key: cord-0016564-loua04wu authors: Farshbaf, Alieh; Zare, Reza; Mohajertehran, Farnaz; Mohtasham, Nooshin title: New diagnostic molecular markers and biomarkers in odontogenic tumors date: 2021-04-06 journal: Mol Biol Rep DOI: 10.1007/s11033-021-06286-0 sha: 313f216bc66f7df1bd8ccaf390bd8af78c561030 doc_id: 16564 cord_uid: loua04wu Odontogenic tumors comprised of complex heterogeneous lesions that diverse from harmatomas to malignant tumors with different behavior and histology. The etiology of odontogenic tumors is not exactly determined and pathologists deal with challenges in diagnosis of odontogenic tumors because they are rare and obtained experiences are difficult to evaluate. In this study, we describe immunohistochemical and molecular markers in diagnosis of odontogenic tumors besides advanced diagnostic technique. Immunohistochemical features of odontogenic tumors beside the clinical features and radiological finding can help us to determine the correct diagnosis. Although these markers are neither specific nor sensitive enough, but analysis of gene expression provides definitive confirmation of diagnosis. In addition, “-omics” technology detected specific molecular alternation associated with etiology such as genomics, epigenomics, transcriptomics, proteomics and metabolomics. The post transcriptional events such as DNA methylation and chromatin remodeling by histone modification affect the changes in epigenome. Furthermore, non-coding RNAs like micro-RNAs, long noncoding RNA (lncRNA) and small non-coding RNA (snoRNA) play regulatory role and impact odontogenesis. Molecular marker propose their potential role in etiopathogenesis of odontogenic tumors and suitable candidate in diagnostic, prognostic and therapeutic approaches in addition to patient management. For future evaluations, organoid represents in vitro tumor model-study for tumor behavior, metastasis and invasion, drug screening, immunotherapy, clinical trial, hallmarks association with prognosis and evolution of personalized anti-cancer therapy. Moreover, organoid biobank help us to check genetic profile. We think more investigation and studies are needed to gain these knowledges that can shift therapeutic approaches to target therapy. Odontogenic tumors comprise of complex heterogeneous lesions that originate from ectomesenchymal and/or epithelial odontogenic tissues and manifest following normal tooth development. They are diverse from harmatomas to malignant tumors with different behavior, histology and even different geographical distribution [1] . The odontogenic tumors manifest variant clinical features including disfigurement of the face, jaw expansion and extension, root and bone resorptions, teeth mobility and alternation in bone density [2] . There are two primary classification for odontogenic tumors including benign odontogenic tumors that arise de novo and malignant odontogenic tumors that almost take from benign precursor, but WHO categorized the new edition based on origin of tissue and histological characteristics in 2017 that are mentioned in Table 1 [3, 4] . It was reported that among all oral tumors, odontogenic tumors are less than 1%, and also 99.2% of them are benign type [5] . Markers are molecules, genes or molecular features in pathogenesis of disease play a critical role in diagnosis and management of patients, especially in tumorigenic cases [6] . It was identified a few markers for evaluation of odontogenic tumor s pathogenesis, but immunohistochemistry (IHC) may be useful for pathologists. Although histological features of odontogenic tumor such as morphology along with radiology provide clinical diagnosis, but cystic lesions, tiny biopsies and determination of malignancy changes are some problems [7] . Also, over/under expression of some genes are reported as molecular marker in odontogenic tumors [8] . In this manner, specific markers help us in the correct diagnosis of special types of odontogenic tumor, and it increases our knowledge about pathogenesis and molecular genetic features of these lesions. In this study, we describe immunohistochemical and molecular markers in diagnosis of odontogenic tumors and investigate recent studies based on "omics" that provide more information about prognosis and therapeutic approach of these tumors in addition to diagnosis. Immunohistochemistry (IHC) is an immunostaining technique that detected antigens (proteins) by binding antibodies in cells or tissue. The main benefit of IHC is detection of a specific target following antibody-antigen interaction and can apply in diagnosis of cancerous tumor subsequent to proliferation or cell death. In addition, location and distribution of expressed protein are emerged in various parts of tissue. For instance, it was reported significant expression of podoplanin in invasive odontogenic tumors by immunohistochemistry technique that emphasized the diagnostic role of this marker on neoplastic behavior [9] . Also, overexpression of MDM2 and p53 was demonstrated in solid multicystic ameloblastoma (SMA) and keratocystic odontogenic tumor (KOT) as IHC markers [10] . In addition, histological features of the lesion can be helpful in differential diagnosis of rare extension cases such as calcifying epithelial odontogenic tumor (CEOT) or Pind-borg tumor that expand to the maxillary sinus [11] . The high expression of Cripto-1 or teratoma-derived growth factor 1 (TDGF-1) in almost of aggressive odontogenic lesions proposed involvement of this molecules in ethiopathogenesis [12] . So, IHC seems to be useful for evaluation of tumors by molecular biomarkers. In this manner, Immunohistochemical features of odontogenic tumors beside the clinical features and radiological finding can help us to determine the correct diagnosis. Because the correct diagnosis helps us for better patient management in therapy. Some side effects of radiotherapy for head and neck cancers include xerostomia, dental caries and oral ulcers that affect oral intake and difficulty in speech. Moreover, radiotherapy increases osteosarcoma and oral infection like oral candidiasis because stomach reflex manifests following nausea and vomiting [13] . So, biomarker diagnosis plays a critical role in patient management. There are restricted studies to share results of The etiology of odontogenic tumors is not exactly determined, but the result of next-generation sequencing demonstrated specific mutation improved the biology process in tumorigenesis of odontogenic tumors. They involve in cell proliferation and differentiation, control of cell cycle, regulation of tooth development or be growth factor and receptors, telomerase, apoptotic factors and extracellular matrix remodeling [16] . Most of them that involve in the molecular pathogenesis of odontogenic tumors are oncogene or tumor suppressor genes that we mentioned in Table 3 [17] [18] [19] . On the other hand, post transcriptional events such as methylation influences gene activity without any changes in DNA sequence. In this manner, DNA methylation and chromatin remodeling by histone modification inhibit recruitment of splicing or transcription factors. So imprinting or suppress of gene expression result in tumor development [20] . Thus, the tumor biology is affected by the changes in the genome and epigenome. In addition, some non-coding RNAs like micro-RNAssmall noncoding RNA with 21-25 nt-have regulatory role and impact odontogenesis. For example, miR-16-1 and miR-15a play tumor suppressor role by repression of BCL-2 gene and induce apoptosis. It was shown that the expression of BCL-2 is increased in KOT, but the expression of mir-16-1 and mir-15a are reduced [21] . Profile of micro-RNA expression emerged 40 micro-RNAs with different expression in ameloblastoma compare to control group [22] . Long-noncoding RNA (lncRNA) is another regulatory molecule-more than 200 nt in length-that participates in chromatin modulation and affects transcription and translation [23] . Result of RNA microarray analysis demonstrated LINC-340 up regulated in ameloblastoma and associated with the size of the tumor [24] . Furthermore, another class of small non-coding RNA (snoRNA) that modified ribosomal RNA positively correlated to size of tumor such as SNORA11 in ameloblastoma [24] . This significant different expression of the molecular marker proposes potential role of them in etiopathogenesis of odontogenic tumors and suitable candidate in diagnostic and therapeutic approaches. In recent years "-omics" studies discover potential candidate biomolecules in pathogenesis of odontogenic lesions [19] . "-omics" technology provides comprehensive biological information that analyses specific types of molecules. For example, genomics, epigenomics, transcriptomics, proteomics and metabolomics are different levels of this technology that evaluates alterations in DNA, non-DNA sequence, RNA, proteins and metabolites, respectively (Fig. 1) [25] . This technology enables to detect molecular mechanism, etiology, for better management of affected odontogenic patients. In this regard, some studies exhibit the result of "-omics" in odontogenic cases that can apply in diagnostic approaches [19] . For example, protein plays a regulatory role during cell function and because of dynamic protein interaction in a complex, proteomics-based technology provides identification and quantification of proteome. So it will be applicable in diagnostic approaches in addition to prognosis and therapeutic to vaccine development [26] . In odontogenic tumors, proteomics emerged significant alternation of protein levels in some classified types. For instance, it was reported the increasing level of AIDA protein in odontogenic keratocyst [27] . Understand of molecular pathology helps us to develop a therapeutic approach in addition to diagnosis. For instance, immunostaining of ameloblastoma cases demonstrated p53 and MDM2 was high in odontogenic keratocyst (OKC) followed by solid multicystic ameloblastoma (SMA) [10] . Also, immunoexpression of PTEN in ameloblastoma cases showed significant reduction in immunoactivity [28] . The pathologists deal with challenges in diagnosis of odontogenic tumors because they are rare and obtained experiences are difficult to be evaluated. The diagnosis is determined based on morphology, clinical manifestation and radiological features, but the outcome of many studies demonstrated immune-histochemical marker can help us to diagnose of some odontogenic tumors. Although these markers are neither specific nor sensitive enough, but analysis of gene expression can help us in definitive confirmation of diagnosis. Based on the molecular pathway that lesions are involved, expression of some genes changes as overexpression or aberrant expression. In addition, "-omics" technology detected specific molecular alternation associated with etiology of disease. But low frequency of odontogenic lesions restricted researches to discover many aspects of disease. Whole genome sequencing and transcriptomics in ghost cell odontogenic carcinoma manifested involving of NOTCH and SHH pathways including increased copy number of SHH, GLI1, JAG1, DTX3, and HEY1 that result in overexpression of them. Furthermore, fusion of TCF4 and PTPRG genes defect tumor suppressor activity of tyrosine phosphatase receptor type G protein [29] . Understand of odontogenic pathogenesis of odontogenic tumors assistances with diagnosis of malignant transformation, development and progression of lesions. It seems if that tissue samples after collection embedded in paraffin or formalin-fixed can be saved as a bio bank for future evaluation. Recent technologies provide easy access to Ameloblastoma CD68, lysozyme Present with macrophage, lysis central odontogenic fibroma S100 A family of calcium-binding proteins Odontogenic myxoma Ki-67 Cell proliferation marker Ameloblastic carcinoma, Ameloblastoma genome, transcriptome or proteome of saved samples with sufficient integrity and quality [30] . As another strategy, organotypic cultures were suggested in an experimental model for detection of molecular aspects of odontogenic tumors. The organotypic cultures provide ex vivo imitated neoplastic microenvironment with suitable reproduction of the growth pattern. In addition, organoid represents in vitro tumor model-study for metastasis and invasion, drug screening, immunotherapy, clinical trial, hallmarks association with prognosis and evolution of personalized anti-cancer therapy [31] . Organoid provide optional treatment for patientʹ s tumor attention to site, stage and personal factors and variation in their genetic profile as personalized medicine. For example, different drug dosage or combination therapy can be applied in an organoid and the outcome determined the best choice for therapy [32] . Further, organoid led to collect biobank from different tumor cell lines and study genome features following cell propagation and development, so alternation in genetic profile such as mutations can be studied between tumouroid line and a derived tumor [33] . Also, we propose application of biobank with collection of odontogenic lesion types from different geographical regions can help us to define a distinct profile change in the genome for therapy. The first study with long-term 3D primary culture was performed for odontogenic myxoma and the cemento-ossifying fibroma with cell expansion more than one month [34] . More investigation is continued for human head and neck tumors with organoid. For example, 3D organoid provides target therapeutic screening based on a non-surgical method to evaluate ameloblastoma pathogenesis and progression for BRAF and LGR5 inhibition [35] . More knowledge about biology and molecular behavior of odontogenic tumors increases our information for better understanding of their nature. Also, we think more investigation and studies are needed to gain these knowledges that can shift therapeutic approaches to target therapy. Detection of genetic factors that are involved in molecular pathogenesis of odontogenic tumors helps us in target therapy, special gene therapy when surgical treatments are contraindicated [36] . In this manner we can find ways for other odontogenic lesions as nonsurgical therapeutic approaches (Fig. 2 ). The restricted origin of odontogenic tumors (epithelial, mesenchymal or mixed) might appear with similar morphology and histochemical features in differential diagnosis. So, mistaken in diagnosis provides improper treatment because some odontogenic tumors need invasive therapy but others not. The molecular advanced technology like next-generation sequencing or "omics" can identify all aspects of tumor changes and help us to consider more candidates in diagnosis, prognosis and therapeutic approaches. Target therapy in oral pathology needs more investigation, and it seems ethiopathological information of familial odontogenic tumors in different geographical regions can help us to modify our attitude to pathogenesis of these lesions. 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