Systematic assessment of the prognostic impact of membranous CD44v6 protein expression in colorectal cancer

Prognostic and clinicopathological value of osteopontin expression in non-small cell lung cancer: a meta-analysis and systematic review

BACKGROUND

Although Osteopontin (OPN) has been reported to be associated with many different human cancers, the data on non-small cell lung cancer (NSCLC) are not definitive. This study aimed to explore the prognostic effect of OPN expression and clinicopathological characteristics in patients with NSCLC.

METHODS

This study followed all aspects of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) report. PubMed, Embase and the Cochrane Library were searched to identify the relative studies. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to estimate the prognostic value of the OPN in patients with NSCLC. The odds ratio (OR) was calculated to represent the relationship between OPN expression and clinicopathological parameters.

RESULTS

A total of fifteen studies with 2173 participants were finally included. The results revealed that high expression of OPN was significantly associated with poorer overall survival (OS) (HR = 1.89; 95%CI = 1.68-2.11; p < 0.001). Moreover, a significant correlation was observed between increased OPN expression and poorly differentiated (well and moderately differentiated vs. poorly differentiated; pooled OR = 0.38; 95% CI = 0.23-0.64; p < 0.001), lymph node metastasis (absence vs. presence; pooled OR = 0.49; 95%CI = 0.32-0.74; p < 0.001), and distant metastasis (absence vs. presence; pooled OR = 0.18; 95%CI = 0.11-0.29; p < 0.001).

CONCLUSION

This meta-analysis implies that OPN might be a valuable biomarker for a poor prognosis and poor clinicopathological outcomes for patients with NSCLC.

CD44v6 downregulation as a prognostic factor for distant recurrence in resected stage I lung adenocarcinomas

CD44 and CD44 variant isoforms have been reported as contributing factors to cancer progression. In this study, we aimed to assess whether CD44 and its variant isoforms were correlated with the prognostic factors for distant metastasis in stage I lung adenocarcinomas using tissue microarray and immunohistochemistry. In this single-center retrospective study, we analyzed the data of 490 patients with stage I lung adenocarcinoma resected between 1999 and 2016. We constructed tissue microarrays and performed immunohistochemistry for CD44s, CD44v6, and CD44v9. The risk of disease recurrence and its associations with clinicopathological risk factors were assessed. CD44v6 expression was significantly associated with recurrence. Patients with CD44v6-negative tumors had a significantly increased risk of developing distant recurrence than patients with CD44v6-positive tumors (5-year cumulative incidence of recurrence (CIR), 10.7% vs. 4.6%; P = 0.009). However, CD44v6-negative tumors were not associated with an increased risk of locoregional recurrence compared to CD44v6-positive tumors (5-year CIR, 6.0% vs. 4.0%; P = 0.39). The overall survival (OS) of patients with CD44v6-negative tumors was significantly lower than that of patients with CD44v6-positive tumors (5-year OS: 87% vs. 94%, P = 0.016). CD44v6-negative tumors were also associated with invasive tumor size and lymphovascular invasion. Even in stage I disease, tumors with negative-CD44v6 expression had more distant recurrences than those with positive-CD44v6 expression and were associated with poor prognosis in resected stage I lung adenocarcinomas. Thus, CD44v6 downregulation may be a prognostic factor for distant metastasis in stage I lung adenocarcinomas.

Development of a Novel Anti-CD44 Variant 6 Monoclonal Antibody C44Mab-9 for Multiple Applications against Colorectal Carcinomas

CD44 is a cell surface glycoprotein, and its isoforms are produced by the alternative splicing with the standard and variant exons. The CD44 variant exon-containing isoforms (CD44v) are overexpressed in carcinomas. CD44v6 is one of the CD44v, and its overexpression predicts poor prognosis in colorectal cancer (CRC) patients. CD44v6 plays critical roles in CRC adhesion, proliferation, stemness, invasiveness, and chemoresistance. Therefore, CD44v6 is a promising target for cancer diagnosis and therapy for CRC. In this study, we established anti-CD44 monoclonal antibodies (mAbs) by immunizing mice with CD44v3-10-overexpressed Chinese hamster ovary (CHO)-K1 cells. We then characterized them using enzyme-linked immunosorbent assay, flow cytometry, western blotting, and immunohistochemistry. One of the established clones (C₄₄Mab-9; IgG₁, kappa) reacted with a peptide of the variant 6-encoded region, indicating that C₄₄Mab-9 recognizes CD44v6. Furthermore, C₄₄Mab-9 reacted with CHO/CD44v3-10 cells or CRC cell lines (COLO201 and COLO205) by flow cytometry. The apparent dissociation constant (K_D) of C₄₄Mab-9 for CHO/CD44v3-10, COLO201, and COLO205 was 8.1 × 10^-9 M, 1.7 × 10^-8 M, and 2.3 × 10^-8 M, respectively. C₄₄Mab-9 detected the CD44v3-10 in western blotting, and partially stained the formalin-fixed paraffin-embedded CRC tissues in immunohistochemistry. Collectively, C₄₄Mab-9 is useful for detecting CD44v6 in various applications.

Membranous CD44v6 is upregulated as an early event in colorectal cancer: Downregulation is associated with circulating tumor cells and poor prognosis

Previous studies have reported that CD44 variant 6 (CD44v6) and metastasis-associated protein 1 (MTA1) are contributing factors to cancer progression. The present study aimed to evaluate the expression profiles for associations with patients' demographic data, clinicopathological characteristics, the presence of partial epithelial-to-mesenchymal transition (pEMT), metastatic potential based on the presence of CK20⁺ CEA⁺ CXCR4⁺ circulating tumor cells (CTCs) and prognosis (median follow-up, 45 months). Thus, frozen tissue samples from 31 patients with stage I–III colorectal cancer (CRC), 15 benign colorectal polyps and seven normal colorectal tissues were analyzed to detect membranous (m)CD44v6 and MTA1 expression via flow cytometry. The results demonstrated that the mCD44v6 and MTA1 expression profiles were significantly correlated (r_s=+0.786, P<0.001). Notably, MTA1 expression was not associated with any of the clinicopathological characteristics assessed. The percentage of mCD44v6-positive cells within tumors was higher in the right-sided cancer lesions (P=0.014), suggesting that proximal and distal CRCs are distinct clinicopathological entities. Furthermore, downregulated mCD44v6 expression was significantly associated with the presence of CTCs (P=0.017). This association was stronger for pEMT (co-expression of N- and E-cadherin mRNAs) primary lesions (P=0.009). In addition, patients with CRC with low levels of mCD44v6 had unfavorable survival outcomes (P=0.037). Taken together, these results suggest that targeted analysis of membranous CD44v6 as opposed to membranous-cytoplasmic expression is important in determining the prognosis of patients with CRC. Furthermore, downregulated mCD44v6 expression in malignancies presenting CTCs reinforces the importance of tumor-stroma reciprocal influence during the metastatic process and encourages the assessment of relevant therapeutic strategies.

MRI features and texture analysis for the early prediction of therapeutic response to neoadjuvant chemoradiotherapy and tumor recurrence of locally advanced rectal cancer

OBJECTIVES

This study aimed to evaluate the efficiency of imaging features and texture analysis (TA) based on baseline rectal MRI for the early prediction of therapeutic response to neoadjuvant chemoradiotherapy (nCRT) and tumor recurrence in patients with locally advanced rectal cancer (LARC).

METHODS

Consecutive patients with LARC who underwent rectal MRI between January 2014 and December 2015 and surgical resection after completing nCRT were retrospectively enrolled. Imaging features were analyzed, and TA parameters were extracted from the tumor volume of interest (VOI) from baseline rectal MRI. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the optimal TA parameter cutoff values to stratify the patients. Logistic and Cox regression analyses were performed to assess the efficacy of each imaging feature and texture parameter in predicting tumor response and disease-free survival.

RESULTS

In total, 78 consecutive patients were enrolled. In the logistic regression, good treatment response was associated with lower tumor location (OR = 13.284, p = 0.012), low Conv_Min (OR = 0.300, p = 0.013) and high Conv_Std (OR = 3.174, p = 0.016), Shape_Sphericity (OR = 3.170, p = 0.015), and Shape_Compacity (OR = 2.779, p = 0.032). In the Cox regression, a greater risk of tumor recurrence was related to higher cT stage (HR = 5.374, p = 0.044), pelvic side wall lymph node positivity (HR = 2.721, p = 0.013), and gray-level run length matrix_long-run low gray-level emphasis (HR = 2.268, p = 0.046).

CONCLUSIONS

Imaging features and TA based on baseline rectal MRI could be valuable for predicting the treatment response to nCRT for rectal cancer and tumor recurrence.

KEY POINTS

• Imaging features and texture parameters of T2-weighted MR images of rectal cancer can help to predict treatment response and the risk for tumor recurrence. • Tumor location as well as conventional and shape indices of texture features can help to predict treatment response for rectal cancer. • Clinical T stage, positive pelvic side wall lymph nodes, and the high-order texture parameter, GLRLM_LRLGE, can help to predict tumor recurrence for rectal cancer.

The Prognostic and Clinical Value of CD44 in Colorectal Cancer: A Meta-Analysis

Background: CD44 is widely used as a putative cancer stem cells (CSCs) marker for colorectal cancer (CRC). However, the prognostic role of CD44 in CRC remains controversial. Methods: We performed a systematic review and meta-analysis to evaluate the association of various CD44 isoforms and overall survival (OS) and clinicopathological features of CRC patients. Results: A total of 48 studies were included in the meta-analysis. Total CD44 isoforms overexpression was significantly correlated with worse OS of patients with CRC (HR = 1.32, 95% CI = 1.08-1.61, P = 0.007). In a stratified analysis, a higher level of either CD44v6 or CD44v2 had an unfavorable impact on OS (HR_CD44v6 = 1.50, 95% CI = 1.10-2.14, P = 0.010; HR_CD44v2 = 2.93, 95% CI = 1.49-5.77, P = 0.002). Additionally, CD44 was shown to be associated with some clinicopathological features, such as lymph node metastasis (OR_CD44 = 1.56, 95% CI = 1.01-2.41, P = 0.044; OR_CD44v6 = 1.97, 95% CI = 1.19-3.26, P = 0.008; OR_{Total CD44 isoforms} = 1.57, 95% CI = 1.15-2.14, P = 0.004), distant metastasis (OR_CD44 = 2.90, 95% CI = 1.08-7.83, P = 0.035; OR_{Total CD44 isoforms} = 1.89, 95% CI = 1.02-3.53, P = 0.044). Moreover, a high level of CD44 showed a possible correlation with poor differentiation (OR_{Total CD44 isoforms} = 1.44, 95% CI = 1.00-2.08, P = 0.051), elevated level of CD44v6 tend to be correlated with tumor size (OR = 1.71, 95% CI = 0.99-2.96, P = 0.056). Conclusions: This meta-analysis demonstrated that CD44 overexpression might be an unfavorable prognostic factor for CRC patients and could be used to predict poor differentiation, lymph node metastasis and distant metastasis.

Spatial distribution of osteopontin, CD44v6 and podoplanin in the lining epithelium of odontogenic keratocyst, and their biological relevance

BACKGROUND AND AIMS

The odontogenic keratocyst (OKC) remains the most challenging jaw cyst to treat because of its locally-aggressive behaviour and high recurrence potential. Emerging evidence suggests that osteopontin, its receptors CD44v6 and integrin α_v, and podoplanin, have a role in the local invasiveness of this cyst. However the spatial distribution characteristics of these pro-invasive markers in the lining epithelium of OKC, and their association with the clinicopathologic parameters of OKC are largely unexplored. This study sought to address these issues in comparison with dentigerous cysts (DCs) and radicular cysts (RCs) and to evaluate their biological relevance.

METHODS

A sample consisting of 20 OKC cases, 10 DCs and 10 RCs was subjected to immunohistochemical staining for osteopontin, CD44v6 and integrin α_v, and podoplanin, and semiquantitative analysis was performed.

RESULTS

All factors (except integrin α_v) were detected heterogeneously in the constitutive layers of the lining epithelium in all three cyst types. Key observations were significant upregulation of CD44v6 and podoplanin in OKC compared to DCs and RCs, suggesting that these protein molecules may play crucial roles in promoting local invasiveness in OKC (P<0.05). Osteopontin underexpression and distribution patterns were indistinctive among all three cysts indicating its limited role as pro-invasive factor. Clinical parameters showed no significant correlations with all protein factors investigated.

CONCLUSIONS

Present findings suggest that an osteopontin^low CD44v6^high and podoplanin^high immunoprofile most probably represent epithelial signatures of OKC and are markers of local invasiveness in this cyst.

CD44v6 overexpression related to metastasis and poor prognosis of colorectal cancer: A meta-analysis

CD44v6 has recently been reported as a biomarker for colorectal cancer. However, the clinical and prognostic significance of CD44v6 in colorectal cancer remains controversial. Therefore, we performed a meta-analysis to clarify this issue. A comprehensive literature search was performed using Medline, Embase and Web of Science, and the statistical analysis was conducted using Stata software. A total of twenty-one studies including 3918 colorectal cancer cases were included. The pooled analysis showed that CD44v6 overexpression in colorectal cancer was an independent prognostic marker correlating with lower 5-year overall survival rate (OR=0.78, 95%CI =0.67-0.91, p=0.001). CD44v6 overexpression was also associated with more lymph node invasion (OR=1.48, 95%CI= 1.02-2.15, p=0.04), and advanced Dukes stage (OR=2.47, 95%CI= 1.29-4.73, p=0.01). In addition, while excluding Zolbec's study, CD44v6 overexpression was associated with distance metastasis (OR=1.65, 95%CI =1.13-2.40, p=0.01). Taken together, this meta-analysis suggested that CD44v6 is an efficient prognostic factor in colorectal cancer.

Intratumoral heterogeneity of CD44v6 in rectal cancer

PURPOSE

CD44v6 plays a controversial role in tumor progression and patient outcome in colorectal cancer by plenty of conflicting reports. The purpose of this study was to profile the intratumoral heterogeneity of CD44v6 in rectal cancer and investigate its role in lymph node metastasis.

METHODS

Sixty patients were included in this study. Immunohistochemistry for CD44v6 was performed in normal mucosa, primary tumor, and lymph node metastasis with whole tissue sections. The staining intensity in tumor center and invasive front was separately measured. Sampling bias was evaluated by quantitative real-time PCR with 15 pairs of frozen tissues from different sites of the primary tumor.

RESULTS

CD44v6 expression increased from normal mucosa to primary tumor to lymph node metastasis. Multiple intratumoral staining patterns was observed in primary tumor, and CD44v6 expression in invasive front was significantly higher than that in tumor center. In addition, mRNA expression levels differed across different geographical regions of the tumor. No association between CD44v6 expression and lymph node metastasis was revealed.

CONCLUSIONS

Substantial intratumoral heterogeneity of CD44v6 exists in rectal cancer that impacts the outcome of individual studies. CD44v6 expression should be assessed in a more precise way with a specified staining pattern and in a designated location.

Impact of CD44v6 overexpression on invasion and metastasis of colon cancer SW480 cells

AIM: To investigate the impact of CD44v6 overexpression on the invasion and metastasis of human colon cancer SW480 cells.

METHODS: SW480 cells stably overexpressing CD44v6 (CD44v6 group) and negative control cells (NC group) were developed through lentivirus infection. Transfection efficiency was evaluated by detecting the expression of enhanced green fluorescent protein (EGFP). CD44v6 mRNA levels were determined using quantitative real-time PCR. Localization of the overexpressed protein was observed by immunofluorescence staining of Flag protein. Cell proliferation was determined by cell counting kit (CCK)-8 assay. Cell invasion and metastasis were examined by scratch assay and transwell assay.

RESULTS: EGFP detection indicated that transfection efficiency was close to 100% in both groups. CD44v6 mRNA levels in CD44v6 overexpressing cells were significantly higher than those in the control cells (P < 0.001). The overexpressed CD44v6 protein was mainly localized on the cell membrane. No difference was revealed in cell proliferation between the two groups by CCK-8 assay. Scratch assay showed that the wound healing index was significantly increased in the CD44v6 group compared with the NC group (P < 0.05). Transwell assay showed that the invasion and metastasis index was significantly increased in the CD44v6 group compared with the NC group (P < 0.05), and the index was significantly decreased after the cells in the CD44v6 group were treated with CD44v6 antibody (P < 0.05).

CONCLUSION: Overexpression of CD44v6 significantly enhances the invasion and metastasis ability of SW480 cells.

Upregulation of CD44v6 contributes to acquired chemoresistance via the modulation of autophagy in colon cancer SW480 cells

The CD44 isoform containing variant exon v6 (CD44v6) plays an important role in the progression, metastasis, and prognosis of colorectal cancer (CRC). Recently, it was found that CD44v6 is involved in acquired drug resistance. This study aimed to investigate the molecular mechanism of CD44v6 in the resistance of CRC cells to chemotherapy. A stable CD44v6 overexpression model in SW480 cells was established via lentiviral transduction. The chemosensitivity of cells to 5-fluorouracil (5-FU) and oxaliplatin (L-OHP) was determined by cell counting kit (CCK)-8, lactate dehydrogenase (LDH) release, and colony formation assays. Immunohistochemical staining of CD44v6 was performed in human CRC tissues. The key components in cell apoptosis, drug efflux and metabolism, mismatch repair, autophagy, epithelial-mesenchymal transition (EMT), and the PI3K-Akt and MAPK-Ras-Erk1/2 pathways were assessed using flow cytometry, quantitative real-time polymerase chain reaction (PCR), and western blot assays. The CD44v6 overexpression cells showed a higher viability, a lower LDH release rate, and an increased clonogenicity than the control cells under drug treatment. Moreover, overexpression of CD44v6 resulted in enhanced autophagy flux, EMT, and phosphorylation of Akt and Erk in the presence of drugs. Furthermore, high CD44v6 expression in the primary tumor was closely associated with an early recurrence in CRC patients who underwent curative surgery and adjuvant chemotherapy. In conclusion, overexpression of CD44v6 contributes to chemoresistance in SW480 cells under cytotoxic stress via the modulation of autophagy, EMT, and activation of the PI3K-Akt and MAPK-Ras-Erk pathways.

Reporting in studies of protein biomarkers of prognosis in colorectal cancer in relation to the REMARK guidelines

PURPOSE

The REMARK guidelines give authors comprehensive and specific advice on the complete and transparent reporting of studies of prognostic tumor markers. The aim of this study was to use the REMARK guidelines to evaluate the quality of reporting in a sample of studies assessing tissue-based protein markers for survival after resection of colorectal cancer.

EXPERIMENTAL DESIGN

Eighty pertinent articles were scored according to their conformity to 26 items derived from the REMARK criteria.

RESULTS

Overall, on a scale of adequacy of reporting that potentially ranged from 26 to 78, the median for these studies was 60 (interquartile range 54-64) and several criteria were adequately covered in a large proportion of studies. However, others were either not dealt with or inadequately covered, including description of the study design (35%), definition of survival endpoints (48%), adjuvant therapy (54%), follow-up procedures and time (59%), neoadjuvant therapy (63%), inclusion/exclusion criteria (73%), multivariable modeling methods and results (74%), and discussion of study limitations (85%).

CONCLUSIONS AND CLINICAL RELEVANCE

Inadequacies in presentation militate against comparability among protein marker studies and undermine the generalizability of their findings. The quality of reporting could be improved if journal editors were to require authors to ensure that their work satisfied the REMARK criteria.

Evaluation of the prognostic value and functional roles of CD44v6 in gastric cancer

PURPOSE

Tumor stem cell surface marker CD44v6, a member of the CD44 protein family, is causally involved in the metastasis of cancer. Little is known about the functions of CD44v6 in gastric cancer. The aim of this study was to evaluate the prognostic value of CD44v6 and investigate its functional roles.

METHODS

The expression of CD44v6 in 208 primary gastric adenocarcinoma patient samples was examined using immunohistochemistry and its correlation with clinicopathological parameters, and 5-year patient survival was assessed. Two pairs of MGC-803 stable cells with either CD44v6 overexpression or knockdown were created. The effect of CD44v6 on cell proliferation, colony formation, migration and apoptosis was investigated using these two pairs of cells.

RESULTS

Overexpression of CD44v6 was observed in all cancer cell lines. The 5-year survival rate of patients with positive CD44v6 expression is significantly worse compared to those with negative expression (38.8 vs. 73.6 %). CD44v6 and TNM stage are two independent prognostic factors of primary gastric adenocarcinoma. The risk factors for the positive CD44v6 expression are location of tumor, depth of invasion, lymph node metastasis, Lauren classification and TNM stage. In MGC-803 cells, CD44 stimulated proliferation and colony formation, antagonized oxaliplatin-induced apoptosis, but did not affect migration.

CONCLUSION

CD44v6 is an important prognosis marker in gastric cancer. Tissue specificity may affect the functions of CD44v6, and further work is needed to elucidate its regulation.

Clinicopathologic significance of Sox2, CD44 and CD44v6 expression in intrahepatic cholangiocarcinoma

Embryonic stem cells (ESC) and cancer stem cells (CSC) have a capacity for self-renewal and differentiation into multiple cell lineages. Sox2 plays a critical role in ESC and has been shown to participate in carcinogenesis and tumor progression in many human cancers. CD44 and CD44v6 are putative CSC markers and their association with tumor progression, metastasis, and tumor relapse after treatment has been demonstrated. We evaluated the immunoexpression of Sox2, CD44, and CD44v6 in 85 cases of Intrahepatic cholangiocarcinomas (IHCC) and assessed their prognostic significance. Sox2 expression showed a significant association with lymph node metastasis (p = 0.025), T4 stage (p = 0.046), and worse overall survival (p = 0.047). Greater expression of Sox2 was observed in IHCC with poor differentiation, vascular invasion, and stage IV, without statistical significance (p > 0.05). CD44 expression showed an association with periductal infiltrative type (p = 0.034), poor differentiation (p = 0.012), and vascular invasion (p = 0.009). CD44v6 expression was evident in patients with stage IV (p = 0.019). These results demonstrated that Sox2 expression is associated with aggressive behavior and poor overall survival in IHCC.

Osteopontin combined with CD44v6, a novel prognostic biomarker in non-small cell lung cancer undergoing curative resection

BACKGROUND

Osteopontin (OPN) is identified as one of the leading genes that promote the metastasis of malignant tumor through binding to CD44v6 and integrin. The purpose of the current study was to assess the prognostic significance of OPN and CD44v6 in patients with non-small cell lung cancer (NSCLC).

METHODS

Tissue microarray was used to detect the expression of OPN and CD44v6 in 159 NSCLC patients undergoing complete pulmonary resection in our hospital between 2003 and 2006. The correlations among OPN, CD44v6, and clinicopathologic data were analyzed using χ(2) testing analysis. The prognostic values of OPN and CD44v6 were evaluated by univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis.

RESULTS

OPN and CD44v6 were both independent predictors for overall survival and disease-free survival. When OPN and CD44v6 were considered together, the predictive range was extended and the sensitivity was improved, especially for those patients with stage I NSCLC. The 6-year overall survival and disease-free survival rates in OPN+ or CD44v6+ patients were 49.1% and 39.6%, respectively, which were significantly lower than those of OPN-/CD44v6- patients (64.4% and 47.7%, respectively), and were higher than those of OPN+/CD44v6+ patients (16.4% and 14.8%, respectively). Stratification into OPN+/CD44v6+, OPN+ or CD44v6+, or OPN-/CD44v6- groups, based on the expression OPN and CD44v6, could efficiently predicted outcomes (p < 0.001) of NSCLC patients.

CONCLUSIONS

The combination of OPN and CD44v6 is a valuable independent predictor of tumor recurrence and survival in NSCLC patients.

Expression of COX-2, CD44v6 and CD147 and relationship with invasion and lymph node metastasis in hypopharyngeal squamous cell carcinoma

To assess the expression of COX-2,CD44v6 and CD147 in hypopharyngeal squamous cell carcinomas and the three biomarkers correlation with tumor invasion and lymph node metastasis of Chinese people. 101 cases of surgically excised primary tumor were included in this study, and 40 tissues of epithelium adjacent to carcinoma were used as controls. We characterized the immunohistochemical expression of COX-2, CD44v6, and CD147 in141 formalin-fixed, paraffin-embedded tissues, and measured the mean optical density (OD) of the positive area to identify the expression of the three bio-markers and relationship with tumor invasion and lymph node metastasis. Our study demonstrates that the expression of the COX-2 and CD147 were significantly increased in carcinoma tissues compared to the epithelium adjacent to carcinoma. We also observed that the expression of COX-2, CD44v6, and CD147 were significantly associated with T classification, lymph node metastasis and clinical stage. There was strong significant correlation among the three biomarkers as well. Additionally, we indicated that recurrence and ≥P₅₀ level of COX-2 expression had an independent prognostic effect on prognosis. In conclusion, the three biomarkers play important roles in tumor invasion and lymph node metastases and might be valuable indicators of tumor metastasis in hypopharyngeal squamous cell carcinoma.

Colorectal cancer defeating? Challenge accepted!

Colorectal tumours are actually considered as aberrant organs, within it is possible to notice a different stage of cell growth and differentiation. Their origin is reported to arise from a subpopulation of tumour cells endowed with, just like the healthy stem cells, self-renewal and aberrant multi-lineage differentiation capacity likely to be called colorectal cancer stem cells (CCSCs). Cancer stem cells (CSCs) fate, since their origin, reflects the influences from their microenvironment (or niche) both in the maintenance of stemness, in promoting their differentiation, and in inducing epithelial-mesenchymal transition, responsible of CSCs dissemination and subsequent formation of metastatic lesions. The tumour cells heterogeneity and their immuno-response resistance nowadays probably responsible of the failure of the conventional therapies, make this research field an open issue. Even more importantly, our increasing understanding of the cellular and molecular mechanisms that regulate CSC quiescence and cell cycle regulation, self-renewal, chemotaxis and resistance to cytotoxic agents, is expected to eventually result in tailor-made therapies with a significant impact on the morbidity and overall survival of colorectal cancer patients.

Combined preoperative CEA and CD44v6 improves prognostic value in patients with stage I and stage II colorectal cancer

AIM

Combination of biomarkers may improve diagnosis and have better prognostic value than single markers. The purpose of this study was to investigate whether combined CEA and CD44v6 improves prognostic value in stage I and stage II (stage I/II) colorectal cancer (CRC).

METHODS

Preoperative serum CEA level and the expression of CD44v6 in CRC tissues were examined by electrochemiluminescence immunoassay and immunohistochemistry, respectively. The association of CEA and CD44v6 with clinicopathological features and their possible prognostic values was analyzed.

RESULTS

The preoperative elevated serum CEA level and positive CD44v6 expression were detected in 30.1 % (52/173) serum samples and 60.5 % (101/167) CRC tissues, respectively. Patients with an elevated-CEA level or a CD44v6-negative tumor had a worse disease-specific survival (DSS) than those with a normal-CEA level or CD44v6-positive tumor (P = 0.024, P = 0.012, respectively). Moreover, CD44v6 expression could be used in discriminating patients from good to poor prognosis in normal-CEA subgroup (P = 0.043), but not in elevated-CEA subgroup (P = 0.563). Multivariate analysis revealed that combined CEA and CD44v6 was an independent prognostic factor for patients with stage I/II CRC (P = 0.023). However, serum CEA level only retained a borderline significance for correlation with a worse DSS (P = 0.059), and CD44v6 expression alone was not an independent prognostic factor for DSS in multivariate analysis (P = 0.123).

CONCLUSION

These results suggested that combined CEA/CD44v6 had better prognostic value than CEA or CD44v6 alone for patients with stage I/II CRC.

Metastasis-associated factors facilitating the progression of colorectal cancer

Tumor metastasis remains the principal cause of treatment failure and poor prognosis in patients with colorectal cancer. It is a multistage process which includes proteolysis, motility and migration of cells, proliferation in a new site, and neoangiogenesis. A crucial step in the process of intra- and extra-vasation is the activation of proteolytic enzymes capable of degrading the extracellular matrix (ECM). In this stage, urokinase plasminogen activator receptor (uPAR) and matrix metalloproteinases (MMPs) are necessary. Micrometastases need the presence of growth factor and vascular growth factor so that they can form macrometastasis. In addition, cell adhesion molecules (CAMs) and guanine nucleotide exchange factors (GEFs) play important roles in the progression of colorectal cancer and metastatic migration. Further elucidation of the mechanisms of how these molecules contribute will aid in the identification of diagnostic and prognostic markers as well as therapeutic targets for patients with colorectal metastasis.

CD44v6 expression is related to mesenchymal phenotype and poor prognosis in patients with colorectal cancer

CD44 standard isoform (CD44s) is a cancer stem cell marker in many tumors, and is one of the CD44 isoforms.CD44v6 has been reported to correlate with tumor progression and poor prognosis in colorectal cancer. However, the relevance of CD44s and CD44v6 to epithelial-mesenchymal transition (EMT) remains unclear. Immunohistochemistry was performed to investigate the clinical importance of CD44s and CD44v6 and their relevance to EMT in 113 patients with stage II/III colorectal cancer treated by curative resection. The relevance of CD44v6 knockdown to the phenotype of colon cancer cells was examined using small interfering RNA (siRNA) specific for CD44v6 in vitro. CD44v6 expression showed a significant inverse correlation with E-cadherin expression (P=0.0007) and a positive correlation with vimentin expression (P=0.0096). A multivariate analysis showed that high CD44v6 expression was an independent poor prognostic factor for disease-free survival (P=0.01, HR=3.05) and overall survival (P=0.025, HR=3.16). The clinical significance and the relevance of CD44s expression to EMT markers was noted to a lesser extent compared to CD44v6 expression. The knockdown of CD44v6 decreased vimentin expression, cell invasion and HGF-induced cell migration, but conferred only a slight effect on E-cadherin expression in colon cancer cells (HCT116 and LoVo). CD44v6 is related to poor outcome of patients with colorectal cancer via upregulation of the mesenchymal phenotype.

Functional effects of SDF-1α on a CD44(+) CXCR4(+) squamous cell carcinoma cell line as a model for interactions in the cancer stem cell niche

Stromal cell-derived factor-1α (SDF-1α), also known as CXCL12, has variable effects on a plurality of cells. It is known to have selective effects on cell migration, morphology, survival and cell homing. As such the SDF-1-CXCR4 axis is postulated to be a crucial key pathway in the interaction between (cancer) stem cells and their surrounding supportive cells, the so-called (cancer) stem cell niche. We evaluated the expression of CD44 as a cancer stem cell (CSC) marker and the expression of CXCR4 in the head and neck squamous cell carcinoma (HNSCC) cell line UM-SCC 11A. In addition, we monitored proliferation, formation of podia and migration of UM-SCC 11A cells under the influence of SDF-1α. Whereas SDF-1α induced the formation of podia of CD44(+) CXCR4(+) UM-SCC 11A cells in a dose-dependent manner and the maximum number of cells exhibiting the formation of podia was observed under the influence of 10 ng/ml SDF-1α (P=5.3x10(-6)), the highest number of migrating cells was noted using a concentration of 100 ng/ml (P=0.027). Proliferation and survival were not affected by SDF-1α. We showed that UM-SCC 11A cells could be a target for SDF-1α by CXCR4 expression and these cells also showed characteristics of HNSCC CSCs via CD44 expression. We demonstrated that SDF-1α is a chemoattractant for UM-SCC 11A cells, and a maximum directed migration was achieved under the influence of 100 ng/ml SDF-1α. Changes in cell morphology by presenting filopodia or a prominent uropod were noted following treatment of 10 ng/ml SDF-1α. The SDF-CXCR4 axis may play a crucial role in the interaction between CSCs and their supportive cells in the CSC niche. Understanding these interactions may help to gain further insight into the pathophysiology of the progression and recurrence of malignant diseases and thus help to develop novel strategies for therapy.

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.

A Pilot Study Assessing the Potential Role of non-CD133 Colorectal Cancer Stem Cells as Biomarkers

Introduction: Over 50% of patients with colorectal cancer (CRC) will progress and/or develop metastases. Biomarkers capable of predicting progression, risk stratification and therapeutic benefit are needed. Cancer stem cells are thought to be responsible for tumor initiation, dissemination and treatment failure. Therefore, we hypothesized that CRC cancer stem cell markers (CRCSC) will identify a group of patients at high risk for progression.

Methods: Paraffin-embedded tissue cores of normal (n=8), and histopathologically well-defined primary (n= 30) and metastatic (n=10) CRC were arrayed in duplicate on tissue microarrays (TMAs). Expression profiles of non-CD133 CRCSC (CD29, CD44, ALDH1A1, ALDH1B1, EpCam, and CD166) were detected by immunohistochemistry and the association with clinicopathological data and patient outcomes was determined using standard statistical methodology. An independent pathologist, blinded to the clinical data scored the samples. Scoring included percent positive cells (0 to 4, 0 = <10%, 1 = 10 - 24%, 2 = 25 - 49%, 3 = 50 - 74%, 4 = 75 - 100%), and the intensity of positively stained cells (0 to 4; 0 = no staining, 1 = diminutive intensity, 2 = low intensity, 3 = intermediate intensity, 4 = high intensity). The pathologic score represents the sum of these two values, reported in this paper as a combined IHC staining score (CSS).

Results: Of 30 patients 7 were AJCC stage IIA, 10 stage IIIB, 7 stage IIIC and 6 stage IV. Median follow-up was 113 months. DFI was 17 months. Median overall survival (OS) was not reached. Stage-specific OS was: II - not reached; III - not reached; IV - 11 months. In a univariate analysis, poor OS was associated with loss of CD29 expression; median OS, 32 months vs. not reached for CSS 3-7 vs. >7.5, respectively; p=0.052 comparing entire curves, after adjustment. In a Cox model analysis, loss of CD29 exhibited a trend toward association with survival (p=0.098) after adjusting for the effect of stage (p=0.0076). Greater expression of ALDH1A1 was associated with increasing stage (p=0.042 over stages 2, 3b, 3c, and 4) while loss of CD29 expression exhibited a trend toward being associated with stages 3 and 4 (p=0.08). Compared to normal colon tissue, primary tumors were associated with increased expression of ALDH1B1 (p=0.008). ALD1H1B1 expression level differed according to whether the tumor was moderately or poorly differentiated, well differentiated, or mucinous; the highest expression levels were associated with moderately or poorly differentiated tumors (p=0.011). Lymph node metastases were associated with a trend toward decreased expression of EpCAM (p = 0.06) when comparing 0 vs. 1 vs. 2+ positive lymph nodes, as was CD29 (p = 0.08) when comparing 0 vs. any positive lymph nodes. Compared to normal colon tissue metastatic colon cancers from different patients were associated with increased ALDH1B1 expression (p=0.001) whereas CD29 expression was higher in normal colonic tissue (p=0.014).

Conclusion: CD29 may be associated with survival as well as clinical stage and number of lymph nodes. ALDH1B1 expression was associated with differentiation as well as type of tissue evaluated. ALDH1A1 was associated with clinical stage, and decreased EpCAM expression was found in patients with advanced lymph node stage. CRCSCs may be useful biomarkers to risk stratify, and estimate outcomes in CRC. Larger prospective studies are required to validate the current findings.

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.

Prognostic impact of the expression of putative cancer stem cell markers CD133, CD166, CD44s, EpCAM, and ALDH1 in colorectal cancer

Background:

The aim of this study was to elucidate the prognostic impact of putative cancer stem cell markers CD133, CD166, CD44s, EpCAM, and aldehyde dehydrogenase-1 (ALDH1) in colorectal cancer.

Methods:

A tissue microarray of 1420 primary colorectal cancers and 57 normal mucosa samples was immunostained for CD133, CD166, CD44s, EpCAM, and ALDH1 in addition to 101 corresponding whole tissue sections. Invasive potential of three colorectal cancer cell lines was tested.

Results:

Differences between normal tissue and cancer were observed for all markers (P<0.001). Loss of membranous CD166 and CD44s were linked to higher pT (P=0.002, P=0.014), pN (P=0.004, P=0.002), an infiltrating growth pattern (P<0.001, P=0.002), and worse survival (P=0.015, P=0.019) in univariate analysis only. Loss of membranous EpCAM expression was also linked to higher pN (P=0.023) and infiltrating growth pattern (P=0.005). The CD44s, CD166, and EpCAM expression were lost towards the invasive front. The CD44−/CD166− cells from three colorectal cancer cell lines exhibited significantly higher invasive potential in vitro than their positive counterparts.

Conclusions:

Loss, rather than overexpression, of membranous CD44s, CD166, and EpCAM is linked to tumour progression. This supports the notion that the membranous evaluation of these proteins assessed by immunohistochemistry may be representative of their cell adhesion rather than their intra-cellular functions.