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。     

PTCH germline mutations in Chinese nevoid basal cell carcinoma syndrome patients

OBJECTIVES: PTCH, the human homologue of the Drosophila segment polarity gene, patched, has been identified as the gene responsible for nevoid basal cell carcinoma syndrome. The aim of this study was to investigate PTCH gene mutation in Chinese patients with nevoid basal cell carcinoma syndrome. MATERIALS AND METHODS: DNA was isolated from both odontogenic keratocyst tissue and peripheral blood of five patients with syndrome and one patient with only multiple odontogenic keratocysts, and mutational analysis of the PTCH gene performed by direct sequencing after amplification of all 23 exons by polymerase chain reaction (PCR). RESULTS: A previously reported germline mutation (c.2619C>A) was identified in two familial cases involving the mother and the daughter, with the mother also carrying a novel somatic mutation (c.361_362insGAGC). Three novel germline PTCH mutations (c.1338_1339insGCG, c.331delG and c.1939A>T) were detected in three unrelated patients with syndrome. The patient with multiple odontogenic keratocysts who failed to fulfill the diagnostic criteria of the syndrome also carried a novel germline mutation (c.317T>G). CONCLUSION: The frequent germline PTCH mutations detected in our series provide further evidence for the crucial role of PTCH in the pathogenesis of nevoid basal cell carcinoma syndrome in Chinese.     

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.     

Development of a targeted gene panel for the diagnosis of Gorlin syndrome

Gorlin syndrome is a rare autosomal dominant disease caused by mutations in the PTCH1, PTCH2, and SUFU genes. Each symptom of the disease has a different time point of onset, which makes early diagnosis based solely on symptoms challenging. In this study, a gene panel was developed to overcome the challenges in the diagnosis of Gorlin syndrome and allow diagnosis using a single test. A custom panel was generated for four genes associated with Gorlin syndrome: PTCH1, PTCH2, SMO, and SUFU. Twenty-seven samples from 12 patients with Gorlin syndrome and three asymptomatic blood relatives of the patients were examined. This panel was highly reliable with a high Q30 quality score, on-target ratio, and coverage. The panel was time- and cost-efficient and enabled the detection of more mutations than whole-exome sequencing for the same patient. Pathogenic mutations in both PTCH1 and PTCH2 were detected in five of the 12 patients with Gorlin syndrome who were diagnosed based on clinical symptoms. Using this panel, the same mutation was identified in the patients and their blood relatives. In summary, this panel facilitated the highly reliable genetic diagnosis of Gorlin syndrome at a low cost, using only blood samples.     

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.     

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。     

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.     

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.     

One germline mutation of PTCH gene in a Chinese family with non-syndromic keratocystic odontogenic tumours

Keratocystic odontogenic tumours (KOCTs) are common benign cystic tumours that arise sporadically or associated with nevoid basal cell carcinoma syndrome (NBCCS). PTCH mutation can be found in sporadically or NBCCS associated KOCTs. Few PTCH mutations in families with non-syndromic KOCTs have been reported. Through PCR and gene sequence analysis, the authors discovered one missense mutation c.3277G>C in exon 19 of PTCH gene in a Chinese family with non-syndromic KOCTs. This mutation causes one highly conserved glycine residue transit to arginine on the 10th transmembrane region of PTCH protein. This work revealed that the missense mutation of PTCH is the causative and dominant gene of KOCTs in this family.     

New mutation of the patched homologue 1 gene in a Chinese family with naevoid basal cell carcinoma syndrome

Naevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome, is inherited in an autosomal dominant mode characterised by a combination of developmental anomalies and a predisposition to form tumours. Our aim was to search for patched homologue 1 (PTHC1) mutations in a Chinese family with NBCCS. Mutation analysis of PTCH1 was done of all 10 members of this family by amplified polymerase chain reaction and direct sequencing. Two novel PTCH1 mutations (3146A→T, 1686C→T) were identified in all five affected members. The mutation, 3146A→T in exon 17, is predicted to lead to different PTCH protein translations. 1686C→T mutation in exon 11 is a nonsense mutation. These mutations were not found in any unaffected members of this family or in 100 unrelated healthy Chinese people. Our findings suggest that the 3146A→T mutation in the PTCH gene may be the cause of NBCCS by affecting the conformation and function of the PTCH protein.     

Contributions of PTCH gene variants to isolated cleft lip and palate.

OBJECTIVE: Mutations in patched (PTCH) cause the nevoid basal cell carcinoma syndrome (NBCCS), or Gorlin syndrome. Nevoid basal cell carcinoma syndrome may present with developmental anomalies, including rib and craniofacial abnormalities, and predisposes to several tumor types, including basal cell carcinoma and medulloblastoma. Cleft palate is found in 4% of individuals with nevoid basal cell carcinoma syndrome. Because there might be specific sequence alterations in PTCH that limit expression to orofacial clefting, a genetic study of PTCH was undertaken in cases with cleft lip and/or palate (CL/P) known not to have nevoid basal cell carcinoma syndrome. RESULTS: Seven new normal variants spread along the entire gene and three missense mutations were found among cases with cleft lip and/or palate. One of these variants (P295S) was not found in any of 1188 control samples. A second variant was found in a case and also in 1 of 1119 controls. The third missense (S827G) was found in 5 of 1369 cases and in 5 of 1104 controls and is likely a rare normal variant. Linkage and linkage desequilibrium also was assessed using normal variants in and adjacent to the PTCH gene in 220 families (1776 individuals), each with two or more individuals with isolated clefting. Although no statistically significant evidence of linkage (multipoint HLOD peak = 2.36) was uncovered, there was borderline evidence of significant transmission distortion for one haplotype of two single nucleotide polymorphisms located within the PTCH gene (p = .08). CONCLUSION: Missense mutations in PTCH may be rare causes of isolated cleft lip and/or palate. An as yet unidentified variant near PTCH may act as a modifier of cleft lip and/or palate.     

Recurrence of keratocysts. A long-term follow-up study

The aim of the study was to investigate the recurrence rate of keratocysts based on a material with a follow-up of at least 5 years, and to evaluate the relationship between different features of these cysts and their recurrence. It was found that of 75 keratocysts with follow-up times ranging from 5 to 17 years (mean 8.3), 32 (43%) recurred. The cumulative recurrence rate of the 67 annually examined cysts increased from 3% after the 1st year following the operation to 37% after the 3rd year. Thereafter, no new recurrences were noted. Recurrence of keratocysts in patients with basal cell nevus syndrome occurred more frequently than that of patients without the syndrome. Keratocysts enucleated in one piece recurred significantly less often than cysts enucleated in several pieces. The recurrence rate of keratocysts with a clinically observable infection, with fistula or with a perforated bony wall was higher than that of keratocysts without these features. Recurrence was also found more frequently in cysts with multilocular radiographic appearance than in unilocular cysts. The size or the location of the keratocysts did not have an influence on the recurrence rate.     

Simultaneous adenomatoid odontogenic and keratocystic odontogenic tumours in a patient with Gorlin‐Goltz syndrome

Gorlin and Goltz described a syndrome in which multiple basal cell carcinomas, odontogenic keratocysts and bifid ribs occurred in combination. The jaw keratocysts are a consistent feature of ‘Gorlin‐Goltz’ or naevoid basal cell carcinoma syndrome. Central nervous system and ocular involvement occurred together with the fairly typical facial features of frontal bossing and hypertelorism. This case report documents the pathology associated with an impacted maxillary canine tooth in a boy with Gorlin‐Goltz syndrome. The patient presented for investigation of the failure of eruption of the right permanent maxillary canine tooth. Radiographic investigation showed the presence of a well circumscribed radiolucency located around the crown of an impacted right maxillary canine tooth. The patient's medical history revealed a medulloblastoma that was treated 13 years ago. The right maxillary canine tooth and associated peri‐coronal tissue were removed under general anaesthetic. A diagnosis of a keratocystic odontogenic tumour with an associated adenomatoid odontogenic tumour was made. The common differential diagnoses for a peri‐coronal radiolucency in the maxilla that need to be considered by dentists include a dentigerous cyst, follicular keratocystic odontogenic tumour and adenomatoid odontogenic tumour. A rare case of both keratocystic odontogenic tumour and associated follicular adenomatoid odontogenic tumour is described in a patient with naevoid basal cell carcinoma syndrome.     

Familial odontogenic keratocysts. Report of 3 cases and review of Japanese dental literature

Familial odontogenic keratocysts are described in this report. The Case 1 patient, who has 3 sisters, developed odontogenic keratocysts. The 2 younger sisters (Cases 2 and 3) also had odontogenic keratocysts, although the elder sister did not have any odontogenic cysts. The father of the patients had a history of removal of a jaw cyst, and the mother was found later to have malignant ameloblastoma. Besides the odontogenic keratocysts, the Case 1 patient had basal cell nevus, prominent frontal process, and ocular hypertelorism; the Case 2 patient had prominent frontal process; the Case 3 patient had prominent frontal process, ocular hypertelorism, and squint. All 3 sisters are suspected of being patients with the basal cell nevus syndrome. The Japanese dental literature concerning the basal cell nevus syndrome is reviewed.     

Glandular odontogenic cyst: absence of PTCH gene mutation

Glandular odontogenic cyst (GOC) is a rare jawbone cyst of odontogenic origin. Human patched (PTCH) is a tumour suppressor gene that has been recently associated with signalling pathways during odontogenesis. Recently alterations of this gene were found on sporadic odontogenic keratocysts. This evidence, together with the biological behaviour similarities of both lesions, and the absence of reports on molecular analysis of GOC, led us to hypothesize that PTCH gene mutations may underlie the tumorigenesis of GOC. Therefore the aim of this study was to report one additional case of GOC and investigate the PTCH gene of the cyst. No mutations were found in the splicing and coding regions of the PTCH gene. In conclusion, the PTCH gene does not seem to be involved in GOC pathogenesis.     

The odontogenic keratocyst. A clinicopathologic study of 312 cases. Part I. Clinical features.

An analysis was made of the clinical features of 312 acceptable cases of odontogenic keratocysts from the files of the Department of Oral Pathology, Indiana University School of Dentistry. A total of 5.1 per cent of the keratocysts were from patients with the basal-cell nevus syndrome and 5.8 per cent were from patients with multiple keratocysts but with no other features of the syndrome. There was a wide age range, with a peak incidence in the second and third decades of life. The mandible: maxilla ratio was 2:1, with the mandibular third molar area and ramus being the most common sites. Dentigerous cyst was the most frequent clinical as well as histologic diagnosis for the majority of the keratocysts in this study. The primordial cyst comprised the greatest percentage of keratocysts (44.4 per cent). A total of 50.3 per cent of the patients were symptomatic before seeking treatment, the most common finding being intraoral drainage and swelling. Their radiographic appearance was quite variable, although they frequently resembled ameloblastoma. These cysts may be very aggressive clinically. They have a relatively high recurrence rate, as previously reported in the literature, in comparison with other types of odontogenic cyst. The findings in this study support the theory that the histologic appearance of an odontogenic keratocyst may be assumed by any of the odontogenic or nonodontogenic cysts.     

Multiple odontogenic keratocysts of the jaws

Single odontogenic cysts are very well documented in the literature. Of those less common reports concerning multiple jaw cysts, many have been associated with systemic conditions or syndromes such as Gorlin-Goltz or basal cell naevus syndrome, Hunter's syndrome and mucopolysaccharidosis, for example, Maroteaux-Lamy syndrome. A case of multiple odontogenic keratocysts unassociated with any syndrome is reported so as to add to the growing number of such cases in the literature. The possibility of this case being a partial expression of the Gorlin-Goltz syndrome is discussed.     

p53 Immunohistochemistry of odontogenic keratocysts in relation to recurrence, basal-cell budding and basal-cell naevus syndrome

Mutation of the p53 tumour suppressor gene can produce a more stable protein that does not inhibit mitosis, accumulates in the nucleus and can then be detected immunohistochemically in many human tumours using antibody CM-1. The protein has also been detected in odontogenic keratocysts. Routinely processed material from 30 odontogenic keratocysts was immunostained with antibody CM-1. Ten were recurrences and five were associated with the basal-cell naevus syndrome (Gorlin-Goltz syndrome). p53 protein was found in 50% (15/30) of the odontogenic keratocysts, in 53.3% (8/15) of non-recurrent cysts, in 40% (4/10) of recurrent cysts and in 60% (3/5) of thsoe associated with the basal-cell naevus syndrome. Staining was weak and speckled and limited to occasional basal and suprabasal cells. There was no statistically significant difference in staining between these groups and no correlation between expression and the presence of satellite cysts, basal-cell budding or islands of odontogenic epithelium. The low levels of expression may represent physiological expression of wild-type p53 protein rather than mutant or complexed p53 protein.     

Blood group antigens A and B in ameloblastomas, odontogenic keratocysts and non-keratinizing cysts

abstract — The expression of blood group antigens A and B has been studied in 8 ameloblastomas, 16 odontogenic keratocysts from patients with basal cell nevus syndrome, 11 odontogenic keratocysts from patients without the syndrome, and 12 non-keratinizing odontogenic cysts, using a double layer immunofluorescence staining technique. The amount of antigen in the lesions was compared with the content of antigen in normal buccal mucosa from each patient. All ameloblastomas reacted negatively, three cysts from the patients with the basal cell nevus syndrome reacted negatively, and the odontogenic keratocysts from patients without the syndrome as well as the non-keratinizing odontogenic cysts all gave a positive reaction.     

Comparative study of keratocysts, associated and non-associated with nevoid basal cell carcinoma syndrome

Keratocysts of the solitary type were histologically and histometrically compared with those associated with the nevoid basal cell carcinoma syndrome (NBS). It was observed that parakeratinization, intramural epithelial remnants and satellite cysts were a more frequent finding among NBS keratocysts than among solitary keratocysts. Conversely, it was also found that the total nuclear density was greater in non-associated cysts and that the total number of nuclei, the number of basal nuclei and the epithelial height values were also higher in solitary keratocysts. NBS-keratocysts and solitary keratocysts are considered to be two morphologically distinct populations of the same entity.