A novel monoclonal antibody against DOG1 is a sensitive and specific marker for gastrointestinal stromal tumors. Am J Surg Pathol. 2008;32:210-218. [PMID: 18223323 DOI: 10.1097/pas.0b013e3181238cec]

ANO1 protein as a potential biomarker for esophageal cancer prognosis and precancerous lesion development prediction

OBJECTIVES

Anoctamin 1 (ANO1) has been found to be overexpressed in esophageal squamous cell carcinoma (ESCC) in our previous study. Herein we showed the clinical relevance of ANO1 alterations with ESCC and esophageal precancerous lesion progression.

RESULTS

ANO1 was detected in 38.1% (109/286) and 25.4% (77/303) of tumors in the two cohorts, but in none of morphologically normal operative margin tissues. ANO1 expression was significantly associated with a shorter overall survival (OS), especially in patients with moderately differentiated and stage IIA tumors. In 499 iodine-unstained biopsies from the endoscopic screening cohort in 2005-2007, all the 72 pathologically normal epithelial mucosa presented negative immunostaining, whereas ANO1 expression was observed in 3/11 tumors and 5/231 intraepithelial lesions. 7/8 ANO1-positive cases had developed unfavorable outcomes revealed by endoscopic follow-up in 2012. Analysis of another independent cohort of 148 intraepithelial lesions further confirmed the correlation between ANO1 expression and progression of precancerous lesions. 3/4 intraepithelial lesions with ANO1 expression had developed ESCC within 4-9 years after the initial endoscopic examination.

METHODS

Immunohistochemistry (IHC) was performed to examine ANO1 expression in surgical ESCC specimens and two independent cohorts of esophageal biopsies from endoscopic screening in high-incidence area of ESCC in northern China. Association between ANO1 expression, clinico-pathologic parameters, and the impact on overall survival was analyzed.

CONCLUSIONS

Positive ANO1 is a promising biomarker to predict the unfavorable outcome for ESCC patients. More importantly, it can predict disease progression of precancerous lesions.

The diagnostic value of endoscopic ultrasonography and contrast-enhanced harmonic endoscopic ultrasonography in gastrointestinal stromal tumors

Objective:

To evaluate the diagnostic value of endoscopic ultrasonography (EUS) and contrast-enhanced harmonic (CEH) EUS in patients with gastrointestinal stromal tumors (GISTs).

Patients and Methods:

About 19 patients with suspected GISTs underwent EUS and CEH-EUS before tumor resection. The malignant potential was assessed according to the modified Fletcher classification system. Patients were divided into lower (Group I) and higher (Group II) malignant potential group. The clinical characteristics and EUS/CEH-EUS features were compared between two groups.

Results:

The tumor size in Group II was significantly larger than that in Group I (14.6 ± 5.8 mm vs. 32.1 ± 8.4 mm, P < 0.05). Heterogeneous echogenicity was observed in 4 (4/8) cases in Group II and none in Group I (P < 0.05). Irregular intratumoral vessels were detected in 6 cases in Group II and none in Group I (P < 0.05). The sensitivity and specificity of irregular vessel detection for discriminating higher from lower malignant potential GISTs were 75% and 100%, respectively. The positive predictive value and negative predictive value of detection of irregular vessels to high malignant potential GISTs were 33% and 100%, respectively.

Conclusion:

Detection of irregular intratumoral vessels can predict higher malignant potential before tumor resection. The tumor size and echogenicity are assistant factors for malignant potential assessment. Endoscopic resection is an efficacious treatment with good security for appropriate patients.

Effects of new-generation inhibitors of the calcium-activated chloride channel anoctamin 1 on slow waves in the gastrointestinal tract

BACKGROUND AND PURPOSE

High-throughput screening of compound libraries using genetically encoded fluorescent biosensors has identified several second-generation. low MW inhibitors of the calcium-activated chloride channel anoctamin 1 (CaCC/Ano1). Here we have (i) examined the effects of these Ano1 inhibitors on gastric and intestinal pacemaker activity; (ii) compared the effects of these inhibitors with those of the more classical CaCC inhibitor, 5-nitro-2-(3-phenylpropylalanine) benzoate (NPPB); (ii) examined the mode of action of these compounds on the waveform of pacemaker activity; and (iii) compared differences in the sensitivity between gastric and intestinal pacemaker activity to the Ano1 inhibitors.

EXPERIMENTAL APPROACH

Using intracellular microelectrode recordings of gastric and intestinal muscle preparations from C57BL/6 mice, the dose-dependent effects of Ano1 inhibitors were examined on spontaneous electrical slow waves.

KEY RESULTS

The efficacy of second-generation Ano1 inhibitors on gastric and intestinal pacemaker activity differed significantly. Antral slow waves were more sensitive to these inhibitors than intestinal slow waves. CaCCinh -A01 and benzbromarone were the most potent at inhibiting slow waves in both muscle preparations and more potent than NPPB. Dichlorophene and hexachlorophene were equally potent at inhibiting slow waves. Surprisingly, slow waves were relatively insensitive to T16Ainh -A01 in both preparations.

CONCLUSIONS AND IMPLICATIONS

We have identified several second-generation Ano1 inhibitors, blocking gastric and intestinal pacemaker activity. Different sensitivities to Ano1 inhibitors between stomach and intestine suggest the possibility of different splice variants in these two organs or the involvement of other conductances in the generation and propagation of pacemaker activity in these tissues.

Novel Use for DOG1 in Discriminating Breast Invasive Carcinoma from Noninvasive Breast Lesions

Aims. DOG1 has proven to be a useful marker of gastrointestinal stromal tumors (GISTs). Recently, DOG1 expression has also been reported in some non-GIST malignant tumors, but the details related to DOG1 expression in breast tissue remain unclear. The aim of this study was to detect the expression of DOG1 in the human breast and to evaluate the feasibility of using DOG1 to discriminate between invasive breast carcinoma and noninvasive breast lesions. Methods and Results. A total of 210 cases, including both invasive and noninvasive breast lesions, were collected to assess DOG1 expression immunohistochemically. DOG1 expression was consistently positive in breast myoepithelial cells (MECs), which was similar to the results obtained for three other MEC markers: calponin, smooth muscle myosin heavy chain (SMMHC), and P63 (P > 0.05 in all). Importantly, DOG1 was useful in discriminating invasive breast carcinoma from noninvasive breast lesions (P < 0.05). Conclusions. DOG1 is a useful marker of breast MECs, and adding DOG1 to the MEC identification panel will provide more sophisticated information when diagnosing uncertain cases in the breast.

Parallelism of DOG1 expression with recurrence risk in gastrointestinal stromal tumors bearing KIT or PDGFRA mutations

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are characterized by mutations of KIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) or PDGFRA (platelet-derived growth factor receptor α) that may be efficiently targeted by tyrosine kinase inhibitors (TKI). Notwithstanding the early responsiveness to TKI, the majority of GISTs progress, imposing the need for alternative therapeutic strategies. DOG1 (discovered on GIST-1) shows a higher sensitivity as a diagnostic marker than KIT, however its prognostic role has been little investigated.

METHODS

We evaluated DOG1 expression by immunohistochemistry (IHC) in 59 patients with GISTs, and correlated its levels with clinical and pathological features as well as mutational status. Kaplan-Meier analysis was also applied to assess correlations of the staining score with patient recurrence-free survival (RFS).

RESULTS

DOG1 was expressed in 66% of CD117(+) GISTs and highly associated with tumor size and the rate of wild-type tumors. Kaplan-Meier survival analysis showed that a strong DOG1 expression demonstrated by IHC correlated with a worse 2-year RFS rate, suggesting its potential ability to predict GISTs with poor prognosis.

CONCLUSIONS

These findings suggest a prognostic role for DOG1, as well as its potential for inclusion in the criteria for risk stratification.

Cellular functions of TMEM16/anoctamin

Ca²⁺-activated Cl⁻ channels (CaCCs) are a class of Cl⁻ channels activated by intracellular Ca²⁺ that are known to mediate numerous physiological functions. In 2008, the molecular identity of CaCCs was found to be anoctamin 1 (ANO1/TMEM16A). Its roles have been studied in electrophysiological, histological, and genetic aspects. ANO1 is known to mediate Cl⁻ secretion in secretory epithelia such as airways, salivary glands, intestines, renal tubules, and sweat glands. ANO1 is a heat sensor activated by noxious heat in somatosensory neurons and mediates acute pain sensation as well as chronic pain. ANO1 is also observed in vascular as well as airway smooth muscles, controlling vascular tone as well as airway hypersensitivity. ANO1 is upregulated in numerous types of cancers and thus thought to be involved in tumorigenesis. ANO1 is also found in proliferating cells. In addition to ANO1, involvement of its paralogs in pathophysiological conditions was also reported. ANO2 is involved in olfaction, whereas ANO6 works as a scramblase whose mutation causes a rare bleeding disorder, the Scott syndrome. ANO5 is associated with muscle and bone diseases. Recently, an X-ray crystal structure of a fungal TMEM16 was reported, which explains a precise molecular gating mechanism as well as ion conduction or phospholipid transport across the plasma membrane.

C-Kit-Negative Gastrointestinal Stromal Tumor in the Stomach

C-kit-negative gastrointestinal stromal tumors (GISTs) are uncommon, and there have been few reports about the diagnosis and treatment of c-kit-negative GISTs in the stomach. We report the case of a patient who was diagnosed with a huge and atypical GIST in the stomach. The GIST was completely resected and finally diagnosed as c-kit-negative GIST based on immunohistochemical staining of tumor cells, which were negative for CD117 and CD34 and positive for Discovered on GIST-1 (DOG1). C-kit-negative GISTs could be treated by complete resection and/or imatinib, which is the same treatment for c-kit-positive GISTs.

Modulating Ca²⁺ signals: a common theme for TMEM16, Ist2, and TMC

Since the discovery of TMEM16A (anoctamin 1, ANO1) as Ca(2+)-activated Cl(-) channel, the protein was found to serve different physiological functions, depending on the type of tissue. Subsequent reports on other members of the anoctamin family demonstrated a broad range of yet poorly understood properties. Compromised anoctamin function is causing a wide range of diseases, such as hearing loss (ANO2), bleeding disorder (ANO6), ataxia and dystonia (ANO3, 10), persistent borrelia and mycobacteria infection (ANO10), skeletal syndromes like gnathodiaphyseal dysplasia and limb girdle muscle dystrophy (ANO5), and cancer (ANO1, 6, 7). Animal models demonstrate CF-like airway disease, asthma, and intestinal hyposecretion (ANO1). Although present data indicate that ANO1 is a Ca(2+)-activated Cl(-) channel, it remains unclear whether all anoctamins form plasma membrane-localized or intracellular chloride channels. We find Ca(2+)-activated Cl(-) currents appearing by expression of most anoctamin paralogs, including the Nectria haematococca homologue nhTMEM16 and the yeast homologue Ist2. As recent studies show a role of anoctamins, Ist2, and the related transmembrane channel-like (TMC) proteins for intracellular Ca(2+) signaling, we will discuss the role of these proteins in generating compartmentalized Ca(2+) signals, which may give a hint as to the broad range of cellular functions of anoctamins.

Role of volume-regulated and calcium-activated anion channels in cell volume homeostasis, cancer and drug resistance

Volume-regulated channels for anions (VRAC) / organic osmolytes (VSOAC) play essential roles in cell volume regulation and other cellular functions, e.g. proliferation, cell migration and apoptosis. LRRC8A, which belongs to the leucine rich-repeat containing protein family, was recently shown to be an essential component of both VRAC and VSOAC. Reduced VRAC and VSOAC activities are seen in drug resistant cancer cells. ANO1 is a calcium-activated chloride channel expressed on the plasma membrane of e.g., secretory epithelia. ANO1 is amplified and highly expressed in a large number of carcinomas. The gene, encoding for ANO1, maps to a region on chromosome 11 (11q13) that is frequently amplified in cancer cells. Knockdown of ANO1 impairs cell proliferation and cell migration in several cancer cells. Below we summarize the basic biophysical properties of VRAC, VSOAC and ANO1 and their most important cellular functions as well as their role in cancer and drug resistance.

TMEM16A/ANO1 is differentially expressed in HPV-negative versus HPV-positive head and neck squamous cell carcinoma through promoter methylation

Head and neck squamous cell carcinoma (HNSCC) has a variety of causes. Recently, the human papilloma virus (HPV) has been implicated in the rising incidence of oropharyngeal cancer and has led to variety of studies exploring the differences between HPV-positive and HPV-negative HNSCC. The calcium-activated chloride channel TMEM16A is overexpressed in a variety of cancers, including HNSCC, but whether or not it plays different roles in HPV-positive and HPV-negative HNSCC is unknown. Here, we demonstrate that TMEM16A is preferentially overexpressed in HPV-negative HNSCC and that this overexpression of TMEM16A is associated with decreased patient survival. We also show that TMEM16A expression is decreased in HPV-positive HNSCC at the DNA, RNA, and protein levels in patient samples as well as cell lines. We demonstrate that the lower levels of TMEM16A expression in HPV-positive tumors can be attributed to both a combination of copy number alteration and promoter methylation at the DNA level. Additionally, our cellular data show that HPV-negative cell lines are more dependent on TMEM16A for survival than HPV-positive cell lines. Therefore, we suspect that the down-regulation of TMEM16A in HPV-positive HNSCC makes TMEM16A a poor therapeutic target in HPV-positive HNSCC, but a potentially useful target in HPV-negative HNSCC.

Histopathological Features of Gastrointestinal Stromal Tumors and the Contribution of DOG1 Expression to the Diagnosis

BACKGROUND

Gastrointestinal stromal tumors (GIST) have KIT or platelet-derived growth factor receptor α (PDGFRα) mutations affecting receptor tyrosine kinase activity and do not benefit from classic treatment regimens.

AIMS

The aim of this study was to review the algorithm that may be followed for the diagnosis and differential diagnosis in GISTs by investigating the histomorphological parameters and expression characteristics of classical immunohistochemical antibodies used in routine tests in addition to DOG1 expression.

STUDY DESIGN

Diagnostic accuracy study.

METHODS

We reevaluated the histological and immunohistochemical parameters of 37 GISTs. The standard immunohistochemical diagnosis and differential diagnosis panel antibodies (CD117, PDGFRα, CD34, vimentin, desmin, SMA, S-100, and Ki67) were studied on the tumor sections. We also used the popular marker DOG1 antibody with accepted sensitivity for GISTs in recent years and the PDGFRα immune marker for which the benefit in routine practice is discussed.

RESULTS

Classification according to progressive disease risk groups of the 37 cases revealed that 54% were in the high risk, 19% in the moderate risk, 16% in the low risk, 8% in the very low risk and 8% in the no risk group. Cytological atypia, necrosis, mucosal invasion and the Ki67 index were found to be related to the progressive disease risk groups of the tumors (p<0.05). Positive immunoreaction was observed with CD117 and PDGFRα in all GISTs in the study (100%). Positivity with the DOG1 antibody was found in 33 (89%) cases. CD34 was positive in 62% (23) of the cases.

CONCLUSION

The CD117 antibody still plays a key role in GIST diagnosis. However, the use of DOG1 and PDGFRα antibodies combined with CD117 as sensitive markers can be beneficial.

DOG1 Expression in Low-Grade Fibromyxoid Sarcoma

DOG1 is a highly sensitive marker for gastrointestinal stromal tumor (GIST) and is in the routine diagnostic antibody repertoire of many surgical pathology laboratories. Moreover, GIST is well recognized by both pathologists and clinicians in the differential diagnosis of intra-abdominal and pelvic neoplasms. Low-grade fibromyxoid sarcoma (LGFMS) is, however, much less frequently anticipated, particularly when occurring at unusual sites, because of its rarity and bland histology, particularly on core biopsy. We describe a case of a 53-year-old male with a large pelvic and pararectal mass, which on biopsy showed a moderately cellular spindle cell neoplasm within fibrous stroma. Immunohistochemistry at the referring center showed diffuse and strong expression of DOG1 with negativity for other markers. After referral to a tertiary center, repeat DOG1 immunohistochemistry again showed diffuse expression, but MUC4 was also positive, and this was confirmed to be LGFMS, harboring FUS-CREB3L2 fusion transcripts by reverse transcription-polymerase chain reaction and FUS rearrangement with fluorescence in situ hybridization. In view of this we assessed DOG1 expression in 10 other LGFMS (all MUC4 positive, and 9 molecularly confirmed to harbor FUS-CREB3L2 fusion transcripts and/or FUS or EWSR1 gene rearrangement), of which 5 showed DOG1 expression in up to 75% of tumor cells, varying in intensity from weak to strong. While LGFMS and GIST are generally morphologically dissimilar, less typical variants of each exist, and both can contain bland spindled cells within fibrous stroma. As the morphologic spectrum of LGFMS is wide, and as it can occur in unusual sites and may not be well recognized by general pathologists and non–soft tissue pathologists, we highlight the potential for diagnostic confusion with GIST owing to aberrant DOG1 expression. This is clinically pertinent, as the management and prognosis of these 2 neoplasms differs significantly.

Getting controls under control: the time is now for immunohistochemistry

For several decades, immunohistochemistry (IHC), more specifically diagnostic IHC (dIHC), has been considered an art rather than a laboratory test. There was no clarity about what test performance characteristics are relevant to dIHC, test performance characteristics were not fully defined for dIHC and partly as a consequence of that, there were no standardised controls or reference standards. Herein, we discuss the role of standardisation of external controls for test performance characteristics and the role of standardised controls and reference standards for overall standardisation of IHC.

ETV1 mRNA is specifically expressed in gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) develop from interstitial cells of Cajal (ICCs) mainly by activating mutations in the KIT or PDGFRA genes. Immunohistochemical analysis for KIT, DOG1, and PKC-θ is used for the diagnosis of GIST. Recently, ETV1 has been shown to be a lineage survival factor for ICCs and required for tumorigenesis of GIST. We investigated the diagnostic value of ETV1expression in GIST. On fresh-frozen tissue samples, RT-PCR analysis showed that ETV1 as well as KIT, DOG1, and PKC-θ are highly expressed in GISTs. On tissue microarrays containing 407 GISTs and 120 non-GIST mesenchymal tumors of GI tract, we performed RNA in situ hybridization (ISH) for ETV1 together with immunohistochemical analysis for KIT, DOG1, PKC-θ, CD133, and CD44. Overall, 387 (95 %) of GISTs were positive for ETV1, while KIT and DOG1 were positive in 381 (94 %) and 392 (96 %) cases, respectively, showing nearly identical overall sensitivity of ETV1, KIT, and DOG1 for GISTs. In addition, ETV1 expression was positively correlated with that of KIT. Notably, ETV1 was positive in 15 of 26 (58 %) KIT-negative GISTs and even positive in 2 cases of GIST negative for KIT and DOG1, whereas only 6 (5 %) non-GIST mesenchymal GI tumors expressed ETV1. We conclude that ETV1 is specifically expressed in the majority of GISTs, even in some KIT-negative cases, suggesting that ETV1 may be useful as ancillary marker in diagnostically difficult select cases of GIST.

Does Immunohistochemistry for Discovered on GIST1 and Minichromosome Maintenance Protein7 Provide Additional Clinicopathological Value in Gastrointestinal Stromal Tumors?

BACKGROUND

The aim of the study was to investigate the expression of discovered on GIST 1 (DOG1) and minichromosome maintenance protein 7 (MCM7) in addition to the traditional markers, C-KIT and Ki-67, in gastrointestinal stromal tumors (GISTs) to specify the diagnosis and to evaluate their clinicopathological significance in GIST patients.

METHODS

Hematoxylin and eosin sections of 43 GISTs were re-examined to review histopathological criteria and risk stratification of these tumors. Immunohistochemistry for DOG1, C-KIT, MCM7, Ki-67 antibodies was performed.

RESULTS

Positive DOG1 and C-KIT expressions were found in 42 (97.7%) and 39 (90.7%) of cases, respectively. DOG1 and C-KIT expression scores were significantly correlated (P < 0.001). Among four C-KIT-negative GISTs, three cases were DOG1-positive. DOG1 was more sensitive and specific than C-KIT in the diagnosis of GISTs. High DOG1 expression scores were significantly associated with tumor size (P = 0.023) and risk (P = 0.037). Significant positive correlation was noted between MCM7 and Ki-67 labeling indices (LIs) (P < 0.001, r = 0.885). MCM7 demonstrated higher proliferation LIs than Ki-67. Significant associations were found between MCM7 and Ki-67 LIs and tumor size (P = 0.001 and 0.003 respectively), mitotic rate (P < 0.001 both) and risk stratification (P < 0.001 both) with a stepwise increase in MCM7 LIs with increasing tumor risk.

CONCLUSION

DOG1 is an important diagnostic tool for GISTs particularly in C-KIT-negative tumors. It may have a role in GISTs tumorogenesis and progression. Despite the established clinicopathological value of Ki-67 in GISTs, detection of MCM7 expression is recommended as a prognostic adjunct, given its better sensitivity for cellular proliferation and stepwise association with tumor risk.

Development of the Olfactory Epithelium and Nasal Glands in TMEM16A-/- and TMEM16A+/+ Mice

TMEM16A/ANO1 is a calcium-activated chloride channel expressed in several types of epithelia and involved in various physiological processes, including proliferation and development. During mouse embryonic development, the expression of TMEM16A in the olfactory epithelium is dynamic. TMEM16A is expressed at the apical surface of the entire olfactory epithelium at embryonic day E12.5 while from E16.5 its expression is restricted to a region near the transition zone with the respiratory epithelium. To investigate whether TMEM16A plays a role in the development of the mouse olfactory epithelium, we obtained the first immunohistochemistry study comparing the morphological properties of the olfactory epithelium and nasal glands in TMEM16A^-/- and TMEM16A^+/+ littermate mice. A comparison between the expression of the olfactory marker protein and adenylyl cyclase III shows that genetic ablation of TMEM16A did not seem to affect the maturation of olfactory sensory neurons and their ciliary layer. As TMEM16A is expressed at the apical part of supporting cells and in their microvilli, we used ezrin and cytokeratin 8 as markers of microvilli and cell body of supporting cells, respectively, and found that morphology and development of supporting cells were similar in TMEM16A^-/- and TMEM16A^+/+ littermate mice. The average number of supporting cells, olfactory sensory neurons, horizontal and globose basal cells were not significantly different in the two types of mice. Moreover, we also observed that the morphology of Bowman’s glands, nasal septal glands and lateral nasal glands did not change in the absence of TMEM16A. Our results indicate that the development of mouse olfactory epithelium and nasal glands does not seem to be affected by the genetic ablation of TMEM16A.

GI Stromal Tumors: 15 Years of Lessons From a Rare Cancer

A confluence of factors, most prominently the recognition of GI stromal tumor (GIST) as a specific sarcoma subtype and the availability of imatinib, led to the “Big Bang” of GIST therapy (ie, the successful treatment of the first patient with GIST with imatinib in 2000). The trail blazed by imatinib for chronic myelogenous leukemia and GIST has become a desired route to regulatory approval of an increasing number of oral kinase inhibitors and other novel therapeutics. In this review, the status of GIST management before and after GIST's “Big Bang” and new steps being taken to further improve on therapy are reviewed.

Association of matrix metalloproteinase (MMP)-2 and -9 expression with extra-gastrointestinal stromal tumor metastasis

Matrix metalloproteinase (MMP)-2 and MMP-9 are important proteases involved in invasion and metastasis of various tumors. Extra-gastrointestinal stromal tumors (EGISTs) are rare neoplasms. This study was performed to assess MMP-2 and MMP-9 expression in EGIST tissue samples for association with clinicopathological data from the patients. Twenty-one surgical EGIST tissue specimens were collected for analysis of MMP-2 and MMP- 9 expression using immunohistochemistry. MMP-2 and MMP-9 proteins were expressed in all of the epithelial cell types of EGISTs, whereas they were only expressed in 75% of the spindle cell type, although there was no statistically significant difference (p>0.05). Expression of MMP-2 and MMP-9 proteins was associated with tumor size, mitotic rate, tumor necrosis, and distant metastasis (p<0.05). MMP-2 expression was linked with MMP-9 levels (p<0.05). However, there was no correlation between MMP-9 expression and age, sex, primary site, or cell morphology in any of these 21 EGIST patients (p>0.05). Moreover, expression of MMP-2 and MMP-9 proteins increased with the degree of EGIST risk. This study provided evidence of an association of MMP-2 and MMP-9 expression with advanced EGIST behavior.

A rare case of giant gastrointestinal stromal tumor of the stomach involving the serosal surface

INTRODUCTION

Although rare, gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors affecting the gastrointestinal tract.

PRESENTATION OF CASE

Here we report the case of a 43-year-old man complaining of abdominal pain along with a painless and palpable mass, which was confirmed on magnetic resonance and multislice computed tomography. Laparotomy revealed a nodular grayish-white firm noninfiltrative mass (39×27×14cm, 6109g) that was well localized within the extramuscular and peritoneal surface of the anterior wall of the stomach; complete tumor resection was performed. Histopathological examination revealed features typical of GIST, including increased cellularity, increased mitotic activity, and spindle shaped cells as well as positive immunoreactivity for KIT, CD34, and vimentin.

DISCUSSION

A review of literature revealed that GISTs of the size and weight similar to the present case has been rarely reported. GIST most frequently involves the stomach. Although the etiopathogenesis of this disease remains unclear, few well-documented familial cases have been associated with GIST syndromes.

CONCLUSION

The primary treatment preferred is complete surgical excision of the tumor.

Targeting Disease Persistence in Gastrointestinal Stromal Tumors

SummaryGastrointestinal stromal tumors (GISTs) represent 20%-40% of human sarcomas. Although approximately half of GISTs are cured by surgery, prognosis of advanced disease used to be poor due to the high resistance of these tumors to conventional chemo- and radiotherapy. The introduction of molecularly targeted therapy (e.g., with imatinib mesylate) following the discovery of the role of oncogenic mutations in the receptor tyrosine kinases KIT and platelet-derived growth factor α (PDGFRA) significantly increased patient survival. However, GIST cells persist in 95%-97% of imatinib-treated patients who eventually progress and die of the disease because of the emergence of clones with drug-resistant mutations. Because these secondary mutations are highly heterogeneous, even second- and third-line drugs that are effective against certain genotypes have only moderately increased progression-free survival. Consequently, alternative strategies such as targeting molecular mechanisms underlying disease persistence should be considered. We reviewed recently discovered cell-autonomous and microenvironmental mechanisms that could promote the survival of GIST cells in the presence of tyrosine kinase inhibitor therapy. We particularly focused on the potential role of adult precursors for interstitial cells of Cajal (ICCs), the normal counterpart of GISTs. ICC precursors share phenotypic characteristics with cells that emerge in a subset of patients treated with imatinib and in young patients with GIST characterized by loss of succinate dehydrogenase complex proteins and lack of KIT or PDGFRA mutations. Eradication of residual GIST cells and cure of GIST will likely require individualized combinations of several approaches tailored to tumor genotype and phenotype.

SIGNIFICANCE

Gastrointestinal stromal tumors (GISTs) are one of the most common connective tissue cancers. Most GISTs that cannot be cured by surgery respond to molecularly targeted therapy (e.g., with imatinib); however, tumor cells persist in almost all patients and eventually acquire drug-resistant mutations. Several mechanisms contribute to the survival of GIST cells in the presence of imatinib, including the activation of "escape" mechanisms and the selection of stem-like cells that are not dependent on the expression of the drug targets for survival. Eradication of residual GIST cells and cure of GIST will likely require individualized combinations of several approaches tailored to the genetic makeup and other characteristics of the tumors.

An update on the application of newly described immunohistochemical markers in soft tissue pathology

CONTEXT

During the last 5 to 10 years, significant progress has been made in the molecular characterization of soft tissue tumors, predominantly with the identification of recurrent translocations or amplification of certain genes in different tumor types. Alongside this, translational efforts have identified many novel and diagnostically useful immunohistochemical markers for many of these tumor types.

OBJECTIVE

This article reviews a select group of recently described immunohistochemical markers of particular use in the evaluation of mesenchymal neoplasms; the underlying biology of the protein product, practical utility, and limitations of each marker are discussed in detail.

DATA SOURCES

Literature review, authors' research data, and personal practice experience serve as sources.

CONCLUSIONS

There are many diagnostically useful immunohistochemical markers to help confirm the diagnosis of many different soft tissue tumor types, some of which have reduced the need for additional, and more costly, studies, such as fluorescence in situ hybridization. However, no one marker is 100% specific for a given tumor, and knowledge of potential pitfalls and overlap in patterns of staining among other tumor types is crucial to ensure the appropriate application of these markers in clinical practice.

Therapeutic targets in gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common type of mesenchymal tumor of the gastrointestinal tract. The tumorigenesis of GISTs is driven by gain-of-function mutations in KIT or platelet-derived growth factor receptor α (PDGFRA), resulting in constitutive activation of the tyrosine kinase and its downstream signaling pathways. Oncogenic KIT or PDGFRA mutations are compelling therapeutic targets for the treatment of GISTs, and the KIT/PDGFRA inhibitor imatinib is the standard of care for patients with metastatic GISTs. However, most GIST patients develop clinical resistance to imatinib and other tyrosine kinase inhibitors. Five mechanisms of resistance have been characterized: (1) acquisition of a secondary point mutation in KIT or PDGFRA; (2) genomic amplification of KIT; (3) activation of an alternative receptor tyrosine kinase; (4) loss of KIT oncoprotein expression; and (5) wild-type GIST. Currently, sunitinib is used as a second-line treatment for patients after imatinib failure, and regorafenib has been approved for patients whose disease is progressing on both imatinib and sunitinib. Phase II/III trials are currently in progress to evaluate novel inhibitors and immunotherapies targeting KIT, its downstream effectors such as phosphatidylinositol 3-kinase, protein kinase B and mammalian target of rapamycin, heat shock protein 90, and histone deacetylase inhibitor. Other candidate targets have been identified, including ETV1, AXL, insulin-like growth factor 1 receptor, KRAS, FAS receptor, protein kinase c theta, ANO1 (DOG1), CDC37, and aurora kinase A. These candidates warrant clinical evaluation as novel therapeutic targets in GIST.

DOG1 is a sensitive and specific immunohistochemical marker for diagnosis of canine gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) and leiomyosarcomas are histologically similar primary neoplasms commonly occurring in the gastrointestinal tract of dogs and humans. Immunohistochemical staining (IHC) is needed to differentiate between these 2 entities and positive reactivity for KIT (cluster of differentiation [CD]117) is regarded as the gold standard for diagnosis of canine GIST. Studies estimate 5–10% of human GISTs stain negative or only weakly positive for KIT and have identified DOG1 (discovered on gastrointestinal stromal tumors protein 1) as a highly sensitive and specific marker for human GISTs. The purpose of this study was to evaluate immunoreactivity of a commercially available DOG1 antibody for use in diagnosis of canine GISTs. Fifty-five primary mesenchymal gastrointestinal tumors with histologic features consistent with GIST or leiomyosarcoma were evaluated via IHC for KIT, DOG1, and desmin. A subset of tumors was additionally evaluated for reactivity for smooth muscle actin (SMA). Thirty-three tumors (60%) were diagnosed as GIST based on positive immunoreactivity for KIT or DOG1 regardless of reactivity for desmin or SMA. Most GISTs (32/33, 97.0%) had similar staining for both KIT and DOG1. DOG1 expression was identified in 2 tumors (1 study tumor and 1 additional tumor) negative for KIT and desmin that had histologic features consistent with KIT-negative, platelet-derived growth factor receptor-alpha (PDGFRA)-mutant human GISTs. Our results suggest that DOG1 has improved specificity and sensitivity to that of KIT for differentiating between canine GISTs and leiomyosarcomas. Inclusion of both DOG1 and KIT IHC in diagnostic panels will improve the accuracy of canine GIST diagnosis.

Reactive nodular fibrous pseudotumor involving the gastrointestinal tract and mesentery: A case report and review of the literature

Reactive nodular fibrous pseudotumor (RNFP) is a tumor-like lesion that is characterized by reactive fibroblast/myofibroblast proliferation within collagenic hyalinized stroma, due to its association with injury or inflammation. The current study describes the case of a 60-year-old female with a history of abdominal surgery and abdominal pain. Upon laparoscopy, multiple nodules attached to the outer layer of the colon and mesentery were identified, and therefore, complete surgical excision was performed. Macroscopically, the nodules were well-circumscribed, firm, tan-white in color and ranged in size between 2.0–10.0 cm at the greatest dimension. Microscopically, the nodules were composed of spindle and stellate cells in a dense collagenic hyalinized background with sparse lymphocytic infiltration. Immunohistochemical analysis demonstrated positive staining for vimentin, smooth muscle actin and cluster of differentiation (CD) 117, and focally-positive keratin staining with AE1/AE3; however, no staining was observed for gastrointestinal stromal tumor 1, CD34, S-100, anaplastic lymphoma kinase or β-catenin. Therefore, it was proposed that the lesion may be most accurately described as an RNFP. The current study reports a rare case of RNFP, emphasizing its histopathological features and differential diagnoses to promote an improved and broader understanding of this poorly understood condition.

Genotyping and immunohistochemistry of gastrointestinal stromal tumors: An update

Gastrointestinal stromal tumors (GISTs) were originally thought to harbor either KIT or platelet-derived growth factor receptor A (PDGFRA) mutations only. However, more recent discoveries have highlighted additional, less common oncogenic driver mutations including NF1, BRAF, and succinate dehydrogenase (SDH) mutations. Genotyping GISTs has become more important since not all genotypes respond equally to FDA-approved tyrosine kinase inhibitors. GIST is a paradigm for personalized cancer therapy. Recent studies demonstrate how immunohistochemistry can be used both to diagnose GIST and to screen for specific mutations. DOG1 is particularly useful in the diagnosis of KIT-negative GIST, including tumors with PDGFRA mutations, which can also potentially be identified by immunohistochemistry for PDGFRA. SDHB immunohistochemistry is useful in characterizing GISTs with SDHA-D mutations, whereas SDHA immunohistochemistry is able to identify SDHA mutant GISTs.

Utility of DOG1 Immunomarker in Fine Needle Aspirates of Gastrointestinal Stromal Tumor

BACKGROUND

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. DOG1 is a sensitive and specific immunohistochemical marker for the diagnosis of GIST. To date, no study has reported the utility of DOG1 immunocytochemistry on aspirate smears.

METHODS

Aspirates with a cytological diagnosis of GIST were retrieved. DOG1 immunocytochemistry was performed on aspirates with adequate material.

RESULTS

23 cases were included (11 primary, 2 recurrent, 10 metastatic). Primary tumors were most frequently located in the stomach; most metastatic tumors were in the liver. Tumor cells were arranged in cohesive clusters with high cellularity. Cells were spindled, had a low N:C ratio, and a moderate amount of cytoplasm, which was elongated and tapering. Characteristic nuclear features included elongated nuclei with blunt or tapering ends, fine chromatin, mild anisonucleosis, and longitudinal grooves. The mitotic count was low, including in metastatic tumors. DOG1 immunopositivity was noted in 57% of the cases examined. Histopathology was available in 5 cases, all diagnosed as GIST.

CONCLUSION

Cytology is a sensitive investigative modality for the preoperative diagnosis and confirmation of metastasis of GISTs. In ambiguous cases, DOG1 immunocytochemistry can serve as a valuable adjunct. Cytologic assessment, however, cannot predict malignant potential of GISTs as even metastatic tumors display bland nuclear features.

Immunohistochemistry in undifferentiated neoplasm/tumor of uncertain origin

CONTEXT

Immunohistochemistry has become an indispensable ancillary study in the identification and classification of undifferentiated neoplasms/tumors of uncertain origin. The diagnostic accuracy has significantly improved because of the continuous discoveries of tissue-specific biomarkers and the development of effective immunohistochemical panels.

OBJECTIVES

To identify and classify undifferentiated neoplasms/tumors of uncertain origin by immunohistochemistry.

DATA SOURCES

Literature review and authors' research data and personal practice experience were used.

CONCLUSIONS

To better guide therapeutic decisions and predict prognostic outcomes, it is crucial to differentiate the specific lineage of an undifferentiated neoplasm. Application of appropriate immunohistochemical panels enables the accurate classification of most undifferentiated neoplasms. Knowing the utilities and pitfalls of each tissue-specific biomarker is essential for avoiding potential diagnostic errors because an absolutely tissue-specific biomarker is exceptionally rare. We review frequently used tissue-specific biomarkers, provide effective panels, and recommend diagnostic algorithms as a standard approach to undifferentiated neoplasms.

Gastrointestinal tract spindle cell lesions--just like real estate, it's all about location

Interpretation of gastrointestinal tract mesenchymal lesions is simplified merely by knowing in which anatomic layer they are usually found. For example, Kaposi sarcoma is detected on mucosal biopsies, whereas inflammatory fibroid polyp is nearly always in the submucosa. Gastrointestinal stromal tumors (GISTs) are generally centered in the muscularis propria. Schwannomas are essentially always in the muscularis propria. Mesenteric lesions are usually found in the small bowel mesentery. Knowledge of the favored layer is even most important in interpreting colon biopsies, as many mesenschymal polyps are encountered in the colon. Although GISTs are among the most common mesenchymal lesions, we will concentrate our discussion on other mesenchymal lesions, some of which are in the differential diagnosis of GIST, and point out some diagnostic pitfalls, particularly in immunolabeling.

[Immunohistochemistry in the diagnosis of sarcomas]

Immunohistochemistry (IHC) is essential in the diagnosis of soft tissue tumor and must rely on good quality technic. Among useful antibodies, it is important to distinguish those with a poor specificity required in order to establish the broad lineage, from those with high specificity, which may lead straightforward towards the entity. Diagnostically useful antibodies such as myogenin, ALK1 and DOG1 have been recently completed by MUC4 and STAT6 which show good sensitivity and specificity in the diagnosis of low-grade fibromyxoid sarcoma and solitary fibrous tumor respectively. ERG is also an interesting antibody. However, it is not completely specific of vascular tumors. Moreover, available material is often limited because of the increase of microbiopsy specimens. Therefore, it is mandatory to optimize this precious tissue by using these new antibodies, especially because molecular technics are increasingly performed in addition to IHC.

TMEM16 proteins: unknown structure and confusing functions

The TMEM16 family of membrane proteins, also known as anoctamins, plays key roles in a variety of physiological functions that range from ion transport to phospholipid scrambling and to regulating other ion channels. The first two family members to be functionally characterized, TMEM16A (ANO1) and TMEM16B (ANO2), form Ca(2+)-activated Cl(-) channels and are important for transepithelial ion transport, olfaction, phototransduction, smooth muscle contraction, nociception, cell proliferation and control of neuronal excitability. The roles of other family members, such as TMEM16C (ANO3), TMEM16D (ANO4), TMEM16F (ANO6), TMEM16G (ANO7) and TMEM16J (ANO9), remain poorly understood and controversial. These homologues were reported to be phospholipid scramblases, ion channels, to have both functions or to be regulatory subunits of other channels. Mutations in TMEM16F cause Scott syndrome, a bleeding disorder caused by impaired Ca(2+)-dependent externalization of phosphatidylserine in activated platelets, suggesting that this homologue might be a scramblase. However, overexpression of TMEM16F has also been associated with a remarkable number of different ion channel types, raising the possibility that this protein might be involved in both ion and lipid transports. The recent identification of an ancestral TMEM16 homologue with intrinsic channel and scramblase activities supports this hypothesis. Thus, the TMEM16 family might have diverged in two or three different subclasses, channels, scramblases and dual-function channel/scramblases. The structural bases and functional implication of such a functional diversity within a single protein family remain to be elucidated and the links between TMEM16 functions and human physiology and pathologies need to be investigated.

Clinical presentations of gastric small gastrointestinal stromal tumors mimics functional dyspepsia symptoms

AIM: To explore whether clinical presentations of gastric small gastrointestinal tumors (GISTs) mimics gastrointestinal dyspepsia symptoms.

METHODS: The endosonographic data of 167 patients who underwent endoscopic submucosal dissection at the Tianjin Medical University General Hospital, China between 2009 and 2011 were analyzed. GISTs and leiomyomas had a similar intragastric distribution and similar locations within the gastric wall. Therefore, patients with GISTs were chosen as the study group and those with leiomyomas were chosen as the control group. Dyspepsia symptom questionnaires were used to investigate and compare the gastrointestinal symptoms of patients with GISTs and those with gastric leiomyomas before and after endoscopic submucosal dissection (ESD). The questionnaires evaluated symptoms such as epigastric pain, heartburn, regurgitation, epigastric discomfort, nausea and vomiting, abdominal bloating, and eructation. Symptoms were assessed using a four-point scoring scale.

RESULTS: GISTs were the most common gastric submucosal lesion (67 cases, 40.12%), followed by leiomyomas (38 cases, 22.75%). Both groups were similar in terms of gender distribution (P = 0.49), intragastric location (P = 0.525), and originating layer within the gastric wall (P = 0.449), but leiomyomas were more commonly found in the proximal fundus (P < 0.05). Overall, 94.2% of the patients with small GISTs and 93.5% of those with gastric leiomyomas experienced some dyspepsia; however, total symptom scores were significantly lower in the GIST group than in the leiomyoma group (1.34 ± 1.27 vs 2.20 ± 1.70, P < 0.05). Each component of the symptom score demonstrated a statistically significant improvement in the GIST patients after ESD (P < 0.05), including epigastric pain (0.80 ± 0.90 vs 0.13 ± 0.46), heartburn (0.63 ± 1.08 vs 0.13 ± 0.41), regurgitation (0.55 ± 0.87 vs 0.22 ± 0.57), epigastric discomfort (0.70 ± 0.98 vs 0.32 ± 0.47), nausea and vomiting (0.27 ± 0.62 vs 0.05 ± 0.21), abdominal bloating (0.70 ± 0.90 vs 0.27 ± 0.49), and eructation (0.36 ± 0.61 vs 0.21 ± 0.46). For leiomyoma patients, symptoms such as heartburn, nausea, vomiting, and eructation improved after treatment; however, these improvements were not statistically significant (P > 0.05). Thus, the pathophysiology of dyspepsia symptoms may be different between the two groups.

CONCLUSION: Symptoms of gastric small GISTs may mimic those of functional dyspepsia. An alternative diagnosis should be considered in patients with functional dyspepsia and treatment failure.

Interstitial cells: regulators of smooth muscle function

Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα(+) cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα(+) cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues.

Histopathological diagnostic discrepancies in soft tissue tumours referred to a specialist centre: reassessment in the era of ancillary molecular diagnosis

Introduction. Soft tissue tumour pathology is a highly specialised area of surgical pathology, but soft tissue neoplasms can occur at virtually all sites and are therefore encountered by a wide population of surgical pathologists. Potential sarcomas require referral to specialist centres for review by pathologists who see a large number of soft tissue lesions and where appropriate ancillary investigations can be performed. We have previously assessed the types of diagnostic discrepancies between referring and final diagnosis for soft tissue lesions referred to our tertiary centre. We now reaudit this 6 years later, assessing changes in discrepancy patterns, particularly in relation to the now widespread use of ancillary molecular diagnostic techniques which were not prevalent in our original study. Materials and Methods. We compared the sarcoma unit's histopathology reports with referring reports on 348 specimens from 286 patients with suspected or proven soft tissue tumours in a one-year period. Results. Diagnostic agreement was seen in 250 cases (71.8%), with 57 (16.4%) major and 41 (11.8%) minor discrepancies. There were 23 cases of benign/malignant discrepancies (23.5% of all discrepancies). 50 ancillary molecular tests were performed, 33 for aiding diagnosis and 17 mutational analyses for gastrointestinal stromal tumour to guide therapy. Findings from ancillary techniques contributed to 3 major and 4 minor discrepancies. While the results were broadly similar to those of the previous study, there was an increase in frequency of major discrepancies. Conclusion. Six years following our previous study and notably now in an era of widespread ancillary molecular diagnosis, the overall discrepancy rate between referral and tertiary centre diagnosis remains similar, but there is an increase in frequency of major discrepancies likely to alter patient management. A possible reason for the increase in major discrepancies is the increasing lack of exposure to soft tissue cases in nonspecialist centres in a time of subspecialisation. The findings support the national guidelines in which all suspected soft tissue tumour pathology specimens should be referred to a specialist sarcoma unit.

Bladder extragastrointestinal stromal tumor in an adolescent patient: A case-based review

Extragastrointestinal stromal tumors (EGISTs) are mesenchymal tumors occurring outside the gastrointestinal tract, with histological, immunohistochemical and molecular genetic characteristics similar to those of gastrointestinal stromal tumors (GISTs). The immunohistochemical examination usually demonstrates a positive expression for CD117. GISTs are rare neoplasms and EGISTs are even less common. This is the report of a case of EGIST in the urinary bladder of a 15-year-old adolescent female patient who presented with painless gross hematuria. Pelvic computed tomography revealed an irregular soft tissue density mass, sized 5.7×4.8 cm, in the bladder. Partial cystectomy was performed in April, 2011. There was no recurrence during follow-up over the next 35 months, as determined by transabdoninal ultrasonography and cystoscopic examination. The patient in this study did not receive any molecular-targeted drugs. To the best of our knowledge, this is the first reported case of an EGIST of the urinary bladder in an adolescent patient.

The significance of interstitial cells in neurogastroenterology

Smooth muscle layers of the gastrointestinal tract consist of a heterogeneous population of cells that include enteric neurons, several classes of interstitial cells of mesenchymal origin, a variety of immune cells and smooth muscle cells (SMCs). Over the last number of years the complexity of the interactions between these cell types has begun to emerge. For example, interstitial cells, consisting of both interstitial cells of Cajal (ICC) and platelet-derived growth factor receptor alpha-positive (PDGFRα(+)) cells generate pacemaker activity throughout the gastrointestinal (GI) tract and also transduce enteric motor nerve signals and mechanosensitivity to adjacent SMCs. ICC and PDGFRα(+) cells are electrically coupled to SMCs possibly via gap junctions forming a multicellular functional syncytium termed the SIP syncytium. Cells that make up the SIP syncytium are highly specialized containing unique receptors, ion channels and intracellular signaling pathways that regulate the excitability of GI muscles. The unique role of these cells in coordinating GI motility is evident by the altered motility patterns in animal models where interstitial cell networks are disrupted. Although considerable advances have been made in recent years on our understanding of the roles of these cells within the SIP syncytium, the full physiological functions of these cells and the consequences of their disruption in GI muscles have not been clearly defined. This review gives a synopsis of the history of interstitial cell discovery and highlights recent advances in structural, molecular expression and functional roles of these cells in the GI tract.

The significance of interstitial cells in neurogastroenterology

Smooth muscle layers of the gastrointestinal tract consist of a heterogeneous population of cells that include enteric neurons, several classes of interstitial cells of mesenchymal origin, a variety of immune cells and smooth muscle cells (SMCs). Over the last number of years the complexity of the interactions between these cell types has begun to emerge. For example, interstitial cells, consisting of both interstitial cells of Cajal (ICC) and platelet-derived growth factor receptor alpha-positive (PDGFRα(+)) cells generate pacemaker activity throughout the gastrointestinal (GI) tract and also transduce enteric motor nerve signals and mechanosensitivity to adjacent SMCs. ICC and PDGFRα(+) cells are electrically coupled to SMCs possibly via gap junctions forming a multicellular functional syncytium termed the SIP syncytium. Cells that make up the SIP syncytium are highly specialized containing unique receptors, ion channels and intracellular signaling pathways that regulate the excitability of GI muscles. The unique role of these cells in coordinating GI motility is evident by the altered motility patterns in animal models where interstitial cell networks are disrupted. Although considerable advances have been made in recent years on our understanding of the roles of these cells within the SIP syncytium, the full physiological functions of these cells and the consequences of their disruption in GI muscles have not been clearly defined. This review gives a synopsis of the history of interstitial cell discovery and highlights recent advances in structural, molecular expression and functional roles of these cells in the GI tract.

ANO1 as a marker of oral squamous cell carcinoma and silencing ANO1 suppresses migration of human SCC-25 cells

OBJECTIVES

The purpose of this study is to confirm that ANO1 correlates with occurrence and metastasis of OSCC.

STUDY DESIGN

Immunohistochemistry was used to detect the expression of ANO1 in 160 specimens of OSCC and normal tissues. Lentiviral silencing ANO1 was used in SCC-25 cell line to study the cell migration and cell detachment.

RESULTS

Immunohistochemical staining revealed that ANO1 was expressed in a large majority (132 out of 160, 82.5%) of OSCC specimens and that the rate of ANO1 expression in OSCC was significantly higher than that of normal tissue (P<0.05); The rate of ANO1 expression was higher in metastatic tumors than in non-metastatic tumors, and the difference was significant (P<0.05). The results of cell migration assay showed that the percentage of cells through the membrane was 26.61 ±0.81 in assay group, and 54.26 ±3.74 in control group, respectively (t=-16.22,P<0.0001). The results of cell detachment assay showed that the percentage of cells detachment was 37.42 ±0.90 in assay group, and 87.38 ±1.59 in control group, respectively (t=-62.34, P<0.0001). The results of wound healing assay showed the assay group had a reduced migration rate compared with the control group in 32 h (F=1038.78, P<0.0001). Wound closure was no significantly different between the assay and control cells when DIDS was used in wound healing assay (F=4.61,P>0.05).

CONCLUSIONS

Our study shows that abnormal expression of ANO1 correlated with the occurrence and metastasis of OSCC in clinical specimens and that silencing ANO1 greatly reduced migration ability of scc-25 cells. Calcium activated chloride channel activity of ANO1 promoted the cell migration. Thus, ANO1 could represent a new diagnostic biomarker and a potentially important therapeutic target of OSCC.

An inflammatory myofibroblastic tumor exhibiting immunoreactivity to KIT: a case report focusing on a diagnostic pitfall

Inflammatory myofibroblastic tumors (IMTs) and gastrointestinal stromal tumors (GISTs) are both spindle cell tumors, and occur rarely in the wall of the urinary bladder. In general, immunostaining allows differentiation of IMTs and GISTs. Most IMTs are positive for anaplastic lymphoma kinase (ALK) and negative for KIT, whereas most GISTs are ALK-negative and KIT-positive. Here, we describe a case of a spindle cell tumor in the wall of the urinary bladder. The spindle cells were positive for both ALK and KIT, and it was thus difficult to determine whether the tumor was an IMT or a GIST. We eventually diagnosed an IMT, because ALK gene rearrangement was confirmed by fluorescent in-situ hybridization. Cytoplasmic staining for KIT and the absence of other GIST markers, including DOG1 and platelet-derived growth factor α, indicated that the tumor was not a GIST. Therefore, IMTs should be included in the differential diagnosis of spindle cell tumors, even those that are KIT-positive.

How our practice of histopathology, especially tumour pathology has changed in the last two decades: reflections from a major referral center in Pakistan

Continued advances in the field of histo-pathology (and cyto-pathology) over the past two decades have resulted in dramatic changes in the manner in which these disciplines are now practiced. This is especially true in the setting of a large university hospital where the role of pathologists as clinicians (diagnosticians), undergraduate and postgraduate educators, and researchers has evolved considerably. The world around us has changed significantly during this period bringing about a considerable change in our lifestyles and the way we live. This is the world of the internet and the world-wide web, the world of Google and Wikipedia, of Youtube and Facebook where anyone can obtain any information one desires at the push of a button. The practice of histo (and cyto) pathology has also evolved in line with these changes. For those practicing this discipline in a poor, developing country these changes have been breathtaking. This is an attempt to document these changes as experienced by histo (and cyto) pathologists practicing in the biggest center for Histopathology in Pakistan, a developing country in South Asia with a large (180 million) and ever growing population. The Section of Histopathology, Department of Pathology and Microbiology at the Aga Khan University Hospital (AKUH) in Karachi, Pakistan's largest city has since its inception in the mid-1980s transformed the way histopathology is practiced in Pakistan by incorporating modern methods and rescuing histopathology in Pakistan from the primitive and outdated groove in which it was stuck for decades. It set histopathology in Pakistan firmly on the path of modernity and change which are essential for better patient management and care through accurate and complete diagnosis and more recently prognostic and predictive information as well.

Therapeutic effect and mechanism of electroacupuncture at Zusanli on plasticity of interstitial cells of Cajal: a study of rat ileum

Background

Electroacupuncture (EA) is one of the techniques of acupuncture and is believed to be an effective alternative and complementary treatment in many disorders. The aims of this study were to investigate the effects and mechanisms of EA at acupoint Zusanli (ST36) on the plasticity of interstitial cells of Cajal (ICCs) in partial bowel obstruction.

Methods

A Sprague Dawley rat model of partial bowel obstruction was established and EA was conducted at Zusanli (ST36) and Yinglingquan (SP9) in test and control groups, respectively. Experiments were performed to study the effects and mechanisms of EA at Zusanli on intestinal myoelectric activity, distribution and alteration of ICCs, expression of inflammatory mediators, and c-Kit expression.

Results

1) EA at Zusanli somewhat improved slow wave amplitude and frequency in the partial obstruction rats. 2) EA at Zusanli significantly stimulated the recovery of ICC networks and numbers. 3) the pro-inflammatory mediator TNF-α and NO activity were significantly reduced after EA at Zusanli, However, no significant changes were observed in the anti-inflammatory mediator IL-10 activity. 4) EA at Zusanli re-expressed c-Kit protein. However, EA at the control acupoint, SP9, significantly improved slow wave frequency and amplitude, but had no effect on ICC or inflammatory mediators.

Conclusions

We concluded that EA at Zusanli might have a therapeutic effect on ICC plasticity, and that this effect might be mediated via a decrease in pro-inflammatory mediators and through the c-Kit signaling pathway, but that the relationship between EA at different acupoints and myoelectric activity needs further study.

Beyond the GIST: mesenchymal tumors of the stomach

Intramural gastric masses arise in the wall of the stomach (generally within the submucosa or muscularis propria), often with intact overlying mucosa. These tumors are typically mesenchymal in origin and have overlapping radiologic appearances. A combination of features such as location, attenuation, enhancement, and growth pattern may suggest one diagnosis over another. Gastrointestinal stromal tumors (GISTs) account for the majority of intramural tumors and can vary widely in appearance, from small intraluminal lesions to exophytic masses that protrude into the peritoneal cavity, commonly with areas of hemorrhage or necrosis. A well-circumscribed mass measuring -70 to -120 HU is a lipoma. Leiomyomas usually manifest as low-attenuation masses at the gastric cardia. Homogeneous attenuation is a noteworthy characteristic of schwannomas, particularly for larger lesions that might otherwise be mistaken for GISTs. A hypervascular mass in the antrum is a common manifestation of glomus tumors. Hemangiomas are also hypervascular but often manifest in childhood. Inflammatory fibroid polyps usually arise as a polypoid mass in the antrum. Inflammatory myofibroblastic tumors are infiltrative neoplasms with a propensity for local recurrence. Plexiform fibromyxomas are rare, usually antral tumors. Carcinoid tumors are epithelial in origin, but often submucosal in location, and therefore should be distinguished from other intramural lesions. Multiple carcinoid tumors are associated with hypergastrinemia, either in the setting of chronic atrophic gastritis or Zollinger-Ellison syndrome. Sporadic solitary carcinoid tumors not associated with hypergastrinemia have a higher rate of metastasis. Histopathologic analysis, including immunohistochemistry, is usually required for diagnosis of intramural masses.

Functional role of the Ca²⁺-activated Cl⁻ channel DOG1/TMEM16A in gastrointestinal stromal tumor cells

DOG1, a Ca(2+)-activated Cl(-) channel (CaCC), was identified in 2004 to be robustly expressed in gastrointestinal stromal tumors (GIST). It was rapidly included as a tumor marker in routine diagnostics, but the functional role remained unknown. CaCCs are important regulators of normal physiological functions, but also implicated in tumorigenesis, cancer progression, metastasis, cell migration, apoptosis, proliferation and viability in several malignancies. We therefore investigated whether DOG1 plays a role in the three latter in GIST by utilizing in vitro cell model systems. Confocal microscopy identified different subcellular localizations of DOG1 in imatinib-sensitive and imatinib-resistant cells. Electrophysiological studies confirmed that DOG1-specific pharmacological agents possess potent activating and inhibiting properties. Proliferation assays showed small effects up to 72 h, and flow cytometric analysis of adherent cells with 7-AAD/Annexin V detected no pharmacological effects on viable GIST cells. However, inhibition of DOG1 conveyed pro-apoptotic effects among early apoptotic imatinib-resistant cells. In conclusion, DOG1 generates Cl(-) currents in GIST that can be regulated pharmacologically, with small effects on cell viability and proliferation in vitro. Inhibition of DOG1 might act pro-apoptotic on some early apoptotic GIST cell populations. Further studies are warranted to fully illuminate the function of DOG1 and its potential as therapeutic target.

Frequent expression of KIT in endometrial stromal sarcoma with YWHAE genetic rearrangement

Endometrial stromal sarcomas with the YWHAE-NUTM2A/B genetic fusion characteristically contain high-grade round to epithelioid cell component that is strongly and diffusely cyclin D1-positive and it may or may not show an associated low-grade fibroblastic/myxoid cell component. They are clinically more aggressive than endometrial stromal sarcomas with the JAZF1-SUZ12 genetic fusion and frequently demonstrate extrauterine extension at initial clinical presentation. In this setting, the tumor may be misdiagnosed as gastrointestinal stromal tumor. This study examines the expression of KIT and ANO1 in 14 YWHAE-NUTM2A/B tumors by immunohistochemistry. Staining localization was determined as membranous and/or cytoplasmic, and the staining intensity was assessed (negative, weak, moderate and strong). Of the 14 tumors, 6 contained only a high-grade round cell component, 2 only a low-grade fibroblastic component and 6 had both components in the slides evaluated. The high-grade round cell component displayed moderate to strong membranous/cytoplasmic KIT staining in all tumors (12 of 12). The low-grade fibroblastic cell component showed only weak cytoplasmic KIT staining in 3 of 8 tumors. In contrast, ANO1 was negative in all 14 neoplasms, irrespective of the component evaluated. Sanger sequencing analysis (exons 9, 11, 13 and 17) and Ampliseq Cancer Panel mutation screen (Ion Torrent) demonstrated no KIT mutations in three KIT-positive YWHAE-NUTM2A/B tumors. This study shows that the high-grade round cell component of YWHAE-NUTM2A/B endometrial stromal sarcoma consistently expresses KIT but lacks KIT hotspot mutations. KIT expression may represent a potential diagnostic pitfall in the evaluation of YWHAE-NUTM2A/B endometrial stromal sarcoma presenting with pelvic/abdominal mass, particularly in situations where its uterine origin is not definitive, and thus a panel of antibodies that includes ANO1 and cyclin D1 is necessary.