Insulin-like Growth Factor II Messenger RNA-binding Protein 3 in Salivary Gland 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.

Immunohistochemical Study of IMP3 Expression in Laryngeal Squamous Cell Carcinoma

BACKGROUND: IMP3 is an RNA binding protein, which is strongly expressed in malignant tumors, promoting tumor cell proliferation. AIM: The aim of the study was to evaluate the expression of IMP3 in laryngeal squamous cell carcinoma (SCC) and to correlate the expression of IMP3 with available clinicopathological data. METHODS: Sixty one total laryngectomy and laryngoscopic biopsies; collected from the Pathology Department, Faculty of Medicine, Cairo University. Two slides were prepared from each paraffin embedded tumor block, one slide for Hematoxylin and Eosin staining, and the other for immunohistochemical staining by IMP3 polyclonal antibody. RESULTS: Thirty-seven cases (60.7%) showed positive IMP3 expression, and a statistically significant correlation was found between IMP3 expressions in normal, dysplastic epithelium/in situ component, and the invasive malignant tumor tissue. Correlations between IMP3 expression and other available clinicopathological data were all non-significant. CONCLUSION: This study suggests that IMP3 might play a role in laryngeal SCC carcinogenesis and progression process from normal to dysplastic to malignant epithelium, and thus IMP3 might be targeted by gene therapy.

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.

MicroRNAs expression pattern related to mast cell activation and angiogenesis in paraffin-embedded salivary gland tumors

The aim of this study was evaluate the expression profile of microRNAs related to mast cells activation and angiogenesis in salivary glands tumors.

METHOD

We have analyzed the expression of miR-9, miR-16, miR-17, miR-132, miR-195 and miR-221 by real-time RT-PCR, in 11 adenoid cystic carcinomas, 9 mucoepidermoid carcinomas and 11 pleomorphic adenomas. Immunohistochemical investigation was performed to detect mast cells tryptase and CD-34 for microvessels biomarkers. miR-16, miR-17, miR-132, miR-195 and miR-221 showed a decreased expression, whereas miR-9 showed an increased expression in most cases compared to normal tissues. However, in all tumors studied only miR-9 showed a statistical significant negative correlation with microvessel density (p=0.001). It was observed a higher density of mast cells in mucoepidermoid carcinomas (10.55 cells/mm2) when compared to adenoid cystic carcinomas (6.27 cells/mm2) and between mucoepidermoid carcinomas and pleomorphic adenomas (5.97células/mm2). miR-17, miR-132, miR-195 and miR-221 seem to play an important role as tumor suppressor in salivary gland tumors. In addition, the significant correlation between mast cell and microvessel density contributes to the growth and pathogenesis of these tumors and they may become strong therapeutic targets in the future.

IMP3 and p16 expression in squamous cell carcinoma of the head and neck: A comparative immunohistochemical analysis

Expression of p16 has been established as a good surrogate marker for high-risk human papillomavirus (HPV) infection in oropharyngeal squamous cell carcinoma (OPSCC) patients, and it has been associated with an improved prognosis, irrespective of the actual HPV status. Conversely, the human insulin-like growth factor II mRNA binding protein 3 (IMP3) has been related to aggressiveness in several types of tumors. The aim of the present study was to investigate and compare p16 and IMP3 as markers of favorable and unfavorable behavior, respectively, in head and neck SCC (HNSCC), with particular reference to the HPV status. Both markers were analyzed by immunohistochemical analysis of 156 HNSCC samples originating from the oropharynx (n=81), oral cavity (n=44), larynx (n=15), hypopharynx (n=10) and nasopharynx (n=6). The HPV status was examined in a randomly selected representative subcohort (n=38) using polymerase chain reaction. Of the 156 HNSCC samples, 81 (51.9%) and 54 (34.6%) were positive for IMP3 and p16, respectively. IMP3 expression (P=0.022), p16 expression (P<0.001) and the combination of these markers (P<0.001) were significantly associated with tumor site. In particular, 69/81 (85%) OPSCC samples were positive for either one or both markers compared with 36/75 (48%) SCC samples from other sites. p16 expression was significantly associated with HPV infection (P=0.017) and a trend towards a negative association between IMP3 expression and HPV infection was observed (P=0.053). The results of the present study suggested that IMP3 and p16 are more frequently expressed in OPSCC compared with other HNSCCs. The prognostic impact of IMP3 on OPSCC remains to be investigated in a larger series with an extended follow-up period.