Objective: To detect the SMO mutations in odontogenic keratocyst (OKC) and to explore the mechanism behind. Methods: Patients with OKC who received treatment in the Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology,Peking University, from September 2012 to June 2017 were enrolled. OKC samples from 10 patients diagnosed as naevoid basal cell carcinoma syndrome (NBCCS)-related OKC (4 females and 6 males) and 20 patients diagnosed as sporadic OKC (7 females and 13 males) were collected. Genomic DNAs were extracted from fibrous capsules and epithelial lining respectively. SMO mutations were detected and analyzed by Sanger sequencing. Results: Three SMO mutations were found in one NBCCS-associated OKC who carrying c.2081C>G (p.P694R) mutation) and two sporadic OKC who carrying c.907C>T (p.L303F) mutation and c.1247_1248delinsAA (p.G416E), respectively), among which the first two mutations were novel mutations that had not been reported before. Besides, two mutations in sporadic OKC were not paired with PTCH1 mutations. Conclusions: In addition to PTCH1 gene mutations, SMO gene mutations also exist in OKC which might be related to the development of OKC.
Basal Cell Nevus Syndrome/genetics* ; Female ; Humans ; Male ; Mutation ; Odontogenic Cysts/genetics* ; Odontogenic Tumors/genetics* ; Smoothened Receptor/genetics*

OBJECTIVETo study hTERT mRNA expression in ameloblastoma (AB) and odontogenic keratocyst (OKC) and to investigate genesis, development and biological characteristics of AB and OKC.

METHODShTERT mRNA expression in 54 cases of AB, 16 cases of OKC, 7 cases of oral normal mucosa was detected by in situ hybridization.

RESULTSThe positive rates of hTERT mRNA in AB, OKC, and oral normal mucosa were 94.4% (51/54), 87.5% (14/16), 1/7, respectively. There was significant statistical difference (P < 0.001). About clinicalpathology of AB, there was no difference for hTERT expression (P > 0.05) hTERT mRNA was positive in peripheral and stellate reticula cells.

CONCLUSIONS(1) hTERT activity plays an important role in genesis, development of AB. (2) hTERT positive rate is related to cell differentiation and clinical biological behavior.

Ameloblastoma ; DNA-Binding Proteins ; metabolism ; Humans ; Jaw Neoplasms ; Odontogenic Cysts ; Odontogenic Tumors ; metabolism ; RNA, Messenger ; metabolism ; Telomerase ; genetics

OBJECTIVETo investigate the proliferative potential of the epithelial cells in odontogenic keratocyst, radicular cyst, dentigerous cyst and ameloblastoma.

METHODSDNA contents and ploidy of basal and spinous cells in keratocyst, radicular cyst, dentigerous cyst, and the peripheral column cells and central reticular cells in ameloblastoma were analysis respectively.

RESULTSThe more and higher DNA contents and the proliferating ploidy of keratocyst and ameloblastoma than those of radicular cyst and dentigerous cyst indicate the active proliferating potential. The spinous cells showed more active proliferating growth than the basal cells of keratocyst. The higher DNA contents of radicular cyst are related to the stimulus of the inflammation. The dentigerous cysts have more di-ploidy cells without active growth potential.

CONCLUSIONSThe active cell proliferating growth in keratocyst and ameloblastoma is probably the pathological basis of their local aggressive biological behavior.

Ameloblastoma ; genetics ; pathology ; Cell Division ; genetics ; DNA ; metabolism ; Humans ; Jaw Neoplasms ; genetics ; pathology ; Odontogenic Cysts ; genetics ; pathology ; Ploidies

Odontogenic keratocysts (OKCs) are common cystic lesions of odontogenic epithelial origin that can occur sporadically or in association with naevoid basal cell carcinoma syndrome (NBCCS). OKCs are locally aggressive, cause marked destruction of the jaw bones and have a propensity to recur. PTCH1 mutations (at ∼80%) are frequently detected in the epithelia of both NBCCS-related and sporadic OKCs, suggesting that PTCH1 inactivation might constitutively activate sonic hedgehog (SHH) signalling and play a major role in disease pathogenesis. Thus, small molecule inhibitors of SHH signalling might represent a new treatment strategy for OKCs. However, studies on the molecular mechanisms associated with OKCs have been hampered by limited epithelial cell yields during OKC explant culture. Here, we constructed an isogenic PTCH1 cellular model of PTCH1 inactivation by introducing a heterozygous mutation, namely, c.403C>T (p.R135X), which has been identified in OKC patients, into a human embryonic stem cell line using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system. This was followed by the induction of epithelial differentiation. Using this in vitro isogenic cellular model, we verified that the PTCH1 heterozygous mutation causes ligand-independent activation of SHH signalling due to PTCH1 haploinsufficiency. This activation was found to be downregulated in a dose-dependent manner by the SHH pathway inhibitor GDC-0449. In addition, through inhibition of activated SHH signalling, the enhanced proliferation observed in these induced cells was suppressed, suggesting that GDC-0449 might represent an effective inhibitor of the SHH pathway for use during OKC treatment.
Anilides ; pharmacology ; Basal Cell Nevus Syndrome ; Hedgehog Proteins ; genetics ; pharmacology ; Humans ; Molecular Targeted Therapy ; Odontogenic Cysts ; genetics ; physiopathology ; therapy ; Odontogenic Tumors ; genetics ; physiopathology ; therapy ; Pyridines ; pharmacology

OBJECTIVETo investigate the frequency, type and distribution of PTCH mutations in odontogenic keratocysts (OKC) and to analyze the molecular pathological relationship between sporadic OKC and OKC associated with nevoid basal cell carcinoma syndrome (NBCCS).

METHODSGenomic DNA was extracted from 8 cases of OKC lesions (4 sporadic OKCs and 4 NBCCS-related OKCs). PTCH gene mutations were detected by PCR-direct sequencing.

RESULTSSix novel PTCH mutations were identified in 6 out of 8 cases (2 sporadic and 4 NBCCS-related OKCs). Two of these were missense mutations leading to substitution of an amino acid residue respectively. The other 4 mutations were identified as insertion or deletion ranging from one single base to 7 bases, three of which caused frame-shift leading to premature truncation of PTCH protein and one resulted in an insertion of 2 amino acid residues. All these identified mutations were novel and have not been previously described.

CONCLUSIONSPTCH gene mutation is a common event in NBCCS-related OKCs and could also be detected in some sporadic OKCs. Abnormalities of PTCH gene may be involved in the pathogenesis of OKC.

Adolescent ; Adult ; Aged ; Basal Cell Nevus Syndrome ; complications ; genetics ; DNA Mutational Analysis ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Odontogenic Cysts ; complications ; genetics ; Patched Receptors ; Patched-1 Receptor ; Receptors, Cell Surface ; genetics ; Young Adult