Diagnostic utility of von Hippel-Lindau gene product, maspin, IMP3, and S100P in adenocarcinoma of the gallbladder

Utility of IMP3, p53, and S100P immunohistochemical stains in distinguishing reactive atypia from dysplasia in cholecystectomy specimens

BACKGROUND

Distinguishing reactive atypia from dysplasia in cholecystectomy specimens can be histologically challenging. The aim of this study was to evaluate the utility of IMP3, p53, and S100P immunostains in differentiating reactive atypia from dysplasia in cholecystectomies.

METHODS

Fifty-four cholecystectomies were reviewed and characterized into 5 groups: 2 normal, 29 reactive atypia, 16 low-grade dysplasia, 2 high-grade dysplasia, and 5 adenocarcinoma. IMP3, p53, and S100P immunostains were performed and evaluated. IMP3 (nuclear) and S100P (nuclear or nuclear/cytoplasmic) were categorized into negative or positive expression, and p53 was categorized into wild-type and aberrant/mutant expression. Chi-square test was used for statistical analysis.

RESULTS

The patients were mostly middle-aged women (mean 44, range 19-87 years, 81% female), with predominantly Hispanic White ethnicity (80%). The majority of the normal and reactive atypia cases showed negative IMP3 (100% and 75.9%, respectively) and wild-type p53 (100% and 89.7%, respectively) staining. Over half (56.3%) of the low-grade dysplasia and all the high-grade dysplasia cases showed IMP3 positivity. Aberrant p53 staining pattern was seen in half of both low and high-grade dysplasia cases. Adenocarcinoma showed IMP3 positivity in 80% and p53 aberrancy in all cases. S100P showed no statistical significance among the diagnostic categories. Significant differences in staining patterns were found between reactive atypia vs. low-grade dysplasia, and reactive atypia vs. low-grade + high-grade dysplasia using a combination of IMP3 and p53 stains (all p < 0.05).

CONCLUSIONS

In challenging cholecystectomies, IMP3 positivity or aberrant p53 expression may serve as a useful adjunct to support a diagnosis of dysplasia over reactive atypia.

Ancillary tests for hepatobiliary neoplasms: what we know and what we need to know

Ancillary tests are commonly used in the surgical pathology setting for diagnosing challenging neoplastic diseases of the liver and biliary tract, while histology and clinical correlation remain to be critically important. With continuous discoveries, more and more useful ancillary tests have become available, which can help distinguish between malignant and benign hepatocellular neoplasms, malignant and benign biliary tract entities, and intrahepatic and metastatic carcinomas. This review will focus on existing and emerging biomarkers (such as glutamine synthetase, organic anion transporting polypeptide 1B3, insulin-like growth factor-II mRNA binding protein-3, S100P, SMAD4, enhancer of zeste homolog 2, albumin, hepatocyte nuclear factor-1β, etc.) that can be used for the diagnosis, classification and prognostication of hepatobiliary neoplasms.

Gallbladder carcinomas: review and updates on morphology, immunohistochemistry, and staging

Gallbladder is a common surgical pathology specimen. However, carcinomas of the gallbladder are relatively rare in most western countries. Hence, general surgical pathologists may not be that familiar and comfortable diagnosing these tumors. In this review, we discuss the morphological and immunohistochemical characteristics of gallbladder carcinomas, provide updates on tumor classification and staging of these tumors as per the most recent WHO classification, and focus on practical considerations that would be most relevant to diagnosis and clinical management of these tumors.

Current Pathology Model of Pancreatic Cancer

Pancreatic cancer (PC) is one of the most aggressive and lethal malignant neoplasms, ranking in seventh place in the world in terms of the incidence of death, with overall 5-year survival rates still below 10%. The knowledge about PC pathomechanisms is rapidly expanding. Daily reports reveal new aspects of tumor biology, including its molecular and morphological heterogeneity, explain complicated "cross-talk" that happens between the cancer cells and tumor stroma, or the nature of the PC-associated neural remodeling (PANR). Staying up-to-date is hard and crucial at the same time. In this review, we are focusing on a comprehensive summary of PC aspects that are important in pathologic reporting, impact patients' outcomes, and bring meaningful information for clinicians. Finally, we show promising new trends in diagnostic technologies that might bring a difference in PC early diagnosis.

S100P as a marker for poor survival and advanced stage in gallbladder carcinoma

AIMS

Gallbladder carcinomas usually present in advanced stages and has a dismal prognosis despite modern imaging techniques and aggressive surgical intervention. Identification of biologic markers for early diagnosis and improved therapeutic strategies is thus of paramount importance. S100P has been identified in a variety of malignant neoplasms of the gastrointestinal and pancreaticobiliary systems, but it is not yet known if S100P expression is associated with clinically-relevant characteristics of gall bladder carcinoma. The aims of the present study were: 1) to investigate the relationship between S100P expression and histological type, grade, tumor-node-metastasis stage, presence of vascular invasion, perineural invasion and necrosis; and 2) to evaluate for any S100P-defined difference in the risk for tumor recurrence or death.

METHOD

Immunostains for S100P were performed on 4 tissue microarray blocks containing 91 cases of gall bladder carcinoma.

RESULT

The intensity of S100P staining was significantly associated with pathological T stage 4 (p = 0. 0238). Staining intensity ≥3 in ≥25% tumor cells was associated with pathological T stage 4 (p = 0.0005). A higher S100P immunoreactivity score (IRS) was significantly associated with higher TNM stage (p = 0.0341). Age (p = 0.0485), presence of vascular invasion (p = 0.0359), pathological T stage (p = 0.0291) and TNM stage (p = 0.0153) were significantly associated with tumor recurrence. Intense S100P reactivity was associated with decreased overall survival [hazard ratio = 9.614; 95% confidence interval (CI), 1.873-49.338; p = 0.0067].

CONCLUSION

Our findings indicate that S100P over-expression is a potential prognostic marker for gall bladder carcinoma and is significantly associated with advanced tumor stage and poorer survival.

Mutational profiling and immunohistochemical analysis of a surgical series of ampullary carcinomas

Aims

Knowledge regarding the genetic features of ampullary carcinoma (AC) in European patients is limited. The utility of tumour markers for the establishment of a malignant diagnosis in biopsies from the ampullary region has not been fully elucidated. We aimed to describe the clinical, pathological, immunohistochemical (IHC) and genetic features of a Danish series of surgically resected ACs.

Methods

Surgically resected ACs (n=59) were examined regarding (1) clinicopathological features, (2) histological subtypes, (3) expression of IMP3, maspin, MUC5AC and S100P and (4) next-generation sequencing using a hybrid capture-based platform (Illumina HiSeq2500), including 315 cancer-related genes plus introns from 28 genes often rearranged or altered in cancer. Tumour mutational burden (TMB) and microsatellite instability (MSI) were also evaluated.

Results

Pancreatobiliary adenocarcinomas (PB-AC), intestinal adenocarcinomas (INT-AC), other ampullary tumours and mixed adenocarcinomas represented 45.8%, 23.7%, 16.9% and 13.6%. The proportion of IHC-positive ACs (score ≥2) was: Maspin (94.9%), IMP3 (67.8%), S100P (39.0%) and MUC5AC (18.6%). Most frequently altered genes were TP53 (59.3%), KRAS (40.7%), APC (27.8%), SMAD4 (20.4%), CDKN2A (16.7%) and ARID2/PIK3CA (each 11.1%). MUC5AC and S100P were frequently expressed in PB-AC, APC alterations frequent in INT-AC, SOX9 alterations were exclusive in INT-AC and MDM2 and FRS2 alterations in PB-AC. Four of 49 ACs (8.2%) were TMB-high/MSI-high and showed loss of MLH1 and PMS2.

Conclusions

PB-AC was the most frequent histological subtype of AC. Maspin and IMP3 were the IHC tumour markers with the highest sensitivity. Adenocarcinoma subtypes differed regarding several genetic alterations, whose predictive value remains to be evaluated.

Subcellular expression of maspin – from normal tissue to tumor cells

Maspin or SerpinB5, a member of the serine protease inhibitor family, was shown to function as a tumor suppressor, especially in carcinomas. It seems to inhibit invasion, tumor cells motility and angiogenesis, and promotes apoptosis. Maspin can also induce epigenetic changes such as cytosine methylation, de-acetylation, chromatin condensation, and histone modulation. In this review, a comprehensive synthesis of the literature was done to present maspin function from normal tissues to pathologic conditions. Data was sourced from MEDLINE and PubMed. Study eligibility criteria included: Published in English, between 1994 and 2019, specific to humans, and with full-text availability. Most of the 118 studies included in the present review focused on maspin immunostaining and mRNA levels. It was shown that maspin function is organ-related and depends on its subcellular localization. In malignant tumors, it might be downregulated or negative (e.g., carcinoma of prostate, stomach, and breast) or upregulated (e.g., colorectal and pancreatic tumors). Its subcellular localization (nuclear vs cytoplasm), which can be proved using immunohistochemical methods, was shown to influence both tumor behavior and response to chemotherapy. Although the number of maspin-related papers increased, the exact role of this protein remains unknown, and its interpretation should be done with extremely high caution.

IMP3 overexpression occurs in various important cancer types and is linked to aggressive tumor features: A tissue microarray study on 8,877 human cancers and normal tissues

IMP3 is an RNA binding protein required for ribosomal RNA processing, which has been suggested to be a prognostic marker in a large variety of human types of cancer. However, available data on the prevalence of IMP3 expression are largely discrepant. To systematically investigate the epidemiology and clinical relevance of IMP3 expression in human cancers we employed a two-step tissue microarrays (TMAs) approach. First, a normal tissue TMA and a multi-tumor TMA were analyzed for immunohistochemically detectable expression of IMP3 in 76 different normal tissue types and 3889 cancer samples from 95 different tumor categories. In a second step, we searched for associations between IMP3 expression and tumor phenotype and patient prognosis in TMAs containing 697 urinary bladder cancers, 1711 colon cancers, 343 esophageal adenocarcinomas, 251 esophageal squamous cell cancers, 673 lung cancers), 275 pancreatic cancers and 230 stomach cancers. In normal tissues, unequivocal IMP3 expression was found in placenta, lymphocytes and some types of glandular epithelial cells. In cancers, at least one case with weak expression could be found in 76 out of 95 (80%) different tumor types and 64 entities (67%) had at least one tumor with strong positivity. IMP3 expression was most frequently found in testicular cancer (including 71% seminomas and 96% non-seminomas), neuroblastoma (88%), and squamous cell cancer of various origins. Significant associations were found between IMP3 and adverse tumor features in esophageal adenocarcinomas and cancers of the urinary bladder, lung, stomach, and pancreas. In summary, IMP3 was frequently expressed in many different tumor types, and was typically associated with aggressive tumor features.

Practical Immunohistochemistry in Neoplastic Pathology of the Gastrointestinal Tract, Liver, Biliary Tract, and Pancreas

CONTEXT

- Immunomarkers with diagnostic, therapeutic, or prognostic values have been increasingly used to maximize the benefits of clinical management of patients with neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas.

OBJECTIVES

- To review the characteristics of immunomarkers that are commonly used in surgical pathology practice for neoplasms of the gastrointestinal tract, liver, biliary tract, and pancreas, and to summarize the clinical usefulness of immunomarkers that have been discovered in recent years in these fields.

DATA SOURCES

- Data sources include literature review, authors' research data, and personal practice experience.

CONCLUSIONS

- Immunohistochemistry is an indispensable tool for the accurate diagnosis of neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas. Useful immunomarkers are available to help distinguish malignant neoplasms from benign conditions, determine organ origins, and subclassify neoplasms that are morphologically and biologically heterogeneous. Specific immunomarkers are also available to help guide patient treatment and assess disease aggressiveness, which are keys to the success of personalized medicine. Pathologists will continue to play a critical role in the discovery, validation, and application of new biomarkers, which will ultimately improve patient care.

IMP2/IGF2BP2 expression, but not IMP1 and IMP3, predicts poor outcome in patients and high tumor growth rate in xenograft models of gallbladder cancer

Overexpression of the oncofetal insulin-like growth factor 2 mRNA-binding protein 2 (IMP2/IGF2BP2) has been described in different cancer types. Gallbladder carcinoma (GBC) is a rare but highly aggressive cancer entity with late clinical detection and poor prognosis.

The aim of this study was to investigate the role of IMP2 in human GBC.

Tissue microarrays (TMAs) of an international multi-center GBC sample collection from n = 483 patients were analyzed by immunohistochemistry. IMP2 immunoreactivity was found in 74.3% of the tumor samples on TMA, of which 14.0% showed strong and 86.0% low staining intensity. 72.4% of the tumor samples were IMP1 positive, but IMP1 showed lower expression in tumor tissue compared to control tissues. IMP3 immunoreactivity was observed in 92.7% of all tumors, of which 53.6% revealed strong IMP3 expression. Kaplan-Meier analysis linked high IMP2 expression to shorter survival time (p = 0.033), whereas neither IMP1 nor IMP3 expression was linked to a decreased survival time. Eight different human biliary tract cancer (BTC) cell lines were evaluated for tumor growth kinetics in mouse xenografts. Cell lines with high IMP2 expression levels showed the fastest increase in tumor volumes in murine xenografts. Furthermore, IMP2 expression in these cells correlated with the generation of reactive oxygen species (ROS) and RAC1 expression in BTC cells, suggesting RAC1-induced ROS generation as a potential mechanism of IMP2-promoted progression of GBC.

In conclusion, IMP2 is frequently overexpressed in GBC and significantly associated with poor prognosis and growth rates in vivo. IMP2 might therefore represent a new target for the treatment of advanced GBC.

IMPs: an RNA-binding protein family that provides a link between stem cell maintenance in normal development and cancer

This review by Degrauwe et al. summarizes our current understanding of the functions of IMPs during normal development and focuses on a series of recent observations that have provided new insight into how their physiological functions enable IMPs to play a potentially key role in cancer stem cell maintenance and tumor growth.

IMPs, also known as insulin-like growth factor 2 (IGF2) messenger RNA (mRNA)-binding proteins (IGF2BPs), are highly conserved oncofetal RNA-binding proteins (RBPs) that regulate RNA processing at several levels, including localization, translation, and stability. Three mammalian IMP paralogs (IMP1–3) have been identified that are expressed in most organs during embryogenesis, where they are believed to play an important role in cell migration, metabolism, and stem cell renewal. Whereas some IMP2 expression is retained in several adult mouse organs, IMP1 and IMP3 are either absent or expressed at very low levels in most tissues after birth. However, all three paralogs can be re-expressed upon malignant transformation and are found in a broad range of cancer types where their expression often correlates with poor prognosis. IMPs appear to resume their physiological functions in malignant cells, which not only contribute to tumor progression but participate in the establishment and maintenance of tumor cell hierarchies. This review summarizes our current understanding of the functions of IMPs during normal development and focuses on a series of recent observations that have provided new insight into how their physiological functions enable IMPs to play a potentially key role in cancer stem cell maintenance and tumor growth.

Genetic alterations in Japanese extrahepatic biliary tract cancer

Biliary tract cancer (BTC) is one of the most devastating types of malignant neoplasms worldwide. However, the mechanisms underlying the development and progression of BTC remain unresolved. BTC includes extrahepatic bile duct carcinoma (EBDC), gallbladder carcinoma (GBC) and ampulla of Vater carcinoma (AVC), named according to the location of the tumor. Although genetic alterations of intrahepatic cholangiocarcinoma have been investigated, those of EBDC, GBC and AVC have not yet been fully understood. The present study analyzed somatic mutations of 50 cancer-associated genes in 27 Japanese BTC cells, including: 11 EBDC, 14 GBC and 2 AVC. Next-generation sequencing using an Ion AmpliSeq Cancer Panel identified a total of 44 somatic mutations across 14 cancer-associated genes. Among the 44 mutations, 42 were judged as pathological mutations. Frequent mutations were identified in tumor protein 53 (TP53) (14/27), SMAD family member 4 (SMAD4) (6/27), phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α (PIK3CA) (6/27), and Kirsten rat sarcoma (KRAS) (6/27); no significant differences were identified between EBDC and GBC tissues. Notably, the frequency of the PIK3CA mutation was higher when compared with previous reports. This result may suggest that the activation of the PIK3CA-protein kinase B signaling pathway, in addition to the abrogation of p53, SMAD4 and RAS mitogen-activated protein kinase may have a crucial role in the carcinogenesis of Japanese BTC. These findings may be useful for the development of personalized therapies for BTC.

The Evolving Role of Pathology in New Developments, Classification, Terminology, and Diagnosis of Pancreatobiliary Neoplasms

Pancreatobiliary tract lesions are increasingly being discovered because of more sensitive imaging modalities. Magnetic resonance imaging has identified incidental pancreatic cysts in 13.5% of patients of progressively increasing age. Pancreatobiliary tissue is more accessible through endoscopic ultrasound and magnetic resonance imaging-guided biopsy procedures, and is now an integral part of pathologists' routine practice. Accordingly, several new tumor categories have been recently recognized, including intraductal tubulopapillary neoplasm, a new addition to tumoral intraepithelial neoplasms. Other entities have been reclassified, including the recent transition to 2-tiered grading of preinvasive neoplasms, as well as new perspectives on the distinctive biologic behavior of oncocytic intraductal papillary mucinous neoplasms (IPMNs) compared with other IPMN subtypes. This has led to proposals for revised staging of virtually every segment of the pancreatobiliary tree, with theranostic markers becoming an integral part of workup. Ki-67 is now an integral part of the classification of neuroendocrine tumors, with new definitions of "high-grade neuroendocrine carcinoma." Although bile duct brushings have opened new avenues for diagnosis, their sensitivity remains low and often requires concomitant fluorescent in situ hybridization to better define ambiguous cases. Various molecular pathways have been elucidated for pancreatic cysts, including KRAS for ductal neoplasia, GNAS for intestinal IPMNs, RNF3 for mucinous cysts, and VHL for serous cystic neoplasms, all key players in diagnostic workup. Integration of these updates into our understanding of pancreatobiliary disease requires active engagement of pathologists for appropriate specimen triage, judicious interpretation of results, and incorporation into reporting and staging. They also provide exciting opportunities for targeted therapy.

SERPINB5 Promoter Hypomethylation Differentiates Pancreatic Ductal Adenocarcinoma From Pancreatitis

OBJECTIVES

The diagnosis of pancreatic ductal adenocarcinoma (PDAC) is challenging in the setting of pancreatitis. We investigated SERPINB5 for its impact on PDAC tumor biology and its use as a diagnostic marker for PDAC in the setting of pancreatitis.

METHODS

Patient samples from PDAC primary tumors, PDAC lymph node metastases, and pancreatitis were investigated for SERPINB5 promoter methylation by methylation-specific polymerase chain reaction (PCR). Six PDAC cell lines were investigated in vitro and in vivo using an orthotopic mouse model to generate primary tumors and metastases. SERPINB5 mRNA expression, protein expression, and promoter methylation were determined by quantitative reverse transcriptase-PCR, methylation-specific PCR, and Western Blot.

RESULTS

In patient samples, detection of an unmethylated SERPINB5 promoter differentiated pancreatitis from PDAC with a sensitivity of 57% and a specificity of 95% (P < 0.001). SERPINB5 was not deregulated in primary tumors versus metastases, but primary tumors without SERPINB5 protein expression had significantly reduced viability (P = 0.02).

CONCLUSIONS

SERPINB5 seems to assume an oncogenic role in PDAC. In clinical samples, detection of unmethylated SERPINB5 was a specific marker for PDAC even in the context of pancreatitis and may provide the basis for a liquid biopsy option to detect PDAC.

Aberrant Maspin mRNA Expression is Associated with Clinical Outcome in Patients with Pulmonary Adenocarcinoma

BACKGROUND

The aim of this study was to investigate the expression level of maspin mRNA in pulmonary adenocarcinoma and to clarify its clinical significance in prediction of prognosis.

MATERIAL/METHODS

RNA was extracted from formalin-fixed paraffin-embedded (FFPE) tumor tissue blocks of 30 pairs of pulmonary adenocarcinoma (AC) tissues and adjacent noncancerous tissues (ANT) and in another 81 AC tissues. Expression of maspin mRNA was tested by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and the potential relationship between maspin mRNA expression and clinic pathological features of AC patients was analyzed.

RESULTS

The expression of maspin mRNA was upregulated in AC samples compared with the ANT (p<0.001). Patients at advanced clinical stage (III) and patients with lymphatic metastasis showed higher maspin mRNA expression level than those in early-stage patients (I and II) (p=0.038) or with non-lymphatic metastasis (p=0.034). The Kaplan-Meier survival curves indicated that disease-free survival (DFS) was significantly worse in high maspin mRNA expression AC patients (p=0.007). Furthermore, multivariate analysis revealed that the expression of maspin mRNA was an independent prognostic marker for AC (p=0.040).

CONCLUSIONS

Our study reveals that maspin mRNA was significantly up-regulated in tissues of AC patients. Maspin mRNA may be useful as a new marker of prognosis in AC.

Diagnostic value of maspin in distinguishing adenocarcinoma from benign biliary epithelium on endoscopic bile duct biopsy

Histopathologic distinction between benign and malignant epithelia on endoscopic bile duct biopsy can be extremely challenging due to small sample size, crush artifact, and a propensity for marked inflammatory and reactive changes after stent placement. Our previous studies have shown that the insulin-like growth factor II mRNA-binding protein 3, S100P, and the von Hippel-Lindau gene product (pVHL) can help the distinction. This study analyzed 134 endoscopic bile duct biopsy specimens (adenocarcinoma 45, atypical 31, and benign 58) by immunohistochemistry for the expression of maspin, a serine protease inhibitor. The results demonstrated that (1) maspin expression was more frequently detected in malignant than in benign biopsies; (2) malignant biopsies frequently showed diffuse, strong/intermediate, and combined nuclear/cytoplasmic staining patterns for maspin, which were much less commonly seen in benign biopsies; (3) the malignant staining patterns for maspin observed in atypical biopsies were consistent with follow-up data showing that 67% of these patients were subsequently diagnosed with adenocarcinoma; (4) a maspin+/S100P+/pVHL- staining profile was seen in 75% of malignant biopsies but in none of the benign cases. These observations demonstrate that maspin is a useful addition to the diagnostic immunohistochemical panel (S100P, pVHL, and insulin-like growth factor II mRNA-binding protein 3) to help distinguish malignant from benign epithelia on challenging bile duct biopsies.

Utility of immunohistochemistry in the pancreatobiliary tract

CONTEXT

Immunohistochemistry has become a useful ancillary study in the identification and classification of pancreatic neoplasms. The diagnostic accuracy has been significantly improved because of the continuous discoveries of tumor-associated biomarkers and the development of effective immunohistochemical panels.

OBJECTIVES

To identify and classify pancreatic neoplasms by immunohistochemistry.

DATA SOURCES

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

CONCLUSIONS

To better guide therapeutic decisions and predict the prognostic outcome, it is crucial to make an accurate diagnosis of a pancreatic neoplasm. Application of appropriate immunohistochemical panels enables pathologists to differentiate pancreaticobiliary adenocarcinomas from reactive conditions and to identify rare types of pancreatic neoplasms. Knowing the utilities and pitfalls of each tumor-associated biomarker is essential to avoiding a potential diagnostic error because an absolutely cancer-specific biomarker does not exist. This article reviews frequently used tumor-associated biomarkers, provides lists of effective immunohistochemical panels, and recommends a diagnostic algorithm as a standard approach to pancreatic neoplasms.

An immunohistochemical marker panel including claudin-18, maspin, and p53 improves diagnostic accuracy of bile duct neoplasms in surgical and presurgical biopsy specimens

Biliary tract cancers have an extremely poor outcome, and specific diagnostic markers and effective treatments are needed urgently. In this study, we assessed the capacity of panel of immunohistochemical markers including claudin-18, maspin, and p53 to distinguish biliary tract carcinoma and biliary intraepithelial neoplasia (BilIN) from non-neoplastic epithelium. We performed a retrospective study of 66 biliary tract cancer specimens and 63 specimens with non-neoplastic lesions. Of the surgical specimens, 96.7 % with adenocarcinoma/BilIN were detected as neoplastic, and all 63 specimens histologically diagnosed as non-neoplastic lesion were detected as non-neoplastic with high sensitivity (91.1 %) and specificity (100 %). Of presurgical endobiliary forceps biopsy specimens, all with adenocarcinoma/BilIN and only 1 of the 19 with a non-neoplastic lesion were distinguished as neoplastic with high sensitivity (100 %) and specificity (94.7 %). Moreover, this panel provided good separation of neoplasm from malignancy-undetermined atypical epithelium (18/21, 85.7 %). This panel achieves a more reliable distinction of biliary tract cancers and BilINs from non-neoplastic epithelia in both surgical and biopsy specimens than immunohistochemical analysis with single antibodies and is useful in supporting a diagnosis of adenocarcinoma and BilIN.

The role of the oncofetal IGF2 mRNA-binding protein 3 (IGF2BP3) in cancer

The post-transcriptional control of gene expression mediated by RNA-binding proteins (RBPs), long non-coding RNAs (lncRNAs) as well as miRNAs is essential to determine tumor cell fate and thus is a major determinant in cancerogenesis. The IGF2 mRNA binding protein family (IGF2BPs) comprises three RBPs. Two members of the family, IGF2BP1 and IGF2BP3, are bona fide oncofetal proteins, which are de novo synthesized in various human cancers. In vitro studies revealed that IGF2BPs serve as post-transcriptional fine-tuners modulating the expression of genes implicated in the control of tumor cell proliferation, survival, chemo-resistance and metastasis. Consistently, the expression of both IGF2BP family members was reported to correlate with an overall poor prognosis and metastasis in various human cancers. Due to the fact that most reports used a pan-IGF2BP antibody for studying IGF2BP expression in cancer, paralogue-specific functions can barely be evaluated at present. Nonetheless, the accordance of IGF2BPs' role in promoting an aggressive phenotype of tumor-derived cells in vitro and their upregulated expression in aggressive malignancies provides strong evidence that IGF2BPs are powerful post-transcriptional oncogenes enhancing tumor growth, drug-resistance and metastasis. This suggests IGF2BPs as powerful biomarkers and candidate targets for cancer therapy.

Immunohistochemical distinction between intrahepatic cholangiocarcinoma and pancreatic ductal adenocarcinoma

Distinction between primary intrahepatic cholangiocarcinoma (ICC) and metastatic pancreatic ductal adenocarcinoma (PDA) on a liver biopsy is essentially impossible histologically but has important clinical implications. In this study, 41 ICCs and 60 PDAs were immunohistochemically evaluated for the expression of S100P, pVHL, IMP3, maspin, MUC5AC, and CK17 proteins. The results showed pVHL expression in 29 (71%) ICCs but in only 3 (5%) PDAs. S100P, MUC5AC, and CK17 were frequently expressed in PDAs, seen in 57 (95%), 40 (67%), and 36 (60%) cases, respectively. In contrast, only 11 (27%), 5 (12%), and 5 (12%) ICC cases expressed these proteins. IMP3 was expressed in 37 (90%) ICC and 54 (90%) PDA cases with equal frequency. All 60 (100%) PDA and 30 (73%) ICC cases showed positive maspin immunoreactivity. A S100P-/pVHL+/MUC5AC-/CK17- staining pattern was essentially indicative of ICC, whereas the S100P+/pVHL-/MUC5AC+/CK17+ and S100P+/pVHL-/MUC5AC-/CK17+ staining patterns were suggestive of PDA. These observations demonstrate that S100P, pVHL, MUC5AC, and CK17 are a useful immunohistochemical panel that may help distinguish primary ICC from metastatic PDA.