invasion and host inflammatory responses. TSP was associated with several adverse pathological characteristics, including advanced T and N stage. Furthermore, TSP was associated with an infiltrative invasive margin and inversely associated with necrosis.

CONCLUSIONS

The TSP was a significant predictor of survival in patients undergoing elective, curative CRC resection, independent of adverse pathological characteristics and host inflammatory responses. In addition, TSP was strongly associated with local tumour growth and invasion.

Atypical mature bone in the otosclerotic otic capsule as the differentiated zone of an invasive osseous neoplasm

CONCLUSION

A large proportion of the mature otic capsule bone in cases of otosclerosis lies in plaques in direct contiguity with active otosclerosis and, because it shows significant structural defects, it should be regarded as part of the otosclerotic process. These appearances support our previously described suggestion that otosclerosis is an invasive osseous neoplasm, the mature atypical bone representing differentiation of earlier-formed invasive neoplastic osseous tissue.

OBJECTIVES

We sought structural features in differentiated bone within the otic capsules of cases of otosclerosis that might indicate a relation to the underlying disease process.

METHODS

Fifty temporal bones from 42 adult patients with otosclerosis were processed into stained histological sections and the appearance of the otic capsule was compared with that of the same tissue, processed in the same way, in 10 cases that did not show otosclerosis.

RESULTS

In the cochlear otic capsules of otosclerotic temporal bones, when traced back along the otosclerotic plaque from the invasive front, atypical shapes and arrangements of osteons were seen, often with otospongiosis (severe dilatation of multiple Volkmann's canals), culminating in larger differentiated osteons with irregularities in structure. In the medial region of the otosclerotic cochlear otic capsule, at a similar position to that where giant normal osteons are present in the normal temporal bone, differentiated, giant abnormal osteons were seen. In the otosclerotic vestibular otic capsule there were changes similar to those of the otosclerotic cochlea (apart from the giant osteons) and many osteons composed of clusters of atypical osteoblast-like cells around highly atypical Volkmann's canals.

FoxP3 demethylation is increased in human colorectal cancer and rat cholangiocarcinoma tissue

OBJECTIVES

FoxP3 expression is a marker for Tregs which are known to be involved in tumor immunity. We aimed to evaluate FoxP3 promoter demethylation in human colorectal cancer (CRC) and rat intrahepatic cholangiocarcinoma (ICC).

DESIGN AND METHODS

Bisulfite-treated genomic DNA templates of shock frozen paired samples were studied from 13 anonymous CRC patients and from 10 male rats (n=6 ICC induced by thioacetamide and n=4 age-matched controls). Real-time PCR was carried out using a LightCycler 480 system. Human FoxP3 and CD3 promoter demethylations were estimated using previously described assays; and rat FoxP3 promoter demethylation using a newly developed assay.

RESULTS

A significant 3.5-fold increase of the demethylation in FoxP3 promoter region was found in human CRC and rat ICC (P<0.05). The average frequency of cells with FoxP3 demethylation in patients suffering from CRC was 0.26% in normal tissue and 0.92% in tumor tissue (n=11 paired samples). Although, no significant difference was found between the mean frequency of CD3 demethylation in normal tissue (4.80%, n=6) and in tumor tissue (4.14%, n=6) from CRC patients, the ratio of demethylated CD3/FoxP3 promoter areas was significantly lower in tumor specimens (P<0.05). Using our novel assay, we found a significant increase in mean frequencies of cells with FoxP3 demethylation in rats with ICC (7.42%, n=6) in comparison to controls (2.14%, n=4).

CONCLUSION

FoxP3 seems to be an interesting biomarker for immune response to epithelial tumors. Functional consequences from the increase of Tregs remain to be demonstrated. Further studies with outcome data are necessary.

Characteristics and significance of colorectal cancer associated lymphoid reaction

A subset of colorectal cancers (CRCs) exhibits so-called Crohn's like lymphoid reaction (CLR), an inflammatory reaction pattern that consists of numerous transmural lymphoid aggregates. However, the composition of these aggregates, their biological mechanisms and their prognostic significance are not well-defined. We analyzed two CRC cohorts (418 and 149 patients) and determined clinicopathological features including survival. A new method for evaluating CLR based on counting the areal density of the lymphoid follicles (CLR density) was adopted. Immune cell densities at intratumoral and peritumoral regions, as well as the composition of the lymphoid follicles, were studied by immunohistochemistry. We found that CLR comprised of lymphoid aggregates with no evidence of granuloma formation. High CLR density associated with lower tumor stage, lack of preoperative radiotherapy or chemoradiotherapy and deficient mismatch repair enzyme expression. CLR density had positive correlations with peritumoral and intratumoral densities of CD83(+) mature dendritic cells and T cells. High CLR density associated with better survival and had prognostic value that was independent of stage, Klintrup-Mäkinen score for peritumoral inflammation and the numbers of tumor infiltrating T cells. CLR density evaluation had excellent intraobserver and interobserver agreement. In conclusion, the results suggest that CLR contributes to the adaptive antitumor immunity. Quantitative evaluation of CLR density is a relevant prognostic indicator in CRC.

Detailed analysis of inflammatory cell infiltration in colorectal cancer

BACKGROUND

Higher-grade inflammatory infiltrate is a promising marker for better prognosis in colorectal cancer (CRC). However, the knowledge on the interrelationships between different inflammatory cells and classifications is fragmentary.

METHODS

We analysed the densities of eight types of inflammatory cells in a prospectively recruited group of 117 CRC patients and determined their interrelationships and contributions to Klintrup-Mäkinen (K-M) score of overall peritumoural inflammation. We characterised the inflammatory infiltrate in relation to stage and recurrences in 24-month follow-up.

RESULTS

There were high positive correlations between the inflammatory cell densities, with the exception of mast cells and CD1a+ immature dendritic cells. High K-M score associated with high peri- and intratumoural densities of CD3+, CD8+, CD68+, CD83+, and FoxP3+ cells and neutrophils. Advanced stage associated with low K-M score, as well as low CD3+, CD8+, CD83+, and FoxP3+ cell counts, of which low K-M score, low CD3(+) T-cell count, and low FoxP3+ T-cell count were linked to higher recurrence rate.

CONCLUSION

The density of CRC inflammatory infiltrate declines as stage advances. Especially, low K-M score and low T-cell counts predict higher recurrence rate. The high positive correlations between the individual inflammatory markers support the value of overall inflammatory reaction scoring.

Digital microscopy assessment of angiogenesis in different breast cancer compartments

Background/Aim. Tumour angiogenesis defined by microvessel density (MVD) is generally accepted as a prognostic factor in breast cancer. However, due to variability of measurement systems and cutoffs, it is questionable to date whether it contributes to predictive outline. Our study aims to grade vascular heterogeneity by comparing clear-cut compartments: tumour associated stroma (TAS), tumour parenchyma, and tumour invasive front. Material and Methods. Computerized vessel area measurement was performed using a tissue cytometry system (TissueFAXS) on slides originated from 50 patients with breast cancer. Vessels were marked using immunohistochemistry with CD34. Regions of interest were manually defined for each tumour compartment. Results. Tumour invasive front vascular endothelia area was 2.15 times higher than that in tumour parenchyma and 4.61 times higher than that in TAS (P < 0.002). Worth to mention that the lymph node negative subgroup of patients show a slight but constant increase of vessel index in all examined compartments of breast tumour. Conclusion. Whole slide digital examination and region of interest (ROI) analysis are a valuable tool in scoring angiogenesis markers and disclosing their prognostic capacity. Our study reveals compartments' variability of vessel density inside the tumour and highlights the propensity of invasive front to associate an active process of angiogenesis with potential implications in adjuvant therapy.

Prognostic value of innate and adaptive immunity in colorectal cancer

Colorectal cancer (CRC) remains one of the major public health problems throughout the world. Originally depicted as a multi-step dynamical disease, CRC develops slowly over several years and progresses through cytologically distinct benign and malignant states, from single crypt lesions through adenoma, to malignant carcinoma with the potential for invasion and metastasis. Moving from histological observations since a long time, it has been recognized that inflammation and immunity actively participate in the pathogenesis, surveillance and progression of CRC. The advent of immunohistochemical techniques and of animal models has improved our understanding of the immune dynamical system in CRC. It is well known that immune cells have variable behavior controlled by complex interactions in the tumor microenvironment. Advances in immunology and molecular biology have shown that CRC is immunogenic and that host immune responses influence survival. Several lines of evidence support the concept that tumor stromal cells, are not merely a scaffold, but rather they influence growth, survival, and invasiveness of cancer cells, dynamically contributing to the tumor microenvironment, together with immune cells. Different types of immune cells infiltrate CRC, comprising cells of both the innate and adaptive immune system. A relevant issue is to unravel the discrepancy between the inhibitory effects on cancer growth exerted by the local immune response and the promoting effects on cancer proliferation, invasion, and dissemination induced by some types of inflammatory cells. Here, we sought to discuss the role played by innate and adaptive immune system in the local progression and metastasis of CRC, and the prognostic information that we can currently understand and exploit.

Morphophenotype of floating colonies derived from a single cancer cell has a critical impact on tumor-forming activity

The anchorage-independent colony growth of cancer cells is reportedly correlated with the tumor-forming activity; however, the correlation between the morphophenotype of each colony and the tumor-forming activity has not been clarified. To assess this problem, we cultured single A549 cells (human lung adenocarcinoma cell line) in growth medium in individual wells (n = 426) for 14 days under anchorage-independent conditions and analyzed the resulting growth characteristics. The single A549 cells formed various sizes of floating colonies. The proportion of large colonies (>400 μm) was 3.8% and this proportion increased dramatically with the exogenous addition of EGF (21.6%) or HGF (27.6%). Morphologically, the floating colonies could be divided into: (ii) Type A, spheroid colony; and (ii) Type B, dispersed villous colony. The Type B colonies expressed significantly higher levels of epithelial-mesenchymal transition (EMT)-related mRNAs (Snail 1, ZEB 1, and ZEB2) than the Type A colonies. Furthermore, the subcutaneous injection of a single cell-derived colony with a large size and a Type B morphology resulted in more efficient tumor formation. The present results indicated that the morphophenotypes of floating colonies derived from single cancer cells have a critical impact on tumor-forming activity.

Epithelial mesenchymal transition in colorectal cancer: Seminal role in promoting disease progression and resistance to neoadjuvant therapy

BACKGROUND

Epithelial mesenchymal transition (EMT) may be physiological as part of embryological development, or pathological as part of cancer development. It is one of the key initiating events in the metastatic cascade. EMT has profound effects on tumour cell invasiveness, proliferation and motility. In the present article we aimed to review the potential role of EMT as a process to explain colorectal cancer progression and resistance to neoadjuvant therapy.

METHODS

Extensive literature searches were performed in Pubmed, EMBASE and Google Scholar databases to identify relevant articles published before March 2012.

RESULTS

There is adequate evidence to support the complex upstream signalling alterations needed for EMT to occur in colorectal cancers. Changes of EMT are likely to be found at the tumour invasive front: the deepest, growing tumour margin. Loss of E-cadherin at the cell membrane causes loss of cellular integrity, with subsequent migration of malignant cells and tumour budding. These processes are associated with metastases and recurrence of colorectal cancer. There is early evidence from a limited number of studies that resistance to neoadjuvant therapy in colorectal cancer is associated with changes of EMT. However, there is a lack of supporting evidence originating from human colorectal cancer tissues.

CONCLUSIONS

Emerging evidence demonstrates that development of EMT in colorectal cancer leads to an aggressive phenotype that may promote metastatic spread, and augment treatment resistance during neoadjuvant therapy. A clearer understanding of the processes and role of EMT in colorectal cancer may also highlight novel therapeutic strategies.

Overexpression of protein S100A4 is independently associated with overall survival in stage C colonic cancer but only in cytoplasm at the advancing tumour front

PURPOSE

S100A4, a multifunctional protein, has been linked to the invasive growth and metastases of several human cancers. This study investigated the association between S100A4 and overall survival and other clinicopathological features in patients with stage C colonic cancer.

METHODS

Clinical and pathological data were obtained from a prospective hospital registry of 409 patients who had a resection for stage C colonic cancer. Tissue microarrays for immunohistochemistry were constructed from archived tissue. S100A4 staining intensity and percentage of stained cells were assessed in nuclei and cytoplasm for both the central part of the tumour and at the advancing front. Overall survival was analysed by the Kaplan-Meier method and Cox regression.

RESULTS

Only a high percentage of cells with S100A4 cytoplasmic staining in frontal tissue was associated with poor survival (hazard ratio, 1.6; 95 % CI 1.1-2.2; p = 0.008) after adjustment for other prognostic variables. There was no association between frontal cytoplasmic S100A4 expression and any of 13 other clinicopathological variables.

CONCLUSIONS

High expression of S100A4 in cytoplasm at the advancing front of stage C colonic tumours indicates a poor prognosis. Whether S100A4 can predict response to adjuvant chemotherapy remains to be investigated in a randomised clinical trial.

Lack of CD44 variant 6 expression in rectal cancer invasive front associates with early recurrence

AIM: To investigate the prognostic value of CD44 variant 6 (CD44v6), a membranous adhesion molecule, in rectal cancer.

METHODS: Altogether, 210 rectal cancer samples from 214 patients treated with short-course radiotherapy (RT, n = 90), long-course (chemo) RT (n = 53) or surgery alone (n = 71) were studied with immunohistochemistry for CD44v6. The extent and intensity of membranous and cytoplasmic CD44v6 staining, and the intratumoral membranous staining pattern, were analyzed.

RESULTS: Membranous CD44v6 expression was seen in 84% and cytoplasmic expression in 81% of the cases. In 59% of the tumors with membranous CD44v6 expression, the staining pattern in the invasive front was determined as “front-positive” and in 41% as “front-negative”. The latter pattern was associated with narrower circumferential margin (P = 0.01), infiltrative growth pattern (P < 0.001), and shorter disease-free survival in univariate survival analysis (P = 0.022) when compared to the “front-positive” tumors.

CONCLUSION: The lack of membranous CD44v6 in the rectal cancer invasive front could be used as a method to identify patients at increased risk for recurrent disease.

Cathepsin D Expression in Colorectal Cancer: From Proteomic Discovery through Validation Using Western Blotting, Immunohistochemistry, and Tissue Microarrays

Despite recent advances in surgical techniques and therapeutic treatments, survival from colorectal cancer (CRC) remains disappointing with some 40–50% of newly diagnosed patients ultimately dying of metastatic disease. Current staging by light microscopy alone is not sufficiently predictive of prognosis and would benefit from additional support from biomarkers in order to stratify patients appropriately for adjuvant therapy. We have identified that cathepsin D expression was significantly greater in cells from invasive front (IF) area and liver metastasis (LM) than those from main tumour body (MTB). Cathepsin D expression was subsequently examined by immunohistochemistry in tissue microarrays from 119 patients with CRC. Strong expression in tumour cells at the IF did not correlate significantly with any clinico-pathological parameters examined or patient survival. However, cathepsin D expression in cells from the MTB was highly elevated in late stage CRC and showed significant correlation with subsequent distant metastasis and shorter cancer-specific survival. We also found that macrophages surrounding tumour cells stained strongly for cathepsin D but there was no significant correlation found between cathepsin D in macrophages at IF and MTB of CRC patient with the clinic-pathological parameters examined.

The relationships between cellular components of the peritumoural inflammatory response, clinicopathological characteristics and survival in patients with primary operable colorectal cancer

Background:

The host inflammatory response is an important determinant of cancer outcome. We examined different methods of assessing the local inflammatory response in colorectal tumours and explored relationships with both clinicopathological characteristics and survival.

Methods:

Cohort study of patients (n=130) with primary operable colorectal cancer and mature follow-up. Local inflammatory response at the invasive margin was assessed with: (1) a semi-quantitative assessment of peritumoural inflammation using Klintrup–Makinen (K–M) grading and (2) an assessment of individual immune cell infiltration (lymphocytes, plasma cells, neutrophils, macrophages and eosinophils).

Results:

The peritumoural inflammatory response was K–M low grade in 48% and high grade in 52%. Inflammatory cells were primarily macrophages, lymphocytes and neutrophils with relatively few plasma cells or eosinophils. On univariate analysis, K–M grade, lymphocyte infiltration and plasma cell infiltration were associated with cancer-specific survival. On multivariate analysis, only systemic inflammatory response, TNM (tumour, node and metastases) stage, venous invasion, tumour necrosis and K–M grade were independently associated with cancer-specific survival. There was no relationship between local infiltration of inflammatory cells and a systemic inflammatory response. However, high K–M grade, lymphocyte infiltration and plasma cell infiltration were associated with a number of favourable pathological characteristics, including an absence of venous invasion.

Conclusion:

Infiltration of inflammatory cells in the invasive margin of colorectal tumours is beneficial to survival. The adaptive immune response appears to have a prominent role in the prevention of tumour progression in patients with colorectal cancer.

An improved image analysis method for cell counting lends credibility to the prognostic significance of T cells in colorectal cancer

Numerous immunohistochemically detectable proteins, such as immune cell surface (CD) proteins, vascular endothelial growth factor, and matrix metalloproteinases, have been proposed as potential prognostic markers in colorectal cancer (CRC) and other malignancies. However, the lack of reproducibility has been a major problem in validating the clinical use of such markers, and this has been attributed to insufficiently robust methods used in immunohistochemical staining or its assessment. In this study, we assessed how computer-assisted image analysis might contribute to the reliable assessment of positive area percentage and immune cell density in CRC specimens, and subsequently, we applied the computer-assisted cell counting method in assessing the prognostic value of T cell infiltration in CRC. The computer-assisted analysis methods were based on separating hematoxylin and diaminobenzidine color layers and then applying a brightness threshold using open source image analysis software ImageJ. We found that computer-based analysis results in a more reproducible assessment of the immune positive area percentage than visual semiquantitative estimation. Computer-assisted immune cell counting was rapid to perform and accurate (Pearson r > 0.96 with exact manual cell counts). Moreover, the computer-assisted determination of peritumoral and stromal T cell density had independent prognostic value. Our results suggest that computer-assisted image analysis, utilizing freely available image analysis software, provides a valuable alternative to semiquantitative assessment of immunohistochemical results in cancer research, as well as in clinical practice. The advantages of using computer-assisted analysis include objectivity, accuracy, reproducibility, and time efficiency. This study supports the prognostic value of assessing T cell infiltration in CRC.

Low expression of Granzyme B in colorectal cancer is associated with signs of early metastastic invasion

AIMS

Tumour-infiltrating forkhead box P3 (FoxP3+ ) regulatory T cells (T(regs) ) have stronger prognostic significance than cytotoxic CD8+ T cells in colorectal cancer (CRC). Because there is evidence that some tumour-infiltrating CD8+ T cells may be inactive, the present study aimed to investigate the prognostic significance of Granzyme B, one of the major effector molecules of T cells.

METHODS AND RESULTS

A tissue microarray containing 963 CRCs was stained immunohistochemically for Granzyme B and the level of expression quantified by digital image analysis. Granzyme B expression was higher in tumours with microsatellite instability (P < 0.0001), a dense lymphocytic infiltrate (P < 0.0001) and location in the proximal colon (P = 0.009), but lower in tumours with vascular invasion (P = 0.007), perineural invasion (P =0.041) and positive nodal status (P < 0.001). Elevated expression of Granzyme B was associated with improved survival on univariate analysis (hazard ratio = 0.65; 95% confidence interval 0.51-0.84; P = 0.001), but not in a multivariate model that included stage, vascular invasion and FoxP3+ T(reg) cell density.

CONCLUSIONS

Low expression of Granzyme B was associated with early signs of metastasis in CRC. The stronger prognostic significance of FoxP3+ T(regs) is in keeping with animal models that suggest these cells act as gatekeepers for the release of Granzyme B from CD8+ T cells.

Immunohistochemical expression profile of β-catenin, E-cadherin, P-cadherin, laminin-5γ2 chain, and SMAD4 in colorectal serrated adenocarcinoma

The immunohistochemical expression of cell adhesion molecules in colorectal serrated adenocarcinoma is still unknown. The immunostaining patterns of β-catenin, E-cadherin, P-cadherin, laminin 5γ2, and SMAD4 and their relationship to survival were studied in different tumor areas, namely, tumor center and invasive front, the latter comprising tumor bud and non-tumor bud clusters, as described in a previous study of 66 serrated adenocarcinomas and matched conventional carcinomas. Compared with conventional carcinomas, serrated adenocarcinomas showed significantly reduced nuclear β-catenin, membranous E-cadherin, and nuclear SMAD4 but an increased cytoplasmic expression of laminin-5γ2 at the invasive front that was particularly pronounced in the tumor buds. E-cadherin loss at the invasive front was identified as an independent prognostic factor for a poorer outcome in serrated adenocarcinoma. Serrated adenocarcinoma shows a distinct immunohistochemical profile at the invasive front compared with conventional carcinoma, which may account for its less favorable outcome. The lower frequency of nuclear β-catenin in SAC, especially in right-sided tumors, suggests that molecular mechanisms other than the canonical Wnt/β-catenin pathway may have a role in tumor bud formation.

Prognostic significance and molecular associations of tumor growth pattern in colorectal cancer

BACKGROUND

Infiltrative growth pattern at the tumor margin has been associated with shorter patient survival. However, little is known about the prognostic significance of tumor growth pattern, independent of tumoral molecular alterations and other histologic features.

METHODS

Utilizing a database of 1139 colon and rectal cancer patients in two prospective cohort studies, histologic features including tumor growth pattern, tumor differentiation, lymphocytic reaction, mucinous component, and signet ring cell component were recorded by a single pathologist. Cox proportional hazard model was used to compute mortality hazard ratio, adjusting for clinical, pathologic, and tumor molecular features, including microsatellite instability, the CpG island methylator phenotype, long interspersed nucleotide element 1 (LINE-1) methylation, and KRAS, BRAF, and PIK3CA mutations.

RESULTS

Among 1139 colorectal cancers, we observed expansile growth pattern in 372 tumors (33%), intermediate growth pattern in 610 tumors (54%), and infiltrative growth pattern in 157 tumors (14%). Compared to patients with expansile growth pattern, those with infiltrative growth pattern experienced shorter cancer-specific survival (log rank P < 0.0001; multivariate hazard ratio 1.74; 95% confidence interval 1.22-2.47) and overall survival (log rank P < 0.0001; multivariate hazard ratio 1.78; 95% confidence interval 1.33-2.39). The prognostic association of infiltrative growth pattern was confined to patients with stage I-III disease (P (interaction) with stage = 0.0001).

CONCLUSIONS

Infiltrative growth pattern was associated with worse prognosis among stage I-III colorectal cancer patients, independent of other clinical, pathologic, and molecular characteristics.

Characterization of the immunophenotype of the tumor budding and its prognostic implications in squamous cell carcinoma of the lung

Tumor budding is morphologically defined as infiltration by small clusters of cancer cells. While the biological properties of budding cells in adenocarcinoma (decreased expression of adhesion molecules and of differentiation markers) have been elucidated, those of the cells in squamous cell carcinoma (SqCC) of the lung still remain to be clarified. We examined the clinicopathological data of 217 patients with SqCC of the lung. Furthermore we evaluated the immunohistochemical properties of the budding cells. Tumor budding was observed in 83 (38.2%) patients. A statistically significant difference was observed in overall 5-year survival rates between the cases showing tumor budding and the cases not showing budding (45.6% vs. 64.0%, p<0.001). As compared with cancer cells forming solid nests, budding cells (BCs) exhibited reduced expression levels of the cellular adhesion molecules (E-cadherin; p=0.004, β-catenin; p=0.002) and increased expression levels of laminin-5γ2 (p=0.001). On the other hand, no significant differences in the staining scores for differentiation markers (p63 and podoplanin) were found between BCs and cancer cells forming nests. Multivariate analysis revealed that tumor budding was a significant independent prognostic factor in patients with SqCC of the lung (p=0.022). Tumor budding is an independent adverse prognostic factor in patients with SqCC of the lung. Although budding cells in SqCC exhibited reduced expression levels of the cellular adhesion molecules, the expression levels of specific differentiation markers were retained, suggesting that the budding mechanism in SqCC may differ, at least in part, from that in adenocarcinoma.

Overexpression of ZEB2 at the invasion front of colorectal cancer is an independent prognostic marker and regulates tumor invasion in vitro

PURPOSE

Epithelial-to-mesenchymal transition (EMT) plays a pivotal role in tumor invasion and dissemination. EMT occurs predominantly at the tumor edge where it is induced by cytokines, the extracellular matrix environment, or hypoxia. In the tumor cell, it is further mediated by several transcription factors and microRNAs. The aim of this study was to explore the expression of EMT-associated genes at the invasive front in colorectal cancer and to evaluate their prognostic significance.

EXPERIMENTAL DESIGN

We evaluated the expression of 13 EMT-associated genes at the invasion front of 30 colorectal liver metastases by quantitative real-time PCR. Immunostaining against zinc finger E-box-binding homeobox 2 (ZEB2) was carried out on 175 primary colorectal cancer specimens and 30 colorectal liver metastases and correlated to clinical and histopathologic data. DLD-1 cells were transfected with siRNA and subjected to migration and invasion assays.

RESULTS

Gene expression analysis and immunohistochemistry showed an upregulation of ZEB2 at the invasion front in primary colorectal cancer and liver metastases. Overexpression of ZEB2 at the invasion front correlated significantly with tumor stage in primary colorectal cancer. Moreover, univariate and multivariate analysis revealed overexpression of ZEB2 at the invasion front as an independent prognostic marker for cancer-specific survival. Downregulation of ZEB2 by siRNA decreased the migration and invasion capacity of DLD-1 cells in vitro.

CONCLUSIONS

Overexpression of ZEB2 at the invasion front correlates with tumor progression and predicts cancer-specific survival in primary colorectal cancer. Therefore, ZEB2 may be interesting as biomarker and potential target for treatment of colorectal cancer.

Assessment of tumor budding in colorectal carcinoma: correlation with β-catenin nuclear expression

BACKGROUND

Tumor budding (TB) is showing increasing promise as a colorectal cancer (CRC) prognosticator that is independent of TNM staging. β-Catenin is a component of the Wingless/Wnt signaling pathway that is bound to membrane-associated E-cadherin and is essential for its correct position and function.

METHODS

This study was designed to detect TB in 44 resected primary CRC cases and also to compare β-catenin expression in the tumor budding sites (TBS) and in the tumor center. Tumor budding was assessed in both H&E and pankeratin immunostained sections. Agreement between TB scoring using pancytokeratin and H&E was tested. Also, typing of the tumor margin and determination of degree of cytoplasmic pseudo-fragmentation was done. Tumor budding, cytoplasmic pseudofragments and β-catenin expression were related to known CRC prognosticators.

RESULTS

Ten tumors (22.7%) showed low grade (LG) budding and 34 tumors (77.3%) showed high grade (HG) budding. The 34 HG budding tumors were further subdivided into moderate and severe (n=13, n=21, respectively) budding cancers. Twenty nine tumors (65.9%) showed LG cytoplasmic pseudofragments and 15 tumors (34.1%) showed HG pseudofragments. Scoring of TB on H&E and pankeratin stained sections revealed moderate agreement (Kappa=.558; p=<.000). A significant relation between TB and cytoplasmic pseudofragments was observed (p=.009). Both TB and cytoplasmic pseudofragments did not significantly associate with clinicopathologic parameters. Immunoreactivity of nuclear and cytoplasmic β-catenin was significantly higher at TBS compared to tumor center (p=.005, p=.000, respectively). In opposition, membranous β-catenin expression was significantly higher in the tumor center than in TBS (p=.001). Although, nuclear β-catenin accumulation at TBS was noted, yet, it did not relate significantly with both TB and cytoplasmic pseudofragments around TBS (p=.649; p=.675, respectively). Also, nuclear β-catenin immunoreactivity did not relate significantly with the various clinicopathological variables.

CONCLUSION

Pankeratin immunostaining facilitates typing of CRC invasive margin, and determination of the degree of TB and cytoplasmic pseudo-fragmentation. β-Catenin expression differs significantly between tumor center and TBS in CRC. Cut-offs for TB assessment should be unified and further studies are recommended to allow a better understanding of this process before establishing TB as a prognostic factor beyond the TNM staging in CRC.

High tumour cannabinoid CB1 receptor immunoreactivity negatively impacts disease-specific survival in stage II microsatellite stable colorectal cancer

Background

There is good evidence in the literature that the cannabinoid system is disturbed in colorectal cancer. In the present study, we have investigated whether CB₁ receptor immunoreactive intensity (CB₁IR intensity) is associated with disease severity and outcome.

Methodology/Principal Findings

CB₁IR was assessed in formalin-fixed, paraffin-embedded specimens collected with a consecutive intent during primary tumour surgical resection from a series of cases diagnosed with colorectal cancer. Tumour centre (n = 483) and invasive front (n = 486) CB₁IR was scored from 0 (absent) to 3 (intense staining) and the data was analysed as a median split i.e. CB₁IR <2 and ≥2. In microsatellite stable, but not microsatellite instable tumours (as adjudged on the basis of immunohistochemical determination of four mismatch repair proteins), there was a significant positive association of the tumour grade with the CB₁IR intensity. The difference between the microsatellite stable and instable tumours for this association of CB₁IR was related to the CpG island methylation status of the cases. Cox proportional hazards regression analyses indicated a significant contribution of CB₁IR to disease-specific survival in the microsatellite stable tumours when adjusting for tumour stage. For the cases with stage II microsatellite stable tumours, there was a significant effect of both tumour centre and front CB₁IR upon disease specific survival. The 5 year probabilities of event-free survival were: 85±5 and 66±8%; tumour interior, 86±4% and 63±8% for the CB₁IR<2 and CB₁IR≥2 groups, respectively.

Conclusions/Significance

The level of CB₁ receptor expression in colorectal cancer is associated with the tumour grade in a manner dependent upon the degree of CpG hypermethylation. A high CB₁IR is indicative of a poorer prognosis in stage II microsatellite stable tumour patients.

Oncosuppressor methylation: a possible key role in colon metastatic progression

K-RAS and BRAF gene mutations are mandatory to set anti-EGFR therapy in metastatic colorectal cancer (mCRC) patients. Due to the relationship of these mutations with tumor epigenotype, we hypothesized the potential role of oncosuppressor methylation of genes involved in K-RAS/BRAF pathway (CDKN2A, RASSF1A, and RARbeta suppressor genes) in inhibiting EGFR signaling cascade. Primary tumor and synchronous liver metastatic tissues of 75 mCRC patients were characterized for promoter methylation by QMSP and for K-RAS and BRAF mutations. RARbeta, RASSF1A, and CDKN2A genes were methylated in 82%, 35%, and 26% of primary tumors, respectively. RASSF1A resulted significantly more frequently methylated in liver metastasis than in primary site (P=0.015), while RARbeta was significantly lower methylated in distant metastasis (P=1.2 × 10(-6)). As regards methylation content, RASSF1A methylation status was significantly higher in liver metastasis with respect to primary tumor (P=0.000) underlying the role of this gene in liver metastatic progression. In our series K-RAS and BRAF were mutated in 39% and 4% of cases, respectively. Methylation frequencies seemed to be unrelated to gene mutations; on the other hand, RASSF1A mean content methylation resulted significantly higher in liver than in primary tumor (288.78 vs. 56.23, respectively, P=0.05) only in K-RAS wild-type cases sustaining a specific role of this gene in metastatic site thus supporting its function in strengthening the apoptotic role of K-RAS. These evidences held the role of oncosuppressor methylation in both colon tumorigenesis and progression and suggested that epigenetic events should be taken into account when biological therapies in mCRC patients have to be set.

Epithelial mesenchymal transition and tumor budding in aggressive colorectal cancer: tumor budding as oncotarget

Epithelial mesenchymal transition (EMT) is proposed as a critical mechanism for the acquisition of malignant phenotypes by epithelial cells. In colorectal cancer, tumor cells having undergone EMT are histologically represented by the presence of tumor buds defined as single cells or small clusters of de-differentiated tumor cells at the invasive front. Tumor budding is not a static, histological feature rather it represents a snap-shot of a dynamic process undertaken by an aggressive tumor with the potential to disseminate and metastasize. Strong, consistent evidence shows that tumor budding is a predictor of lymph node metastasis, distant metastatic disease, local recurrence, worse overall and disease-free survival time and an independent prognostic factor. Moreover, the International Union against Cancer (UICC) recognizes tumor budding as a highly relevant, additional prognostic parameter. The aim of this review is to summarize the evidence supporting the implementation of tumor budding into diagnostic pathology and patient management and additionally to illustrate its worthiness as a potential therapeutic target.

Correlation between tumor budding and post-resection prognosis in patients with invasive squamous cell carcinoma of the thoracic esophagus

BACKGROUND

Tumor budding is defined as an isolated single cancer cell or a cluster of cancer cells composed of fewer than five cells at the invasive front of a tumor. The aim of the present study was to identify correlations between tumor budding and clinicopathological factors and their impact on postoperative prognosis in invasive squamous cell carcinoma of the thoracic esophagus.

METHODS

The subjects were 82 patients who underwent curative resection. The number of tumors showing budding was counted immunohistochemically based on positivity for cytokeratin (AE1/AE3) to distinguish cancer cells from inflammatory cells, and the patients were divided into low-grade and high-grade budding groups. High-grade budding was defined as ≥5 budding foci per field under a 20× objective lens.

RESULTS

One group of 36 patients (43.9%) and a second group of 46 patients (56.1%) were classified into the low-grade and high-grade budding groups, respectively. Patients in the high-grade budding group had significantly larger tumor size, deeper depth of invasion, more frequent lymphatic invasion and venous invasion, as well as more lymph node metastases, than those in the low-grade budding group. Disease-free and overall survivals were worse in the high-grade budding group than in the low-grade budding group (P<0.0001 and P=0.0002, respectively). Three of four patients who had tumor recurrence more than 5 years postoperatively belonged to the low-grade budding group.

CONCLUSIONS

Tumor budding appears to be an indicator of tumor growth and invasiveness. Patients with low-grade budding are likely to have a better prognosis than those with high-grade budding, but the tumor may recur in the late phase postoperatively in patients with low-grade budding.

Origin and growth of otosclerosis

CONCLUSION

The external layer of the otic capsule arises from periosteal osteoblasts, which produce large numbers of Volkmann's canals as well as lamellar bone. The main plaque of otosclerosis is a histologic replica of the external layer and seems to arise from similar cells in the periosteum and to follow a defined invasive course into the footplate of the stapes, the basal coil of the cochlea and the saccule.

OBJECTIVES

To determine by histologic study of the developing otic capsule and temporal bones with otosclerosis the site, tissue of origin, and pathways of growth of the disease.

METHODS

Step sections of 60 celloidin-embedded temporal bones from fetuses and 24 from patients aged between 1 and 52 years were examined in the study of the development of the otic capsule. Step sections of 65 temporal bones each with 2 or more deposits of otosclerosis were surveyed to obtain data on the site, tissue of origin, and pathways of its growth.

RESULTS

The otic capsule differs from other bones in that the formation of the ultimate lamellar bone tissue is accompanied by very numerous intercommunicating channels. In the middle (cartilage origin) layer these are chondro-osseous canals and Volkmann's canals (like Haversian canals, but multidirectional). In the external (periosteal origin) layer these are Volkmann's canals only. In all, 63 of the 65 temporal bones with otosclerosis that were studied showed a prominent posterior otic capsule plaque. Evidence that this is derived from the periosteum of the external canal is as follows. (a) The otosclerotic tissue of the plaque--like all otosclerotic tissue--is composed of Volkmann's canals and lamellar bone only, as does external layer tissue. (b) All posterior plaques have an edge at the periosteum bordering the processus cochleariformis and tensor tympani muscle. The presumed invasive edge of the plaque on the opposite (cochlear) side shows a variable level of its front. (c) The tissue on the cochlear side of the plaque has a darkly stained appearance with large numbers of osteoblasts and poorly differentiated Volkmann's canals, suggesting that this is an invasive front. The otosclerosis becomes progressively better differentiated away from the darkly stained zone, indicating increasing maturation, which is greatest in the suggested origin of the plaque at the processus/tensor tympani muscle region because this would be the oldest region of the plaque. The pathway of the growth indicated by this study suggests a possible time sequence in the symptomatology of otosclerosis as it moves first to stapes footplate and then through the spiral ligament of cochlea to the saccule. An anterior plaque was seen in 42 of the 65 temporal bones with multiple sites of otosclerosis examined. These showed features similar to those listed above for the posterior plaque, with a base on the periosteum bordering the canal for the internal carotid artery, dark zonation at the invasive front near the cochlea, and increasing differentiation towards the base.

Cell surface markers in colorectal cancer prognosis

The classification of colorectal cancers (CRC) is currently based largely on histologically determined tumour characteristics, such as differentiation status and tumour stage, i.e., depth of tumour invasion, involvement of regional lymph nodes and the occurrence of metastatic spread to other organs. These are the conventional prognostic factors for patient survival and often determine the requirement for adjuvant therapy after surgical resection of the primary tumour. However, patients with the same CRC stage can have very different disease-related outcomes. For some, surgical removal of early-stage tumours leads to full recovery, while for others, disease recurrence and metastasis may occur regardless of adjuvant therapy. It is therefore important to understand the molecular processes that lead to disease progression and metastasis and to find more reliable prognostic markers and novel targets for therapy. This review focuses on cell surface proteins that correlate with tumour progression, metastasis and patient outcome, and discusses some of the challenges in finding prognostic protein markers in CRC.

The expression and distribution of group IIA phospholipase A2 in human colorectal tumours

Secretory phospholipase A2 group IIA (IIA PLA2) is a protein shown to be increased in various human malignancies. The expression profile of this protein, however, is controversial in colorectal carcinoma. The aim of this study was to examine the distribution and expression of IIA PLA2 protein in benign, premalignant and malignant colorectal tumours as well as in peritumoural mucosa. Seven hyperplastic polyps, 24 adenomas and 83 colorectal carcinomas were stained with immunohistochemistry (IHC) for IIA PLA2. Four hyperplastic polyps, 12 adenomas and nine carcinomas were also evaluated for the sites of IIA PLA2 expression using mRNA in situ hybridisation (ISH). There was no immunoreactivity for IIA PLA2 in hyperplastic polyps. A total of 79% of adenomas and 31% of carcinomas showed IIA PLA2-immunopositive tumour cells in IHC, and the expression was localised to epithelial cells with ISH. In carcinomas, IIA PLA2-immunopositive apoptotic cells and necrosis were also found. The epithelial cells in the peritumoural mucosa showed immunopositivity for IIA PLA2 in 96% of cases, with considerably stronger intensity adjacent to carcinoma than in the more distal mucosa. Moreover, IIA PLA2-immunopositive malignant epithelial cells were found in 44% of cases in the invasive front of carcinomas. Our results suggest that the IIA PLA2 protein content is dramatically decreased in malignant colorectal tumours as compared with adenomas. The protein is also found in the apoptotic cells, necrosis, peritumoural mucosa and in the invasive front of carcinomas.