Insulin-like growth factor mRNA binding protein 3 (IMP3) is differentially expressed in benign and malignant follicular patterned thyroid tumors

IGF2BPs as novel m6A readers: Diverse roles in regulating cancer cell biological functions, hypoxia adaptation, metabolism, and immunosuppressive tumor microenvironment

m6A methylation is the most frequent modification of mRNA in eukaryotes and plays a crucial role in cancer progression by regulating biological functions. Insulin-like growth factor 2 mRNA-binding proteins (IGF2BP) are newly identified m6A 'readers'. They belong to a family of RNA-binding proteins, which bind to the m6A sites on different RNA sequences and stabilize them to promote cancer progression. In this review, we summarize the mechanisms by which different upstream factors regulate IGF2BP in cancer. The current literature analyzed here reveals that the IGF2BP family proteins promote cancer cell proliferation, survival, and chemoresistance, inhibit apoptosis, and are also associated with cancer glycolysis, angiogenesis, and the immune response in the tumor microenvironment. Therefore, with the discovery of their role as 'readers' of m6A and the characteristic re-expression of IGF2BPs in cancers, it is important to elucidate their mechanism of action in the immunosuppressive tumor microenvironment. We also describe in detail the regulatory and interaction network of the IGF2BP family in downstream target RNAs and discuss their potential clinical applications as diagnostic and prognostic markers, as well as recent advances in IGF2BP biology and associated therapeutic value.

Diagnostic Challenges during Inflammation and Cancer: Current Biomarkers and Future Perspectives in Navigating through the Minefield of Reactive versus Dysplastic and Cancerous Lesions in the Digestive System

In the setting of pronounced inflammation, changes in the epithelium may overlap with neoplasia, often rendering it impossible to establish a diagnosis with certainty in daily clinical practice. Here, we discuss the underlying molecular mechanisms driving tissue response during persistent inflammatory signaling along with the potential association with cancer in the gastrointestinal tract, pancreas, extrahepatic bile ducts, and liver. We highlight the histopathological challenges encountered in the diagnosis of chronic inflammation in routine practice and pinpoint tissue-based biomarkers that could complement morphology to differentiate reactive from dysplastic or cancerous lesions. We refer to the advantages and limitations of existing biomarkers employing immunohistochemistry and point to promising new markers, including the generation of novel antibodies targeting mutant proteins, miRNAs, and array assays. Advancements in experimental models, including mouse and 3D models, have improved our understanding of tissue response. The integration of digital pathology along with artificial intelligence may also complement routine visual inspections. Navigating through tissue responses in various chronic inflammatory contexts will help us develop novel and reliable biomarkers that will improve diagnostic decisions and ultimately patient treatment.

Fasting regulates mitochondrial function through lncRNA PRKCQ-AS1-mediated IGF2BPs in papillary thyroid carcinoma

Recurring evidence suggests that fasting has extensive antitumor effects in various cancers, including papillary thyroid carcinoma (PTC). However, the underlying mechanism of this relationship with PTC is unknown. In this study, we study the effect of fasting on glycolysis and mitochondrial function in PTC. We find that fasting impairs glycolysis and reduces mitochondrial dysfunction in vitro and in vivo and also fasting in vitro and fasting mimicking diets (FMD) in vivo significantly increase the expression of lncRNA-protein kinase C theta antisense RNA 1 (PRKCQ-AS1), during the inhibition of TPC cell glycolysis and mitochondrial function. Moreover, lncRNA PRKCQ-AS1 was significantly lower in PTC tissues and cells. In addition, PRKCQ-AS1 overexpression increased PTC cell glycolysis and mitochondrial function; PRKCQ-AS1 knockdown has the opposite effect. On further mechanistic analysis, we identified that PRKCQ-AS1 physically interacts with IGF2BPs and enhances protein arginine methyltransferases 7 (PRMT7) mRNA, which is the key player in regulating glycolysis and mitochondrial function in PTC. Hence, PRKCQ-AS1 inhibits tumor growth while regulating glycolysis and mitochondrial functions via IGF2BPs/PRMT7 signaling. These results indicate that lncRNA PRKCQ-AS1 is a key downstream target of fasting and is involved in PTC metabolic reprogramming. Further, the PRKCQ-AS1/IGF2BPs/PRMT7 axis is an ideal therapeutic target for PTC diagnosis and treatment.

IGF Bioregulation System in Benign and Malignant Thyroid Nodular Disease: A Systematic Review

BACKGROUND/AIM

The insulin-like growth factor bioregulation system is implicated in cancer biology. Herein, we aim to review the evidence on the expression of the insulin-like growth factor 1 and 2 (IGF1 and IGF2), their receptors (IGF-Rs) and IGF-binding proteins (IGFBPs) in thyroid tissue and their possible association with benign and malignant thyroid nodular diseases.

MATERIALS AND METHODS

We systematically reviewed Pubmed and Scopus databases up to May 2020. A total of 375 articles were retrieved and analyzed.

RESULTS

Among 375 articles, 45 were included in this systematic review study. IGF1 was investigated in 31 studies, IGF2 in 1, IGF1 receptor in 15 and IGF-binding proteins in 13 articles. IGF1 expression in humans was dependent on the number and compound of benign nodules as well as the method of measurement. In differentiated thyroid carcinoma, a positive correlation between IGF1 and immunohistological stage was documented in some studies while in others only a positive trend was observed. IGF-1R and IGFBPs expression was higher in malignant rather than benign lesions. There was only a positive trend for increased IGF2 expression in malignancy, while IGFBPs were in most studies statistically increased in various cancer types compared to benign nodular disease.

CONCLUSION

The present data demonstrate that in most studies there is statistically positive expression of IGF-1 and less of IGF-2 in thyroid cancer compared to normal thyroid tissue.

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.

A Concise Atlas of Thyroid Cancer Next-Generation Sequencing Panel ThyroSeq v.2

The next-generation sequencing technology allows high out-put genomic analysis. An innovative assay in thyroid cancer, ThyroSeq® was developed for targeted mutation detection by next generation sequencing technology in fine needle aspiration and tissue samples. ThyroSeq v.2 next generation sequencing panel offers simultaneous sequencing and detection in >1000 hotspots of 14 thyroid cancer-related genes and for 42 types of gene fusions known to occur in thyroid cancer. ThyroSeq is being increasingly used to further narrow the indeterminate category defined by cytology for thyroid nodules. From a surgical perspective, genomic profiling also provides prognostic and predictive information and closely relates to determination of surgical strategy. Both the genomic analysis technology and the informatics for the cancer genome data base are rapidly developing. In this paper, we have gathered existing information on the thyroid cancer-related genes involved in the initiation and progression of thyroid cancer. Our goal is to assemble a glossary for the current ThyroSeq genomic panel that can help elucidate the role genomics play in thyroid cancer oncogenesis.

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is a new term replacing what was previously known as non-invasive encapsulated follicular variant of papillary thyroid carcinoma (FVPTC). These tumors show benign/indolent clinical behavior when compared with invasive FVPTC, which led to their reclassification as a "non-malignant" neoplasm. NIFTP shares essentially similar cytomorphologic features as FVPTC, and can only be definitively diagnosed on surgical excision specimens. This article provides an update on morphologic characteristics of NIFTP, along with pertinent molecular studies and management algorithms.

Five Top Stories in Thyroid Pathology

CONTEXT

Thyroid carcinoma is the most common malignant tumor of endocrine organs, yet it only accounts for approximately 1% of all cancers in the United States with more than 35,000 new cases diagnosed each year and more than 450,000 people living with this disease. While most tumors can be diagnosed without much difficulty, a few tumor types, especially tumors with follicular pattern, sometimes pose a diagnostic challenge.

OBJECTIVE

To discuss morphologic, immunohistochemical, and molecular features of thyroid tumors. We also explore the clinicopathologic features of papillary microcarcinoma and medullary microcarcinoma and how the latter is related and differentiated from C-cell hyperplasia. Finally with the ever-growing list of organ systems involved in immunoglobulin (Ig) G4-related diseases, we discuss the still not completely explored IgG-4-related thyroid disease.

DATA SOURCES

Data were obtained from review of the pertinent peer-reviewed literature and institutional experience.

CONCLUSIONS

Histomorphologic evaluation still remains the gold standard for diagnosis in most cases of thyroid diseases. The application of ancillary studies such as immunohistochemistry and molecular diagnosis, including next-generation sequencing, is becoming more common.

The diagnostic utility of combination of HMGA2 and IMP3 qRT-PCR testing in thyroid neoplasms

The diagnosis of malignant thyroid tumors in some cytologic and histologic specimens remains challenging. High-mobility group A2 (HMGA2) expression and insulin-like growth factor II mRNA-binding protein-3 (IMP3) expression were evaluated by relative quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The aim of this study was to evaluate whether the combination of HMGA2 and IMP3 qRT-PCR was diagnostically useful in differentiating benign from malignant thyroid neoplasms. Fine-needle aspiration (FNA) specimens from 120 patients including 56 benign lesions and 64 carcinomas were used. The available 80 corresponding formalin-fixed paraffin-embedded (FFPE) thyroid tissues from 66 patients were also included in this study. HMGA2 and IMP3 expression levels were detected by qRT-PCR and reported as relative fold change after normalizing with a calibrator. The diagnostic utilities of HMGA2 and IMP3 qRT-PCR tests were evaluated individually and in combination. In FNA specimens, HMGA2 and IMP3 expression was consistently higher in thyroid malignancies compared with benign lesions in all subgroups except in Hürthle cell tumors. After exclusion of Hürthle cell tumors, the sensitivity was 90.2% for HMGA2, 88.2% for IMP3, and 98% for HMGA2+IMP3; the specificity was 97.1% for HMGA2, 79.4% for IMP3, and 79.4% for HMGA+IMP3. qRT-PCR data showed similar results in FFPE tissues: the sensitivity was 84.2% for HMGA2, 85.7% for IMP3, and 94.7% for HMGA2+IMP3; the specificity was 96.9% for HMGA2, 91.2% for IMP3, and 90.6% for HMGA2+IMP3. qRT-PCR data were concordant between FNA and FFPE samples for HMGA2 (97.4%) and IMP3 (96.9%). The results indicate that HMGA2 qRT-PCR with high specificity may be a useful ancillary technique to assist in the classification of difficult thyroid specimens, excluding Hürthle cell tumors. The HMGA2 and IMP3 qRT-PCR combination model with increased sensitivity and negative predictive value (96.4%) may be useful in screening thyroid cytology specimens.

Comparison of the clinicopathological behavior of the follicular variant of papillary thyroid carcinoma and classical papillary thyroid carcinoma: A systematic review and meta-analysis

The follicular variant of papillary thyroid carcinoma (FV-PTC) is the second most common type of papillary thyroid carcinoma (PTC), and it has been increasingly diagnosed in recent years. However, whether FV-PTC behaves differently from classical PTC (C-PTC) remains controversial. To address this controversy, a meta-analysis was performed to determine the potential differences between FV-PTC and C-PTC in their clinicopathological behavior. The relevant published studies between January 1, 2003 and August 31, 2014 were reviewed according to the defined selection criteria using the PubMed database. Review Manager was used to calculate the pooled odds ratio (OR) or the mean difference (MD) with a 95% confidence interval (CI), using a random- or fixed-effect model for all analyses. In total, 112 studies were identified and examined; finally, only 36 studies met the inclusion criteria. In the 36 studies, compared to the clinicopathological behavior of patients with C-PTC, patients with FV-PTC had the following parameters: Similar mean age and similar prevalence of gender, tumor size ≥10 mm, multifocality, capsular invasion, vascular invasion, lymphocytic and/or Hashimoto's thyroiditis, and clinical stage; a larger mean tumor size and higher prevalence of age ≥45 years; and lower prevalence of extrathyroidal extensions, lymph node metastases, BRAF mutation and recurrence. The meta-analysis suggested that patients with FV-PTC have a more favorable clinicopathological behavior and improved prognosis compared to patients with C-PTC. Thus, patients with FV-PTC and C-PTC may be managed differently, and the two types of PTC should be clearly distinguished in future retrospective or prospective studies.

Imp3 expression in benign and malignant thyroid tumors and hyperplastic nodules

BACKGROUND

IMP3, a member of insulin-like growth factor II m RNA binding protein family, seems to be promising in the diagnosis of carcinomas of many organs as well as malignant melanomas and some sarcomas. It is postulated that it might be a marker of malignancy. The results of the few prior studies indicate that IMP3 has the potential to be useful in distinguishing benign and malignant tumors of thyroid.

AIMS

We aimed to evaluate the immunohistochemical expression of IMP3 in non-neoplastic nodules and benign and malignant tumors of the thyroid.

STUDY DESIGN

Diagnostic accuracy study.

METHODS

Overall, 92 thyroid lesions, including 22 nodular hyperplasia (NH), 14 follicular adenoma (FA), 9 follicular carcinoma (FC), 37 papillary carcinoma (PC) (15 follicular variant), 3 well differentiated carcinoma-not otherwise specified (WDC-NOS), 4 poorly differentiated carcinoma (PDC) and anaplastic carcinoma (AC) were included. Immunohistochemically, cytoplasmic expression of IMP3 was evaluated in terms of extent and intensity of the staining semi-quantitatively and an immunohistochemical score (IHS) was obtained for each case. A score higher than 2 was considered positive staining.

RESULTS

In contrast with previous studies, we observed positive staining in benign lesions, especially in benign tumors. For identifying malignant tumors, the sensitivity of IMP3 was 82.1%, specificity was 33.3%, positive predictive value (PPV) was 65.7% and negative predictive value (NPV) was 54.5%. In distinguishing neoplastic and hyperplastic lesions, the sensitivity was 50%, specificity was 15.7%, PPV was 15.7% and NPV was 50%. The IMP3 expression was similar for FA and well differentiated carcinomas (p=0.434), but there was a significant difference between hyperplastic nodules and FA (p=0.011).

CONCLUSION

Our data suggest that IMP3 is effective in discriminating hyperplastic and neoplastic lesions but not useful in differentiating benign tumors from malignant tumors.

Significance of IMP3, Nucleophosmin, and Ki-67 Expression in Papillary Thyroid Carcinoma

The purpose of our study was to investigate the diagnostic value of expression of IMP3, nucleophosmin, and correlation of these markers with Ki-67 proliferation index in papillary thyroid carcinoma and benign neoplasms of thyroid gland. The aim was also to investigate whether there is a difference between papillary and micropapillary carcinomas with regard to clinicopathologic parameters beside IMP3, nucleophosmin, and Ki-67 proliferation index. It was concluded that IMP3 and nucleophosmin cannot be a routine diagnostic marker for discrimination of papillary carcinomas and benign lesions. IMP3 positive staining was quite scarce in IMP3 positive papillary carcinomas although specifity of IMP3 is 100%. A statistically significant correlation was not detected between nucleophosmin, IMP-3, and Ki-67 proliferation index. A statistically significant correlation was found between tumor size, lymphovascular embolism, and Ki-67 proliferation index. There was also significant correlation between tumor size and lymphovascular embolism.

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.

Fibroepithelial tumors of the breast: pathologic and immunohistochemical features and molecular mechanisms

CONTEXT

The 2 main prototypes of fibroepithelial tumors of the breast include fibroadenoma and phyllodes tumor (PT). Although both tumors share some overlapping histologic features, there are significant differences in their clinical behavior and management. Phyllodes tumors have been further divided into clinically relevant subtypes, and there is more than one classification scheme for PT currently in use, suggesting a lack of consistency within different practices. Accurate differentiation between fibroadenoma and PT, as well as the grading of PT, may sometimes be challenging on preoperative core needle biopsy. Some immunohistochemical markers have been suggested to aid in the pathologic classification of these lesions.

OBJECTIVE

To discuss the salient histopathologic features of fibroepithelial tumors and review the molecular pathways proposed for the initiation, progression, and metastasis of PTs. Also, to provide an update on immunohistochemical markers that may be useful in their differential diagnosis and outline the practice and experience at our institution from a pathologic perspective.

DATA SOURCES

Sources included published articles from peer-reviewed journals in PubMed (US National Library of Medicine).

CONCLUSIONS

Fibroepithelial tumor of the breast is a heterogenous group of lesions ranging from fibroadenoma at the benign end of the spectrum to malignant PT. There are overlapping histologic features among various subtypes, and transformation and progression to a more malignant phenotype may also occur. Given the significant clinical differences within various subtypes, accurate pathologic classification is important for appropriate management. Although some immunohistochemical markers may be useful in this differential diagnosis, histomorphology still remains the gold standard.

Molecular diagnosis for indeterminate thyroid nodules on fine needle aspiration: advances and limitations

Indeterminate thyroid lesions are diagnosed in up to 30% of fine needle aspirations. These nodules harbor malignancy in more than 25% of cases, and hemithyroidectomy or total thyroidectomy has therefore been advocated in order to achieve definitive diagnosis. Recently, many molecular markers have been investigated in an attempt to increase diagnostic accuracy of indeterminate fine needle aspiration cytology and thereby avoid unnecessary complications and costs associated with thyroid surgery. Somatic mutation testing, mRNA gene expression platforms, protein immunocytochemistry and miRNA panels have improved the diagnostic accuracy of indeterminate thyroid nodules, and although no test is perfectly accurate, in the authors' opinion, these methods will most certainly become an important part of the diagnostic tools for clinicians and cytopathologists in the future.

Insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs): post-transcriptional drivers of cancer progression?

The insulin-like growth factor-2 mRNA-binding proteins 1, 2, and 3 (IGF2BP1, IGF2BP2, IGF2BP3) belong to a conserved family of RNA-binding, oncofetal proteins. Several studies have shown that these proteins act in various important aspects of cell function, such as cell polarization, migration, morphology, metabolism, proliferation and differentiation. In this review, we discuss the IGF2BP family’s role in cancer biology and how this correlates with their proposed functions during embryogenesis. IGF2BPs are mainly expressed in the embryo, in contrast with comparatively lower or negotiable levels in adult tissues. IGF2BP1 and IGF2BP3 have been found to be re-expressed in several aggressive cancer types. Control of IGF2BPs’ expression is not well understood; however, let-7 microRNAs, β-catenin (CTNNB1) and MYC have been proposed to be involved in their regulation. In contrast to many other RNA-binding proteins, IGF2BPs are almost exclusively observed in the cytoplasm where they associate with target mRNAs in cytoplasmic ribonucleoprotein complexes (mRNPs). During development, IGF2BPs are required for proper nerve cell migration and morphological development, presumably involving the control of cytoskeletal remodeling and dynamics, respectively. Likewise, IGF2BPs modulate cell polarization, adhesion and migration in tumor-derived cells. Moreover, they are highly associated with cancer metastasis and the expression of oncogenic factors (KRAS, MYC and MDR1). However, a pro-metastatic role of IGF2BPs remains controversial due to the lack of ‘classical’ in vivo studies. Nonetheless, IGF2BPs could provide valuable targets in cancer treatment with many of their in vivo roles to be fully elucidated.

The quest for diagnostic molecular markers for thyroid nodules with indeterminate or suspicious cytology

Thyroid nodules are very common and fine needle aspiration (FNA) is a very sensitive means of diagnosis. However, its limitations include the fact that the cytology reports are often indeterminate or suspicious only. The quest for adjunctive measures to improve its specificity has been ongoing for decades, but significant results have remained elusive. The potential use of diagnostic molecular markers appears to be the most promising area of research at this time.

Insulin growth factor-2 binding protein 3 (IGF2BP3) is a glioblastoma-specific marker that activates phosphatidylinositol 3-kinase/mitogen-activated protein kinase (PI3K/MAPK) pathways by modulating IGF-2

Glioblastoma is the most common and malignant form of primary astrocytoma. Upon investigation of the insulin-like growth factor (IGF) pathway, we found the IGF2BP3/IMP3 transcript and protein to be up-regulated in GBMs but not in lower grade astrocytomas (p < 0.0001). IMP3 is an RNA binding protein known to bind to the 5′-untranslated region of IGF-2 mRNA, thereby activating its translation. Overexpression- and knockdown-based studies establish a role for IMP3 in promoting proliferation, anchorage-independent growth, invasion, and chemoresistance. IMP3 overexpressing B16F10 cells also showed increased tumor growth, angiogenesis, and metastasis, resulting in poor survival in a mouse model. Additionally, the infiltrating front, perivascular, and subpial regions in a majority of the GBMs stained positive for IMP3. Furthermore, two different murine glioma models were used to substantiate the above findings. In agreement with the translation activation functions of IMP3, we also found increased IGF-2 protein in the GBM tumor samples without a corresponding increase in its transcript levels. Also, in vitro IMP3 overexpression/knockdown modulated the IGF-2 protein levels without altering its transcript levels. Additionally, IGF-2 neutralization and supplementation studies established that the proproliferative effects of IMP3 were indeed mediated through IGF-2. Concordantly, PI3K and MAPK, the downstream effectors of IGF-2, are activated by IMP3 and are found to be essential for IMP3-induced cell proliferation. Thus, we have identified IMP3 as a GBM-specific proproliferative and proinvasive marker acting through IGF-2 resulting in the activation of oncogenic PI3K and MAPK pathways.

Characteristics of hepatic igf-ii expression and monitored levels of circulating igf-ii mRNA in metastasis of hepatocellular carcinoma

The prognosis of hepatocellular carcinoma (HCC) remains dismal. Insulin-like growth factor II (IGF-II), a fetal growth factor, is highly expressed during HCC development. We examined serum IGF-II levels and circulating IGF-II messenger RNA (mRNA) expression and analyzed the clinicopathologic characteristics in patients with liver diseases. The higher IGF-II level in the serum of patients with HCC could be correlated with hepatitis B virus infection but not with patient sex, age, tumor size, or α-fetoprotein (AFP) level. Total RNAs were extracted from liver tissues or peripheral blood mononuclear cells, and IGF-II complementary DNA (cDNA) and AFP cDNA were synthesized through random primers and reverse transcriptase; gene fragments were amplified by nested polymerase chain reaction and confirmed by sequencing. The incidence of the hepatic IGF-II gene was 100% in HCC, 54.3% in paracancerous tissues, and none in noncancerous tissues. The incidence rates for circulating IGF-II and AFP genes were 34.3% and 52.7%, respectively, and for both, 61.6% in patients with HCC. They were 100% in cases with extrahepatic metastasis. The IGF-II abnormality associates with HCC, and circulating IGF-II and IGF-II mRNA are useful molecular markers for HCC differential diagnosis and hematogenous metastasis.

Poorly differentiated carcinoma of the thyroid: validation of the Turin proposal and analysis of IMP3 expression

The Turin Proposal algorithm defines poorly differentiated carcinoma on the basis of the presence of solid/trabecular/insular growth pattern, absence of conventional nuclear features of papillary carcinoma, and the presence of at least one of the following features: convoluted nuclei, mitotic activity > or =3/10 HPF, or tumor necrosis. IMP3 appears to have diagnostic and prognostic value in many solid tumors, including thyroid carcinomas. We examined a series of follicular-cell carcinomas with prominent solid patterns diagnosed at Mayo Clinic (56 cases) (Rochester, MN, USA) and at the University of Turin (96 cases) (Northern Italy) to validate the Turin consensus criteria defining poorly differentiated carcinoma of the thyroid and to evaluate the prevalence and prognostic behavior of this tumor. On this series, we analyzed the expression of conventional markers by immunohistochemistry and we investigated the expression of IMP3 by both immunohistochemistry and qRT-PCR. The prevalence of poorly differentiated carcinoma among the USA cases was 1.8% (56/3128) and that in the cases of Northern Italy was 6.7% (96/1442). Tumor characteristics were similar in the cases from the USA and from Italy except for extensive vascular invasion and a prevalent insular growth pattern (lower the former, higher the latter in the Italian series). In univariate analysis, the risk of death was higher for age > or =45, tumors > or =4 cm, and IMP3 positivity. Multivariate analysis showed that the risk of death from poorly differentiated carcinoma was higher for age > or =45. The Turin consensus criteria can reliably select poorly differentiated carcinomas. Tumors from the USA and from Italy showed similar overall survival, although the prevalence of poorly differentiated carcinoma was higher in Northern Italy. Expression of IMP3 appears to be an adverse prognostic factor for poorly differentiated thyroid carcinoma.

Insulin-like growth factor II mRNA binding protein 3 (IMP3) is overexpressed in prostate cancer and correlates with higher Gleason scores

Background

The oncofetal protein insulin-like growth factor II mRNA binding protein 3 (IMP3) is an important factor for cell-migration and adhesion in malignancies. Recent studies have shown a remarkable overexpression of IMP3 in different human malignant neoplasms and also revealed it as an important prognostic marker in some tumor entities. To our knowledge, IMP3 expression has not been investigated in prostate carcinomas so far.

Methods

Immunohistochemical stainings for IMP3 were performed on tissue microarray (TMA) organized samples from 507 patients: 31 normal prostate tissues, 425 primary carcinomas and 51 prostate cancer metastases or castration-resistant prostate cancers (CRPC). IMP3 immunoreactivity was semiquantitatively scored and correlated with clinical-pathologic parameters including survival.

Results

IMP3 is significantly stronger expressed in prostate carcinomas compared to normal prostate tissues (p < 0.0001), but did not show significant correlation with the pT-stage, the proliferation index (MIB1), preoperative serum PSA level and the margin status. Only a weak and slightly significant correlation was found with the Gleason score and IMP3 expression failed to show prognostic significance in clinico-pathological correlation-analyses.

Conclusions

Although IMP3 is overexpressed in a significant proportion of prostate cancer cases, which might be of importance for novel therapeutic approaches, it does not appear to possess any immediate diagnostic or prognostic value, limiting its potential as a tissue biomarker for prostate cancer. These results might be corroborated by the fact, that two independent tumor cohorts were separately reviewed.

Analysis of IMP3 expression in normal and neoplastic human pituitary tissues

Insulin-like growth factor II mRNA-binding protein 3 (IMP3) is an oncofetal protein highly expressed in fetal tissue and malignant tumors but rarely found in adult benign tissues. In various tumors, IMP3 expression is correlated with increased tumor aggressiveness and reduced overall survival. To our knowledge, IMP3 expression has not been investigated in pituitary tumors. We analyzed the immunohistochemical expression of IMP3 in five normal pituitary tissues and 75 pituitary tumors (64 adenomas and 11 carcinomas) to determine if specific tumor types expressed IMP3 and if there were differences in IMP3 expression between adenomas and carcinomas. Immunohistochemical analysis showed that IMP3 was positive in four (80%) normal pituitaries with focal stain in a subset of normal anterior pituitary cells. IMP3 was expressed in 31% (20/64) of adenomas and in 36% (4/11) of carcinomas. A slightly higher level of IMP3 expression was observed in PRL-GH-TSH adenomas compared to the other types of pituitary adenomas. Expression of IMP3 was not significantly higher in carcinomas than in adenomas (p = 0.737). RT-PCR and Western Blotting supported the heterogeneous expression of IMP3. These results indicate that IMP3 is expressed both in normal and in neoplastic pituitary gland tissues without significant differences in expression levels in pituitary carcinomas.