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

Potential role of the Eph/ephrin system in colorectal cancer: emerging druggable molecular targets

The Eph/ephrin system regulates many developmental processes and adult tissue homeostasis. In colorectal cancer (CRC), it is involved in different processes including tumorigenesis, tumor angiogenesis, metastasis development, and cancer stem cell regeneration. However, conflicting data regarding Eph receptors in CRC, especially in its putative role as an oncogene or a suppressor gene, make the precise role of Eph-ephrin interaction confusing in CRC development. In this review, we provide an overview of the literature and highlight evidence that collaborates with these ambiguous roles of the Eph/ephrin system in CRC, as well as the molecular findings that represent promising therapeutic targets.

The ypT may better predict the efficacy of neoadjuvant chemoradiotherapy than tumor regression grade in locally advanced rectal cancer patients diagnosed ypT1-4N0

PURPOSE

This study aimed to assess the impact of ypT stage and tumor regression grade (TRG) on the long-term prognosis of patients with locally advanced rectal cancer (LARC) stage ypT1-4N0 after neoadjuvant chemoradiotherapy (NCRT).

METHODS

We retrospectively analyzed 585 patients with histologically diagnosed middle-low LARC (cT3-4 or cN + by pelvic MRI) from 2014 to 2019. All patients underwent NCRT, followed by total mesorectal excision. Disease-free survival (DFS) rates were compared among patients with different ypT stages and TRGs by Kaplan-Meier survival analysis. The chi-square test was used to analyze the relationship between clinicopathological or therapeutic factors and ypT stage.

RESULTS

The median follow-up was 35.8 months (range 2.8-71.8 months). The 3-year DFS was 79.5%. A better 3-year DFS was achieved in patients with a pathologic complete response (94.0% vs. 74.3%, p < 0.001) and those in the ypT0-2 (86.5% vs. 66.6%, p < 0.001), ypN0 (85.0% vs. 60.2%, p < 0.001), and TRG0 + 1 (83.1% vs. 73.0%, p = 0.004) subgroups. A total of 309 patients (52.8%) achieved stage ypT1-4N0 after surgery. Among these patients, the ypT1-2N0 subgroup achieved a significantly higher 3-year DFS than the ypT3-4N0 subgroup (85.4% vs. 72.8%, p = 0.018); in contrast, the 3-year DFS did not significantly differ between the TRG1 and TRG2 + 3 subgroups (79.9% vs. 81.1%, p = 0.833). In the ypT1-2N0 or ypT3-4N0 subgroup, different TRG had no significant effect on failure patterns.

CONCLUSIONS

For LARC patients with a ypT1-4N0 status after NCRT, ypT stage may be a more effective predictor of long-term prognosis than TRG.

Systematic Analysis of the Clinical Significance of Hyaluronan-Mediated Motility Receptor in Colorectal Cancer

Background: The role of hyaluronan-mediated motility receptor (HMMR) in colorectal cancer (CRC) remains unclear. The present study aimed to explore the association of HMMR with the development and prognosis of CRC using sequence datasets, clinical tissues, blood samples, and cell lines.

Methods: CRC datasets were downloaded from TCGA and GEO databases. Forty CRC tissue samples, 120 CRC blood samples, and 100 healthy controls were collected. Four CRC cell lines (HCT116, HT-29, LoVo, and SW480) and one normal human colon mucosal epithelial cell line (NCM460) were cultured. RT-qPCR was used to determine the expression of HMMR in the tissues and cell lines. ELISA was used to measure HMMR levels in the blood samples.

Results: The expression of HMMR was significantly increased in CRC tissues than in corresponding adjacent tissues based on TCGA and GEO datasets, and clinical CRC tissues. No associations were found between the expression of HMMR and the TNM stage or other clinical parameters. The expression of HMMR varied in different CRC cell lines. The blood levels of HMMR tended to be higher in patients with CRC than in healthy controls. TCGA and GEO datasets showed inconsistent results regarding the association of HMMR expression with the survival of patients with CRC.

Conclusion: The expression of HMMR is increased in CRC tissues but not in the blood. The expression of HMMR is independent of CRC development and has no prognostic significance in patients with CRC.

CD133 Expression Predicts Relapse in Patients With Locally Advanced Rectal Cancer Treated With Neoadjuvant Chemotherapy

AIM

The aim of the present study was to explore the association between CD133 expression and postoperative relapses in patients with locally advanced rectal cancer (LARC) who received neoadjuvant chemotherapy (NAC).

PATIENTS AND METHODS

We retrospectively examined 52 patients with LARC (cT3-4, Nany, M0) who received oxaliplatin-based NAC before surgery. CD133 expression was evaluated using immunohistochemistry and divided into low and high expression groups.

RESULTS

High CD133 expression was observed in 22 patients (42.3%). Patients with high CD133 expression had more frequent vessel invasion and relapse than those with low CD133 expression (p=0.013 and p=0.036, respectively). Comparing the low with high CD133 expression groups, the 4-year relapse-free survival rates were 82.2% vs. 46.3% (p=0.009). Multivariate analysis indicated that CD133 expression was an independent risk factor for relapse (HR=3.138; 95%CI=1.046-9.412; p=0.041).

CONCLUSION

CD133 expression may be a predictive biomarker for postoperative relapse in patients with LARC who received NAC before surgery.

Prognostic value of noggin protein expression in patients with resected gastric cancer

Background

Noggin and RNA-binding protein for multiple splicing 2 (RBPMS2) are known to regulate the expression of smooth muscle cells, endothelial cells, and osteoblasts. However, the prognostic role of combined Noggin and RBPMS2 expression in resected gastric cancer (GC) is unclear.

Methods

A total of 163 patients with GC who underwent gastrectomy were included in this study. The expression of Noggin and RBPMS2 proteins in tumor cells at the tumor center and invasive front of resected GC was evaluated by immunohistochemistry, and in conjunction with clinicopathological parameters the patient survival was analyzed.

Results

RBPMS2 protein expression was high at the tumor center (n = 86, 52.8%) and low at the invasive front (n = 69, 42.3%), while Noggin protein expression was high in both tumor center (n = 91, 55.8%) and the invasive front (n = 90, 55.2%). Noggin expression at the invasive front and tumor center was significantly decreased in advanced T stage, non-intestinal-type (invasive front, P = 0.008 and P <  0.001; tumor center lesion, P = 0.013 and P = 0.001). RBPMS2 expression at the invasive front was significantly decreased in non-intestinal-type and positive lymphatic invasion (P <  0.001 and P = 0.013). Multivariate analysis revealed that high Noggin protein expression of the invasive front was an independent prognostic factor for overall survival (hazard ratio [HR], 0.58; 95% confidence interval [CI]; 0.35–0.97, P <  0.036), but not at the tumor center (HR, 1.35; 95% CI; 0.81–2.26, P = 0.251).

Conclusions

Our study indicates that high Noggin expression is a crucial prognostic factor for favorable outcomes in patients with resected GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08273-x.

Expression level of E-, N- and P-cadherin proteins in endometrial cancer

The aim of the present study was to examine the protein expression levels of E-, N- and P-cadherin, which are involved in the proliferation of neoplastic cells, in cancer tissue from patients with endometrial cancer. Furthermore, the present study aimed to investigate the effect of these proteins on clinicopathological parameters. Immunohistochemistry was performed to detect the protein expression levels of the aforementioned cadherins in 38 primary endometrial tumors, 20 metastatic tumors (nine metastases to the lymph nodes and 11 distant metastases) and five cases of atypical hyperplasia as the control group. It was found that the E-, N- and P-cadherin proteins in hyperplastic endometrial lesions with atypia were weakly expressed in the cytoplasm, while the expression levels of E-, N- and P-cadherin proteins, in endometrial cancer tissue, were located in the membrane and/or in the cytoplasm, and was found to be unevenly distributed. Furthermore, increased expressed level of the three cadherin proteins was observed at the tumor front, as opposed to in the main mass, of endometrial cancer tumor. It was demonstrated that membrane expression levels of the 3 cadherin proteins were lower in metastatic cancer cells compared with that in the primary tumor cells. In addition, a significantly higher cytoplasmic expression level of E-cadherin and increased membranous and cytoplasmic expression of P-cadherin, were associated with high-grade tumor budding. Furthermore, a higher percentage of P-cadherin membrane expression level was associated with poorly differentiated cancer cell types. The present results suggested that the increased membrane expression level of E-cadherin was associated with the presence of local lymph node involvement.

Elevated ZBTB7A expression in the tumor invasive front correlates with more tumor budding formation in gastric adenocarcinoma

PURPOSE

Tumor budding (TB) is reported to predict nodal involvement and recurrence in multiple human malignancies. However, it is not clear how TB forms. The purpose of this study is to find markers related to TB formation in gastric cancer and to investigate the underlying mechanisms.

METHODS

TB was scored on hematoxylin-eosin staining slides in 122 gastric cancer cases. Immunostaining score of CREB1, GAGE12I, CTNND1, KIF26B and ZBTB7A both at the invasive front and in the center of the tumor were assigned to each case. Spearman's correlation with the TB score was performed to find the TB-related markers. In vitro study and RNA-seq using gastric cancer cell lines were done to unveil the mechanisms.

RESULTS

TB could predict lymph node metastasis and is negatively associated with overall survival of the patients. The expression of ZBTB7A in the invasive front, rather than the other four markers, was much higher than that in the tumor center and was positively correlated with TB score. ZBTB7A could enhance migration and invasion of gastric cancer cells in vitro. RNA-seq data followed by RT-qPCR and western blot verification demonstrated the activation of EGFR-MAPK-ERK and PI3K-AKT-mTOR pathways and increased expression of EMT related markers upon ZBTB7A over-expression.

CONCLUSION

Higher ZBTB7A expression in the tumor margin may contribute to the dissociation of tumor cells from the tumor mass to form TB by initiating EMT via EGFR-MEK-ERK and PI3K-AKT-mTOR pathway.

The role of transcription factor caudal-related homeobox transcription factor 2 in colorectal cancer

Colorectal cancer (CRC) is one of the most malignant tumors in humans and causes mass mortality. In the age of precise medicine, more and more subtypes of CRC were classified. The caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor which is implicated in differentiation, proliferation, cell-adhesion, and migration. The loss of CDX2 in immunohistochemical stain was reported to be a prognostic factor of colon cancer, but the clinical application remained controversial. Most of the CRCs expressed or over-expressed CDX2. Homeobox genes can display either an oncogenic or a tumor-suppressing activity. CDX2 regulates the developing intestinal epithelium and CRC by different pathways. The complex regulation of CDX2 and its complex targets cause the difficulties of application for CDX2 in the prediction of prognosis. However, CDX2 is a potential biomarker applied in the precise classification of CRC for personalized medicine. This review partially clarifies the role of CDX2 in CRC.

Markers of Cancer Cell Invasion: Are They Good Enough?

Invasion, or directed migration of tumor cells into adjacent tissues, is one of the hallmarks of cancer and the first step towards metastasis. Penetrating to adjacent tissues, tumor cells form the so-called invasive front/edge. The cellular plasticity afforded by different kinds of phenotypic transitions (epithelial-mesenchymal, collective-amoeboid, mesenchymal-amoeboid, and vice versa) significantly contributes to the diversity of cancer cell invasion patterns and mechanisms. Nevertheless, despite the advances in the understanding of invasion, it is problematic to identify tumor cells with the motile phenotype in cancer tissue specimens due to the absence of reliable and acceptable molecular markers. In this review, we summarize the current information about molecules such as extracellular matrix components, factors of epithelial-mesenchymal transition, proteases, cell adhesion, and actin cytoskeleton proteins involved in cell migration and invasion that could be used as invasive markers and discuss their advantages and limitations. Based on the reviewed data, we conclude that future studies focused on the identification of specific invasive markers should use new models one of which may be the intratumor morphological heterogeneity in breast cancer reflecting different patterns of cancer cell invasion.

CDX2 expression is concordant between primary colorectal cancer lesions and corresponding liver metastases independent of chemotherapy: a single-center retrospective study in Japan

Objective

Loss of caudal-type homeobox transcription factor 2 (CDX2) expression in colorectal cancers (CRCs) has recently been proposed as a promising predictive biomarker for not only prognosis but also response to chemotherapy. However, the relationship between alterations in CDX2 expression during cancer progression and response to chemotherapy remains unclear. We herein aimed to determine the concordance of CDX2 expression between primary CRCs and corresponding liver metastases, in association with chemotherapy.

Results

Primary CRCs exhibited heterogeneous CDX2 expression. Seven of the 144 CRCs in the cohort (4.9%, 95% confidential interval, 2.0%–9.8%) were CDX2-negative. The concordance rate of the CDX2 expression status in patients who did not receive chemotherapy was 100% (P = 0.041), whereas the concordance rate among patients who received chemotherapy only after primary resection was 96.3% (P = 0.005). Moreover, the concordance rate in patients who received chemotherapy before both primary resection and liver metastasectomy was 100% (P < 0.001).

Conclusion

CDX2 expression status was highly concordant between primary CRCs and corresponding liver metastases, independent of chemotherapy, suggesting that the CDX2 expression status in CRCs was not affected by metastasis or chemotherapy.

Methods

A total of 144 consecutive patients with CRC who were treated at a single center in Japan between 2006 and 2014 were included. Formalin-fixed paraffin-embedded whole sections of surgically resected primary CRCs and corresponding liver metastases were assessed for CDX2 expression by immunohistochemistry.

MicroRNA-148b inhibits proliferation and the epithelial-mesenchymal transition and increases radiosensitivity in non-small cell lung carcinomas by regulating ROCK1

Non-small cell lung cancer (NSCLC) accounts for ~80% of all types of lung cancer, which has the highest morbidity and mortality of all types of cancer worldwide. It is important to identify novel biomarkers and the molecular mechanism of NSCLC to improve current treatments of NSCLC. The present study aimed to investigate the effect of miR-148b expression on the proliferation, epithelial-mesenchymal transition (EMT) and radiosensitivity of NSCLC cells. It was demonstrated that miR-148b expression was significantly decreased in NSCLC tissues and cell lines. A549 cells were then transfected with a miR-148b mimic and a miR-148b inhibitor. Transfection with the miR-148b mimic decreased proliferation whereas transfection with the miR-148b inhibitor increased the proliferation of A549 cells. Additionally, the miR-148b mimic increased E-cadherin expression and decreased N-cadherin and vimentin expression. By contrast, transfection with the miR-148b inhibitor decreased E-cadherin expression and increased N-cadherin and vimentin expression. Irradiation-induced cell death was significantly promoted by the miR-148b mimic but inhibited by the miR-148b inhibitor. The miR-148b mimic significantly decreased the expression of Rho-associated protein kinase 1 (ROCK1) and it was demonstrated that overexpression of ROCK1 significantly inhibited the effects of miR-148b on cell proliferation, the EMT and irradiation-induced cell death. Therefore, the current study revealed that miR-148b inhibited NSCLC cell proliferation and the EMT, and increased the radiosensitivity of NSCLC cells by inhibiting ROCK1 expression. Therefore, miR-148b/ROCK1 signaling may be a novel therapeutic target to inhibit the growth of NSCLC cells and enhance the effects of radiotherapy to treat patients with NSCLC.

Prognostic significance of CDX2 immunoexpression in poorly differentiated clusters of colorectal carcinoma

CDX2 is a transcription factor that acts as a tumor suppressor in colorectal cancer (CRC). Its loss triggers metastatic process and tumor progression; however, its prognostic role in patients with CRC is still controversial. Poorly differentiated clusters (PDCs) are aggregates of neoplastic cells which likely have high metastatic potential in CRC. In this study, we analyzed and compared CDX2 expression in PDC (CDX2-PDC) and corresponding main tumor (CDX2 main tumor) in 42 CRCs showing at least 10 PDC (PDC G3). Five of 42 CRCs (12%) were classified as CDX2 main tumor negative (4/5 were also PDC-CDX2 negative); all had tumor recurrence and died of CRC. Twenty nine of 42 cases were CDX2-PDC negative. Among CRC CDX2 main tumor positive, 15 had recurrences and 13 died from CRC; 13 and 11 of them, respectively, were CDX2-PDC negative. By assigning one point to CDX2 main tumor or CDX2-PDC positivity, we assessed CDX2-staining score for each case. Twelve cases had CDX2-staining score 2 (CDX2 positive in main tumor and PDC); 26 had score 1 (CDX2 positive in main tumor or PDC), and 4 had CDX2 score 0 (CDX2 negative in main tumor and PDC). In our patients, CDX2-staining score had higher prognostic value compared to CDX2 main tumor or CDX2-PDC alone. In addition, it represented a significant and independent prognostic variable for disease-free survival (DFS) and cancer-specific survival (CSS). Our findings suggest that, although loss of CDX2 in the main tumor identifies high-risk patients with high specificity, CDX2-PDC should also be considered in CDX2 main tumor positive cases to predict prognosis.

Vascular Invasion and Stromal S100A4 Expression at the Invasive Front of Colorectal Cancer are Novel Determinants and Tumor Prognostic Markers

Object: The aim of the present study was to investigate the clinicopathological characteristics and prognostic factors associated with sporadic colorectal cancer (CRC). We examined the clinicopathological findings and immunohistochemical expression of tumor prognostic markers at tumor budding sites to determine their predictive value for patient prognosis.

Materials and Methods: Immunohistochemical examination was performed by tissue microarray (TMA) of specimens from 106 patients with CRC. On hematoxylin and eosin (H&E)-stained tumor tissue slides, a representative area of tumor budding at the invasive front was selected for the construction of a TMA. Immunostaining for matrix metalloproteinase-7 (MMP7), the laminin-5 (ln-5) γ2 chain and S100A4 was performed to determine the association between patient survival and these markers.

Results: Clinicopathological variables were also assessed. Tumor location, histological type, degree of lymphatic invasion and vascular invasion, tumor stage, epithelial expression of S100A4, stromal cell expression of S100A4 and expression of the ln-5γ2 chain were associated with an increased risk of mortality. Five factors were retained in the multivariate logistic regression analysis. Specifically, the tumor location, degree of lymphatic invasion and vascular invasion, tumor stage and stromal cell expression of S100A4 remained significant predictors of patient survival after controlling for the other variables.

Conclusion: Vascular invasion and stromal expression of S100A4 in the tumor budding areas correlated with patient survival. Stromal immunostaining of S100A4 may be useful for identifying high-risk patients with advanced CRC.

OCF can repress tumor metastasis by inhibiting epithelial-mesenchymal transition involved in PTEN/PI3K/AKT pathway in lung cancer cells

A component formula with definite compositions provides a new approach to treat various diseases. Salvia miltiorrhiza and Panax ginseng are widely used in China because of their antitumor properties. In the previous study, the optimizing component formula (OCF), prepared with salvianolic acids, ginsenosides, and ginseng polysaccharides (5, 10, and 5 mg·L⁻¹, respectively) extracted from S. miltiorrhiza and P. ginseng on the basis of IC₅₀ in lung cancer A549 cells and damage minimization on human bronchial epithelial cells in vitro. Currently, we also have demonstrated the inhibitory effect of OCF on A549 cell migration and invasion in vitro. According to Lewis lung cancer cells (LLC) allograft in C57BL/6 mice and A549 xenograft in nude mice experiment, we found that the anti-tumor and anti-metastasis effects of OCF treatment were related to the inhibition of epithelial–mesenchymal transition (EMT). Further studies showed that the inhibitory effect of OCF on EMT was associated with the PTEN/PI3K/AKT pathway. Therefore, all studies revealed that OCF could prevent cancer progression and tumor metastasis by inhibiting EMT involved PTEN/PI3K/AKT signaling pathway in lung cancer cells.

DAPK loss in colon cancer tumor buds: implications for migration capacity of disseminating tumor cells

Defining new therapeutic strategies to overcome therapy resistance due to tumor heterogeneity in colon cancer is challenging. One option is to explore the molecular profile of aggressive disseminating tumor cells. The cytoskeleton-associated Death-associated protein kinase (DAPK) is involved in the cross talk between tumor and immune cells at the invasion front of colorectal cancer. Here dedifferentiated tumor cells histologically defined as tumor budding are associated with a high risk of metastasis and poor prognosis. Analyzing samples from 144 colorectal cancer patients we investigated immunhistochemical DAPK expression in different tumor regions such as center, invasion front, and buds. Functional consequences for tumor aggressiveness were studied in a panel of colon tumor cell lines using different migration, wound healing, and invasion assays. DAPK levels were experimentally modified by siRNA transfection and overexpression as well as inhibitor treatments. We found that DAPK expression was reduced towards the invasion front and was nearly absent in tumor buds. Applying the ECIS system with HCT116 and HCT116 stable lentiviral DAPK knock down cells (HCTshDAPK) we identified an important role for DAPK in decreasing the migratory capacity whereas proliferation was not affected. Furthermore, the migration pattern differed with HCTshDAPK cells showing a cluster-like migration of tumor cell groups. DAPK inhibitor treatment revealed that the migration rate was independent of DAPK's catalytic activity. Modulation of DAPK expression level in SW480 and DLD1 colorectal cancer cells significantly influenced wound closure rate. DAPK seems to be a major player that influences the migratory capability of disseminating tumor cells and possibly affects the dynamic interface between pro- and anti-survival factors at the invasion front of colorectal cancer. This interesting and new finding requires further evaluation.

Expression patterns of CD168 correlate with the stage and grade of squamous cell carcinoma of head and neck

The receptor for hyaluronan-mediated motility CD168 is associated with the processes of oncogenesis and metastasis. The objective of the present study was to determine the possible association between the expression and distribution of CD168 and the tumor stage of head-and-neck squamous cell carcinoma (SCC). Formalin-fixed and paraffin-embedded tumor samples obtained from 100 patients during primary resection of SCC from the oral cavity, oropharynx, hypopharynx or larynx were included in the present study. The patients were divided into two risk groups: Low risk, representing the early stage of completely resected SCCs with good-to-moderate differentiation, and the high-risk group, representing the advanced stage SCCs with positive resection margins, vascular invasion or locoregional metastasis. All specimens were stained with a monoclonal antibody against CD168. Percentage and staining intensity of CD168-positive cells were scored, and their spatial distribution within the tumor nests was noted. The results obtained were correlated with the tumor stage. The quantification of CD168 expression revealed significant differences between the two risk groups (t-test, P=0.002), with higher scores in tumors resected from the high-risk SSC group compared with those from the low-risk group. In addition, in the high-risk group, the CD168-positive cells were present predominantly in the periphery (70.4%) of tumor nests, whereas in the low-risk group, only 56.6% were located there; however, this trend did not reach the level of statistical significance. Taken together, the results from the present study suggested that CD168 expression patterns could potentially be used as a predictor of tumor aggressiveness, and therefore they may be a prognostic factor in head-and-neck SCC.

The Importance of Histology and Pathology in Mass Spectrometry Imaging

Mass spectrometry imaging (MSI) has become a valuable tool in cancer research. Even more, due to its capability to directly link molecular changes with histology, it holds the prospect to revolutionize tissue-based diagnostics. In order to learn to walk before running, however, information obtained through classical histology should not be neglected but rather used to its full capacity and integrated with mass spectrometry data to lead to a superior molecular histology synthesis. In order to achieve this, pathomorphological analyses have to be integrated into MSI analyses right from the beginning to avoid errors and pitfalls of MSI application possibly leading to incorrect or imprecise study outcomes. Such errors can be caused by different sample or tissue inherent factors or through factors in sample preparation. Future studies should, therefore, aim for a comprehensive incorporation of histology and pathology characteristics to ensure the generation of high-quality data in MSI to exploit its full capacity in tissue-based basic and translational research.

Effects of Raf kinase inhibitor protein expression on pancreatic cancer cell growth and motility: an in vivo and in vitro study

PURPOSE

Raf kinase inhibitor protein (RKIP) is a tumor suppressor that inhibits cell growth and metastasis of malignant tumors. Pancreatic cancer is a leading cause of cancer death with a low survival rate. RKIP expression and its role in tumorigenesis and metastasis in pancreatic cancer are poorly understood. The aims of our study were to assess the effects of RKIP on pancreatic carcinoma cells in vitro and in tumor tissues in vivo.

METHODS

This study included 84 patients with histologically confirmed pancreatic adenocarcinoma. The expression levels of RKIP were measured in pancreatic cancer tissues and adjacent normal tissues using real-time PCR and immunohistochemistry. Overexpression plasmid of RKIP was transfected into SW1990 and AsPC-1 cell lines, and the effects on cell proliferation were studied using a Cell Counting Kit-8 assay. MEK1/2 and ERK1/2 were detected by Western blot and immunofluorescence assay.

RESULTS

Results showed a reduced expression of RKIP in pancreatic carcinoma tissues compared with adjacent normal tissues, which closely correlated with patient outcomes. Overexpression of RKIP suppressed cell proliferation and promoted apoptosis in cultured SW1990 and AsPC-1 cell lines. Transwell assay showed RKIP can inhibit cell migration and invasion, and in vivo RKIP can suppress tumorigenesis by diminishing the volume of the tumors.

CONCLUSIONS

In conclusion, expression of RKIP is closely correlated with the survival of pancreatic cancer patients. RKIP can inhibit pancreatic adenocarcinoma cells proliferation, activities of migration and invasion, through downregulating Raf-1-MEK1/2-ERK1/2 signaling pathway.

Tumor Microenvironment in Gene Signatures: Critical Biology or Confounding Noise?

The tumor microenvironment contributes important information in gene expression signatures but may be susceptible to sampling variance. Mesenchymal signatures in particular may be influenced by sampling of nonrepresentative regions with high stromal content. Appropriate pathology quality control is required to ensure reproducibility of gene expression signatures. Clin Cancer Res; 22(16); 3989-91. ©2016 AACRSee related article by Dunne et al., p. 4095.

CDX2 downregulation is associated with poor differentiation and MMR deficiency in colon cancer

BACKGROUND

Homeobox genes are often deregulated in cancer and can have both oncogenic and tumor-suppressing potential. The Caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor. CDX2 has been implicated in differentiation, proliferation, cell adhesion, and migration. In this study, we investigated CDX2 mRNA and protein expression in relation to the clinicopathological characteristics of colon cancer, including mismatch repair status and recurrence risk.

METHODS

Tumor samples were obtained from colon cancer patients. Biopsies from tumor tissue and normal adjacent tissue were fixed in liquid nitrogen for RNA extraction or in formalin and paraffin embedded (FFPE) for immunohistochemical staining. CDX2 mRNA expression was evaluated by RT-qPCR. FFPE sections were stained for MLH1, MSH2, MSH6, PMS2, and CDX2.

RESULTS

A total of 191 patient samples were included in the study and analyzed by immunohistochemistry. Of these samples, 97 were further evaluated by RT-qPCR. There was no significant difference in CDX2 mRNA expression between tumor and normal tissues. CDX2 mRNA expression was significantly lower in right-sided tumors (p<0.05), poorly differentiated tumors (p<0.05), and MMR-deficient tumors (p<0.05). Similarly, CDX2 protein expression was more often low or absent in right-sided tumors (p<0.01), poorly differentiated tumors (p<0.001), and MMR-deficient tumors (p<0.001). Low CDX2 protein or mRNA expression was not associated with recurrence risk.

CONCLUSION

We found that CDX2 downregulation is associated with MMR deficiency, right-sided tumors, and poor differentiation at both the mRNA and protein level. Whether CDX2 plays an active role in tumor progression in MSI/MMR-deficient tumors remains to be elucidated.

Quantitative Image Analysis of Epithelial and Stromal Area in Histological Sections of Colorectal Cancer: An Emerging Diagnostic Tool

In colorectal cancer (CRC), an increase in the stromal (S) area with the reduction of the epithelial (E) parts has been suggested as an indication of tumor progression. Therefore, an automated image method capable of discriminating E and S areas would allow an improved diagnosis. Immunofluorescence staining was performed on paraffin-embedded sections from colorectal tumors (16 samples from patients with liver metastasis and 18 without). Noncancerous tumor adjacent mucosa (n = 5) and normal mucosa (n = 4) were taken as controls. Epithelial cells were identified by an anti-keratin 8 (K8) antibody. Large tissue areas (5–63 mm²/slide) including tumor center, tumor front, and adjacent mucosa were scanned using an automated microscopy system (TissueFAXS). With our newly developed algorithms, we showed that there is more K8-immunoreactive E in the tumor center than in tumor adjacent and normal mucosa. Comparing patients with and without metastasis, the E/S ratio decreased by 20% in the tumor center and by 40% at tumor front in metastatic samples. The reduction of E might be due to a more aggressive phenotype in metastasis patients. The novel software allowed a detailed morphometric analysis of cancer tissue compartments as tools for objective quantitative measurements, reduced analysis time, and increased reproducibility of the data.

Expression Level of Genes Coding for Cell Adhesion Molecules of Cadherin Group in Colorectal Cancer Patients

Background

Colorectal Cancer (CRC) is one of the most frequently diagnosed neoplasms and also one of the main death causes. Cell adhesion molecules are taking part in specific junctions, contributing to tissue integrality. Lower expression of the cadherins may be correlated with poorer differentiation of the CRC, and its more aggressive phenotype. The aim of the study is to designate the cadherin genes potentially useful for the diagnostics, prognostics, and the treatment of CRC.

Material/Method

Specimens were collected from 28 persons (14 female and 14 male), who were operated for CRC. The molecular analysis was performed using oligonucleotide microarrays, mRNA used was collected from adenocarcinoma, and macroscopically healthy tissue. The results were validated using qRT-PCR technique.

Results

Agglomerative hierarchical clustering of normalized mRNA levels has shown 4 groups with statistically different gene expression. The control group was divided into 2 groups, the one was appropriate control (C1), the second (C2) had the genetic properties of the CRC, without pathological changes histologically and macroscopically. The other 2 groups were: LSC (Low stage cancer) and HSC (High stage cancer). Consolidated results of the fluorescency of all of the differential genes, designated two coding E-cadherin (CDH1) with the lower expression, and P-cadherin (CDH3) with higher expression in CRC tissue.

Conclusions

The levels of genes expression are different for several groups of cadherins, and are related with the stage of CRC, therefore could be potentially the useful marker of the stage of the disease, also applicable in treatment and diagnostics of CRC.

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.

Loss of CDX2 expression is associated with poor prognosis in colorectal cancer patients

AIM: To investigate the clinicopathologic characteristics and prognostic implications associated with loss of CDX2 expression in colorectal cancers (CRCs).

METHODS: We immunohistochemically evaluated CDX2 expression in 713 CRCs and paired our findings to clinicopathologic and molecular characteristics of each individual. Endpoints included cytokeratin 7 and CK20 expression, microsatellite instability, CpG island methylator phenotype, and KRAS and BRAF mutation statuses. Univariate and multivariate survival analysis was performed to reveal the prognostic value of CDX2 downregulation.

RESULTS: CDX2 expression was lost in 42 (5.9%) patients. Moreover, loss of CDX2 expression was associated with proximal location, infiltrative growth, advanced T, N, M and overall stage. On microscopic examination, loss of CDX2 expression was associated with poor differentiation, increased number of tumor-infiltrating lymphocytes, luminal serration and mucin production. Loss of CDX2 expression was also associated with increased CK7 expression, decreased CK20 expression, CpG island methylator phenotype, microsatellite instability and BRAF mutation. In a univariate survival analysis, patients with loss of CDX2 expression showed worse overall survival (P < 0.001) and progression-free survival (P < 0.001). In a multivariate survival analysis, loss of CDX2 expression was an independent poor prognostic factor of overall survival [hazard ratio (HR) = 1.72, 95%CI: 1.04-2.85, P = 0.034] and progression-free survival (HR = 1.94, 95%CI: 1.22-3.07, P = 0.005).

CONCLUSION: Loss of CDX2 expression is associated with aggressive clinical behavior and can be used as a prognostic marker in CRCs.

Nuclear expression of histone deacetylases and their histone modifications predicts clinical outcome in colorectal cancer

AIMS

Epigenetic changes are of crucial importance in cancer development and are potentially reversible; they are therefore targets of interest for anti-cancer therapy. The aim of this study was to investigate the clinical prognostic value of the histone deacetylases SIRT1, HDAC1 and HDAC2 and the histone modifications H4K16Ac and H3K56Ac in colorectal cancer.

METHODS AND RESULTS

The epigenetic markers were immunohistochemically stained on tissue microarrays containing colorectal tumours (n = 254) and normal colorectal tissues (n = 50). Nuclear expression was assessed on the semi-automated Ariol system. Multivariate trend survival analyses of the combined markers showed better patient survival and less tumour recurrence when more markers showed high nuclear expression. For the combination of the histone deacetylases and H3K56Ac, the hazard ratio (HR) for overall survival (OS) was 0.82 [95% confidence interval (CI) 0.72-0.94; P = 0.005] and the HR for distant recurrence-free survival (DRFS) was 0.77 (95% CI 0.64-0.92; P = 0.003) per additional marker showing high expression. Similarly, for the combination of histone deactylases and H4K16Ac, HRs of 0.86 (95% CI 0.76-0.97; P = 0.01) for OS and 0.79 (95% CI 0.68-0.93; P = 0.006) for DRFS were observed per additional marker showing high expression.

CONCLUSIONS

The studied epigenetic markers showed clinical prognostic value in colorectal cancer, both as individual markers and when combined into multimarker analyses. These results indicate that epigenetic mechanisms play an important role in colorectal carcinogenesis.

The clinical perspectives of CDX2 expression in colorectal cancer: a qualitative systematic review

INTRODUCTION

Homeobox genes are often deregulated in cancer. They can have both oncogenic and tumor-suppressing potential. The Caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor. It is implicated in differentiation, proliferation, cell-adhesion, and migration. CDX2 has been proposed as a tumor suppressor in colorectal cancer but its role is still controversial. This systematic review were undertaken in order to clarify CDX2s role in colorectal cancer.

METHODS

A literature search was performed in the MEDLINE database from 1966 to February 2014. Only studies in which all or a part of the experimental design were performed on human colorectal cancer tissue were included. Thus, studies solely performed in cell-lines or animal models were excluded.

RESULTS

Fifty-two articles of relevance were identified. CDX2 expression was rarely lost in colorectal cancers, however the expression pattern may often be heterogeneous within the tumor and can be selectively down regulated at the invasive front and in tumor buddings. Loss of CDX2 expression is probably correlated to tumor grade, stage, right-sided tumor location, MMR-deficiency, CIMP, and BRAF mutations. The CDX2 gene is rarely mutated but the locus harboring the gene is often amplified and may suggest CDX2 as a linage-survival oncogene. CDX2 might be implicated in cell proliferation and migration through cross-talk with the Wnt-signaling pathway, tumor-stroma proteins, and inflammatory cytokines.

CONCLUSION

A clear role for CDX2 expression in colorectal cancer remains to be elucidated, and it might differ in relation to the underlying molecular pathways leading to the cancer formation.

Tropomyosin-related receptor kinase B at the invasive front and tumour cell dedifferentiation in gastric cancer

Background:

Tropomyosin-related receptor kinase B (TrkB) promotes proliferation and invasion, relating to poor prognosis of various malignancies. We examined the role of TrkB at the invasive front of gastric cancer (GC) and its association with tumour cell dedifferentiation and tumour budding.

Methods:

Immunoreactive TrkB was evaluated at the tumour centre and margin using whole-tissue sections of 320 GC patients. Tumour cell dedifferentiation was defined as higher histologic grade at the tumour margin than the surface or tumour centre. Tumour budding was also scored on cytokeratin-stained sections.

Results:

Sixty-five patients (20%) showed higher TrkB expression at the invasive front (TrkB expression was higher at the tumour margin than tumour centre). It was significantly associated with several aggressive phenotypes in the full cohort (n=320). It showed a prognostic significance in test subgroup (n=98) and was identified as an independent prognostic factor (HR=2.09; 95% CI: 1.26–3.53) by multivariate analysis in validation subgroup (n=222). Twenty-one patients showed tumour cell dedifferentiation. In predominantly differentiated tumour, higher TrkB at the invasive front was significantly associated with tumour budding rather than tumour cell dedifferentiation.

Conclusions:

Assessment of immunoreactive TrkB at the invasive front by whole-tissue sections provides prognostic information for GC patients.

Frequent copy number variations of PI3K/AKT pathway and aberrant protein expressions of PI3K subunits are associated with inferior survival in diffuse large B cell lymphoma. J Transl Med. 2014;12:10. [PMID: 24418330 DOI: 10.1186/1479-5876-12-10]

BACKGROUND

It has been reported that the PI3K/AKT signaling pathway is activated in diffuse large B-cell lymphoma (DLBCL), PI3K constitutive activation plays a crucial role in PI3K/AKT pathway. However, the copy number variations (CNVs) of PI3K subunits on gene level remain unknown in DLBCL. Therefore, the aim of the study is to investigate the CNV of PI3K subunits and their relationship with clinicopathological features exploring the possible mechanism underlying of PI3K activation in DLBCL.

METHODS

CNV of 12 genes in the PI3K/AKT pathway was detected by NanoString nCounter in 60 de novo DLBCLs and 10 reactive hyperplasia specimens as controls. Meanwhile, immunohistochemistry (IHC) was performed to examine the expression of p110α, p110β, p110γ, p110δ, and pAKT on DLBCL tissue microarrays.

RESULTS

All PI3K and AKT subunits, except for PIK3R1, had various CNVs in the form of copy number amplifications and copy number losses. Their rates were in the range of 8.3-20.0%. Of them PIK3CA and PIK3CB gene CNVs were significantly associated with decreased overall survival (P = 0.029 and P = 0.019, respectively). IHC showed that the frequency of strong positive expression of p110α, p110β, p110γ, and p110δ were 26.7%, 25.0%, 18.3%, and 25.0% respectively, and they were found to be associated with decreased survival (P = 0.022, P = 0.015, P = 0.015, and P = 0.008, respectively). Expression of p110α was not only significantly associated with CNVs of PIK3CA (P = 0.002) but also positively correlated with strong positive expression of pAKT (P = 0.026).

CONCLUSIONS

CNV of PIK3CA is highly associated with aberrant p110α protein expression and subsequent activation of PI3K/AKT pathway. CNVs of PIK3CA and PIK3CB, and aberrant protein expression of p110 isoforms are of great important value for predicting inferior prognosis in DLBCL. Frequent CNVs of PI3K/AKT subunits may play an important role in the tumorigenesis of DLBCL.

Interference of mucin 1 inhibits progression of colon carcinoma by repression of Wnt/β-catenin signaling

Mucin 1 (Muc1) is a tumor-associated glycoprotein and has an important role in cancer progression and metastasis. The aim of the study was to explore the effects and mechanism of Muc1 silencing on proliferation and tumor-forming capacity of colon cancer cell lines. In the present study, we first screened the colon cancer cell lines with high expression of Muc1 by western blot analysis. Then, the effective siRNA was selected and used for silencing endogenous Muc1. The results by MTT and vitro scratch assay showed that interference of Muc1 could effectively inhibit HCC2998 proliferation and migration (p<0.01). Also, colony-forming ability in Muc1-siRNA groups was significantly decreased compared with the control group (p<0.01). Cell cycle is detected by flow cytometry that suggested that Muc1-siRNA1 induced cell cycle arrest at S phase in HCC2998. Next, the expression and distribution of β-catenin in cytoplasm and the nucleus was detected by western blot and the results revealed that the expression of β-catenin was redistributed in Muc1-siRNA group. A higher β-catenin level was detected in cytoplasm, while a lower β-catenin level was located in nucleus, compared with controls (p<0.05). The tumorigenicity experiments showed that inhibition of Muc1 could significantly suppress the growth of HCC2998 in nude mice models (p<0.01). This study would effectively provide new clues for colon cancer therapy.

Loss of Raf-1 kinase inhibitor protein (RKIP) is strongly associated with high-grade tumor budding and correlates with an aggressive phenotype in pancreatic ductal adenocarcinoma (PDAC)

BACKGROUND

Raf-1 kinase inhibitor protein (RKIP) has emerged as a significant metastatic suppressor in a variety of human cancers and is known to inhibit Ras/Raf/MEK/ERK signaling. By suppressing the activation of the NFkB/SNAIL circuit, RKIP can regulate the induction of epithelial-mesenchymal transition (EMT). The aim of this study was to evaluate RKIP expression and to determine its association with clinicopathological features, including EMT in form of tumor budding in pancreatic ductal adenocarcinoma (PDAC).

METHODS

Staining for RKIP was performed on a multipunch Tissue Microarray (TMA) of 114 well-characterized PDACs with clinico-pathological, follow-up and adjuvant therapy information. RKIP-expression was assessed separately in the main tumor body and in the tumor buds. Another 3 TMAs containing normal pancreatic tissue, precursor lesions (Pancreatic Intraepithelial Neoplasia, PanINs) and matched lymph node metastases were stained in parallel. Cut-off values were calculated by receiver operating characteristic (ROC) curve analysis.

RESULTS

We found a significant progressive loss of RKIP expression between normal pancreatic ductal epithelia (average: 74%), precursor lesions (PanINs; average: 37%), PDAC (average 20%) and lymph node metastases (average 8%, p<0.0001). RKIP expression was significantly lower in tumor buds (average: 6%) compared to the main tumor body (average 20%; p<0.005). RKIP loss in the tumor body was marginally associated with advanced T-stage (p=0.0599) as well as high-grade peritumoral (p=0.0048) and intratumoral budding (p=0.0373). RKIP loss in the buds showed a clear association with advanced T stage (p=0.0089).

CONCLUSIONS

The progressive loss of RKIP seems to play a major role in the neoplastic transformation of pancreas, correlates with aggressive features in PDAC and is associated with the presence of EMT in form of tumor budding.

Neonatal Fc receptor expression in dendritic cells mediates protective immunity against colorectal cancer

Cancers arising in mucosal tissues account for a disproportionately large fraction of malignancies. Immunoglobulin G (IgG) and the neonatal Fc receptor for IgG (FcRn) have an important function in the mucosal immune system that we have now shown extends to the induction of CD8(+) T cell-mediated antitumor immunity. We demonstrate that FcRn within dendritic cells (DCs) was critical for homeostatic activation of mucosal CD8(+) T cells that drove protection against the development of colorectal cancers and lung metastases. FcRn-mediated tumor protection was driven by DCs activation of endogenous tumor-reactive CD8(+) T cells via the cross-presentation of IgG complexed antigens (IgG IC), as well as the induction of cytotoxicity-promoting cytokine secretion, particularly interleukin-12, both of which were independently triggered by the FcRn-IgG IC interaction in murine and human DCs. FcRn thus has a primary role within mucosal tissues in activating local immune responses that are critical for priming efficient anti-tumor immunosurveillance.

RKIP phosphorylation and STAT3 activation is inhibited by oxaliplatin and camptothecin and are associated with poor prognosis in stage II colon cancer patients

Background

A major obstacle in treating colorectal cancer (CRC) is the acquired resistance to chemotherapeutic agents. An important protein in the regulation of cancer cell death and clinical outcome is Raf kinase inhibitor protein (RKIP). In contrast, activated signal transducer and activator of transcription 3 (STAT3) is a protein that promotes tumor cell survival by inhibiting apoptosis and has an important role in cancer progression in many of cancer types. The aim of this study was to evaluate the regulation of RKIP and STAT3 after treatment with clinically relevant chemotherapeutic agents (camptothecin (CPT) and oxaliplatin (OXP)) and the cytokine interleukin-6 (IL-6) in HCT116 colon cancer cells as well as evaluate the association between RKIP and STAT3 with clinical outcome of Stage II colon cancer patients.

Methods

HCT-116 colon cancer cells were treated with CPT, OXP, and IL-6 separately or in combination in a time and dose-dependent manner and examined for phosphorylated and non-phosphorylated RKIP and STAT3 via Western blot analysis. STAT3 transcriptional activity was measured via a luciferase reporter assay in HCT116 cells treated with CPT, IL-6 or transfected with JAK 1, 2 separately or in combination. We extended these observations and determined STAT3 and RKIP/ pRKIP in tumor microarrays (TMA) in stage II colon cancer patients.

Results

We demonstrate IL-6-mediated activation of STAT3 occurs in conjunction with the phosphorylation of RKIP in vitro in human colon cancer cells. OXP and CPT block IL-6 mediated STAT3 activation and RKIP phosphorylation via the inhibition of the interaction of STAT3 with gp130. We determined that STAT3 and nuclear pRKIP are significantly associated with poor patient prognosis in stage II colon cancer patients.

Conclusions

In the analysis of tumor samples from stage II colon cancer patients and the human colon carcinoma cell line HCT116, pRKIP and STAT3, 2 proteins potentially involved in the resistance to conventional treatments were detected. The phosphorylation of pRKIP and STAT3 are induced by the cytokine IL-6 and suppressed by the chemotherapeutic drugs CPT and OXP. Therefore, these results suggest that STAT3 and pRKIP may serve as prognostic biomarkers in stage II colon cancer patients and may improve chemotherapy.

HMGA2 is a driver of tumor metastasis

The non-histone chromatin-binding protein HMGA2 is expressed predominantly in the mesenchyme before its differentiation, but it is also expressed in tumors of epithelial origin. Ectopic expression of HMGA2 in epithelial cells induces epithelial-mesenchymal transition (EMT), which has been implicated in the acquisition of metastatic characters in tumor cells. However, little is known about in vivo modulation of HMGA2 and its effector functions in tumor metastasis. Here, we report that HMGA2 loss of function in a mouse model of cancer reduces tumor multiplicity. HMGA2-positive cells were identified at the invasive front of human and mouse tumors. In addition, in a mouse allograft model, HMGA2 overexpression converted nonmetastatic 4TO7 breast cancer cells to metastatic cells that homed specifically to liver. Interestingly, expression of HMGA2 enhanced TGFβ signaling by activating expression of the TGFβ type II receptor, which also localized to the invasive front of tumors. Together our results argued that HMGA2 plays a critical role in EMT by activating the TGFβ signaling pathway, thereby inducing invasion and metastasis of human epithelial cancers.

Geographic analysis of RKIP expression and its clinical relevance in colorectal cancer

Background:

This study evaluates the geographic expression pattern of Raf-1 Kinase Inhibitor Protein (RKIP) in colorectal cancer (CRC) in correlation with clinicopathological and molecular features, markers of epithelial-mesenchymal transition (EMT) and survival outcome.

Methods:

Whole-tissue sections of 220 well-characterised CRCs were immunostained for RKIP. NF-κB and E-Cadherin expression was assessed using a matched multi-punch tissue microarray. Analysis of mismatch repair (MMR) protein expression, B-Raf and KRAS mutations was performed. RKIP expression in normal mucosa, tumour centre, invasion front and tumour buds was each assessed for clinical relevance.

Results:

RKIP was diffusely expressed in normal mucosa and progressively lost towards tumour centre and front (P<0.0001). Only 0.9% of tumour buds were RKIP-positive. In the tumour centre, RKIP deficiency predicted metastatic disease (P=0.0307), vascular invasion (P=0.0506), tumour budding (P=0.0112) and an invasive border configuration (P=0.0084). Loss of RKIP correlated with NF-κB activation (P=0.0002) and loss of E-Cadherin (P<0.0001). Absence of RKIP was more common in MMR-deficient cancers (P=0.0191), while no impact of KRAS and B-Raf mutation was observed. RKIP in the tumour centre was identified as a strong prognostic indicator (HR (95% CI): 2.13 (1.27–3.56); P=0.0042) independently of TNM classification and therapy (P=0.0474).

Conclusion:

The clinical relevance of RKIP expression as an independent prognostic factor is restricted to the tumour centre. Loss of RKIP predicts features of EMT and correlates with frequent distant metastasis.

Distribution of residual cancer cells in the bowel wall after neoadjuvant chemoradiation in patients with rectal cancer

BACKGROUND

The standard treatment for locally advanced rectal cancer is preoperative chemoradiation and total mesorectal excision. After surgery, tumors are classified according to the depth of tumor invasion, nodal involvement, and tumor regression grade. However, these staging systems do not provide information about the distribution of residual cancer cells within the bowel wall.

OBJECTIVE

This study aimed to determine the distribution of residual cancer cells in each layer of the bowel wall in rectal cancer specimens.

DESIGN

This was a secondary analysis of data from a prospective phase II study.

SETTING

This study was performed in a multi-institutional setting.

PATIENTS

Included were 153 patients with stage II or stage III rectal cancer.

INTERVENTIONS

Patients were treated with chemoradiation and surgery. The surgical specimen tumor tissue was analyzed, and the distribution of residual cancer cells in each layer of the bowel wall was determined.

MAIN OUTCOME MEASURES

Statistical analysis was used to examine the correlation of residual cancer cells in each layer of the bowel wall with the clinical/pathologic stage and tumor regression grade.

RESULTS

Forty-two of 153 (27%) patients had complete response in the bowel wall (ypT0). Of the remaining 111 patients who had residual cancer cells, 5 (3%) were ypTis, 12 (8%) were ypT1, 41 (27%) were ypT2, 50 (33%) were ypT3, and 3 (2%) were ypT4. Of the 94 patients with ypT2-4 tumors, 12 (13%) had cancer cells in the mucosa, and 53 (56%) had cancer cells in the submucosa; 92 (98%) had cancer cells in the muscularis propria. Pretreatment cT correlated with the distribution of residual cancer cells. Tumor regression grade was not associated with the distribution of residual cancer cells after chemoradiation.

LIMITATIONS

: Patients received different chemotherapy regimens.

CONCLUSIONS

Residual cancer cells in rectal cancer specimens after chemoradiation are preferentially located close to the invasive front. This should be considered when designing strategies to diagnose complete pathologic response and when investigating the mechanisms of tumor resistance to chemoradiation.

Tumor budding cells, cancer stem cells and epithelial-mesenchymal transition-type cells in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers with a 5-year survival rate of less than 5%. Moreover, PDAC escapes early detection and resists treatment. Multiple combinations of genetic alterations are known to occur in PDAC including mutational activation of KRAS, inactivation of p16/CDKN2A and SMAD4 (DPC4) and dysregulation of PTEN/PI3K/AKT signaling. Through their interaction with Wingless-INT pathway, the downstream molecules of these pathways have been implicated in the promotion of epithelial-mesenchymal transition (EMT). Emerging evidence has demonstrated that cancer stem cells (CSCs), small populations of which have been identified in PDAC, and EMT-type cells play critical roles in drug resistance, invasion, and metastasis in pancreatic cancer. EMT may be histologically represented by the presence of tumor budding which is described as the occurrence of single tumor cells or small clusters (<5) of dedifferentiated cells at the invasive front of gastrointestinal (including colorectal, oesophageal, gastric, and ampullary) carcinomas and is linked to poor prognosis. Tumor budding has recently been shown to occur frequently in PDAC and to be associated with adverse clinicopathological features and decreased disease-free and overall survival. The aim of this review is to present a short overview on the morphological and molecular aspects that underline the relationship between tumor budding cells, CSCs, and EMT-type cells in PDAC.

Heterogeneity of epidermal growth factor receptor status and mutations of KRAS/PIK3CA in circulating tumor cells of patients with colorectal cancer

BACKGROUND

Molecular characterization of circulating tumor cells (CTCs) is pivotal to increasing the diagnostic specificity of CTC assays and investigating therapeutic targets and their downstream pathways on CTCs. We focused on epidermal growth factor receptor (EGFR) and genes relevant for its inhibition in patients with colorectal cancer (CRC).

METHODS

We used the CellSearch® system for CTC detection in peripheral blood samples from 49 patients with metastatic CRC (mCRC) and 32 patients with nonmetastatic CRC (nmCRC). We assessed EGFR expression in 741 CTCs from 27 patients with mCRC and 6 patients with nmCRC using a fluorescein-conjugated antibody with the CellSearch Epithelial Cell Kit. DNA of a single CTC isolated by micromanipulation was propagated by whole-genome amplification and analyzed by quantitative PCR for EGFR gene amplification and sequencing for KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog), BRAF (v-raf murine sarcoma viral oncogene homolog B1), and PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α) mutations.

RESULTS

At least 2 CTCs were detected in 24 of 49 patients with mCRC and 7 of 32 patients with nmCRC. In 7 of 33 patients, CTCs with increased EGFR expression were identified. Heterogeneity in EGFR expression was observed between CTCs from the same patient. EGFR gene amplification was found in 7 of 26 CTCs from 3 patients. The investigated BRAF gene locus was not mutated in 44 analyzed CTCs, whereas KRAS mutations were detected in 5 of 15 CTCs from 1 patient and PIK3CA mutations in 14 of 36 CTCs from 4 patients.

CONCLUSIONS

Molecular characterization of single CTCs demonstrated considerable intra- and interpatient heterogeneity of EGFR expression and genetic alterations in EGFR, KRAS, and PIK3CA, possibly explaining the variable response rates to EGFR inhibition in patients with CRC.

(-)-Epigallocatechin 3-gallate inhibits invasion by inducing the expression of Raf kinase inhibitor protein in AsPC‑1 human pancreatic adenocarcinoma cells through the modulation of histone deacetylase activity

The aim of the present study was to assess whether (-)-epigallocatechin 3-gallate (EGCG) via epigenetic modifications, regulates Raf kinase inhibitor protein (RKIP) expression and invasive metastatic activity in AsPC-1 pancreatic adenocarcinoma cells. Basal levels of RKIP were examined in various human pancreatic cancer cell lines and MTT assay was used to assess cell viability. AsPC-1 cells were treated with EGCG with/without trichostatin A (TSA), as the positive control, for 24 h. The levels of RKIP and histone H3 induction were analyzed by immunoblot analysis. In order to determine the role of RKIP induction in NF-κB translocation and invasive metastatic activity in AsPC-1 cells, we examined NF-κB translocation, invasive metastatic parameters by RT-PCR, metastasis-related proteins by western blot analysis and matrix metalloproteinase (MMP)-2 and -9 activity by gelatin zymography. To validate RKIP induction through the extracellular signal regulated kinase (ERK) pathway, the cells were treated with U0126, an ERK inhibitor. Our results showed that EGCG induced RKIP upregulation via the inhibition of histone deacetylase (HDAC) activity which increased histone H3 expression and inhibited Snail expression, NF-κB nuclear translocation, MMP-2 and -9 activity and Matrigel invasion in AsPC-1 cells. The expression of E-cadherin in the cells was upregulated. The phosphorylation of ERK was decreased by RKIP induction following EGCG treatment. Furthermore, our results confirmed that U0126 treatment repressed ERK phosphorylation and induced RKIP expression. Taken together, our results strongly suggest that EGCG regulates RKIP/ERK/NF-κB and/or RKIP/NF-κB/Snail and inhibits invasive metastasis in the AsPC-1 human pancreatic adenocarcinoma cell line.