CD44 loss in gastric stromal tumors as a prognostic marker

Pharmacokinetics and pharmacodynamic evaluation of hyaluronic acid-modified imatinib-loaded PEGylated liposomes in CD44-positive Gist882 tumor-bearing mice

To develop a PEGylated and CD44-targeted liposomes, enabled by surface coating with hyaluronic acid (HA) via amide bond to improve the efficacy of imatinib mesylate (IM), for tumor-targeted cytoplasmic drug delivery. HA was covalently grafted on DSPE-PEG2000-NH2 polymer. HA-modified or unmodified PEGylated liposomes were prepared with ethanol injection method, and the stability, drug release, and cytotoxicity of these liposomes were studied. Meanwhile, intracellular drug delivery efficiency, antitumor efficacy, and pharmacokinetics were also investigated. Ex vivo fluorescence biodistribution was also detected by small animal imaging. In addition, endocytosis mechanism was also explored HA-coated PEGylated liposomes (137.5 nm ± 10.24) had a negative zeta potential (-29.3 mV ± 5.44) and high drug loading (27.8%, w/w). The liposomes were stable with cumulative drug leakage (<60%) under physiological conditions. Blank liposomes were nontoxic to Gist882 cells, and IM-loaded liposomes had higher cytotoxicity to Gist882 cells. HA-modified PEGylated liposomes were internalized more effectively than non-HA coating via CD44-mediated endocytosis. Besides, the cellular uptake of HA-modified liposomes also partly depends on caveolin-medicated endocytosis and micropinocytosis. In rats, both liposomes produced a prolonged half-life of IM (HA/Lp/IM: 14.97h; Lp/IM: 11.15h) by 3- to 4.5-folds compared with the IM solution (3.61h). HA-decorated PEGylated liposomes encapsulated IM exhibited strong inhibitory effect on tumor growth in Gist882 cell-bearing nude mice and formation of 2D/3D tumor spheroids. The Ki67 immunohistochemistry result was consistent with the above results. IM-loaded PEGylated liposomes modified with HA exerted the excellent anti-tumor effect on tumor-bearing mice and more drugs accumulated into the tumor site.

Relationship between Ki-67 and CD44 expression and microvascular formation in gastric stromal tumor tissues

BACKGROUND

A gastric stromal tumor (GST) is a mesenchymal tumor that occurs in the gastrointestinal tract; its biological characteristics are highly complex. Clinically, the severity of a GST is often evaluated by factors such as risk classification, tumor size, and mitotic figures. However, these indicators are not very accurate. Even patients classified as low risk are also at risk of metastasis and recurrence. Therefore, more accurate and objective clinical biological behavior evaluations are urgently needed.

AIM

To determine the relationship between Ki-67 and CD44 expression in GSTs and microvessel formation and prognosis.

METHODS

Eighty-six GST tissue specimens from our hospital were selected for this study. The immunohistochemical staining technique was used to detect Ki-67, CD44, and microvessel density (MVD) in the collected samples to analyze the different risk grades and mitotic figures. In addition, this approach was used to determine the differences in the expression of Ki-67 and CD44 in GST tissues with varying lesion diameters.

RESULTS

In GSTs with positive expression of the Ki-67 protein, the proportions of patients with medium-to-high risk and more than five mitotic counts were 24.07% and 38.89%, respectively. In GSTs with positive expression of the CD44 protein, the proportions of patients with medium-to-high risk and more than five mitotic counts were 23.73% and 38.98%, respectively. In GSTs with negative expression of the Ki-67 protein, these values were relatively high (3.70% and 11.11%, respectively). The MVD in GSTs with positive and negative expression of the CD44 protein was 15.92 ± 2.94 and 13.86 ± 2.98/Hp, respectively; the difference between the two groups was significant (P < 0.05).

CONCLUSION

Ki-67 and CD44 expression in GSTs is correlated with the grade of tumor risk and mitotic figures. CD44 expression is correlated with microvessel formation in tumor tissues.

The Role of Breast Cancer Stem Cell-Related Biomarkers as Prognostic Factors

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide, and its incidence is on the rise. A small fraction of cancer stem cells was identified within the tumour bulk, which are regarded as cancer-initiating cells, possess self-renewal and propagation potential, and a key driver for tumour heterogeneity and disease progression. Cancer heterogeneity reduces the overall efficacy of chemotherapy and contributes to treatment failure and relapse. The cell-surface and subcellular biomarkers related to breast cancer stem cell (BCSC) phenotypes are increasingly being recognised. These biomarkers are useful for the isolation of BCSCs and can serve as potential therapeutic targets and prognostic tools to monitor treatment responses. Recently, the role of noncoding microRNAs (miRNAs) has extensively been explored as novel biomarker molecules for breast cancer diagnosis and prognosis with high specificity and sensitivity. An in-depth understanding of the biological roles of miRNA in breast carcinogenesis provides insights into the pathways of cancer development and its utility for disease prognostication. This review gives an overview of stem cells, highlights the biomarkers expressed in BCSCs and describes their potential role as prognostic indicators.

Paradoxical expression pattern of the epithelial mesenchymal transition-related biomarkers CD44, SLUG, N-cadherin and VSIG1/Glycoprotein A34 in gastrointestinal stromal tumors

AIM

To evaluate the immunohistochemical (IHC) expression of five biomarkers, commonly involved in epithelial mesenchymal/mesenchymal epithelial transition (EMT/MET), in gastrointestinal stromal tumors (GISTs).

METHODS

In 80 consecutive GISTs the IHC examinations were performed using the EMT-related antibodies E-cadherin, N-cadherin, SLUG, V-set and immunoglobulin domain containing 1 (VSIG1) and CD44.

RESULTS

The positivity rate was 88.75% for SLUG, 83.75% for VSIG1, 36.25% for CD44 and 10% for N-cadherin. No correlation was noted between the examined markers and clinicopathological parameters. Nuclear positivity for SLUG and VSIG1 was observed in all cases with distant metastasis. The extra-gastrointestinal stromal tumors (e-GISTs) expressed nuclear positivity for VSIG1 and SLUG, with infrequent positivity for N-cadherin and CD44. The low overall survival was mainly dependent on VSIG1 negativity (P = 0.01) and nuclear positivity for SLUG and/or CD44.

CONCLUSION

GIST aggressivity may be induced by nuclear up-regulation of SLUG and loss or cytoplasm-to-nuclear translocation of VSIG1. SLUG and VSIG1 may act as activated nuclear transcription factors. The CD44, but not N-cadherin, might also have an independent prognostic value in these tumors. The role of the EMT/MET-related transcription factors in the evolution of GISTs, should be revisited with a larger dataset. This is the first study exploring the IHC pattern of VSIG1 in GISTs.

Lrig1 Expression in Human Sebaceous Gland Tumors

Background

Sebaceous glands contribute significantly to the barrier functions of the skin. However, little is known about their homeostasis and tumorigenesis. Recently, increased expression of stem cell marker Lrig1 has been reported in sebaceous carcinoma-like tumors of K14ΔNLef1 transgenic mice. In this study, we analyzed the Lrig1 expression in human sebaceous tumors.

Methods

Twenty-eight formalin-fixed paraffin-embedded sebaceous tumor specimens (7 sebaceous hyperplasias, 7 sebaceous adenomas, 10 sebaceomas and 4 sebaceous carcinomas) were stained with anti-Lrig1, anti-CD44v3 and anti-Ki67 antibody.

Results

Four (100%) sebaceous carcinomas, 8 (80%) sebaceomas, 3 (43%) sebaceous adenomas and no sebaceous hyperplasia showed Lrig1 overexpression.

Discussion and Conclusion

Lrig1 is a known tumor suppressor gene and is usually considered to be an indicator of poorly aggressive tumors. In human sebaceous tumors, the stronger Lrig1 staining in sebaceous carcinoma compared to other sebaceous tumors might be a feature of an advanced stage in tumorigenesis and a bad prognosis. In our study, 100% of sebaceous carcinomas revealed Lrig1 overexpression. We propose that Lrig1 may be used as a possible new marker of poorly differentiated sebaceous carcinoma.

CD44v/CD44s expression patterns are associated with the survival of pancreatic carcinoma patients

Background and purpose

CD44 variants have been associated with tumor invasion and metastasis, but CD44 expression patterns have not been systematically investigated in pancreatic carcinoma. This study systematically investigated whether CD44 expression patterns are involved in pancreatic carcinoma metastasis and prognosis.

Methods

We applied primers specific for all CD44 variants and CD44s to analyze the expression patterns of CD44 (CD44v2-CD44v10 and CD44s) using quantitative real-time PCR (qRT-PCR). We then further evaluated their roles in pancreatic carcinoma metastasis and prognosis using clinical survival analysis.

Results

Increased CD44v expression and decreased CD44s expression were found in metastatic pancreatic carcinoma in three different cell lines and in human tumor tissue. Clinical analysis showed that CD44v6⁺ and CD44v9⁺ were correlated with lymph node metastasis, liver metastasis and TNM stage. However, CD44s⁻ was associated with liver metastasis, tumor differentiation and TNM stage. Survival analysis showed that patients with CD44v6⁺/CD44s⁻ or CD44v6⁺/CD44s⁻ had lower overall survival (OS) rates, although the individual expression of CD44v6, CD44v9 and CD44s was also related to decreased OS rates. Univariate analysis showed that lymph node metastasis; vessel invasion; hepatic metastases; TNM stage; and individual or co-expression of CD44v6, CD44v9 and CD44s were risk factors affecting survival. Multivariate analysis showed that CD44v6⁺/CD44s⁻ was an independent predictor of survival.

Conclusions

We found that CD44v6⁺, CD44v9⁺ and CD44s⁻ were associated with pancreatic carcinoma metastasis and progression and that CD44v6⁺/CD44s⁻ was an independent risk factor affecting survival in pancreatic carcinoma. Therefore, the different expression patterns of CD44v/CD44s may determine pancreatic carcinoma prognosis.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1579257224116287.

Proteomic approach toward personalized sarcoma treatment: lessons from prognostic biomarker discovery in gastrointestinal stromal tumor

Sarcomas range from curable tumors to those causing death via metastasis and recurrence. Thus, there is an urgent need for biomarker identification in order to assess the degree of malignancy, predict prognosis, and evaluate possible therapies. Various proteomic approaches and different clinical materials have been used to this end, and candidate biomarkers have been reported for the different types of sarcomas. However, the sample size used in these biomarker studies was generally insufficient, and thus far, no biomarker has been proved useful in clinics. Given that sarcomas are rare, biomarker validation in this setting is more challenging than in other malignancies. In gastrointestinal stromal tumor, adjuvant therapy has proven to be effective. However, only 40% patients experience metastasis after curative surgery alone, and the rest of the patients may not need adjuvant therapy. Using a proteomic approach, we identified pfetin (potassium channel tetramerization domain containing 12, KCTD 12) as a novel prognostic biomarker for sarcoma, and immunohistochemically confirmed its clinical usefulness by a multiinstitutional validation study. Here, we describe our experience and discuss the critical points in the discovery of this biomarker.

Tissue microarrays: fast-tracking protein expression at the cellular level

Tissue microarrays maximize returns in cellular pathology whilst minimizing the use of cells and tissues. They are made by arraying cores of tissue taken from multiple donor blocks into a single recipient block. Accordingly, the histology and pathology of several hundred tissues can be represented in one tissue microarray that, when stained by immunohistochemistry, provides comprehensive topographic information on protein expression. Used with complimentary techniques, such as complementary DNA microarray analysis, tissue microarrays are providing valuable data for the identification of new markers of disease and assisting in the discovery of therapeutic targets. They are also leading a revolution in cellular pathology as high-throughput technology is introduced to maximize the information provided.

CD44 expression in intraoral salivary ductal papillomas and oral papillary squamous cell carcinoma

CD44 is a transmembrane adhesion molecule which has been previously shown to be useful in the differentiation of benign papillary lesions from invasive carcinoma in several different areas including sinonasal mucosa and breast tissue. CD44 expression has previously been shown to be lost in invasive carcinoma and retained in benign papillary lesions in both of the above locations. In addition, studies have evaluated oral mucosal lesions for CD44 expression and found a loss with invasive squamous cell carcinoma when compared to normal epithelium, hyperplasia, and squamous papillomas, which stained particularly strongly. To the best of our knowledge, no study has evaluated CD44 expression when comparing salivary ductal papillomas in comparison to oral papillary SCCA. In this study 18 cases of intraductal papilloma were compared to 19 cases of oral papillary SCCA. Within the ductal papilloma group, all cases stained either absent (6%), weakly (33%), or moderately (61%) with 76% expressing the stain diffusely and 24% focally. In comparison, the papillary squamous cell carcinoma cases expressed the CD44 moderately (26%) or strongly (74%) with 100 % showing diffuse staining. Thus, the CD44 expression was contrary to expectation based on previous studies, which we hypothesize is due to the extremely well differentiated nature of papillary SCCA which expressed CD44 staining compatible with levels previously reported with oral squamous papillomas than invasive carcinoma.

DcR3 binds to ovarian cancer via heparan sulfate proteoglycans and modulates tumor cells response to platinum with corresponding alteration in the expression of BRCA1

BACKGROUND

Overcoming platinum resistance is a major obstacle in the treatment of Epithelial Ovarian Cancer (EOC). In our previous work Decoy Receptor 3 (DcR3) was found to be related to platinum resistance. The major objective of this work was to define the cellular interaction of DcR3 with EOC and to explore its effects on platinum responsiveness.

METHODS

We studied cell lines and primary cultures for the expression of and the cells ability to bind DcR3. Cells were cultured with DcR3 and then exposed to platinum. Cell viability was determined by MTT assay. Finally, the cells molecular response to DcR3 was studied using real time RT-PCR based differential expression arrays, standard RT-PCR, and Western blot.

RESULTS

High DcR3 in the peritoneal cavity of women with EOC is associated with significantly shorter time to first recurrence after platinum based therapy (p = 0.02). None-malignant cells contribute DcR3 in the peritoneal cavity. The cell lines studied do not secrete DcR3; however they all bind exogenous DcR3 to their surface implying that they can be effected by DcR3 from other sources. DcR3s protein binding partners are minimally expressed or negative, however, all cells expressed the DcR3 binding Heparan Sulfate Proteoglycans (HSPGs) Syndecans-2, and CD44v3. DcR3 binding was inhibited by heparin and heparinase. After DcR3 exposure both SKOV-3 and OVCAR-3 became more resistant to platinum with 15% more cells surviving at high doses. On the contrary CaOV3 became more sensitive to platinum with 20-25% more cell death. PCR array analysis showed increase expression of BRCA1 mRNA in SKOV-3 and OVCAR-3 and decreased BRCA1 expression in CaOV-3 after exposure to DcR3. This was confirmed by gene specific real time PCR and Western blot analysis.

CONCLUSIONS

Non-malignant cells contribute to the high levels of DcR3 in ovarian cancer. DcR3 binds readily to EOC cells via HSPGs and alter their responsiveness to platinum chemotherapy. The paradoxical responses seen were related to the expression pattern of HSPGs available on the cells surface to interact with. Although the mechanism behind this is not completely known alterations in DNA repair pathways including the expression of BRCA1 appear to be involved.

Prognostic significance of PTEN, Ki-67 and CD44s expression patterns in gastrointestinal stromal tumors

AIM: To develop a prognostic approach for gastrointestinal stromal tumors (GISTs) using a cluster of indicators and follow-up information.

METHODS: One hundred and four GISTs that had not been subjected to targeted therapies were collected and classified by NIH risk assessment and anatomic location. By immunohistochemistry, the expressions of PTEN, Ki-67, CD44s matrix metalloproteinase (MMP)-9 and TIMP-1 were detected on tissue microarray. Univariate and multimarker survival analyses were performed and then a COX hazard proportion model was constructed to evaluate a cluster of predictors of GIST.

RESULTS: Our data showed small intestinal GIST are more aggressive than gastric GIST. The NIH risk assessment correlated with disease-free survival for either gastric GIST or small intestinal GIST. Immunohistochemical analysis revealed that Ki-67 labeling indexes (LIs) < 5% predicted higher disease-specific survival (DSS) in gastric and small intestinal GIST. CD44s positivity and PTEN LIs ≥ 50% correlated with higher DSS in gastric GIST. MMP-9 and TIMP-1 had no correlation with survival. Multimarker analysis revealed that the expression pattern of PTEN LIs ≥ 50% combined with Ki-67 LIs < 5% and CD44s positivity reliably predicted favorable outcomes for gastric GIST (P = 0.009), as did the combination of PTEN LIs ≥ 50% and Ki-67 LIs < 5% for small intestinal GIST (P = 0.011). Authors also found that high NIH risk grade was correlated with DSS in patients with gastric GIST and disease-free survival in patients with small intestinal GIST.

CONCLUSION: PTEN LIs ≥ 50%, Ki-67 LIs < 5% and CD44s positivity provides an accurate, favorable prognosis for gastric GIST. PTEN LIs ≥ 50% and Ki-67 LIs < 5% does the same for small intestinal GIST. Ki-67 LIs enhances the NIH assessment.

Cancer stem cells hypothesis and stem cells in head and neck cancers

There is increasing evidence that the growth and spread of cancer is driven by a small subpopulation of cancer cells, defined as cancer stem cells (CSCs). Recent data indicate that the initiation, growth, recurrence and metastasis of cancers are related to the behavior of a small population of malignant cells with properties of stem cells, and information about them are potentially helpful in identifying the target for the tumor's therapeutic elimination. The presence of subpopulation cells with phenotypic and behavioral characteristics corresponding to both normal epithelial stem cells and to cells capable of initiating tumors has been also reported in head and neck squamous cell carcinomas (HNSCCs).

Clinical proteomics identified ATP-dependent RNA helicase DDX39 as a novel biomarker to predict poor prognosis of patients with gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal malignancy of the gastrointestinal tract, comprising a wide spectrum from a curable disorder to highly malignant disease. GIST is characterized by tyrosine kinase mutations, and molecular targeting therapies against these abnormal enzymes require prognostic biomarkers. To identify candidate prognostic biomarkers, we examined proteomic features corresponding to metastasis after surgery. Using two-dimensional difference gel electrophoresis with a large format gel, we compared the primary tumor tissues of GIST patients free of metastasis for two years after surgery (eight cases) with those of patients who developed metastasis within one year after surgery (nine cases). We found the intensities of 38 protein spots to differ significantly between the two groups. Mass spectrometric protein identification revealed that these corresponded to 25 unique genes. Immunohistochemical validation demonstrated ATP-dependent RNA helicase DDX39 to be significantly associated with metastasis and poor clinical outcomes in a group of 72 GIST patients. In conclusion, we have established a novel prognostic utility of ATP-dependent RNA helicase DDX39 in GIST.ATP-dependent RNA helicase DDX39, a novel biomarker for GIST likely to be associated with metastatic disease, can identify patients likely to benefit from new therapeutic strategies such as tyrosine kinase inhibitors.

A genomic approach to investigate expression profiles in Slovenian patients with gastric cancer

Despite its decreasing frequency in developed countries, gastric cancer remains a significant health burden. The aim of the present study was to construct cDNA libraries and analyze differentially expressed genes related to this disease. Gene expression profiles were generated with suppressive subtraction hybridization (SSH). We constructed eight SSH libraries, four representing up-regulated genes and four representing down-regulated genes in tumor tissues. Our approach revealed that several genes are abnormally expressed in gastric cancer. We also identified global deregulation of several pathways involved in the maintenance of normal gastric homeostasis. The results of this study support the view that, as a result of complex pathogenesis, diversity of genomic aberrations and multiplicity of carcinogenic causes, gastric cancer cannot be reduced to a single molecule. Our results may contribute new insight into molecular aspects of the disease and may prove advantageous for future development of therapeutic targets and diagnostic molecular markers.

Role of alternative splicing events in gastric carcinogenesis

Alternative splicing affects many essential biologic processes and is the basis for a number of pathologic conditions, including cancer. Inherited and acquired changes in pre-mRNA splicing have been documented to play a significant role in human disease development. Many cancer-associated genes are regulated by alternative splicing. In this review, we will summarize the evidence supporting the association between alternative splicing and gastric carcinogenesis. The potential significance of alternative splicing events as a target for the diagnosis and treatment of gastric cancer will also be discussed.

Expression of melanoma antigens in epithelioid gastrointestinal stromal tumors: a potential diagnostic pitfall

CONTEXT

Most gastric gastrointestinal stromal tumors (GISTs) express CD117/c-kit, as do a subset of metastatic melanomas, leading to a diagnostic dilemma in some cases.

OBJECTIVE

To further differentiate GISTs from melanoma, we investigated expression of melanoma markers in GISTs using a well-characterized set of gastric lesions on tissue microarrays.

DESIGN

Tissue microarrays from paraffin-embedded tissue cores from 38 patients were stained with S100 protein, HMB-45, and Melan-A antibodies. All cases had been previously stained with CD117/c-kit and CD34 antibodies. All were reactive with CD117/c-kit, and 88.2% expressed CD34.

RESULTS

S100 protein was focally expressed in 2 (5.3%) of 38 GISTs; these lesions lacked HMB-45 and Melan-A labeling. No tumor labeled with HMB-45, but 4 (10.6%) of 38 cases labeled with Melan-A antibodies. The Melan-A-reactive cases were all S100 negative and CD34 positive. The S100-reactive cases were spindle cell neoplasms, whereas the Melan-A-reactive cases were epithelioid neoplasms (4/9; 44%). An additional 15 standard sections of separate cases of epithelioid GISTs were then labeled with Melan-A, and 5 (33%) of 15 showed at least focal labeling.

CONCLUSIONS

Melan-A staining can be encountered in a subset of epithelioid GISTs, a finding that can suggest a differential diagnosis of melanoma. In this series, the Melan-A-reactive cases lacked S100 protein and expressed CD34, both of which would be unlikely in melanoma. As such, a panel approach is best in differentiating epithelioid GISTs from melanoma.

Expression of EGFR in gastric stromal tumors: a clinicopathologic study

Epidermal growth factor receptor (EGFR) plays an important role in cancer biology and offers a promising molecular therapeutic target. The expression profile of EGFR in gastrointestinal stromal tumors (GISTs) is derived from a limited number of small series samples and case reports. We evaluated the involvement of EGFR in human gastric GISTs. Tissue microarray sections representing 33 gastric GISTs with known follow-up were surveyed by immunohistochemistry, using antibodies specific for EGFR. Expression of EGFR was identified in 8/33 (24.2%) cases, and tended to be present in tumors of smaller size (3.69+/-0.66 cm vs. 10.69+/-1.52 cm, P=0.0001), fewer mitoses (3.5+/-1.0/50 high power field vs. 23.44+/-7.61, P=0.0073), and lower necrosis percentages (0% vs. 5.37+/-1.37%, P=0.0003); the expression was more frequently seen in the benign/probably benign category (6/8, 75%, P=0.047), than in gastric GISTs that lacked EGFR expression. Expression showed a trend as a favorable prognostic indicator but did not reach statistical significance, although the number of cases was limited. This observation suggests that EGFR is present in some gastric GISTs, especially in small tumors, and might participate in the growth regulation of human gastric GISTs. Expression of EGFR in some gastric GISTs might be of clinical significance with the recent emergence of EGFR-targeted therapies.

Gastrointestinal stromal tumor in Brazil: clinicopathology, immunohistochemistry, and molecular genetics of 513 cases

The aim of the present study was to evaluate the clinicopathological, immunohistochemical, and molecular genetic features of gastrointestinal stromal tumors in Brazil and compare them with cases from other countries. Five hundred and thirteen cases were retrospectively analyzed. HE-stained sections and clinical information were reviewed and the immunohistochemical expression of CD117, CD34, smooth-muscle actin, S-100 protein, desmin, CD44v3 adhesion molecule, p53 protein, epidermal growth factor receptor, and Ki-67 antigen was studied using tissue microarrays. Mutation analysis of KIT and platelet-derived growth factor receptor-alpha genes was also performed. There was a slight female predominance (50.3%) and the median age at diagnosis was 59 years. The tumors were mainly located in the stomach (38.4%). Immunohistochemistry showed that CD117 was expressed in 95.7% of cases. Epidermal growth factor receptor expression was observed in 84.4% of tumors. p53 protein expression was found only in 2.6% of cases but all belonged to the high-risk group for aggressive behavior according to the National Institutes of Health consensus approach. No CD44v3 adhesion molecule expression was detected. KIT exon 11 mutations were the most frequent (62.2%). The present data confirm that gastrointestinal stromal tumors in Brazilian patients do not differ from tumors occurring in other countries.

Pfetin as a prognostic biomarker of gastrointestinal stromal tumors revealed by proteomics

PURPOSE

We aimed to develop prognostic biomarkers for gastrointestinal stromal tumors (GIST) using a proteomic approach.

EXPERIMENTAL DESIGN

We examined the proteomic profile of GISTs using two-dimensional difference gel electrophoresis. The prognostic performance of biomarker candidates was examined using a large-scale sample set and specific antibodies.

RESULTS

We identified 43 protein spots whose intensity was statistically different between GISTs with good and poor prognosis. Mass spectrometric protein identification showed that the 43 spots corresponded to 25 distinct gene products. Eight of the 43 spots derived from pfetin, a potassium channel protein, and four of the eight pfetin spots had a high discriminative power between the two groups. Western blotting and real-time PCR showed that pfetin expression and tumor metastasis were inversely related. The prognostic performance of pfetin was also examined by immunohistochemistry on 210 GIST cases. The 5-year metastasis-free survival rate was 93.9% and 36.2% for patients with pfetin-positive and pfetin-negative tumors, respectively (P < 0.0001). Univariate and multivariate analyses revealed that pfetin expression was a powerful prognostic factor among the clinicopathologic variables examined, including risk classification and c-kit- or platelet-derived growth factor receptor A mutation status.

CONCLUSIONS

These results establish pfetin as a powerful prognostic marker for GISTs and may provide novel therapeutic strategies to prevent metastasis of GIST.

The epidemiologic, health-related quality of life, and economic burden of gastrointestinal stromal tumours

BACKGROUND AND OBJECTIVES

Gastrointestinal stromal tumours (GIST) are uncommon tumours believed to arise from interstitial cells of Cajal or their precursors in the gastrointestinal (GI) tract, accounting for a small percentage of GI neoplasms and sarcomas. Given the recent recognition of GIST as a distinct cancer, as well as new treatment options available today, a review of the epidemiologic, health-related quality of life (HRQL), and economic burden of GIST is timely from a payer, provider and patient perspective and may provide guidance for treatment decision making and reimbursement.

METHODS

A systematic literature review of PubMed and five scientific meeting databases, was conducted to identify published studies and abstracts describing the epidemiologic, HRQL and economic impact of GIST. Publications deemed worthy of further review, based on the information available in the abstract, were retrieved in full text.

RESULTS AND DISCUSSION

Thirty-four publications met the review criteria: 29 provided data on GIST epidemiology, one provided cost data, three reported HRQL outcomes, and one reported cost and HRQL outcomes. The annual incidence of GIST (cases per million) ranged from 6.8 in the USA to 14.5 in Sweden, with an estimated 5-year survival rate of 45-64%. On the Functional Illness of Chronic Therapy-fatigue instrument, GIST patients scored 40.0 compared with 37.6 in anaemic cancer patients (0 = worst; 52 = least fatigue). Total costs over 10 years for managing GIST patients with molecularly targeted treatment was estimated at pounds 47 521- pounds 56 146 per patient compared with pounds 4047- pounds 4230 per patient with best supportive care.

CONCLUSIONS

The incidence of GIST appears to be similar by country; the lower estimate in one country could be explained by differences in method of case ascertainment. Data suggest that the HRQL burden of GIST is similar to that with other cancers although this requires further exploration. The value of new therapies in GIST needs to consider not only cost but also anticipated benefits and the unmet medical need in this condition.

Increased expression of SRp40 affecting CD44 splicing is associated with the clinical outcome of lymph node metastasis in human breast cancer

BACKGROUND

During the malignant transformation of breast tissues, the pre-mRNA precursor splicing of specific genes can be flexibly regulated, leading to the formation of different forms or amounts of mRNA in response to the cellular microenvironment, and is frequently associated with cell tumorigenesis and may even cause tumor metastasis. Regulation of pre-mRNA splicing by serine-arginine (SR)-rich phosphoprotein is hypothesized to be associated with tumor cell metastasis.

METHODS

We enrolled 55 breast cancer patients (32 with lymph node metastasis; LNM) with paired tissue samples consisting of cancerous and tumor-adjacent normal portions and assayed these tissues for gene expression of the SR family using quantitative real-time RT-PCR (qRT-PCR), then evaluated an association with LNM of breast cancer. Furthermore, we examined whether increased expression of a specific SR gene was associated with the presence of specific CD44 spliced variants using qualitative reverse-transcription PCR (RT-PCR).

RESULTS

Support for our hypothesis came from the observations that breast tumor tissues displayed higher level of SRp40 expression as compared with the paired non-cancerous tissues, which manifested the significant association between increased SRp40 expression and LNM (OR=4.48, 95% CI, 1.08-19.50, P=0.018). In addition, the primary tumors of breast with increased expression of SRp40 gene were associated with the presence of the large CD44 inclusion variants, CD44v2, CD44v3, CD44v5, and CD44v6 (P<0.05).

CONCLUSION

Increased expression of SRp40 can be detected in breast tumor tissues with a high degree of sensitivity, and that higher expression of SRp40 closely correlates with alternative pre-mRNA splicing of CD44, which may serve as an earlier marker in predicting the risk to breast cancer patients of developing LNM.

Significance of CD44 expression in gastrointestinal stromal tumors in relation to disease progression and survival

BACKGROUND

CD44 is a transmembrane glycoprotein belonging to the cell-adhesion molecule family. It has been identified as being involved in tumor progression and metastasis, and its expression has been found to be of prognostic significance in several human malignancies. The aim of this study was to assess CD44 expression in gastrointestinal stromal tumors (GISTs), the most common mesenchymal tumor of the gastrointestinal tract.

METHODS

Between January 1995 and March 2006, 92 patients undergoing surgical resection for GIST in National Cheng Kung University Hospital were evaluated. To study the significance of CD44 expression, immunohistochemical staining of CD44 in tumor specimens was performed, and the clinicopathological information of patients was reviewed.

RESULTS

Fifty-nine of 81 patients (73%) showed positive CD44 expression. Loss of CD44 expression was associated with disease progression (p = 0.019). Kaplan-Meier analysis revealed better progression-free survival among patients with strong CD44 expression (++ and +++) (p = 0.034), absence of disease progression (p < 0.001), and lower risk, according to National Institutes of Health (NIH) Consensus Criteria for GIST risk stratification (p = 0.003). Multivariate analysis demonstrated that high-risk status was the only independent risk factor for disease progression and the only independent predictor for a poor progression-free survival (p = 0.023 and 0.045, respectively).

CONCLUSIONS

It is demonstrated that high-risk status by NIH criteria is significantly associated with disease progression and poor progression-free survival in GIST.

Gastrointestinal stromal tumors: pathology and prognosis at different sites

Gastrointestinal (GI) stromal tumors (GISTs) are the most common mesenchymal tumors specific to the GI tract, generally defined as KIT (CD117)-positive tumors with a characteristic set of histologic features. These tumors, derived from Cajal cells or their precursors, most commonly occur at the age >50 years in the stomach (60%), jejunum and ileum (30%), duodenum (4-5%), rectum (4%), colon and appendix (1-2%), and esophagus (<1%), and rarely as apparent primary extragastrointestinal tumors in the vicinity of stomach or intestines. Their overall incidence has been estimated as 10 to 20 per million, including incidental minimal tumors. GISTs are rare in children (<1%) and almost exclusively occur in stomach. They are common in patients with neurofibromatosis 1, who have a predisposition to (multiple) small intestinal GISTs. GISTs contain a spectrum from minute indolent tumors to sarcomas at all sites of occurrence. Their gross patterns are diverse, including nodular, cystic, and diverticular tumors. External involvement of pancreas and liver can simulate primary tumor in these organs. In general, gastric tumors have a more favorable prognosis than the intestinal ones with similar parameters. Gastric GISTs < or =10 cm and < or =5 mitoses per 50 HPFs have a low risk for metastasis, whereas those with >5 per 50 HPFs and >5 cm in diameter have a high risk for metastasis. In contrast, all intestinal GISTs >5 cm independent of mitotic rate have at least moderate risk for metastases, and all >5 mitoses per 50 HPFs have a high risk for metastases. Intestinal GISTs < or =5 cm with < or =5 mitoses per 50 HPFs have a low risk for metastases. Gastric GISTs can be divided into histologic subgroups including 4 spindle cell and 4 epithelioid variants. Intestinal GISTs are a histologically more homogeneous group and often contain distinctive extracellular collagen globules, skeinoid fibers. Immunohistochemical demonstration of KIT, CD34, or protein kinase theta positivity helps to properly identify these tumors.

Gastrointestinal stromal tumours overexpress fatty acid synthase

Fatty acid synthase (FASN), a key enzyme for de novo lipogenesis, is overexpressed in many malignant tumours and is associated with aggressive biological behaviour. FASN expression and its possible relationship with more aggressive behaviour in gastrointestinal stromal tumours (GISTs) have not been addressed to date. Here, FASN expression was assessed by immunohistochemistry in 60 primary GISTs (28 low/intermediate risk and 32 high risk) and seven metastatic GISTs. Sixteen smooth muscle gastrointestinal tumours were used as controls. FASN was overexpressed in 36 of 60 GISTs (60%): in 12 of 28 (42%) low/intermediate-risk GISTs and in 24 of 32 (75%) high-risk GISTs (p<0.05). Two primary and seven metastatic GISTs and five GIST cell lines (GIST882, GIST430, GIST522, GIST62, and GIST48), analysed by western blot, showed variable FASN expression. Most metastatic samples expressed high levels of FASN protein. Additionally, seven of 60 GISTs showed a proliferation rate higher than 10% by Ki67 and all of them expressed FASN (p<0.04). Finally, proliferation and apoptosis were investigated after FASN silencing in GIST882 cells, which displayed the highest FASN expression. siRNA-mediated FASN knock-down inhibited expression of the proliferation marker cyclin A, whereas no changes in p27 and cleaved PARP expression were seen. It is concluded that FASN is preferentially overexpressed in high-risk and metastatic GISTs, and that its overexpression likely contributes to cell proliferation.

[Gastrointestinal stromal tumors: definition, histological, immunohistochemical, and molecular features, and diagnostic strategy]

Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal tumors of the gastrointestinal tract. Major advances in their definition and classification and the understanding of their molecular mechanisms have recently been made. These advances have resulted in the delineation of a treatment that has become a model of targeted therapy in oncology. GISTs are defined as tumors of the gastrointestinal tract, but also of the mesentery and peritoneum, constituted by a proliferation of usually spindle-shaped, rarely epithelioid cells, usually, but not consistently expressing the KIT protein. Most GISTs are associated with molecular abnormalities in two target genes: KIT (which encodes the KIT protein) and PDGFRA (which encodes the A chain of the PDGF receptor). The diagnosis of GIST relies on histological arguments (proliferation of spindle-shaped cells in 70% of cases, of epithelioid cells in 20%; histological variants are rare and sometimes misleading) and on immunohistochemical arguments (expression of KIT in 95%, usually associated with CD34 expression in 60%-70% of cases). The demonstration of mutations in target genes is required only in cases that are histologically suggestive but KIT-negative; beyond this indication, this is only undertaken in research protocols. The differential diagnosis of GIST includes the other mesenchymal tumors of the gastrointestinal tract, such as leiomyomas and leiomyosarcomas, and the digestive locations of some sarcomas; it relies on both histological and immunohistochemical arguments. The evaluation of the prognosis is essential. According to the current concept, every GIST carries a risk of malignancy, which may vary from very low to very high. Prognosis is based on a simple algorithm using two histoprognostic parameters, i.e., tumor size and mitotic index. The treatment of localized GIST is surgical resection, which must be complete; that of advanced or unresectable GIST is based on the use of a targeted therapy, imatinib, which is a pharmacological antagonist of the KIT protein. Proper understanding and utilisation of the diagnostic criteria and classification of GIST by pathologists are essential for good patient management.

Expression and significance of CD44s, CD44v6, and nm23 mRNA in human cancer

AIM: To investigate the relationship between the expression levels of nm23 mRNA, CD44s, and CD44v6, and oncogenesis, development and metastasis of human gastric adenocarcinoma, colorectal adenocarcinoma, intraductal carcinoma of breast, and lung cancer.

METHODS: Using tissue microarray by immu-histochemical (IHC) staining and in situ hybri-dization (ISH), we examined the expression levels of nm23 mRNA, CD44s, and CD44v6 in 62 specimens of human gastric adenocarcinoma and 62 specimens of colorectal adenocarcinoma; the expression of CD44s and CD44v6 in 120 specimens of intraductal carcinoma of breast and 20 specimens of normal breast tissue; the expression of nm23 mRNA in 72 specimens of human lung cancer and 23 specimens of normal tissue adjacent to cancer.

RESULTS: The expression of nm23 mRNA in the tissues of gastric and colorectal adenocarcinoma was not significantly different from that in the normal tissues adjacent to cancer (P>0.05), and was not associated with the invasion of tumor and the pathology grade of adenocarcinoma (P>0.05). However, the expression of nm23 mRNA was correlated negatively to the lymph node metastasis of gastric and colorectal adenocarcinoma (r = -0.49, P<0.01; r = -4.93, P<0.01). The expression of CD44s in the tissues of gastric and colorectal adenocarcinoma was significantly different from that in the normal tissues adjacent to cancer (P<0.05; P<0.01). CD44v6 was expressed in the tissues of gastric and colorectal adenocarcinoma only, the expression of CD44v6 was significantly associated with the lymph node metastasis, invasion and pathological grade of the tumor (r = 0.47, P<0.01; r = 5.04, P<0.01). CD44s and CD44v6 were expressed in intraductal carcinoma of breast, the expression of CD44s and CD44v6 was significantly associated with lymph node metastases and invasion (P<0.01). However, neither of them was expressed in the normal breast tissue. In addition, the expression of CD44v6 was closely related to the degree of cell differentiation of intraductal carcinoma of breast (χ² = 5.68, P<0.05). The expressional level of nm23 mRNA was closely related to the degree of cell differentiation (P<0.05) and lymph node metastasis (P<0.01), but the expression of nm23 gene was not related to sex, age, and type of histological classification (P>0.05).

CONCLUSION: Patients with overexpression of CD44s and CD44v6 and low expression of nm23 mRNA have a higher lymph node metastatic rate and invasion. In addition, overexpression of CD44v6 is closely related to the degree of cell differentiation. Detection of the three genes is able to provide a reliable index to evaluate the invasion and metastasis of tumor cells.

Endothelial adhesion of synchronized gastric tumor cells changes during cell cycle transit and correlates with the expression level of CD44 splice variants

AIM: To study adhesion capacity and CD44 expression of human gastric adenocarcinoma MKN45 cells at different stages of a first cell cycle.

METHODS: MKN45 cells were synchronized by aphidicolin and assayed for adhesion to an endothelial cell (HUVEC) monolayer. Surface expression of CD44 and CD44 splice variants on MKN45 cells was evaluated by flow cytometry. Functional relevance of CD44 adhesion receptors was investigated by blocking studies using anti CD44 monoclonal antibodies or by hyaluronan digestion.

RESULTS: Adhesion of MKN45 to HUVEC was increased during G2/M transit, after which adhesion returned to baseline levels with cell cycle completion. In parallel, CD44 splice variants CD44v4, CD44v5, and CD44v7 were all up-regulated on MKN45 during cell cycle progression with a maximum effect in G2/M. The function of CD44 surface receptors was assessed with specific receptor blocking monoclonal antibodies or removal of hyaluronan by digestion with hyaluronidase. Both strategies inhibited tumor cell adhesion to HUVEC by nearly 50%, which indicates that MKN45-HUVEC-interaction is CD44 dependent.

CONCLUSION: CD44 expression level is linked to the cell cycle in gastrointestinal tumor cells, which in turn leads to cell cycle dependent alterations of their adhesion behaviour to endothelium.

CD44 expression is associated with increased survival in node-negative invasive breast carcinoma

PURPOSE

CD44 is a multifunctional cell surface receptor with many known splice variants, some of which have been reported to play a role in tumor progression. The purpose of this study was to evaluate the prognostic significance of CD44 isoforms in early-stage, lymph node-negative invasive breast carcinoma.

EXPERIMENTAL DESIGN

Immunohistochemical staining for CD44 isoforms was done on archival paraffin tissue sections of invasive breast carcinoma from a cohort of lymph node-negative patients who received no adjuvant tamoxifen or chemotherapy and who had a mean clinical follow-up period of 15 years. Immunohistochemical staining was done with antibodies to CD44s, the standard isoform of CD44, and to isoforms containing variant exon 6 (CD44v6); levels of staining were correlated with clinical outcome data.

RESULTS

There was a trend towards increased disease-free survival for patients whose tumors had high anti-CD44s positivity (P = 0.05), and a significant association was observed between anti-CD44s positivity and disease-related survival (P = 0.04). Expression of CD44v6 isoforms did not correlate with clinical outcome.

CONCLUSION

CD44 expression, as assessed by immunohistochemical staining with anti-CD44s, may be a favorable prognostic factor in patients with node-negative invasive breast carcinoma.

Down-regulation of CD9 in human ovarian carcinoma cell might contribute to peritoneal dissemination: morphologic alteration and reduced expression of beta1 integrin subsets

Peritoneal dissemination is one of the main causes of death in cancer patients. Pathophysiology of metastasis has been well investigated, but the mechanism of diffuse spread of tumor colonies in the peritoneal cavity is not fully understood. CD9 is a member of tetraspanin and its down-regulation is known to be involved in poor prognosis. To investigate the significance of the down-regulation of CD9, HTOA, an ovarian carcinoma cell line that highly expressed CD9, was transiently transfected with small interfering RNA (siRNA) against CD9, and CD9-negative cells (HTOA(CD9-)) were purified. HTOA(CD9-) showed altered adhesion patterns on Matrigel, collagen, fibronectin, and laminin compared with those of control siRNA-transfected HTOA (control-HTOA). Flow cytometry and fluorescence cytostainings revealed that the expression levels of integrins beta1, alpha2, alpha3beta1, alpha5, and alpha6 were lower in HTOA(CD9-) than those of control-HTOA. HTOA(CD9-) showed altered expression of junctional and cytoskeletal molecules. By time-lapse video microscopy, control-HTOA showed solid adhesion to extracellular matrix and formed cobblestone pattern, whereas HTOA(CD9-) showed weaker adhesion and were distributed as diffuse spots. To examine whether the expression level of CD9 change during tumor dissemination, HTOA-P, a highly disseminative subclone of HTOA, was established. HTOA-P showed distinctive down-regulation of CD9 at mRNA and protein levels, and showed similar morphologic alteration as HTOA(CD9-) did. These findings indicate that the down-regulation of CD9 may be an acquired event in the process of tumor dissemination. Down-regulated CD9 may attenuate the expression of several integrins and rearrange junctional and cytoskeletal molecules that might contribute to dissemination of ovarian carcinomas.

Endosonographic diagnosis of recurrent gastrointestinal stromal tumors associated with Carney's syndrome

This is a report of a patient who manifests all of the features of Carney's syndrome, including gastrointestinal stromal tumors (GISTs), extra-adrenal paragangliomas, and pulmonary chondromas. The patient underwent surgical resection of a gastric GIST; a retroperitoneal, nonfunctional paraganglioma; and a mediastinal, catecholamine-secreting paraganglioma (pheochromocytoma). Recently, new gastric GISTs were diagnosed by endoscopic, ultrasound-guided, fine-needle aspiration (EUS-FNA) biopsy and were resected. Recurrence of stromal tumors following complete resection is common in Carney's syndrome and presents considerable management challenges. This case illustrates several important points: (1) Carney's syndrome, although rare, should be considered in patients with foregut GISTs; (2) GISTs associated with Carney's syndrome, like sporadic gastric GISTs, may have a more indolent clinical course; and (3) EUS-FNA may be useful for the diagnosis and management of GISTs in this syndrome.