Elevated CD133, but not VEGF or EGFR, as a predictive marker of distant recurrence after preoperative chemoradiotherapy in rectal cancer

Immunohistochemical Markers as Predictors of Histopathologic Response and Prognosis in Rectal Cancer Treated with Preoperative Adjuvant Therapy: State of the Art

We explain the state of the art of the immunohistochemical markers of response in rectal cancers treated with neoadjuvant medical therapies and its implication with prognosis. Neoadjuvant chemoradiotherapy is widely used to improve the outcome of patients with locally advanced rectal cancer, and the evaluation of the effects of medical therapy is to date based on histomorphological examination by applying four grading systems of response to therapy (tumor regression grade (TRG)). The need to identify immunohistochemical markers that could ensure a better assessment of response and possibly provide additional prognostic information has emerged. We identified p53, p27kip1, Ki67, matrix metalloprotease-9, survivin, Ki67 proliferative index, CD133, COX2, CD44v6, thymidylate synthase, thymidine phosphorylase, and dihydropyrimidine dehydrogenase as the most common markers studied in literature to date, and we explained their prognostic potential and their implications in the evaluation of the response to preoperative therapies in rectal cancers.

Understanding molecular markers in recurrent oral squamous cell carcinoma treated with chemoradiation

Introduction

Oral cancer accounts for approximately 2.1% of all cancers worldwide. In India, oral squamous cell carcinoma (OSCC) is the most common cancer with half a million new cases diagnosed every year. More than 50% of patients eventually develop local recurrence or metastasis usually within the first 2-years following completion of treatment. It is beneficial to analyze the prognostic significance of Cyclin D1, p53 and EGFR which are critical mediators in the pathogenesis of OSCC. The objective of this study was to assess the association of expression of these markers with recurrence and pattern of recurrence in OSCC patients undergoing chemoradiation.

Materials and Methods

A Total 290 OSCC cases of locally advanced stage (III, IV) oral cancer with World Health Organization (W.H.O.) performance status of grade 0/1 in the year 2009–2012 were enrolled in the study. Treatment response was assessed according to W.H.O. criteria. Cyclin D1, EGFR and p53 expression in tumor tissue was estimated by immunohistochemical (IHC) method and quantified as percentage positive nuclei.

Results

During the 2-years follow up, 56 (19.3%) patients recurred, out of which, 47 (83.9%) were locoregional and 9 (16.1%) distant sites. On correlating, χ² test showed significant (P < 0.05 or P < 0.01 or P < 0.001) association of marker expressions (Cyclin D1, EGFR and p53) with recurrence. The strong positive expressions of all three markers showed significant association with early time of recurrence. The multivariate logistic regression analysis showed significant (P < 0.05 or P < 0.01 or P < 0.001) association of recurrence with primary site, differentiation, Cyclin D1 and p53 expressions indicating these as an independent predictors of recurrence in OSCC. The Cyclin D1, EGFR and p53 expressions also showed significant (P < 0.001) poor survivals (OS, DFS and RFS) in patients with positive/strong positive expressions than negative expression suggesting their prognosis in OSCC.

Conclusion

Our results signifies that tumors over expressing Cyclin D1, EGFR and p53 are resistant to chemoradiation and are associated with increased risk of locoregional recurrence and metastasis in OSCC patients undergoing chemoradiation.

Prognostic value of CD133 expression in cancer patients treated with chemoradiotherapy: a meta-analysis

Many studies evaluated the correlations of CD133 expression with the clinical outcomes in patients treated with chemoradiotherapy (CRT) but yielded controversial results. This meta-analysis was performed to identify the impacts of CD133 expression on the prognosis of cancer patients treated with CRT. Electronic databases updated up to March 2014 were searched to find relevant studies. Relevant literatures without any language restrictions were searched via electronic databases as follows: Web of Science (1945 ~ 2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966 ~ 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013). STATA software was used for the current meta-analysis. Hazard ratios (HR) and its corresponding 95% confidence interval (95% CI) were calculated. Six studies were identified with a total of 470 cancer patients treated with CRT. The meta-analysis results showed that CD133-positive patients had poorer overall survival (OS) than that of CD133-negative patients (HR = 2.13, 95% CI = 1.20 ~ 3.07, P < 0.001). Furthermore, CD133-positive patients displayed shorter disease-free survival (DFS) than that of CD133-negative patients (HR = 1.74, 95% CI = 0.08 ~ 3.40, P = 0.039). Ethnicity-stratified analysis indicated that CD133 expression positively correlated with shorter OS among the Japanese, Chinese, and Spanish populations (all P < 0.05). In conclusion, our findings suggest that CD133 expression may be positively correlated with poorer prognosis in cancer patients treated with CRT.

Prognostic impact of MGMT promoter methylation and MGMT and CD133 expression in colorectal adenocarcinoma

BACKGROUND

New biomarkers are needed for the prognosis of advanced colorectal cancer, which remains incurable by conventional treatments. O6-methylguanine DNA methyltransferase (MGMT) methylation and protein expression have been related to colorectal cancer treatment failure and tumor progression. Moreover, the presence in these tumors of cancer stem cells, which are characterized by CD133 expression, has been associated with chemoresistance, radioresistance, metastasis, and local recurrence. The objective of this study was to determine the prognostic value of CD133 and MGMT and their possible interaction in colorectal cancer patients.

METHODS

MGMT and CD133 expression was analyzed by immunohistochemistry in 123 paraffin-embedded colorectal adenocarcinoma samples, obtaining the percentage staining and intensity. MGMT promoter methylation status was obtained by using bisulfite modification and methylation-specific PCR (MSP). These values were correlated with clinical data, including overall survival (OS), disease-free survival (DFS), tumor stage, and differentiation grade.

RESULTS

Low MGMT expression intensity was significantly correlated with shorter OS and was a prognostic factor independently of treatment and histopathological variables. High percentage of CD133 expression was significantly correlated with shorter DFS but was not an independent factor. Patients with low-intensity MGMT expression and ≥50% CD133 expression had the poorest DFS and OS outcomes.

CONCLUSIONS

Our results support the hypothesis that MGMT expression may be an OS biomarker as useful as tumor stage or differentiation grade and that CD133 expression may be a predictive biomarker of DFS. Thus, MGMT and CD133 may both be useful for determining the prognosis of colorectal cancer patients and to identify those requiring more aggressive adjuvant therapies. Future studies will be necessary to determine its clinical utility.

Preliminary Study on the Expression and the Clinical Significance of CD133 in Peripheral Blood of Patients with Gastric Adenocarcinoma

Background. Significances of CD133 mRNA in peripheral blood mononuclear cells (PBMCs) of gastric adenocarcinoma (GC) patients were investigated. Methods. Correlations of CD133 mRNA expression in PBMCs on clinicopathological parameters or CD133 protein expression were analyzed. Receiver operating characteristic curve according to bright scale value (BSV) of CD133 mRNA was used to group patients for prognosis analysis. Results. BSV of preoperative CD133 mRNA in PBMCs in GC was significantly higher than that in volunteers or in GU. Invasive depth or metastatic lymph node number for higher BSV of preoperative CD133 mRNA and invasive depth or lymphatic vessel invasion for higher BSV of postoperative CD133 mRNA in the PBMCs were identified. Patients with CD133⁺ expression in primary lesion had a significantly higher expression of preoperative CD133 mRNA in the PBMCs. The expression of preoperative or postoperative CD133 mRNA in PBMCs related positively to CD133 mRNA expression in primary lesion. Patients with higher expression of preoperative or postoperative CD133 mRNA shared significantly shorter survival compared with that in lower expression group. Conclusion. Higher levels of preoperative or postoperative CD133 mRNA in PBMCs of GC correlated positively to the lymphatic metastasis and the BSV of CD133 mRNA in primary lesion, indicating the poorer survival.

Concomitant tumor expression of EGFR and TATI/SPINK1 associates with better prognosis in colorectal cancer

Background

Epidermal growth factor receptor (EGFR) activation plays a role in colorectal cancer (CRC) carcinogenesis, and anti-EGFR drugs are used in treatment of advanced CRC. One of the EGFR ligands is tumor-associated trypsinogen inhibitor TATI, also called serine protease inhibitor Kazal type1 (SPINK 1), which we recently showed to be an independent prognostic marker in CRC.

Methods

We studied the prognostic value of immunohistochemical expression of EGFR and concomitant expression of EGFR and TATI/SPINK1 in a series of 619 colorectal cancer patients.

Results

Of the samples, 92% were positive for EGFR. EGFR+/TATI+ was seen in 62.8%, EGFR+/TATI− in 29.5%, EGFR−/TATI+ in 4.9%, and EGFR−/TATI− in 2.7% of patients. EGFR expression correlated with WHO grade (p = 0.040). In univariate analysis, EGFR expression correlated with favourable survival (p = 0.006). EGFR+/TATI+ patients showed better survival than did those with other combinations (p<0.001). In multivariate analysis, EGFR+/TATI+ was an independent prognostic factor of favourable prognosis (p<0.001).

Conclusion

Concomitant positivity of EGFR and TATI/SPINK1 predicts favourable prognosis in CRC.

CD133 expression and the prognosis of colorectal cancer: a systematic review and meta-analysis

Objective

CD133 has recently been reported as a marker of cancer stem-like cells in colorectal cancer (CRC). However, its predictive value in CRC still remains controversial. In this study, we aimed to evaluate the association between the expression of CD133 and clinicopathological features and the outcome of CRC patients by performing a meta-analysis.

Methods

A comprehensive literature search for relevant studies published up to December 2012 was performed using PubMed, MEDLINE and ISI Web of Science. Only articles in which CD133 antigen was detected in situ localisation by immunohistochemical staining were included. This meta-analysis was done using RevMan 4.2 software.

Results

We found that a total of 15 studies involving 810 CD133-high and 1487 CD133-low patients met the inclusion criteria for the analysis of 5-year overall survival (OS) rate. In a random-effects model, the results showed that CD133-high expression in colorectal cancer was an independent prognostic marker correlating with both OS rate (RR = 0.67, 95%CI 0.54–0.82, P<0.01) and disease free survival (DFS) rate (RR = 0.71, 95%CI 0.52–0.96, P = 0.03). CD133-high expression was also associated with more T3,4 tumor invasion, N positive and vascular invasion cases, corresponding to a risk difference of 1.12 (95%CI 1.01–1.23, P = 0.03), 1.31 (95%CI 1.06–1.63, P = 0.01) and 1.24 (95%CI 1.08–1.41, P<0.01), respectively. However, when types of histology, lymphatic invasion and distant metastasis were considered, CD133 overexpression was not significantly related with these clinicopathological parameters.

Conclusion

Our meta-analysis results suggest that CD133 is an efficient prognostic factor in CRC. Higher CD133 expression is significantly associated with poorer clinical outcome and some clinicopathological factors such as T category, N category and vascular invasion in CRC patients.

Immunohistochemical detection of CD133 is associated with tumor regression grade after chemoradiotherapy in rectal cancer

CD133 has been identified as a putative cancer stem cell (CSC) marker in various cancers including colorectal cancer. The relation between CD133 expression and biological characteristics of colorectal cancer remains to be clarified. Protein expression of CD133 was immunohistochemically evaluated in surgical specimens of 225 patients with colorectal cancer who were treated by surgery, as well as those of 78 patients with rectal cancer who received preoperative chemoradiotherapy (CRT) followed by curative resection. The correlation between CD133 expression and clinicopathological features, tumor recurrence and overall survival was analyzed in both populations. Among 225 colorectal cancers without CRT, 93 (41.3%) were positive for CD133 expression, which was enhanced in cases with advanced T stage and venous invasion. Moreover, CD133 was positive in 47 (60.3%) of 78 cases with CRT, which was significantly higher than the CD133-positive rate in non-CRT specimens (P=0.05). Expression of CD133 was independently correlated with the histological tumor regression grade (P<0.01). These results suggest that CD133 is not a distinctive colorectal CSC marker; expression of CD133 is suggested to be one of the key factors associated with resistance to CRT in colorectal cancer.

Rapid re-expression of CD133 protein in colorectal cancer cell lines in vitro and in vivo

Studies related to the cancer stem cell hypothesis are challenging because of the imperfect tools to identify cell populations of interest and controversy on the usefulness of established cancer cell lines. We previously found CD133 to not be selective for a tumor-propagating or radioresistant population in a near-diploid, microsatellite-instable colorectal carcinoma (CRC) cell line. Because of discrepant literature data, we herein systematically analyzed the behavior of microsatellite-stable cell line subpopulations reflecting the more frequent carcinogenesis pathway in spontaneous CRC. CD133⁺ and CD133(-/low) populations were isolated by fluorescence-activated cell sorting and further processed. HT29 and SW620 cells were studied in detail in monolayer and/or spheroid culture assays and upon subcutaneous injection in NMRI (nu/nu) mice using a limiting dilution approach. CD133(-/low) HT29 cells showed a significantly lower clonogenic survival and reduced spheroid formation capacity than their CD133⁺ counterparts. However, the cell populations neither differed in growth kinetics and response to treatment in vitro nor in tumor formation capacity when injecting as low as 10 cells. CD133(-/low) HT29 cells rapidly re-expressed CD133 protein in vitro and in vivo as shown by flow cytometry and/or western blot analyses, and they also showed a particular survival benefit under tissue normoxic conditions. In contrast, CD133 protein in the CD133⁺ population was quite stable throughout culturing. The observation of CD133 re-expression and lack of difference in tumor take rate of subpopulations was confirmed in SW620 cells. Here, we found cell density to affect CD133 re-expression in the CD133(-)-sorted population. And even SW480 cells, classified as a CD133⁻ cell line, presented some CD133 protein on their surface upon in vivo engraftment. We conclude that (i) CD133 protein expression shows high plasticity in CRC cell lines, and (ii) in vitro CD133 status on the cell surface neither determines tumorigenic potential nor CD133 profile in vivo.

VEGF levels and the angiogenic potential of the microenvironment can affect surgical strategy for colorectal liver metastasis

The hypotheses emerging from basic research on colorectal liver metastases must be tested in clinical situations for the adaptation of current treatment strategies. Pre-metastatic niches have been shown to exist in human colorectal synchronous metastases, with the liver parenchyma adjacent to the synchronous liver metastases providing a favorable, angiogenic environment for metastatic tumor growth. The role of the VEGF signaling pathway in liver regeneration and tumor growth remains unclear, but the use of antiangiogenic agents in combination with surgical treatment is almost certainly beneficial.

CD133+ colon cancer cells are more interactive with the tumor microenvironment than CD133- cells

Experimental data indicate that colorectal cancer cells with CD133 expression exhibit enhanced tumorigenicity over CD133-negative (CD133-) cells. We hypothesized that CD133-positive (CD133+) cells, compared with CD133-, are more tumorigenic because they are more interactive with and responsive to their stromal microenvironment. Freshly dissected and dissociated cells from a primary colon cancer were separated into carcinoma-associated fibroblasts (CAF) and the epithelial cells; the latter were further separated into CD133+ and CD133- cells using fluorescence-activated cell sorter. The CD133+ cells formed large tumors in non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice, demonstrating the phenotypic cellular diversity of the original tumor, whereas CD133- cells were unable to sustain significant growth. Affymetrix gene array analyses using t-test, fold-change and multiple test correction identified candidate genes that were differentially expressed between the CD133+ vs CD133- cells. RT-PCR verified differences in expression for 30 of the 46 genes selected. Genes upregulated (+ vs - cells) included CD133 (9.3-fold) and CXCR4 (4-fold), integrin β8 and fibroblast growth factor receptor 2. The CAF highly express the respective ligands: stromal-derived factor-1 (SDF-1), vitronectin and FGF family members, suggesting a reciprocal relationship between the CD133+ and CAF cells. SDF-1 caused an increase in intracellular calcium in cells expressing both CD133 and CXCR4, confirming functional CXCR4. The CD133+/CXCR4+ phenotype is increased to 32% when the cells are grown in suspension compared with only 9% when the cells were allowed to attach. In Matrigel 3-D culture, the CD133+/CXCR4+ group treated with SDF-1 grew more colonies compared with vehicle, as well as significantly larger colony sizes of tumor spheres. These data demonstrate proof of principle that the enhanced tumorigenic potential of CD133+, compared with CD133-, cells is due to their increased ability to interact with their neighboring CAF.

Preclinical evaluation of Mab CC188 for ovarian cancer imaging

Cancer stem cells (CSCs) have been successfully isolated from solid tumors and are believed to be initiating cells of primary, metastatic and recurrent tumors. Imaging and therapeutic reagents targeted to CSCs have potential to detect subclinical tumors and completely eradicate the disease. Previously, we have demonstrated that Mab CC188 binds to colon cancer CD133- and CD133+ (CSCs) cells. In this study, we examined the reactivity of Mab CC188 to ovarian cancer cells including CD133+ cells and primary tumor tissues using immunofluorescence staining methods and tissue microarray technique. We also explored the feasibility of using NIR dye-labeled Mab CC188 probe to image ovarian tumors in vivo. Mab CC188 stains both CD133- and CD133+ cells of ovarian cancer. Tissue microarray analysis reveals that 75% (92/123) of ovarian cancer cases are positively stained with Mab CC188. Weak positive (±), positive (+), strong positive (++) and very strong positive (+++) stains are 14.8, 3.7, 11 and 24.4%, respectively. In contrast, Mab CC188 staining is low in normal cells and tissues. In vivo study show that significant amounts of the probe accumulates in the excretion organs in the early period postinjection. At 24 hr, the imaging probes have largely accumulates in the tumor, while the intensity of the imaging probe decreases in the liver. The tumor uptake was still evident at 120-hr postinjection. Our work suggests that Mab CC188-based imaging and therapeutic reagents are capable of detecting early stage ovarian tumors and effectively treating the tumor.

Pharmacogenomics and cancer stem cells: a changing landscape?

Pharmacogenomics in oncology holds the promise to personalize cancer therapy. However, its clinical application is still limited to a few genes, and, in the large majority of cancers, the correlation between genotype and clinical outcome has been disappointing. One possible explanation is that current pharmacogenomic studies do not take into account the emerging role of cancer stem cells (CSCs) in drug sensitivity and resistance. CSCs are a subpopulation of cells driven by specific signal-transduction pathways, but genetic variants affecting their activity are generally neglected in current pharmacogenomic studies. Moreover, in several malignancies, CSCs represent a rare sub-population; therefore, whole tumor profiling might mask CSC gene expression patterns. This article reviews current evidence on CSC chemoresistance and shows how common genetic variations in CSC-related genes may predict individual response to anti-cancer agents. Furthermore, we provide insights into the design of pharmacogenomic studies to address the clinical usefulness of CSC genetic profiling.

Genome and transcriptome profiles of CD133-positive colorectal cancer cells

Colorectal carcinomas (CRC) might be organized hierarchically and contain a subpopulation of tumorigenic, putative cancer stem cells that are CD133 positive. We studied the biological and genetic characteristics of such cells in CRC cell lines and primary tumors. Three CRC cell lines were sorted in CD133 positive and negative fractions. The respective genetic aberration profiles were studied using array comparative genomic hybridization (aCGH) and expression profiling. Tumorigenicity for each cellular population was tested by injection into nude mice. Additionally, we compared CD133+ and CD133- cells of 12 primary colorectal tumors using laser capture microdissection and aCGH. Three of five CRC cell lines displayed both CD133+ and CD133- cells, but tumorigenicity of these subfractions did not differ significantly and aCGH revealed essentially identical genomic imbalances. However, 96 genes were differentially expressed between the two populations. Array comparative genomic hybridization analysis after laser capture microdissection of CD133+ and CD133- areas in primary colorectal tumors revealed genetic differences in 7 of 12 cases. The use of cell lines for studying genomic alterations that define cancer stem cell characteristics, therefore, seems questionable. In contrast, CD133+ cells in primary cancer samples showed a unique genomic aberration profile. In conclusion, our data suggest that CD133 positivity defines a genetically distinct cellular compartment in primary CRC, which potentially includes tumor initiating cells.

Metastatic breast cancer cells in the bone marrow microenvironment: novel insights into oncoprotection

Among all cancers, malignancies of the breast are the second leading cause of cancer death in the United States after carcinoma of the lung. One of the major factors considered when assessing the prognosis of breast cancer patients is whether the tumor has metastasized to distant organs. Although the exact phenotype of the malignant cells responsible for metastasis and dormancy is still unknown, growing evidence has revealed that they may have stem cell-like properties that may account for resistance to chemotherapy and radiation. One process that has been attributed to primary tumor metastasis is the epithelial-to-mesenchymal transition. In this review, we specifically discuss breast cancer dissemination to the bone marrow and factors that ultimately serve to shelter and promote tumor growth, including the complex relationship between mesenchymal stem cells (MSCs) and various aspects of the immune system, carcinoma-associated fibroblasts, and the diverse components of the tumor microenvironment. A better understanding of the journey from the primary tumor site to the bone marrow and subsequently the oncoprotective role of MSCs and other factors within that microenvironment can potentially lead to development of novel therapeutic targets.

Emerging strategies for the identification and targeting of cancer stem cells

The hypothesis of cancer stem cells (CSCs) is receiving increasing interest and has become the subject of considerable debate among cancer researchers. Recent rapid progress in CSC research has encountered increasing difficulties and challenges. Understanding the biologic characteristic of CSCs is crucial to start with better identification and diagnosis based on CSC markers and eventually targeting to CSCs will undoubtedly result in improved prevention and treatment of many types of CSCs. We discuss here some of the approaching strategies that include establishing special methods of identifying CSCs and targeting therapies of CSCs.