Initial Exploration Of Significance Of Testing Human Papillomaviruse 18E6 In Ameloblastoma

ObjectiveAmeloblastoma(AB) is the most common odontogenic neoplasm, causing localdiscomfort.lt is characterized by a benign clinical behavior, possibly leading to localrecurrences but distant metastases from ameloblastoma are exceedingly rare.Athistology, ameloblastoma may display a protean appearance giving rise to severalgrowth patterns, such as follicular, plexiform, acanthomatous, basaloid, granular anddesmoplastic. The pathogenesis of such tumors is still unclear.Human papillomaviruses(HPVs) are nonenveloped viruses that contain an (?)8,000-bp circular DNAgenome.HPVs infect mucosal and cutaneous stratified squamous epithelia and aredivided into high-risk and low-risk viruses based on their pathogenicity. The low-riskviruses,e.g.,HPV-6 and HPV-11 ,mainly cause benign hyperproliferative disease,including the most prevalent viral sexually transmitted disease, condyloma acuminateor genital warts. The high-risk viruses,e.g., HPV-16 and HPV-18,and HPV-31,arenormally found in malignant tumors, including cervical cancer and some head and neckcancers. E6 is essential for the tumorigenicity of HPV infection. p53 can be inactivatedby binding to E6 protein of HPVs.The tumor suppressor p53 plays a pivotal role incancer development and can be activated by DNA damage, hypoxia, or aberrantoncogene expression to promote cell-cycle checkpoints, DNA repair, cellularsenescence, and apoptosis.I investigated the expression of HPV18E6 DNA and protein in AB using acomprehensive approach including immunohistochemistry, polymerase chain reactionand western blotting analysis.Discussing the association between HPV18E6 and thebiological behavior of AB and the roles of HPV18E6 in the genesis and developmentof AB.Materials and Methdods 1,Immunohistochemical stainingA total of 45 AB, 5 malignant ameloblastoma and 5 normal oral mucosas fromparaffin-embedded tissue were collected from School of Stomatology and the FirstAffiliated Hospital of China Medical University between 1987-2005．The AB included22 follicular patterns, 13 plexiform patterns, 5 unicystic ameloblastomas, 1 granulartypes, 1 desmoplastic type, and 2 peripheral ameloblastomas. I use theimmunohistochemical staining S-P to observe the change of the HPV18E6．2,Western Blot18 AB and 2 normal oral mucosas from frozen tissue were collected from Schoolof Stomatology between 2004-2006 to measure the expression of HPV18E6 protein.The AB included 2 follicular types, 7 plexiform patterns, 2 acanthomatous types, 2basal cell types, 2 desmoplastic types, 3 unicystic ameloblastoma.3,PCR12 AB and 11 normal oral mucosas from frozen tissue were collected from Schoolof Stomatology between 2004-2005 to measure the expression of HPV18E6 DNA. TheAB included 1 follicular patterns, 5 plexiform patterns, 2 acanthomatous types, 1 basalcell types, 1 desmoplastic type, 2 unicystic ameloblastoma.Experiment Results1,Immunohistochemical stainingThe immunohistochemical staining of HPV18E6 was observed in 46．67% (21/45) of AB tissues, in 20% (1/5) of malignant ameloblastoma, in 0 (0/5) of normal mucosas.They were significantly different with each other (X=4．023, P?0．05) . HPV18E6 waspositive expressed in the nuclear and plasma of peripheral cells, stellate central cells inAB.2,Western BlotThe positive rates of HPV18E6 in AB and normal mucosas with the Western blotapproach were 100% (18/18) and 0(0/2) , respectively.There was a significant differentamong AB and normal mucosas (F=4．670, P<0．05) .3,PCRThe positive rates of HPV18E6 in AB and normal mucosas with the PCR approach were 58．33% (7/12) and 18．18%(2/11) , respectively.There was a siginificant differentamong AB and normal mucosas(X=3．884, P<0．05) .Conclusions1,HPV18E6 DNA and protein were positive expressed in the partial AB. Thepositive rates of them in the AB were much higher than in the normal mucosas.2,HPV18e6 may involve in the genesis and development of the AB and induceproliferation disorder of AB.