PTCH gene mutations in odontogenic keratocysts

An odontogenic keratocyst (OKC) is a benign cystic lesion of the jaws that occurs sporadically or in association with nevoid basal cell carcinoma syndrome (NBCCS). Recently, the gene for NBCCS was cloned and shown to be the human homologue of the Drosophila segment polarity gene Patched (PTCH), a tumor suppressor gene. The PTCH gene encodes a transmembrane protein that acts in opposition to the Hedgehog signaling protein, controlling cell fates, patterning, and growth in numerous tissues, including tooth. We investigated three cases of sporadic odontogenic keratocysts and three other cases associated with NBCCS, looking for mutations of the PTCH gene. Non-radioactive single-strand conformational polymorphism and direct sequencing of PCR products revealed a deletion of 5 base pairs (bp) in exon 3 (518delAAGCG) in one sporadic cyst as well as mutations in two cysts associated with NBCCS, a nonsense (C2760A) and a missense (G3499A) alteration. This report is the first to describe a somatic mutation of PTCH in sporadic odontogenic keratocysts as well as two novel mutations in cysts associated with NBCCS, indicating a similar pathogenesis in a subset of sporadic keratocysts.     

Immunohistochemical analysis of the biological potential of odontogenic keratocysts

BACKGROUND: The aim of this study was to analyse the usefulness of detecting important apoptosis and proliferation markers in assessing the biological potential of odontogenic keratocysts (OKC) and thus selecting the optimal diagnostic algorithm for these lesions. METHODS: Indirect immunohistochemistry and relevant statistical methods were used for analysis of formalin-fixed and paraffin-embedded samples from 98 patients. RESULTS: Nevoid basal cell carcinoma syndrome (NBCCS) keratocysts were characterized by higher expression of Bcl-2, p27Kip1 and c-erbB-2 as well as by lower proliferative activity measured by Ki-67 in basal cell epithelium and by a lower inflammatory response in comparison with sporadic keratocysts. Dentigerous, radicular and non-specified odontogenic cysts differed from both NBCCS and sporadic keratocysts in a wide spectrum of apoptosis and/or cell cycle-related protein expressions, higher proliferation in the basal cell layer, and vice versa, lower proliferation in the suprabasal cell layer. CONCLUSIONS: The NBCCS keratocysts have a different immunophenotype from sporadic keratocysts and both types are distinguishable from dentigerous, radicular and non-specified odontogenic cysts. These findings confirm the separate biological potential of these lesions and the results of the immunohistochemical analysis have diagnostic and prognostic implications.     

PTCH1 and SMO gene alterations in keratocystic odontogenic tumors

Keratocystic odontogenic tumors (KCOTs, previously known as odontogenic keratocysts) are aggressive jaw lesions that may occur in isolation or in association with nevoid basal cell carcinoma syndrome (NBCCS). Mutations in the PTCH1 (PTCH) gene are responsible for NBCCS and are related in tumors associated with this syndrome. Mutations in the SMO gene have been identified in basal cell carcinoma and in medulloblastoma, both of which are features of NBCCS. To clarify the role of PTCH1 and SMO in KCOTs, we undertook mutational analysis of PTCH1 and SMO in 20 sporadic and 10 NBCCS-associated KCOTs, and for SMO, 20 additional cases of KCOTs with known PTCH1 status were also included. Eleven novel (1 of which occurred twice) and 5 known PTCH1 mutations were identified. However, no pathogenic mutation was detected in SMO. Our findings suggest that mutations are rare in SMO, but frequent in PTCH1 in sporadic and NBCCS-associated KCOTs. Abbreviations: NBCCS, nevoid basal cell carcinoma syndrome; KCOTs, keratocystic odontogenic tumors; BCCs, basal cell carcinomas.     

Imaging modality correlations of an odontogenic keratocyst in the nevoid basal cell carcinoma syndrome: a family case report

Multiple maxillary and mandibular cysts are principle features of nevoid basal cell carcinoma syndrome (NBCCS; Gorlin-Goltz syndrome). We present a family case report of NBCCS with odontogenic keratocyst where the findings on plain films, CT, clinical, and histopathologic examinations are compared and analyzed. The systemic manifestations included frontal bossing, odontogenic keratocyst, ectopic calcification in 1 patient, and bifid rib in 1 patient. CT examination displayed aspects of bone morphology not visible on the plain films. Odontogenic keratocyst diagnosis was confirmed by histopathological examination. The features identified by these combined clinical, imaging, and histologic findings are helpful in identifying an NBCCS patient, distinguishing keratocyst from others cysts or neoplasic lesions, and can therefore influence surgical management. NBCCS is a rare autosomal dominant cancer predisposition syndrome, which is important to recognize when a patient has multiple odontogenic keratocysts, because lifelong monitoring is essential for patient management.     

Situs inversus in a patient with nevoid basal cell carcinoma syndrome: a histogenetic relationship?

Nevoid basal cell carcinoma syndrome (NBCCS) is an uncommon autosomal dominant inherited disorder with high penetrance and variable expressivity. It affects multiple organ systems, including the stomatological, skeletal, skin, eye, reproductive, and central nervous systems. It is caused by mutations in the patched tumor suppressor gene, PTCHI, located in the 9q22.3-q31 chromosome. To our knowledge, this is the first report of a patient with unusual radiological features, i. e. dextrocardia and situs inversus totalis, in conjunction with common features including multiple keratocystic odontogenic tumors, bifid ribs, palmar and plantar pits, bridging of the sella turcica and calcification of the falx cerebri. We examined whether these genetic conditions were associated, as both involve ciliary dysfunction.     

Odontogenic keratocyst and uterus bicornis in nevoid basal cell carcinoma syndrome: case report and literature review

Nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant disorder with a high degree of penetrance and variable expressivity, is characterized by basal cell carcinomas, odontogenic keratocysts, palmar and/or plantar pits, and ectopic calcifications of the falx cerebri. More than 100 minor criteria have been described, but 2 major and 1 minor criteria or 1 major and 3 minor criteria are necessary for the diagnosis. In this report we present an 8-year-old girl affected by NBCCS showing a uterus bicornis, a hitherto unreported association. However, further research is needed to confirm the association between NBCCS and mullerian fusion defects and to assess the hypothesis that focuses on chromosome 9 the mutant gene for NBCCS and fusion defects of female genital tract.     

The odontogenic keratocyst and its occurrence in the nevoid basal cell carcinoma syndrome

There are histologic differences between odontogenic keratocysts occurring in the basal cell carcinoma syndrome (NBCCS) and as single lesions in otherwise healthy persons. This study identifies certain differences in age, gender, and site between the two groups. The age at removal of the first keratocyst is significantly lower in the syndrome group. On more thorough examination, patients with multiple keratocysts (excluding recurrences) are found to have other features of NBCCS. The term multiple cysts refers to the lifetime history of the patient and does not necessarily imply that more than one cyst is present at any one time.     

Gorlin-Goltz syndrome

Gorlin-Goltz syndrome is an uncommon autosomal dominant inherited disorder, which is characterized by multiple odontogenic Keratocysts and basal cell carcinomas, skeletal, dental, ophthalmic, and neurological abnormalities, intracranial ectopic calcifications of the falx cerebri, and facial dysmorphism. Pathogenesis of the syndrome is attributed to abnormalities in the long arm of chromosome 9 (q22.3-q31) and loss or mutations of human patched gene (PTCH1 gene). Diagnosis is based upon established major and minor clinical and radiological criteria and ideally confirmed by deoxyribo nucleic acid analysis. We report a case of a 9-year-old girl presenting with three major and one minor feature of Gorlin-Goltz syndrome. Radiologic findings of the syndrome are easily identifiable on Orthopantomogram, chest X-ray, and Computed tomography scans. These investigations prompt an early verification of the disease, which is very important to prevent recurrence and better survival rates from the coexistent diseases.     

PCR-SSCP和DNA测序检测牙源性角化囊肿中PTCH基因的突变

目的 检测牙源性角化囊肿（OKC）中PTCH基因突变的特点。方法 采用PCR-SSCP筛查与DNA直接测序的方法对12例OKC进行PTCH基因突变的检测, 其中2例为痣样基底细胞癌综合征（NBCCS）相关OKC,10例为散发OKC。 结果 在4例OKC中发现了4处突变,其中2处生殖细胞突变发生在2例NBCCS相关OKC,2处体细胞突变发生在2例散发OKC。另外,还在10例OKC中检测到了8处PTCH基因多态性。结论 NBCCS相关OKC和散发OKC均可发生PTCH基因突变,但突变水平不同,PTCH基因的突变在二者的发病中可能均起重要作用。     

Gorlin's syndrome. Case report

The authors present a case of Gorlin's Syndrome, more satisfactorily defined as nevoid basal cell carcinoma syndrome (NBCS), a rare genetic disorder characterized mainly by multiple basal cell carcinomas and odontogenic keratocysts and other less frequent skeletal, sexual and neurological manifestations. Patient 75 years old, male. Previously treated surgically for multiple cutaneous basal cell carcinomas, comes to our Department to remove a suspected asymptomatic keratocyst. Clinical examination reveals cutaneous alterations of hands and feet (webbed hands and feet), a little progenism and multiple nevi and basal cell carcinomas on the body and the head. The oral cavity is free of alterations or clinical signs. NBCS is probably caused by chromosomal abnormalities of chromosome 5 and 9. The abnormalities seen in the latter are similar to those seen in people exposed for long periods to UV radiation. These abnormalities could determine malignant cutaneous tumors removing anti neoplastic protection. The association with odontogenic keratocysts, however not clearly understood, appears in more than 90% of cases. All the other disorders are less frequent. Juvenile basal cell carcinomas, especially if associated with odontogenic keratocysts suggest, the hypothesis of NBCS; if confirmed, this diagnosis makes further familial investigations necessary, to diagnose other cases, at the time unknown.     

PTCH gene altered in dentigerous cysts

Motivated by the evidence that odontogenic keratocysts are associated with genetic alterations, we examined the possibility that development of other odontogenic cysts can be attributed to gene malfunctioning, in particular to the PTCH gene. Cyst epithelium was examined for polymorphism on chromosome 9q22.3, the region that contains the PTCH gene. Loss of heterozygosity (LOH) for the D9S287 marker and/or D9S180 marker was observed in about 50% of dentigerous cysts, whereas radicular cysts gave no indication of lesions in the PTCH region. As a more direct argument for PTCH involvement in cystic growth, we report evidence of PTCH expression in dentigerous cyst lining, which indicates malfunctioning of the relevant signaling pathway. While we found no reason to believe that PTCH should be associated with radicular cysts, other genes may be implicated in their development. We performed immunohistochemical comparisons of keratocysts, dentigerous and radicular cysts for the nonmetastatic marker Nm23. A graded response placed radicular cysts in between the other two types, suggesting a similar neoplastic character for their epithelial proliferation.     

Ameloblastoma associated with the nevoid basal cell carcinoma (Gorlin) syndrome

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by a wide range of clinical signs and symptoms. The major criteria for the diagnosis are multiple cutaneous basal cell carcinomas, multiple odontogenic keratocysts of the jaw, palmar and plantar pits, and skeletal abnormalities. Here, we report an unusual case of NBCCS in a 68-year-old woman with late onset of clinical signs and symptoms and with an associated ameloblastoma. Only 4 other cases of this unusual association have been reported.     

牙源性角化囊肿中PTCH基因的突变检测

目的检测牙源性角化囊肿（OKC）中PTCH基因突变的发生频率、类型及分布特点，分析散发OKC与伴发痣样基底细胞癌综合征（NBCCS）OKC之间的分子病理联系。方法收集8例OKC新鲜病变组织（4例散发，4例伴发NBCCS），提取DNA，采用PCR直接测序法检测OKC病变组织中的PTCH基因突变。结果分别于4例NBCCS—OKC和2例散发OKC中检测到6处PTCH基因突变，2例为错义突变，引起1个氨基酸的改变；其余4例突变分别为1～7个碱基插入或缺失，其中3例引起读码框的改变（移码突变），并导致蛋白质的提前截断，1例导致了2个氨基酸的插入。结论PTCH基因突变不仅常见于NBCCS—OKC，部分散发OKC病变也可以发生该基因的异常。     

Evidence of loss of heterozygosity of the PTCH gene in orthokeratinized odontogenic cyst

J Oral Pathol Med (2011) 40 : 277–280 The orthokeratinized odontogenic cyst (OOC) is an odontogenic cyst of unknown etiology. Clinical, histological, and biological differences are reported between keratocystic odontogenic tumor (KOT) and OOC. PTCH is a tumor suppressor gene related to sonic hedgehog (SHH) pathway important in embryological development. Considering that alterations in this pathway have been described in sporadic and nevoid basal cell syndrome‐associated KOT, we tested the hypothesis that OOC is also associated with loss of heterozygosity (LOH) of the PTCH gene. Seven samples of OOC and seven of KOT were included in the study. D9S287, D9S196, and D9S127 microsatellite markers located in the region of PTCH gene, at chromosome 9q, were investigated for LOH. There was loss in at least one locus in 5/7 KOT and in 4/7 OOC samples. The present finding demonstrates that, despite the existence of clinical, morphological, immunohistochemical, and biological behavior differences between OOC and KOT, both harbor similar genetic alterations at 9q.     

Recurrence of the odontogenic keratocyst in 13 patients with the nevoid basal cell carcinoma syndrome. A 6-year follow-up

A 6-year follow-up study of 44 primarily enucleated odontogenic keratocysts from 13 patients with the characteristics signs and symptoms of the nevoid basal cell carcinoma syndrome (NBS) is presented. The 2-, 3-, 4-, 5- and 6-year follow-ups revealed an incidence of recurrence by the single keratocyst of 20, 30, 39, 50 and 55%, respectively. These figures demonstrate that the majority of the recurrences occurred within a period of 5 years postoperatively. However, as the proportion of increased recurrence in the period from 5 to 6 years postoperatively was 5%, a follow-up period of more than 6 years is necessary in order to make the diagnosis of recurrence without any delay in all patients with NBS. The occurrence of odontogenic epithelium and/or microcysts in the cyst wall of keratocysts without any recurrence at the 5-year follow-up was compared with the occurrence of similar histopathologic features in keratocysts which at the 5-year follow-up had shown recurrence. The occurrence of odontogenic epithelium and/or microcysts was demonstrated in 43% of the group of keratocysts without recurrence and in 57% of the group of keratocysts with recurrence. However, this difference is not statistically significant (P > 0.10) and indicates that the high occurrence (50%) of odontogenic epithelium and/or microcysts in NBS-keratocysts is not significantly correlated to the recurrence.     

Analysis of the neoplastic nature and biological potential of sporadic and nevoid basal cell carcinoma syndrome-associated keratocystic odontogenic tumor

BACKGROUND: Keratocystic odontogenic tumor (KCOT), also known as odontogenic keratocyst, is a benign cystic neoplasm, which may be associated with nevoid basal cell carcinoma syndrome (NBCCS) and if it does, will occur as multiple cystic lesions. KCOT is locally destructive despite its bland histological features. However, the neoplastic nature of KCOT is not well established. Heparanase is an endo-d-glucuronidase enzyme that specifically cleaves heparan sulfate (HS) and the increase of its level in tumors promotes invasion, angiogenesis, and metastasis. METHODS: To investigate the neoplastic character of KCOT, we studied the localization patterns of heparanase in KCOT, focusing on the differences between sporadic and NBCCS-associated KCOTs, by immunohistochemistry and in situ hybridization. To compare the expression pattern of these cysts with non-tumorous odontogenic developmental cyst, dentigerous cyst was included. RESULTS: All the odontogenic cysts showed positive immunoreaction for heparanase protein in various intensities. The expression pattern of heparanase gene corresponded to that of protein expression. Interestingly, intense gene and protein expressions were observed in KCOT associated with NBCCS compared with sporadic ones and dentigerous cyst. CONCLUSIONS: The results implied that heparanase expression may be correlated with the neoplastic properties of KCOT, particularly in NBCCS-associated cases.     

Central carcinoma of the jaws. A radiography and pathological analysis of 36 cases]

Records of 36 cases of central carcinoma of the jaws were collected, including 25 cases of squamous cell carcinoma; 9 cases of salivary gland carcinoma; one case of undifferentiated carcinoma and one case of basal cell carcinoma. The correlation between roentgenographic appearance and the histopathologic types are: (1) most lesions of osteolytic destruction are primary intraosseous carcinoma of the jaws (14/16); (2) most lesions of multilocular destruction are salivary gland carcinoma (8/11); (3) most lesions of unilocular destruction are malignant change of odontogenic cysts (7/9). Among 25 cases of squamous cell carcinoma, 7 cases are malignant change of typical keratocyst; 3 cases are similar to dentigerous cysts; 7 cases though show diffuse osseous destruction, they partly have characters of keratocyst in light microscope. So, the authors suggest that perhaps more central carcinomas of the jaws are arising from odontogenic keratocysts.     

Immunolocalization of PTCH protein in odontogenic cysts and tumors

The human patched gene (PTCH) functions in both embryologic development and tumor suppression. PTCH mutations have been found in odontogenic keratocysts. However, the expression and localization of the protein product of the gene have not been determined in odontogenic tumors and cysts. We investigated 68 odontogenic lesions by immunohistochemistry, and compared their PTCH expression with that in basal cell carcinomas. All odontogenic lesions, including two keratocysts with truncating mutations, were positive for PTCH. Different types of lesions had different amounts of staining. Lack of staining was noted in the majority of basal cell carcinomas. Taken together, these data suggest that odontogenic keratocysts arise with heterozygous mutations of the PTCH gene.     

Familial multiple odontogenic keratocysts

Multiple odontogenic keratocysts (OKCs) are principle features of nevoid basal cell carcinoma syndrome (NBCCS; Gorlin-Goltz syndrome). NBCCS is a genetic disorder transmitted by an autosomal dominant gene with variable expressivity, which is important to recognize when a patient has multiple OKCs. The cysts of the jaws are among the most common findings. Another feature is a certain appearance of the face, such as: large calvaria, high-arched eyebrows, broad nasal root, and mild hypertelorism. Before-therapy diagnosis is, therefore, as important as after-therapy diagnosis. Genetic counseling and examination may also be indicated. The purpose of this paper was to present a family case report of nevoid basal cell carcinoma syndrome with multiple odontogenic keratocysts. The features identified by these combined clinical, imaging, and histologic findings are described, along with a brief mention of the family history and a review of the literature.     

Discrimination of parakeratinised odontogenic keratocysts from other odontogenic and non-odontogenic cyst types by expression of a 38kd cell-surface glycoprotein

We have identified strong expression of a 38-kD cell surface glycoprotein (gp38), a marker of basal cell carcinomas (BCCs), in basal and suprabasal epithelial cell membranes of parakeratinised odontogenic keratocysts. In contrast, orthokeratinised cysts and most other odontogenic cyst types, ameloblastomas, normal stratified oral epithelium, cell rests of Malassez and glands of Serres, all proved negative. To our knowledge this is the first histochemical marker to distinguish between these major cyst types. It has obvious uses in the diagnosis of inflamed keratocysts and the separation of ameloblastomas from BCCs and may find a role in studies of the developmental biology of other odontogenic structures.