Expression of calcium-binding proteins S100A2 and S100A4 in Barrett's adenocarcinomas

Differential Expression of NEK Kinase Family Members in Esophageal Adenocarcinoma and Barrett's Esophagus

The incidence of esophageal adenocarcinoma (EAC) has risen rapidly during the past four decades, making it the most common type of esophageal cancer in the USA and Western countries. The NEK (Never in mitosis A (NIMA) related kinase) gene family is a group of serine/threonine kinases with 11 members. Aberrant expression of NEKs has been recently found in a variety of human cancers and plays important roles in tumorigenesis, progression, and drug-resistance. However, the expression of the NEKs in EAC and its precancerous condition (Barrett's esophagus, BE) has not been investigated. In the present study, we first analyzed the TCGA and 9 GEO databases (a total of 10 databases in which 8 contain EAC and 6 contain BE) using bioinformatic approaches for NEKs expression in EAC and BE. We identified that several NEK members, such as NEK2 (7/8), NEK3 (6/8), and NEK6 (6/8), were significantly upregulated in EAC as compared to normal esophagus samples. Alternatively, NEK1 was downregulated in EAC as compared to the normal esophagus. On the contrary, genomic alterations of these NEKs are not frequent in EAC. We validated the above findings using qRT-PCR and the protein expression of NEKs in EAC cell lines using Western blotting and in primary EAC tissues using immunohistochemistry and immunofluorescence. Our data suggest that frequent upregulation of NEK2, NEK3, and NEK7 may be important in EAC.

Influence of S100A2 in Human Diseases

S100 proteins are a family of low-molecular-weight proteins characterized by two calcium-binding sites with a helix-loop-helix (“EF-hand-type”) domain. The S100 family of proteins is distributed across various organs and can interact with diverse molecules. Among the proteins of the S100 family, S100 calcium-binding protein A2 (S100A2) has been identified in mammary epithelial cells, glands, lungs, kidneys, and prostate gland, exhibiting various physiological and pathological actions in human disorders, such as inflammatory diseases and malignant tumors. In this review, we introduce basic knowledge regarding S100A2 regulatory mechanisms. Although S100A2 is a tumor suppressor, we describe the various influences of S100A2 on cancer and inflammatory diseases.

Pediatric Patient With Concurrent Eosinophilic Esophagitis, Erosive Reflux Esophagitis, and Barrett's Esophagus

Eosinophilic esophagitis and Barrett's esophagus are believed to be separate disease processes, with erosive esophagitis leading to Barrett's esophagus. We report a rare case of concurrent diagnoses in a pediatric patient and examine the relevant genetic profiles in the esophagus.

Targeting AXL and RAGE to prevent geminin overexpression-induced triple-negative breast cancer metastasis

Dissemination of metastatic precursors from primaries is the primary reason for patient death. Dissemination encompasses tumor cells invasion of stroma, followed by intravasation through the endothelium barrier into the bloodstream. Here, we describe how geminin-overexpressing tumor cells acquire dissemination ability. Acetylated HMGB1 (Ac-HMGB1) secreted by geminin-overexpressing cells activates RAGE and CXCR4 expression on mesenchymal stem cells (MSCs) located in tumor stroma. Through secreting CXCL12, geminin-overexpressing cells recruit these CXCR4⁺-MSCs into the tumor. Within the tumor, MSCs differentiate into S100A4-secreting cancer-associated fibroblasts (CAFs). S100A4, in a reciprocal manner, activates geminin-overexpressing cells to secrete CCL2 that recruits M0-macrophages from the stroma into the tumor. Within the tumor, CCL2 polarizes M0-macrophages into Gas6-secreting M2-tumor-associated macrophages (M2-TAMs). In concert, geminin-overexpression, S100A4/RAGE and Gas6/AXL signaling promote the invasive and intravasation abilities in geminin-overexpressing cells through exacerbating their stemness and epithelial-to-mesenchymal phenotypes and enhancing expression and functional interaction of CD151 and α3β1-integrin in geminin-overexpressing cells. Tumors formed following injection of geminin-overexpressing cells admixed with MSCs/CAFs grew faster, metastasized earlier, especially to lungs, and were extremely sensitive to anti-c-Abl, anti-RAGE, and anti-AXL drugs. These data support an intrinsic ability in geminin-overexpressing tumor cells to promote their metastatic potential through recruitment and bi-directional interactions with MSCs/CAFs and M2-TAMs.

A review of S100 protein family in lung cancer

S100 protein family, representing 25 relatively small calcium binding proteins, has been reported to be involved in multiple stages of tumorigenesis and progression. These proteins are considered having potential value to be adopted as novel biomarkers in the detection and accurate prediction of many kinds of tumors, including lung cancer. As the one having the highest morbidity and mortality among all cancers, lung carcinoma is still occult for detection, especially at early stage. S100 proteins take participation in the lung neoplasia through playing intracellular and/or extracellular functions, therefore getting involved in a variety of biological processes such as differentiation, proliferation, and migration. A few members have also been testified to modulate TGF-β/Smad-3 mediated transcriptional activity of target genes involved in tumor promotion. In addition to that, a number of proteins in this family have already been reported to experience an abnormal trend in lung cancer at cell, serum and tissue levels. Thus, S100 proteins may serve as effective biomarkers for suspected or already diagnosed lung cancer patients. In future, S100 protein family might be applied as therapeutic targets in clinical treatment of lung cancer. In this review, we firstly summed up the biological and clinical evidence connecting S100 proteins and lung cancer, which has not been summarized before.

Role of S100 Proteins in Colorectal Carcinogenesis

The family of S100 proteins represents 25 relatively small (9-13 kD) calcium binding proteins. These proteins possess a broad spectrum of important intracellular and extracellular functions. Colorectal cancer is the third most common cancer in men (after lung and prostate cancer) and the second most frequent cancer in women (after breast cancer) worldwide. S100 proteins are involved in the colorectal carcinogenesis through different mechanisms: they enable proliferation, invasion, and migration of the tumour cells; furthermore, S100 proteins increase angiogenesis and activate NF-κβ signaling pathway, which plays a key role in the molecular pathogenesis especially of colitis-associated carcinoma. The expression of S100 proteins in the cancerous tissue and serum levels of S100 proteins might be used as a precise diagnostic and prognostic marker in patients with suspected or already diagnosed colorectal neoplasia. Possibly, in the future, S100 proteins will be a therapeutic target for tailored anticancer therapy.

Whole Exome- and mRNA-Sequencing of an AT/RT Case Reveals Few Somatic Mutations and Several Deregulated Signalling Pathways in the Context of SMARCB1 Deficiency

Background. AT/RTs are rare aggressive brain tumours, mainly affecting young children. Most cases present with genetic inactivation of SMARCB1, a core member of the SWI/SNF chromatin-remodeling complex. We have performed whole exome- and mRNA-sequencing on an early onset AT/RT case for detection of genetic events potentially contributing to the disease. Results. A de novo germline variant in SMARCB1, c.601C>T p.Arg201^∗, in combination with somatic deletion of the healthy allele is likely the major tumour causing event. Only seven somatic small scale mutations were discovered (hitting SEPT03, H2BFM, ZIC4, HIST2H2AB, ZIK1, KRTAP6-3, and IFNA8). All were found with subclonal allele frequencies (range 5.7–17%) and none were expressed. However, besides SMARCB1, candidate genes affected by predicted damaging germline variants that were expressed were detected (KDM5C, NUMA1, and PCM1). Analysis of differently expressed genes revealed many dysregulated pathways in the tumour, such as cell cycle, CXCR4 pathway, GPCR-signalling, and neuronal system. FGFR1, CXCR4, and MDK were upregulated and may represent possible drug targets. Conclusion. The loss of SMARCB1 function leads to AT/RT development and deregulated genes and pathways. Additional predisposing events may however contribute. Studies utilizing NGS technologies in larger cohorts will probably identify recurrent genetic and epigenetic alterations and molecular subgroups with implications for clinical practice and development of targeted therapies.

Epigenetic silencing of S100A2 in bladder and head and neck cancers

S100A2, a member of the S100 protein family, is known to be downregulated in a number of human cancers, leading to its designation as a potential tumor suppressor gene. Here, we investigated the expression and methylation status of S100A2 in head&neck and bladder cancer. Reduced mRNA and protein expression was observed in 8 head&neck and bladder cancer cell lines. To explore the mechanism responsible for the downregulation of S100A2, we treated six cell lines with 5-aza-2'-deoxycytidine. We found S100A2 is silenced in association with aberrant promoter-region methylation and its expression is restored with 5-aza-2'-deoxycytidine treatment. Of 31 primary head&neck cancer cases and 31 bladder cancer cases, promoter methylation was detected in 90% and 80% of cases, respectively. Interestingly, only 1/9 of normal head&neck tissues and 2/6 of normal bladder tissues showed promoter methylation. S100A2 promoter methylation can be detected in urine and is more frequent in bladder cancer patients than in healthy subjects (96% vs 48% respectively). Moreover, increased methylation of S100A2 is linked to the progression of the tumor in bladder cancer (p<0.01). Together, this data shows that methylation-associated inactivation of S100A2 is frequent and may be an important event in the tumorigenesis of head&neck and bladder cancer.

S100A2 protein and non-small cell lung cancer. The dual role concept

S100A2 is a member of the EF-hand motif family S100. Its role has been recently implicated in carcinogenesis and metastasis. Although its precise role in NSCLC patients is debated and conflicting results have been published, it has been associated with patient survival. S100A2 expression was downregulated in some studies while others disagree that S100A2 is strongly expressed in lung cancer. It has been recently published by Hountis et al. that there is a significant association between nuclear S100A2 positivity and better disease-free interval. Intensity of expression was the highest in the early and advanced stages, and equally distributed in the middle stages. This is indicative for a dual role of this protein in carcinogenesis. The expression of S100A2 in operable NSCLC varies widely, and this differential location and expression pattern (nuclear or cytoplasmic or both) seem to correlate with prognosis. The precise role for the movement of S100A2 protein between cytoplasm and nucleus is still unclear. We present here a literature review, and we propose the dual concept on its substantial role as a prognostic or predictive indicator in this unfavorable group of patients.

S100 protein family in human cancer

S100 protein family has been implicated in multiple stages of tumorigenesis and progression. Among the S100 genes, 22 are clustered at chromosome locus 1q21, a region frequently rearranged in cancers. S100 protein possesses a wide range of intracellular and extracellular functions such as regulation of calcium homeostasis, cell proliferation, apoptosis, cell invasion and motility, cytoskeleton interactions, protein phosphorylation, regulation of transcriptional factors, autoimmunity, chemotaxis, inflammation and pluripotency. Many lines of evidence suggest that altered expression of S100 proteins was associated with tumor progression and prognosis. Therefore, S100 proteins might also represent potential tumor biomarkers and therapeutic targets. In this review, we summarize the evidence connecting S100 protein family and cancer and discuss the mechanisms by which S100 exerts its diverse functions.

Distribution of lymphocyte subpopulations in thyroid glands of human autoimmune thyroid disease

BACKGROUND

The autoimmune thyroid disease (AITD) is an organ-specific autoimmune disease characterized by the breakdown of self-tolerance to thyroid antigens. Some lymphocytes have been identified to be related notably to the pathogenesis of AITD. This article evaluated the distribution of the lymphocytic subpopulation in thyroid glands in order to develop the immunospecific forms of therapy for AITD.

METHODS

Damaged thyroid specimens were obtained from 18 Graves' disease (GD) and 17 Hashimoto's thyroiditis (HT) patients. Normal thyroid specimens were obtained from unaffected glands of 17 patients who underwent parathyroidectomy. We evaluated the distribution of lymphocytic subpopulation by analyzing the expression difference and correlationship among CD4+ T lymphocyte, CD8+ T lymphocyte, CD20+ B lymphocyte as well as regulatory T cells(Tregs)' marker FoxP3 in the thyroid tissues via immunohistochemistry.

RESULTS

Our research uncovered that no distinct lymphocyte infiltrated in the normal thyroid specimens. Scarcely any lymphocyte infiltration could be found in half of the totally 18 GD thyroid specimens. For the rest 9 GD specimens, CD8+ T cells and CD20+ B cells were expressed more or less in all of them, FoxP3+ Tregs were detected in 7 of them and CD4+ T cells were weakly expressed in only 2 of them. For the 17 HT thyroid specimens, CD20+ B cells were stained strongly in all of them, CD4+, CD8+ T cells were expressed more or less in most of them and FoxP3+ Tregs could be detected in 9 of them.

CONCLUSION

Based on CD20+ B cells predominantly infiltrating in all HT thyroid tissues we suggested CD20 antibody might be of help for HT treatment. Furthermore based on FoxP3+ Tregs abundantly infiltrating in some of the AITD thyroid specimens, we considered that activating the Tregs' function in comparison to increasing the Tregs' number only, may be a more effective approach to the treatment of AITD in some cases.

Overexpression of S100A4 is closely associated with the progression and prognosis of gastric cancer in young patients

The aim of this study was to determine the correlation of S100A4 expression with the progression, prognosis and clinical pathology of gastric cancer (GC) in young pateints. A total of 85 tumor tissues with corresponding adjacent normal tissues and 62 non-metastatic lymph nodes (LNs) with corresponding metastatic LNs were obtained from young GC patients (<40 years old) who underwent surgery between January 2001 and December 2006. The expression of S100A4 was detected by RT-PCR and immunohistochemistry. Differences in the expression of S100A4 mRNA or protein were observed among the GC tissues, matched normal gastric mucosa, non-metastatic LNs and metastatic LNs. The expression of S100A4 mRNA and protein in GC tissues and metastatic LNs was significantly higher compared with that in the matched normal gastric mucosa and non-metastatic LNs, respectively (P<0.05). The overexpression of S100A4 was significantly associated with parameters involved in tumor progression and poor prognosis, including tumor size (P=0.017), Lauren classification (P=0.002), histological classification (P= 0.010), histological differentiation (P= 0.000), Borrmann classification (P=0.020), tumor-node-metastasis (TNM) stage (P=0.000), LN metastasis (P=0.000) and distant metastasis (P=0.024). Multivariate analysis suggested that patient age (P=0.035), tumor size (P=0.002), TNM stage (P=0.001) and S100A4 upregulation (P=0.000) were independent prognostic indicators for the disease. The overexpression of S100A4 in young GC patients is significantly associated with the clinicopathological characteristics. S100A4 may be used as a biomarker to predict the progression and poor prognosis of GC in young patients.

Clinical significance of altered S100A2 expression in gastric cancer

The S100A2 gene has been reported to be a putative tumor‑suppressor gene. Nevertheless, overexpression of S100A2 has been found in certain types of cancer. This study investigated S100A2 expression in tissue specimens of gastritis, intestinal metaplasia, adenomatous dysplasia and gastric cancer to determine its association with clinical features. A serial of tissue samples (gastritis, intestinal metaplasia, adenomatous dysplasia and gastric cancer samples) were used for quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), western blotting and immunohistochemical analyses of S100A2 expression. The data revealed that there was a gradual loss of S100A2 expression from gastritis, intestinal metaplasia and dysplasia to cancer tissue specimens (p<0.001). In gastric cancer samples, loss of S100A2 expression was associated with increased tumor size, depth of invasion, lymph node metastasis and a poor prognosis (p<0.001). However, the intestinal type of gastric cancer expressed more S100A2 protein than the diffuse type (p<0.001). In conclusion, data from the present study demonstrated that loss of S100A2 expression contributes to gastric cancer development and progression; therefore, the determination of S100A2 expression levels may help to predict the carcinogenesis and aggressiveness of gastric cancer as well as patient survival.

S100A4 in esophageal cancer: Is this the one to blame?

Metastasis is the main reason for cancer-related death. S100A4 is one of the key molecules involved in this event. Several studies have shown that overexpression of S100A4 in non-metastatic cancer cells can make them become metastatic, and knockdown of S100A4 in metastatic cancer cells can curtail their invasive nature. A study by Chen et al^[2] published in the World J Gastroenterol 18(9): 915-922, 2012 is a typical example. This study showed in vitro and in vivo evidence that S100A4 expression level determines the invasiveness of esophageal squamous carcinoma. Considering the fact that more than half of the cancer-related deaths are caused by malignancies derived from the digestive system and esophageal cancer is the 4th top contributor to this fraction, this study warrants more attention.

Frequent S100A4 Expression with Unique Splicing Pattern in Gastric Cancers: A Hypomethylation Event Paralleled with E-cadherin Reduction and Wnt Activation

S100A4 promotes cancer metastasis, but its overall status and splicing manner during gastrocarcinogenesis remains less known. We therefore examined S100A4 frequencies, splicing pattern(s) and the underlying reason(s) for S100A4 expression in gastric cancers. Immunohistochemistry revealed frequent S100A4 expression in intestinal gastric cancers (37/45; 82%) and diffuse gastric cancers (12/20; 60%), but uncommon in noncancerous epithelia (0/12), chronic gastritis (2/24; 8%), and intestinal metaplasia (3/15; 20%). Of 65 primary tumors, 18 were found with focal S100A4 expression, while their LN metastases showed homogenous distribution. S100A4-oriented reverse transcription-polymerase chain reaction yielded a transcript containing exons 1, 3, and 4 (AS1) in 20% of noncancerous, 84% premalignant, and 92% tumor tissues and a transcript harboring exons 1 to 4 (AS2) in 65% of gastric cancers (GCs), 26% premalignant but none in noncancerous tissues. Further analyses found AS1 expression in stromal but not epithelial cells of premalignant tissues, absence of AS2 in endoscopic inflammatory mucosa, and the coexistence of AS1/AS2 in the cultured fibroblasts. Methylation DNA sequencing revealed hypermethylation of four critical CpG sites within S100A4 intron first among S100A4-negative gastric tissues and hypomethylation in S100A4-expressing GC tissues/cell lines. E-cadherin reduction and Wnt activation were common in gastric cancers, which were closely correlated but unnecessarily overlapped with S100A4 expression. Our findings suggest that S100A4 expression is closely related with GC formation, which, as a hypomethylation event, is accompanied with E-cadherin reduction and Wnt activation. The preferential S100A4 AS2 expression in GC cells would have potential values in GC surveillance and prognostic assessment.

S100A4 over-expression underlies lymph node metastasis and poor prognosis in colorectal cancer

AIM: To develop lymph node metastasis (LNM)-associated biomarkers for colorectal cancer (CRC) using quantitative proteome analysis.

METHODS: Differences in protein expression between primary CRC with LNM (LNM CRC) and without LNM (non-LNM CRC) were assessed using methyl esterification stable isotope labeling coupled with 2D liquid chromatography followed by tandem mass spectrometry (2D-LC-MS/MS). The relationship to clinicopathological parameters and prognosis of candidate biomarkers was examined using an independent sample set.

RESULTS: Forty-three proteins were found to be differentially expressed by at least 2.5-fold in two types of CRC. S100A4 was significantly upregulated in LNM CRC compared with non-LNM CRC, which was confirmed by Western blotting, immunohistochemistry and real-time quantitative polymerase chain reaction. Further immunohistochemistry on another 112 CRC cases showed that overexpression of S100A4 frequently existed in LNM CRC compared with non-LNM CRC (P < 0.001). Overexpression of S100A4 was significantly associated with LNM (P < 0.001), advanced TNM stage (P < 0.001), increased 5-year recurrence rate (P < 0.001) and decreased 5-year overall survival rate (P < 0.001). Univariate and multivariate analyses indicated that S100A4 expression was an independent prognostic factor for recurrence and survival of CRC patients (P < 0.05).

CONCLUSION: S100A4 might serve as a powerful biomarker for LNM and a prognostic factor in CRC.

t-DARPP regulates phosphatidylinositol-3-kinase-dependent cell growth in breast cancer

Background

Recent reports have shown that t-DARPP (truncated isoform of DARPP-32) can mediate trastuzumab resistance in breast cancer cell models. In this study, we evaluated expression of t-DARPP in human primary breast tumors, and investigated the role of t-DARPP in regulating growth and proliferation in breast cancer cells.

Results

Quantitative real time RT-PCR analysis using primers specific for t-DARPP demonstrated overexpression of t-DARPP in 36% of breast cancers (13/36) as opposed to absent to very low t-DARPP expression in normal breast tissue (p < 0.05). The mRNA overexpression of t-DARPP was overwhelmingly observed in ductal carcinomas, including invasive ductal carcinomas and intraductal carcinomas, rather than other types of breast cancers. The immunohistochemistry analysis of DARPP-32/t-DARPP protein(s) expression in breast cancer tissue microarray that contained 59 tumors and matched normal tissues when available indicated overexpression in 35.5% of primary breast tumors that were more frequent in invasive ductal carcinomas (43.7%; 21/48). In vitro studies showed that stable overexpression of t-DARPP in MCF-7 cells positively regulated proliferation and anchorage-dependent and -independent growth. Furthermore, this effect was concomitant with induction of phosphorylation of AKT^ser473 and its downstream target phospho^ser9 GSK3β, and increased Cyclin D1 and C-Myc protein levels. The knockdown of endogenous t-DARPP in HCC1569 cells led to a marked decrease in phosphorylation of AKTs^ser473 and GSK3β^ser9. The use of PI3K inhibitor LY294002 or Akt siRNA abrogated the t-DARPP-mediated phosphorylation of AKT^ser473 and led to a significant reduction in cell growth.

Conclusions

Our findings underscore the potential role of t-DARPP in regulating cell growth and proliferation through PI3 kinase-dependent mechanism.

S100A2 in cancerogenesis: a friend or a foe?

Owing to the exceptional intracellular distribution and the heterogeneous expression pattern during transformation and metastasis in various tumors, the EF-hand calcium-binding protein S100A2 attracts increasing attention. Unlike the majority of S100 proteins, S100A2 expression is downregulated in many cancers and the loss in nuclear expression has been associated with poor prognosis. On the other hand, S100A2 is upregulated in some cancers. This mini review highlights the general characteristics of S100A2 and discusses recent findings on its putative functional implication as a suppressor or promoter in cancerogenesis.

Accurate molecular classification of cancer using simple rules

BACKGROUND

One intractable problem with using microarray data analysis for cancer classification is how to reduce the extremely high-dimensionality gene feature data to remove the effects of noise. Feature selection is often used to address this problem by selecting informative genes from among thousands or tens of thousands of genes. However, most of the existing methods of microarray-based cancer classification utilize too many genes to achieve accurate classification, which often hampers the interpretability of the models. For a better understanding of the classification results, it is desirable to develop simpler rule-based models with as few marker genes as possible.

METHODS

We screened a small number of informative single genes and gene pairs on the basis of their depended degrees proposed in rough sets. Applying the decision rules induced by the selected genes or gene pairs, we constructed cancer classifiers. We tested the efficacy of the classifiers by leave-one-out cross-validation (LOOCV) of training sets and classification of independent test sets.

RESULTS

We applied our methods to five cancerous gene expression datasets: leukemia (acute lymphoblastic leukemia [ALL] vs. acute myeloid leukemia [AML]), lung cancer, prostate cancer, breast cancer, and leukemia (ALL vs. mixed-lineage leukemia [MLL] vs. AML). Accurate classification outcomes were obtained by utilizing just one or two genes. Some genes that correlated closely with the pathogenesis of relevant cancers were identified. In terms of both classification performance and algorithm simplicity, our approach outperformed or at least matched existing methods.

CONCLUSION

In cancerous gene expression datasets, a small number of genes, even one or two if selected correctly, is capable of achieving an ideal cancer classification effect. This finding also means that very simple rules may perform well for cancerous class prediction.

High-level expression of S100A4 correlates with lymph node metastasis and poor prognosis in patients with gastric cancer

BACKGROUND

The present study investigated the clinical significance of S100 calcium binding protein A4 in the development, progression, and metastasis of gastric cancer.

METHODS

Tumor tissue, adjacent normal tissue, and lymph node and peritoneal metastases were obtained from patients with gastric cancer, and their gene expression profiles were analyzed by Affymetrix GeneChip HG-U133A2.0 array. The expression of S100A4 was detected by real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) in gastric tumor tissue and lymph node and peritoneum metastasis. Immunohistochemistry was employed to analyze S100A4 expression in 436 clinicopathologically characterized gastric cancer cases and in corresponding distant metastases from 61 patients.

RESULTS

A total of 434 genes and 169 expressed sequence tags were upregulated by at least twofold in the tumor tissue. The expression of S100A4 in lymph node and peritoneal metastases was significantly higher than that in gastric tumor tissue. The expression of S100A4 messenger RNA (mRNA) or protein differed significantly among gastric tumor tissue, matched normal gastric mucosa, and lymph node and peritoneal metastases. Further multivariate analysis suggested that depth of invasion, lymph node and distant metastases, tumor-node-metastasis (TNM) stage, and upregulation of S100A4 were independent prognostic indicators for the disease.

CONCLUSION

Gene expression profiles are a useful way to perform simultaneously large-scale analysis of the expression level of thousands of genes. Expression of S100A4 in gastric cancer is associated significantly with lymph node and distant metastases, and poor prognosis. S100A4 may be a useful marker to predict development, progression, and metastasis of gastric cancer.

Neoplasia: the second decade

This issue marks the end of the 10-year anniversary of Neoplasia where we have seen exciting growth in both number of submitted and published articles in Neoplasia. Neoplasia was first published in 1999. During the past 10 years, Neoplasia has dynamically adapted to the needs of the cancer research community as technologies have advanced. Neoplasia is currently providing access to articles through PubMed Central to continue to facilitate rapid broad-based dissemination of published findings to the scientific community through an Open Access model. This has in part helped Neoplasia to achieve an improved impact factor this past year, demonstrating that the manuscripts published by Neoplasia are of great interest to the overall cancer research community. This past year, Neoplasia received a record number of articles for review and has had a 21% increase in the number of published articles.

Advances in calcium-binding protein S100A4 and digestive neoplasms

S100A4 protein, encoded by S100A4 gene, is a kind of calcium-binding regulatory proteins. Combining with the calcium ions, this protein plays an important role in the progress of tumor growth and metastasis. Recent investigations concluded that there is a relationship between S100A4 protein and tumor invasion or metastasis. This article reviews the biochemical property of this protein and summarizes its action and potential mechanism in digestive tumor progression and metastasis.

DNA hypermethylation regulates the expression of members of the Mu-class glutathione S-transferases and glutathione peroxidases in Barrett's adenocarcinoma

BACKGROUND

The accumulation of reactive oxygen species and subsequent oxidative DNA damage underlie the development of Barrett's oesophagus (BO) and its progression to Barrett's dysplasia (BD) and adenocarcinoma (BAC).

METHODS

The promoter regions of 23 genes of the glutathione S-transferase (GST) and glutathione peroxidase (GPX) families were systematically analysed. Quantitative bisulfite pyrosequencing, real-time RT-PCR, western blot and immunohistochemical (IHC) analysis methods were utilised in this study.

RESULTS

14 genes were identified that have CpG islands around their transcription start sites: GSTs (GSTM2-M5, GSTA4, GSTP1, GSTZ1, GSTT2, GSTO1 and GSTO2) and GPXs (GPX1, GPX3, GPX4 and GPX7). Analysis of an initial set of 20 primary samples demonstrated promoter DNA hypermethylation and mRNA downregulation of GPX3, GPX7, GSTM2, GSTM3 and GSTM5 in more than half of the BAC samples. Further analysis of 159 primary human samples (37 normal, 11 BO, 11 BD and 100 BACs) indicated frequent hypermethylation (>or=10% methylation) of GPX3 (62%), GPX7 (67%), GSTM2 (69.1%) and GSTM3 (15%) in BACs. A significant inverse correlation between DNA methylation and mRNA expression level was shown for GPX3 (p<0.001), GPX7 (p = 0.002), GSTM2 (p<0.001) and GSTM5 (p = 0.01). Treatment of oesophageal cancer cell lines with 5-aza-2'-deoxycytidine and trichostatin-A led to reversal of the methylation pattern and re-expression of these genes at the mRNA and protein levels. The IHC analysis of GPX3, GPX7 and GSTM2 on a tissue microarray that contained 75 BACs with normal squamous oesophageal samples demonstrated an absent to weak staining in tumours (52% for GPX3, 57% for GPX7 and 45% for GSTM2) and a moderate to strong immunostaining in normal samples.

CONCLUSION

Epigenetic inactivation of members of the glutathione pathway can be an important mechanism in Barrett's tumourigenesis.

Alterations in Barrett's-related adenocarcinomas: a proteomic approach

In this study, we applied high-resolution, two-dimensional, gel electrophoresis and matrix-assisted laser desorption/ionization, time-of-flight and tandem mass spectrometry analysis (MALDI TOF MS) to identify novel proteins that are involved in Barrett's tumorigenesis. We analyzed 12 primary tissue samples that included 8 Barrett's-related adenocarcinomas (BA) and 4 normal mucosae samples. Twenty-three spots were consistently altered (>or=2-fold) in at least half of the tumors when compared with all normal samples and thus subjected to further analysis. The MALDI TOF MS analysis demonstrated biologically interesting upregulated proteins such as ErbB3, Dr5 and Cyclin D1 as well as several members of the zinc finger proteins (Znf146, Znf212 and Znf363). Examples of downregulated proteins included Lgi1 and Klf6. We selected four proteins (ErbB3, Dr5, Znf146 and Lgi1) that are novel for BAs for validation using quantitative real-time reverse-transcription PCR on 39 BA tissue samples when compared with normal samples. We demonstrated mRNA upregulation of ERBB3 (51.3%), DR5 (41%) and ZNF146 (30.7%) and downregulation of LGI1 (100%) in BA. We have further validated the protein overexpression of ErbB3, Dr5 and Znf146, using immunohistochemical (IHC) analysis on a tissue microarray that contained 75 BAs and normal gastric and esophageal mucosae samples. BA tissue samples demonstrated overexpression of ErbB3 (42%), Dr5 (90%) and Znf146 (30%) when compared with normal tissues. In conclusion, we have identified and validated several novel proteins that are involved in Barrett's carcinogenesis.

S100A4 gene expression in matched gastric cancer samples

AIM: To examine the expression of S100A4 protein in gastric cancer and its correlation with the prognosis and clinical pathology.

METHODS: Archival tissues from 80 patients with gastric cancer were retrieved. Matched samples including adjacent normal gastric tissues, primary tumor and metastasis lymph node tissues were applied in tissue array technology, and investigated immunohistochemically. The correlations of S100A4 protein expression with clinicopathologic factors and survival were analyzed.

RESULTS: The positive rates of S100A4 protein in non-neoplastic mucosa, primary tumor and metastasis lymph node tissues were 7.5%, 23.8%, and 30.0%, respectively (P = 0.001). In primary tumor lesions, S100A4 expression was correlated significantly with the deeper invasion and TNM stages (P = 0.051). S100A4 expression in lymph node metastasis tissues was associated with a poor survival (P = 0.0009). In multivariate Cox's regression analysis, S100A4 expression was significantly variable (P = 0.031, OR = 1.756) in lymph node metastasis tissues and was an independent prognostic factor in patients (P = 0.030, OR = 2.103).

CONCLUSION: S100A4 protein expression may be a late event that takes part in the progression of gastric cancer. The status detection of S100A4 protein expression in metastasis lymph node tissues may enhance the accuracy to prognosticate gastric cancer patients.

Adenosquamous carcinoma of extrahepatic bile duct: clinicopathologic study of 12 cases

Adenosquamous carcinoma is a rare histologic subtype of extrahepatic bile duct (EBD) carcinoma and limited information is available on its clinicopathologic characteristics. Twelve cases of adenosquamous carcinoma were collected from 3 institutions and their clinicopathologic characteristics were examined and compared with those of 176 EBD adenocarcinomas. The adenocarcinoma component was more often seen at the surface of the tumor (7 of 12 cases, 58%), while the squamous carcinoma component was slightly more frequent at the advanced edge (7 of 12 cases, 58%). Immunohistochemistry, available in 10 cases, revealed that S100A2 was positive in the squamous carcinoma component in all 10 cases (100%), while it was present in the adenocarcinoma component in only 2 of 10 cases (20%, chi-square test, p=0.001). S100A4 expression did not show any difference between the two components. Patients with adenosquamous carcinomas had worse survival (median survival, 11 months) than those with adenocarcinoma (median survival, 32 months; log-rank test, p=0.003). Patients with predominant squamous cell carcinoma component at the leading edge had worse survival than those without it. In conclusion, patients with adenosquamous carcinoma demonstrated worse survival than those with pure adenocarcinoma. S100A2 immunohistochemical staining may be helpful in detecting the squamous component.

A review of the S100 proteins in cancer

AIM

In the quest to reduce mortality and morbidity from cancer, there is continued effort to identify novel biomarkers to aid in the early detection and the accurate prediction of tumour behaviour. One group of proteins that is emerging as a potentially important group of markers in multiple tumour types is the S100 family. This review summarises the biological and clinical relevance of these proteins in relation to different tumour types.

METHODS

A literature search was performed using the PubMed database and the reference lists of relevant articles. Single case studies were excluded and only reports with a clinical relevance from 1961 to 2007 were included.

RESULTS

The search yielded over 1000 published articles and reports. Important reports and studies were reviewed, screened and tracked for further relevant publications. Only the most relevant publications are discussed with relation to individual members of the S100 family.

CONCLUSION

There is increasing evidence that altered expression of S100 family members is seen in many cancers including breast, lung, bladder, kidney, thyroid, gastric, prostate and oral cancers. S100 proteins are commonly up-regulated in tumours and this is often associated with tumour progression. In contrast S100A2, S100A11 and S100A9 have been documented as tumour suppressors in some cancers but as tumour promoters in others. This demonstrates the complexity of the family and variability of their functions. Although the precise roles of these proteins in cancer is still to be discovered many of the family are associated with promoting metastases through interactions with matrix metalloproteinases or by acting as chemoattractants. There is also evidence that some members can regulate transcription factors such as p53. S100B already has a role in a clinical setting in the diagnosis and therapeutic monitoring of malignant melanoma. As our understanding of this family develops it is likely that many more members will aid the diagnosis, monitoring and potential treatment of cancers in the future.