Feasibility of oral microbiome profiles associated with oral squamous cell carcinoma

Objective

Recently, the possibility that oral microbiomes is associated with oral squamous cell carcinoma (OSCC) initiation and progression has attracted attention; however, this association is still unclear. Here, we comprehensively analyze the microbiome profiles of saliva samples using next-generation sequencing followed by determining the association between oral microbiome profiles and OSCC.

Materials and Methods

Microbiome profiles in saliva samples from patients with OSCC, oral leukoplakia (OLK), and postoperative OSCC (Post) were analyzed. Candidate OSCC-associated bacteria were identified by comparing the bacterial diversity and relative abundance of each group based on these microbiome profiles, and their applicability as OSCC detection tools were evaluated.

Results

There were significant differences in genus abundances (Streptococcus, Aggregatibacter, and Alloprevotella) among the groups from saliva samples. In the OSCC group, compared with the OLK and Post groups, abundances of the genus Fusobacterium, phylum Fusobacteria and phylum Bacteroidetes were markedly increased and that of the genus Streptococcus and phylum Firmicutes were decreased.

Conclusion

The results suggested a strong association of these bacteria with OSCC. Especially, phylum Fusobacterium was significantly associated with early recurrence of OSCC. Thus, oral microbiome analysis may have a potential of novel OSCC detection and prognostic tool.

Salivary NUS1 and RCN1 Levels as Biomarkers for Oral Squamous Cell Carcinoma Diagnosis

BACKGROUND/AIM

Oral cancer may become advanced because of delay in diagnosis. In order to promote oral cancer screening, simple and highly reliable screening methods that can be implemented at general dental clinics are required. Herein we investigated differential salivary gene expression between oral squamous cell carcinoma (OSCC) patients and healthy volunteers (HV) to identify new biomarkers for OSCC detection.

MATERIALS AND METHODS

Candidate genes were selected by microarrays, nuclear undecaprenyl pyrophosphate synthase 1 (NUS1) and reticulocalbin 1 (RCN1) were selected for further investigation. We used real-time quantitative reverse transcription PCR (qRT-PCR) to determine NUS1 and RCN1 expression levels in saliva and tissues.

RESULTS

qRT-PCR analysis of clinical samples revealed that OSCC patients had significantly higher expression of salivary NUS1 and RCN1 than HV.

CONCLUSION

A combination of NUS1 and RCN1 accurately distinguished patients from controls, and this combination can be implemented as a screening test for OSCC.

Salivary CCL20 Level as a Biomarker for Oral Squamous Cell Carcinoma

BACKGROUND/AIM

This study investigated the utility of C-C motif chemokine ligand 20 (CCL20) expression in saliva as a biomarker for oral squamous cell carcinoma (OSCC) and also examined the associated microbiome.

MATERIALS AND METHODS

The study group included patients with OSCC or oral potentially malignant disorder (OPMD), and healthy volunteers (HVs). microarray and qRT-PCR were used to compare salivary CCL20 expression levels among groups. Data on CCL20 levels in oral cancer tissues and normal tissues were retrieved from a public database and examined. Furthermore, next-generation sequencing was used to investigate the salivary microbiome.

RESULTS

A significant increase in the expression level of CCL20 was observed in both OSCC tissues and saliva from patients with oral cancer. Fusobacterium was identified as the predominant bacteria in OSCC and correlated with CCL20 expression level. OSCC screening based on salivary CCL20 expression enabled successful differentiation between patients with OSCC and HVs.

CONCLUSION

CCL20 expression may be a useful biomarker for OSCC.

Salivary CPLANE1 Levels as a Biomarker of Oral Squamous Cell Carcinoma

BACKGROUND/AIM

This study aimed to identify novel biomarkers for oral squamous cell carcinoma (OSCC) screening to improve the survival rate of patients with oral cancer.

MATERIALS AND METHODS

We investigated differential salivary gene expression in patients with OSCC, those with oral potentially malignant disorders (OPMDs), and healthy volunteers (HVs). CPLANE1 was selected for further investigation by microarray analysis. We used quantitative reverse transcription PCR (qRT-PCR) to determine CPLANE1 expression levels in the saliva. The expression of CPLANE1 in normal and oral cancer tissues was analyzed using the Gene Expression database of Normal and Tumor tissues.

RESULTS

qRT-PCR analysis of saliva samples showed that CPLANE1 expression levels were significantly higher in OSCC patients than in HVs and OPMDs patients. Furthermore, we developed a screening test for OSCC using CPLANE1 and showed that it had good accuracy.

CONCLUSION

Salivary CPLANE1 could be a useful biomarker for OSCC screening and early detection.

Relationship between age and sex and the numbers of ingestions and swallows for foods of different textures among healthy adults

BACKGROUND

The number of swallows needed per single ingestion of food is an important index when assisting a patient with dysphagia in eating. While providing meal assistance, the caregiver may assume that one ingestion is completed with one swallow and then may administer the next ingestion even if the individual's mouth still has remaining food from the previous ingestions, increasing the risk for aspiration and choking.

OBJECTIVE

The objective of this pilot study was to clarify the differences in foods ingested and swallowed because of influencing factors such as age and gender among healthy adults.

METHODS

The study enrolled 110 healthy adults (47.4 ± 15.8 years; 57 males, 53 females). The numbers of ingestions and swallows were counted and evaluated by food type (pilaf, 100 g; yogurt 80 g; and sponge cake, 35 g) and participant age and sex and analyzed by least-squares multiple regression analysis.

RESULTS

The mean numbers of ingestion/swallows were pilaf, 12.5 ± 3.2/13.4 ± 4.2; yogurt, 8.8 ± 2.1/10.8 ± 2.1; and sponge cake, 5.8 ± 2.1/7.0 ± 2.1. The mean number of ingestions and swallows for all foods were higher for female participants compared with male participants. Statistical analysis identified sex as a significant influencing factor for the number of ingestion for all foods. For the number of swallows, the significant influencing factors were sex for sponge cake and age for pilaf and yogurt.

CONCLUSION

For the test foods of different textures, sex and age were significant influencing factors for the numbers of ingestions and swallows. Further research is needed to elucidate the problem areas in this pilot study.

Changes in oral microbial profiles associated with oral squamous cell carcinoma vs leukoplakia

AIM

Oral squamous cell carcinoma (OSCC) is the most frequently occurring cancer among head and neck SCC worldwide. The identification of novel effective biomarkers for early detection may greatly improve the survival rate and prognosis of patients with OSCC. This study aimed to identify specific oral microbial profiles associated with OSCC.

METHODS

Saliva samples were collected from oral leukoplakia (OLK) and OSCC patients (N = 6 each) and healthy controls (HC; N = 4). Total bacterial genomic DNA was isolated and 16S rRNA gene survey was performed by next-generation sequencing of the V4 region. The relative distribution of abundance for phylogenetic groups was compared among the OSCC and OLK groups.

RESULTS

The 448 operational taxonomic units detected from the libraries were classified into 133 genera, 69 families, 41 orders, 26 classes and 12 phyla. The abundance of phyla Bacteroidetes and genus Solobacterium was notably higher in the OSCC group when compared with the OLK group, whereas those of genus Streptococcus was significantly lower in the OSCC group when compared with the OLK.

CONCLUSION

These changes in the salivary microbiome may have potential applications as a novel diagnostic tool for the early detection of OSCC.

Reconsideration of three screening tests for dysphagia in patients with cerebrovascular disease performed by non-expert examiners

Dysphagia prevalence has increased with increasing elderly population worldwide. Therefore, early detection of dysphagia has become increasingly important. Repetitive saliva swallowing test (RSST), modified water swallowing test (MWST), and cervical auscultation, which are convenient for non-experts to assess eating and swallowing and have been frequently used in Japan since 20 years. Using aspiration and pharyngeal residues, the objective of this study was to elucidate the efficacy of the three screening tests performed by non-experts in patients who had swallowing disorders. In total, 102 patients with cerebrovascular diseases who were suspected of having dysphagia were assessed. A swallowing team assessed their swallowing capabilities; videofluoroscopy and screening tests were performed. RSST, MWST, and cervical auscultation were performed by junior dentists who were non-experts in dysphagia. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio in each examination were evaluated using results of aspiration in videofluoroscopy and pharyngeal residues. For aspiration, the highest sensitivity with cervical auscultation (VES) was 93.7%. For pharyngeal residue, the highest sensitivity with cervical auscultation (VES) was 84.3%. For piriform sinus residue, the highest sensitivity with cervical auscultation (VES) was 86.4%. Despite being evaluated by a non-expert, the sensitivity of cervical auscultation (VES) and MWST was ≥ 80%, suggesting their effectiveness as prescreening tests, although the range of specificity was 25.5-68.4% in all examinations. These tests are easy to perform and useful to screen for aspiration or pharyngeal residues before precision tests.

Postoperative radiotherapy for T1/2N0M0 mucoepidermoid carcinoma positive for CRTC1/3-MAML2 fusions

BACKGROUND

The National Comprehensive Cancer Network (NCCN) guidelines recommend considering postoperative radiotherapy (PORT) for completely resected T1/2N0M0 salivary mucoepidermoid carcinomas when they show tumor spillage, perineural invasion, or intermediate/high-grade histology. CRTC1/3-MAML2 fusions have been associated with a favorable clinical outcome.

METHODS

Forty-seven T1/2N0M0 mucoepidermoid carcinoma cases positive for CRTC1/3-MAML2 fusions were completely resected and were not treated with PORT.

RESULTS

Pathologically, none of the cases showed tumor spillage or perineural invasion. Cases with intermediate/high-grade histology numbered 9 (19%) to 26 (55%) with the currently used 3 different grading systems. During the follow-up (median 60 months), locoregional tumor recurrence occurred in 4 cases, which were treated with surgery alone. At the last follow-up (median 60 months; 7-160), all patients were alive with no evidence of disease.

CONCLUSION

An excellent prognosis may be achieved without PORT in T1/2N0M0 mucoepidermoid carcinoma patients positive for CRTC1/3-MAML2 fusions when the tumors are completely resected without tumor spillage.

Abstract 5123: Changes of oral microbiome profiles associated with oral squamous cell carcinoma

[Background] Oral squamous cell carcinoma (OSCC) is the most frequently occurring cancer among the head and neck SCCs worldwide. Despite significant efforts in OSCC research and advanced surgical treatments, radiotherapy, and chemotherapy, the 5-year overall survival rate has remained < 50% for the last few decades. OSCC prognosis remains poor due to late diagnosis. Therefore, clinically effective biomarkers for the early detection of OSCC can greatly improve the survival rate and prognosis. Approximately 15% of oral cancers cannot be explained by major risk factors, such as tobacco and alcohol use. A growing body of evidence supports an association between specific microorganisms, including those in the oral cavity, and various types of cancers. Because the role of bacteria in OSCC development has not been completely described, we investigated the changes in abundance of oral microbiota associated with OSCC. [AIMS] To identify the association between the oral microbiome and OSCC for the early detection and prevention. [Materials and methods] Unstimulated saliva samples were collected from 4 OSCC-free, 6 leukoplakia, and 6 OSCC subjects. Total bacterial genomic DNA from saliva was isolated, and 16S rRNA gene survey was performed by next-generation sequencing of the V4 region. The sequences were analyzed against reference sequences from the Human Oral Microbiome Database, and the relative abundance distribution for phylogenetic groups in 3 different libraries was compared. [Results] In total, 448 bacterial species from combined (OSCC-free, leukoplakia, and OSCC) libraries were detected, which were classified into 133 genera, 69 families, 41 orders, 26 classes, and 12 phyla. The frequency of phylum Bacteroidetes was more notably abundant in OSCC subjects compared with leukoplakia and OSCC-free subjects. In contrast, the abundances of genera Streptococcus and Rothia were significantly lower in OSCC subjects compared with leukoplakia and OSCC-free subjects using the Mann-Whitney U test. [Conclusion] This study revealed some OSCC-associated shifts in oral microbial communities. Salivary screening is suitable for the primary screening procedure because of its noninvasiveness and easy accessibility. Therefore, these changes in the saliva microbiome may have potential application as a useful diagnostic tool for the early detection of OSCC and malignant transformation of pre-cancerous regions.

Citation Format: Kengo Hashimoto, Shuji Nomoto, Sho Hirabayashi, Sei Ueda, Ichiro Oh-iwa, Toru Nagao, Kazuo Shimozato. Changes of oral microbiome profiles associated with oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5123.

Mutation analysis of the EGFR pathway genes, EGFR, RAS, PIK3CA, BRAF, and AKT1, in salivary gland adenoid cystic carcinoma

Adenoid cystic carcinoma (AdCC), one of the most common salivary gland carcinomas, usually has a fatal outcome. Epidermal growth factor receptor (EGFR) pathway gene mutations are important in predicting a patient's prognosis and estimating the efficacy of molecular therapy targeting the EGFR pathway. In this study of salivary gland AdCC (SAdCC), we looked for gene mutations in EGFR, RAS family (KRAS, HRAS, and NRAS), PIK3CA, BRAF, and AKT1, using a highly sensitive single-base extension multiplex assay, SNaPshot. Out of 70 cases, EGFR pathway missense mutations were found in 13 (18.6%): RAS mutations in 10 (14.3%), EGFR in one (1.4%), and PIK3CA in 5 (7.1%). None of the cases showed an EGFR deletion by direct sequencing. Concurrent gene mutations were found in three cases (4.3%). EGFR pathway mutations were significantly associated with a shorter disease-free (p = 0.011) and overall survival (p = 0.049) and RAS mutations were as well; (p = 0.010) and (p = 0.024), respectively. The gene fusion status as determined by a FISH assay had no significant association with mutations of the genes involved in the EGFR pathway. In conclusion, EGFR pathway mutations, especially RAS mutations, may be frequent in SAdCC, and associated with a poor prognosis for the patient.

Identification of nuclear localization signals in the human homeoprotein MSX1

MSX1 is one of the homeoproteins with the homeodomain (HD) sequence, which regulates proliferation and differentiation of mesenchymal cells. In this study, we investigated the nuclear localization signal (NLS) in the MSX1 HD by deletion and amino acid substitution analyses. The web-based tool NLStradamus predicted 2 putative basic motifs in the N- and C-termini of the MSX1 HD. Green fluorescent protein (GFP) chimera studies revealed that NLS1 (₁₆₁RKHKTNRKPR₁₇₀) and NLS2 (₂₁₆NRRAKAKR₂₂₃) were independently insufficient for robust nuclear localization. However, they can work cooperatively to promote nuclear localization of MSX1, as was shown by the 2 tandem NLS motifs partially restoring functional NLS, leading to a significant nuclear accumulation of the GFP chimera. These results demonstrate a unique NLS motif in MSX1, which consists of an essential single core motif in helix-I, with weak potency, and an auxiliary subdomain in helix-III, which alone does not have nuclear localization potency. Additionally, other peptide sequences, other than predicted 2 motifs in the spacer, may be necessary for complete nuclear localization in MSX1 HD.

Long-term outcomes after carbon-ion radiotherapy for oral mucosal malignant melanoma

Oral mucosal malignant melanoma (OMM) is extremely rare and has a poor prognosis. Owing to its rarity, it has not yet been possible to establish an optimal treatment modality. The objective of this study was to evaluate the long-term efficacy of carbon-ion radiotherapy (C-ion RT) for OMM. Between 1997 and 2013, 19 patients with OMM were treated with C-ion RT alone. Patient ages ranged from 44 to 84 years (median, 69 years). Nine men and 10 women were included. OMMs were restaged in accordance with the seventh edition of the tumour/node/metastasis (TNM) Staging System of the International Union Against Cancer. Before treatment, 14 patients had T3 disease and 5 had T4a disease. Three patients were classified as having N1 disease. All patients were classified as having M0. The hard palate was the most frequently involved oral subsite. All patients were treated with 57.6 Gy (relative biological effectiveness) in 16 fractions. The median follow-up period was 61 months (range, 8-190 months). The 5-year local control, overall survival and progression-free survival rates were 89.5%, 57.4% and 51.6%, respectively. For local control and overall survival, T classification was found to be a significant prognostic factor. Grade 2 and 3 osteoradionecrosis was observed in three and four patients, respectively. The presence of teeth within the planning target volume was a significant risk factor for developing osteoradionecrosis. C-ion RT was an effective treatment option with acceptable toxicity for OMM.

Unique mouse monoclonal antibodies reactive with maturation-related epitopes on type VII collagen

In this study, we generated a new set of monoclonal antibodies (mAbs) to bovine and human type VII collagen (COL7) by immunizing mice with bovine cornea-derived basement membrane zone (BMZ) fraction. The four mAbs, tentatively named as COL7-like mAbs, showed speckled subepidermal staining in addition to linear BMZ staining of normal human skin and bovine cornea, a characteristic immunofluorescence feature of COL7, but showed no reactivity with COL7 by in vitro biochemical analyses. Taking advantage of the phenomenon that COL7-like mAbs did not react with mouse BMZ, we compared immunofluorescence reactivity between wild-type and COL7-rescued humanized mice and found that COL7-like mAbs reacted with BMZ of COL7-rescued humanized mice. In ELISAs, COL7-like mAbs reacted with intact triple-helical mammalian recombinant protein (RP) of COL7 but not with bacterial RP. Furthermore, COL7-like mAbs did not react with COL7 within either cultured DJM-1 cells or basal cells of skin of a bullous dermolysis of the newborn patient. These results confirmed that COL7-like mAbs reacted with human and bovine COL7. The epitopes for COL7-like mAbs were considered to be present only on mature COL7 after secretion from keratinocytes and deposition to BMZ and to be easily destroyed during immunoblotting procedure. Additional studies indicated association of the speckled subepidermal staining with both type IV collagen and elastin. These unique anti-COL7 mAbs should be useful in studies of both normal and diseased conditions, particularly dystrophic epidermolysis bullosa, which produces only immature COL7.

Three-dimensional finite element model to predict patterns of pterygomaxillary dysjunction during Le Fort I osteotomy

The aim of this study was to determine whether non-linear three-dimensional finite element analysis (3D-FEA) can be applied to simulate pterygomaxillary dysjunction during Le Fort I osteotomy (LFI) not involving a curved osteotome (LFI-non-COSep), and to predict potential changes in the fracture pattern associated with extending the cutting line. Computed tomography (CT) image data (100 snapshots) after LFI were converted to 3D-CT images. 3D-FEA models were built using preoperative CT matrix data and used to simulate pterygomaxillary dysjunction. The pterygomaxillary dysjunction patterns predicted by the 3D-FEA models of pterygomaxillary dysjunction were classified into three categories and compared to the pterygomaxillary dysjunction patterns observed in the postoperative 3D-CT images. Extension of the cutting line was also simulated using the 3D-FEA models to predict the risk and position of pterygoid process fracture. The rate of agreement between the predicted pterygomaxillary dysjunction patterns and those observed in the postoperative 3D-CT images was 87.0% (κ coefficient 0.79). The predicted incidence of pterygoid process fracture was higher for cutting lines that extended to the pterygomaxillary junction than for conventional cutting lines (odds ratio 4.75; P<0.0001). 3D-FEA can be used to predict pterygomaxillary dysjunction patterns during LFI-non-COSep and provides useful information for selecting safer procedures during LFI-non-COSep.

p53 and ki67 as biomarkers in determining response to chemoprevention for oral leukoplakia

BACKGROUND

We performed a randomized controlled chemoprevention trial of oral leukoplakia by administrating a low dose of beta-carotene and vitamin C supplements. 17% of subjects in the experimental arm (4/23) demonstrated clinical remission (complete or partial response) at completion of the trial. The objective of this study was to determine whether baseline expression of p53 and ki67 demonstrated any differences between those responding or not responding to our intervention. A secondary objective was to elucidate any relationship between dietary factors and clinical responses.

METHODS

For this biomarker study, we included all subjects in the experimental group (n = 23) who were non-smokers. Among 16 who completed the trial for 1 year of supplementation, there were four responders and 12 non-responders at 1-year follow-up. Following immuno-staining for p53 and ki67, the percentage of positive cell nuclei were analyzed as labeling index (LI).

RESULTS

Expression of p53 was greater in basal layers than in para-basal layers. Mean para-basal LI of p53 was higher in non-responding (26.0) than in responding subjects (11.2) (P = 0.028). ki67 LIs were not significantly different in the two groups.

CONCLUSIONS

Expression of p53 was inversely related to clinical response to the supplements. Other biomarkers that may recognize subject's responsiveness to chemoprevention require further study.

Elucidating risk factors for oral leukoplakia affecting gingivae in Japanese subjects

Background:

Clinicopathological studies have revealed some distinct anatomical variations in the clinical presentation of oral leukoplakia (OL). Screening studies have shown that gingival leukoplakia (GL) to be more common among the Japanese.

Objective:

A hospital-based case-control study was undertaken among patients diagnosed with OL to compare clinico-pathological data between GL and OL affecting other sites (n-GL).

Methods:

One hundred fifty-one subjects attending four city hospitals in Japan diagnosed with OL were recruited to this study. OL was diagnosed by World Health Organization criteria. They were interviewed for risk factors, clinical presentations were charted and investigated by patch testing for allergy to dental materials and by biopsy for dysplasia.

Results:

Eighty-eight with GL and 63 with n-GL were included in the study. GL lesions were predominantly white (93%) though n-GL leukoplakia had red (speckled) foci in 26%. Eighty percent of GL were seen in association with prosthesis or restorations. There were no significant differences by age or in tobacco and alcohol use in the two groups. Metal allergy test was positive in 58% of the GL but was not significantly higher compared to the n-GL (41%). Histopathological features showed that inflammatory cell infiltrate was predominant in n-GL group ( p = 0.021). Higher dysplasia grades were also found in n-GL ( p = 0.018). During follow-up, nine oral cancers (14%) were detected in n-GL group and among GL cases four developed oral carcinomas (5%) ( p = 0.043). Cox hazard regression analysis revealed that after adjusting for age and sex, GL group was found to have a lower malignant risk, with a hazard ratio of 0.89 (95% CI: 0.51–1.04) when compared to n-GL.

Conclusions:

GL was more benign compared to n-GL in Japanese subjects, though risk factors appear similar. Further study is warranted to ascertain whether trauma may play an important role for hyperkeratinization of gingival tissues and possible evolution of GL to proliferative verrucous leukoplakia in later years.

Clinical and immunological profiles of anti-BP230-type bullous pemphigoid: Restriction of epitopes to the C-terminal domain of BP230, shown by novel ELISAs of BP230-domain specific recombinant proteins

OBJECTIVES

To confirm that sera from some BP patients reactive exclusively to the BP230 and to study the clinical and immunological characteristics of this condition.

MATERIALS AND METHODS

BP patients were divided into three groups: BP reactive only to BP230 (BP230-BP), BP reactive to both BP180 and BP230 (BP180-BP230-BP) and BP reactive only to BP180 (BP180-BP), based on the results of standard ELISAs for BP180 and BP230. Clinical features were statistically analyzed among the three groups. Then, targeted epitopes in each group were studied by immunoblotting and novel ELISAs using three domain-specific BP230 recombinant proteins.

RESULTS

Forty-one, 65 and 47 of 153 BP patients were categorized as BP230-BP, BP180-BP230-BP and BP180-BP, respectively. Clinically, BP230-BP patients showed significantly lower severity, less need of systemic steroids and better responses to various treatments, suggesting that BP230-BP is a milder condition. Immunoblotting and ELISAs of domain-specific BP230 recombinant proteins indicated that, while BP180-BP230-BP sera reacted with all three domains of BP230, BP230-BP sera reacted more frequently with epitopes in the BP230 C-terminal domain.

CONCLUSION

We propose a new disease entity, named anti-BP230-type BP, in which anti-BP230 antibodies might be pathogenic and react specifically with the BP230 C-terminal domain. While anti-BP230 antibodies in BP180-BP230-BP seem to be produced via intermolecular epitope spreading, anti-BP230 antibodies in BP230-BP are considered to be produced by different mechanisms.

Characterisation of novel RUNX2 mutation with alanine tract expansion from Japanese cleidocranial dysplasia patient

Cleidocranial dysplasia (CCD; MIM 119600) is an autosomal dominant skeletal dysplasia characterised by hypopalstic and/or aplastic clavicles, midface hypoplasia, absent or delayed closure of cranial sutures, moderately short stature, delayed eruption of permanent dentition and supernumerary teeth. The molecular pathogenesis can be explained in about two-thirds of CCD patients by haploinsufficiency of the RUNX2 gene. In our current study, we identified a novel and rare variant of the RUNX2 gene (c.181_189dupGCGGCGGCT) in a Japanese patient with phenotypic features of CCD. The insertion led an alanine tripeptide expansion (+3Ala) in the polyalanine tract. To date, a RUNX2 variant with alanine decapeptide expansion (+10Ala) is the only example of a causative variant of RUNX2 with polyalanine tract expansion to be reported, whilst RUNX2 (+1Ala) has been isolated from the healthy population. Thus, precise analyses of the RUNX2 (+3Ala) variant were needed to clarify whether the tripeptide expanded RUNX2 is a second disease-causing mutant with alanine tract expansion. We therefore investigated the biochemical properties of the mutant RUNX2 (+3Ala), which contains 20 alanine residues in the polyalanine tract. When transfected in COS7 cells, RUNX2 (+3Ala) formed intracellular ubiquitinated aggregates after 24h, and exerted a dominant negative effect in vitro. At 24h after gene transfection, whereas slight reduction was observed in RUNX2 (+10Ala), all of these mutants significantly activated osteoblast-specific element-2, a cis-acting sequence in the promoter of the RUNX2 target gene osteocalcin. The aggregation growth of RUNX2 (+3Ala) was clearly lower and slower than that of RUNX2 (+10Ala). Furthermore, we investigated several other RUNX2 variants with various alanine tract lengths, and found that the threshold for aggregation may be RUNX2 (+3Ala). We conclude that RUNX2 (+3Ala) is the cause of CCD in our current case, and that the accumulation of intracellular aggregates in vitro is related to the length of the alanine tract.

An aberrant splice acceptor site due to a novel intronic nucleotide substitution in MSX1 gene is the cause of congenital tooth agenesis in a Japanese family

Congenital tooth agenesis is caused by mutations in the MSX1, PAX9, WNT10A, or AXIN2 genes. Here, we report a Japanese family with nonsyndromic tooth agenesis caused by a novel nucleotide substitution in the intronic region between exons 1 and 2 of the MSX1 gene. Because the mutation is located 9 bp before exon 2 (c.452-9G>A), we speculated that the nucleotide substitution would generate an abnormal splice site. Using cDNA analysis of an immortalized patient blood cell, we confirmed that an additional 7-nucleotide sequence was inserted at the splice junction between exons 1 and 2 (c.451_452insCCCTCAG). The consequent frameshift generated a homeodomain-truncated MSX1 (p.R151fsX20). We then studied the subcellular localization of truncated MSX1 protein in COS cells, and observed that it had a whole cell distribution more than a nuclear localization, compared to that of wild-type protein. This result suggests a deletion of the nuclear localization signal, which is mapped to the MSX1 homeodomain. These results indicate that this novel intronic nucleotide substitution is the cause of tooth agenesis in this family. To date, most MSX1 variants isolated from patients with tooth agenesis involve single amino acid substitutions in the highly conserved homeodomain or deletion mutants caused by frameshift or nonsense mutations. We here report a rare case of an intronic mutation of the MSX1 gene responsible for human tooth agenesis. In addition, the missing tooth patterns were slightly but significantly different between an affected monozygotic twin pair of this family, showing that epigenetic or environmental factors also affect the phenotypic variations of missing teeth among patients with nonsyndromic tooth agenesis caused by an MSX1 haploinsufficiency.

Mammary analogue secretory carcinoma of salivary glands: a clinicopathologic and molecular study including 2 cases harboring ETV6-X fusion

Mammary analogue secretory carcinoma (MASC) is a recently described low-grade carcinoma with morphologic and genetic similarity, including ETV6-NTRK3 fusion, to secretory carcinoma of the breast. ETV6 is frequently involved in other epithelial and nonepithelial tumors, and many fusion partners of ETV6 have been reported. In the present study, 14 Japanese MASC cases were clinicopathologically and molecularly analyzed. The median age of the patients was 39 years, and the male:female ratio was 6:8. All cases showed histopathologic findings compatible with those previously described for MASC and harbored an ETV6 split as visualized by fluorescence in situ hybridization. Two cases showed thick fibrous septa and invasive features including vascular or perineural tumor involvement, findings that are rare in MASC. In addition, in these 2 cases, non-NTRK3 genes appeared to fuse with ETV6 (ETV6-X fusion). NTRK1 and NTRK2, both members of the NTRK family, were not involved. Of the 14 MASC cases, the ETV6-NTRK3 fusion transcript was positive in 6 cases, and the relative expression level of the ETV6-NTRK3 fusion transcript was variable, ranging from 1 to 5.8. Results of the present study of MASC suggest that (1) ETV6 occasionally fuses with unknown non-NTRK3 genes, (2) ETV6-X cases might have an invasive histology, (3) for molecular diagnosis of MASC, fluorescence in situ hybridization to detect ETV6 splits is the method of choice, and (4) the expression level of the ETV6-NTRK3 fusion transcript is considerably variable. These findings provide a novel insight into the oncogenesis, histopathology, diagnosis, treatment, and prognosis of this newly recognized carcinoma.

Androgen receptor-positive mucoepidermoid carcinoma: case report and literature review

Androgen receptor (AR) is usually expressed in salivary duct carcinoma (SDC), but only infrequently in other carcinoma types including mucoepidermoid carcinoma (MEC). The clinicopathological characteristics of AR-positive MEC remain to be clarified. Here we report a case of AR-positive MEC. A 76-year-old man presented with a growing painless tumor of the right parotid. The resected tumor was a high-grade tumor with necroses. Since the tumor was positive for AR, GCDFP-15, and HER2, SDC was first suspected, but it was also positive for CK5/6 and P63, and negative for S-100 protein and α-smooth muscle actin. In addition, scattered mucous secreting tumor cells were found in the tumor nests, and they were positive for Alcian blue. A diagnosis of AR-positive MEC was finally made. The patient died of the tumor 5 years after the surgery. The present case may expand the histopathological spectrum of high-grade MEC.

Genetic epidemiology of tooth agenesis in Japan: a population- and family-based study

Tooth agenesis is one of the most common congenital anomalies in humans. However, the etiology of tooth agenesis remains largely unclear, as well as evidence base useful for genetic counseling. Therefore, we estimated the prevalence and sibling recurrence risk, and investigated agenetic patterns systematically. Tooth agenesis was classified into two subtypes: hypodontia (one to five missing teeth) and oligodontia (six or more missing teeth). The prevalence of these two subtypes were 6.8% [95% confidence interval (CI): 6.1-7.7%] and 0.1% (95% CI: 0.04-0.3%), respectively, and sibling recurrence risk of these were 24.5% (95% CI: 13.8-38.3%) and 43.8% (95% CI: 26.4-62.3%), respectively. This result suggests that the severe phenotype, oligodontia, might be mostly transmitted in a dominant fashion. Using a simple statistical modeling approach, our data were found to be consistent with a bilateral symmetry model, meaning that there was equal probability of missing teeth from the right and left sides.

Treatment of oral leukoplakia with a low-dose of beta-carotene and vitamin C supplements: a randomized controlled trial

Management of oral leukoplakia-a potentially malignant disorder-is currently not evidence-based. Of the few randomized trials that have been reported, most have negative data. Therefore, a multi-centre, randomized, double-blind controlled trial (RCT) was undertaken to evaluate the use of low-dose beta-carotene combined with vitamin C supplements for the treatment and to prevent malignant transformation of oral leukoplakia. 46 Japanese participants with oral leukoplakia were allocated randomly either to an experimental arm (10 mg day(-1) of beta-carotene and 500 mg day(-1) of vitamin C) or placebo arm (50 mg day(-1) of vitamin C). Current or ex-smokers within 3 months of cessation were excluded. The supplements were continued over a period of 1 year. The primary endpoint was clinical remission at 1-year and the likelihood of malignant transformation during a 5-year follow-up period as a secondary endpoint. The overall clinical response rate in the experimental arm was 17.4% (4/23) and 4.3% (1/23) in the placebo arm (p = 0.346). During the median 60-month follow-up period, two subjects in the experimental arm and three in the control arm developed oral cancer. Under the intention-to-treat principle, relative risk by supplementing with beta-carotene and vitamin C was 0.77 (95%CI: 0.28-1.89) (p = 0.580) by the Cox proportional hazards model. No unfavorable side-effects were noted. Beta-carotene (10 mg day(-1) ) and vitamin C were neither effective for clinical remission, nor for protection against the development of cancer. Data from this RCT does not support the hypothesis that chemoprevention with this treatment is effective for oral leukoplakia.

A novel PITX2 mutation causing iris hypoplasia

Iris hypoplasia (IH) is rare autosomal dominant disorder characterized by a poorly developed iris stroma and malformations of the eyes and umbilicus. This disorder is caused by mutation of the paired-like homeodomain 2 (PITX2) gene. Here, we describe a novel PITX2 mutation (c.205C>T) in an IH family presenting with very mild eye features but with tooth agenesis as the most obvious clinical feature.

Novel nonsense mutation in MSX1 in familial nonsyndromic oligodontia: subcellular localization and role of homeodomain/MH4

Nonsyndromic tooth agenesis is one of the most common anomalies in human development. Part of the malformation is inherited and is associated with paired box 9 (PAX9), msh homeobox 1 (MSX1), and axin 2 (AXIN2) mutations. To obtain a comprehensive understanding of the genetic and molecular mechanisms that underlie this genetic disease, we investigated six familial and seven sporadic Japanese cases of nonsyndromic tooth agenesis. Searches for mutations in these candidate genes detected a novel nonsense mutation (c.416G>A) in exon 1 of MSX1 from a family with oligodontia. This mutation co-segregated in the affected family members. Moreover, this mutation produced a termination codon in the first exon and therefore the gene product (W139X) was truncated at the C terminus, hence, the entire homeodomain/MH4, which has many functions, such as DNA binding, protein-protein interaction, and nuclear localization, was absent. We characterized the properties of this truncated MSX1 by investigating the subcellular localization of the mutant gene product in transfected cells. The wild-type MSX1 localized exclusively at the nuclear periphery of transfected cells, whereas the mutant MSX1 was stable but localized diffusely throughout the whole cell. These results indicate that W139X MSX1 is responsible for tooth agenesis.

Morphologic features of the mandibular ramus associated with increased surgical time and blood loss in sagittal split-ramus osteotomy

PURPOSE

To determine whether specific morphologic features of the mandibular ramus can predict increased surgical time and blood loss in sagittal split-ramus osteotomy (SSRO).

MATERIALS AND METHODS

The clinical and morphologic features of the mandibular ramus, obtained from computed tomographic images (n=50), were analyzed to predict the surgical time, the time required for ablation of the medial mandibular ramus, and the time required for sectioning of the mandible in performing a modified Obwegeser SSRO.

RESULTS

Significant factors associated with surgical time were an anterior border of the ramus at least 10.5 mm wide, a maximal length of the thickened ramus of at least 8.5 mm, and a distance from the mandibular incisor to the posterior border of the mandible of at least 97.5 mm. There were significant differences in blood loss between the 2 axial aspects of the medial ramus.

CONCLUSIONS

The greater protrusion of the medial oblique ridge, thickened ramus, and longer distance from the mandibular incisors to the posterior border of the mandible may increase the surgical time and blood loss in patients undergoing classic SSRO. When planning or performing an SSRO, the morphologic features obtained from computed tomographic images may help surgeons gain a better understanding of the potential difficulties when the surgical site involves the medial aspect of the ascending ramus of the mandible.

Endoscopic-assisted resection of peripheral osteoma using piezosurgery

Endoscopic-assisted surgery has gained widespread popularity as a minimally invasive procedure, particularly in the field of maxillofacial surgery. Because the surgical field around the mandibular angle is extremely narrow, the surrounding tissues may get caught in sharp rotary cutting instruments. In piezosurgery, bone tissues are selectively cut. This technique has various applications because minimal damage is caused by the rotary cutting instruments when they briefly come in contact with soft tissues. We report the case of a 33-year-old man who underwent resection of an osteoma in the region of the mandibular angle region via an intraoral approach. During surgery, the complete surgical field was within the view of the endoscope, thereby enabling the surgeon to easily resection the osteoma with the piezosurgery device. Considering that piezosurgery limits the extent of surgical invasion, this is an excellent low-risk technique that can be used in the field of maxillofacial surgery.

Clinicopathological significance of MAML2 gene split in mucoepidermoid carcinoma

CRTC1-MAML2 and CRTC3-MAML2 fusions have been associated with favorable clinicopathological features of mucoepidermoid carcinomas. However, the significance of the MAML2 gene split has not been fully clarified. In the present study, 95 mucoepidermoid carcinomas (paraffin-embedded materials) were analyzed for CRTC1-MAML2 and CRTC3-MAML2 fusions by RT-PCR and for the MAML2 gene split by FISH. Quantitative RT-PCR for the CRTC1-MAML2 transcript was performed in selected cases. MLL gene involvement, which has been reported in some leukemia cases, was examined by FISH in fusion partner-unknown cases. CRTC1-MAML2 and CRTC3-MAML2 fusions were detected in 37 and 6 cases, respectively. The MAML2 gene split was detected in 62 cases, which included all CRTC1/3-MAML2 fusion-positive cases. The level of CRTC1-MAML2 transcript expression was highly variable, and its clinicopathological impact was unclear. The MLL gene split was not detected. Mucoepidermoid carcinomas negative for CRTC1/3-MAML2 and positive for the MAML2 gene split (n = 19) showed favorable clinicopathological tumor features similar to those positive for CRTC1/3-MAML2 fusions. Compared with negative cases (n = 33), mucoepidermoid carcinomas positive for the MAML2 split (n = 62) were associated with lower patient age, a mild female predilection, a smaller tumor size, less frequent nodal metastasis, a lower clinical stage, a lower histological grade, and longer overall and disease-free survival. The MAML2 gene split emerged as an independent prognostic factor for both overall and disease-free survival in multivariate prognostic analysis. The presence of the MAML2 gene split defines a distinct mucoepidermoid carcinoma subset that is associated clinicopathologically with favorable tumor features.

General rules for clinical and pathological studies on oral cancer: a synopsis

For the doctors and other medical staff treating oral cancers, it is necessary to standardize basic concepts and rules on oral cancers to progress in the treatment, research and diagnosis. Oral cancers are integrated in head and neck cancers and are applied to the general rules on head and neck cancer, but it is considered that more detailed rules based on the characteristics of oral cancers are essential. The objectives of this 'General Rules for Clinical and Pathological Studies on Oral Cancer' are to contribute to the development of the diagnosis, treatment and research of oral cancers based on the correct and useful medical information of clinical, surgical, pathological and image findings accumulated from individual patients at various institutions.

Factors predictive of pterygoid process fractures after pterygomaxillary separation without using an osteotome in Le Fort I osteotomy

OBJECTIVE

This study demonstrated pterygomaxillary disjunction patterns and elucidated factors related to unfavorable pterygomaxillary junction fractures in Le Fort I osteotomy without using an osteotome.

STUDY DESIGN

Clinical and anatomical data obtained from computed tomography images (100 sides) were analyzed for their ability to predict patterns of pterygomaxillary disjunction.

RESULTS

Separation of the pterygomaxillary junction was most frequently performed at the maxillary tuberosity (48.0%). Twenty-eight pterygoid plates were fractured. Male gender, increased age, thickness of the pterygomaxillary junction, and length of the maxillary tuberosity were significant risk factors for pterygoid process fractures. We also identified that a pterygomaxillary junction thickness less than 2.6 mm and a maxillary tuberosity length of more than 11.5 mm indicated a statistically significant risk of pterygoid process fractures.

CONCLUSIONS

Prediction of frangible pterygoid plates by preoperative quantitative evaluation of morphometric values provides useful information for selecting safe procedures.

Genotypes of Candida albicans involved in development of candidiasis and their distribution in oral cavity of non-candidiasis individuals

Genotype characteristics and distribution of commensal Candida albicans should be studied to predict the development of candidiasis, however, extensive genotype analysis of commensal C. albicans has not been made. In this study, 508 C. albicans isolates were collected from patients with/without candidiasis and divided into 4 isolate groups (SG-1, oral cavity of non-candidiasis patients; SG-2, patients with cutaneous candidiasis; SG-3, patients with vaginal candidiasis; SG-4, patients with candidemia). These isolates were characterized to study the relationship between genotypes and pathogenicity using microsatellite analysis. Using CDC3 and CAI, 5 genotypes (I, 111: 115/33: 41; II, 115: 119/23: 23; III, 115: 123/18: 27; IV, 115: 123/33: 40; and V, 123: 127/32: 41) were found in 4.2%, 8.9%, 7.1%, 2.2% and 3.1% of the isolates, respectively. Genotypes II and III were commonly found in all isolate groups. These genotypes were further divided into 28 types by additional HIS3 and CAIII microsatellite markers. In this analysis, C. albicans with type 6 and type 23 was widely distributed as a commensal species in the oral cavity of non-candidiasis patients and found to be related with candidiasis development. Additionally, genotypes I and IV were found in SG-2 and/or SG-4, suggesting that the fungus with those genotypes is also involved in this development. In contrast, genotype V was not identified in any infective isolates.

Risk of surgical glove perforation in oral and maxillofacial surgery

Oral and maxillofacial surgery, which involves several sharp instruments and fixation materials, is consistently at a high risk for cross-contamination due to perforated gloves, but it is unclear how often such perforations occur. This study aimed to address this issue. The frequency of the perforation of surgical gloves (n=1436) in 150 oral and maxillofacial surgeries including orthognathic surgery (n=45) was assessed by the hydroinsufflation technique. Orthognathic surgery had the highest perforation rate in at least 1 glove in 1 operation (91.1%), followed by cleft lip and palate surgery (55.0%), excision of oral soft tumour (54.5%) and dental implantation (50.0%). The perforation rate in scrub nurses was 63.4%, followed by 44.4% in surgeons and first assistants, and 16.3% in second assistants. The odds ratio for the perforation rate in orthognathic surgery versus other surgeries was 16.0 (95% confidence interval: 5.3-48.0). The protection rate offered by double gloving in orthognathic surgery was 95.2%. These results suggest that, regardless of the surgical duration and blood loss in all fields of surgery, orthognathic surgery must be categorized in the highest risk group for glove perforation, following gynaecological and open lung surgery, due to the involvement of sharp objects.

OmpA-like protein influences cell shape and adhesive activity of Tannerella forsythia

Tannerella forsythia, a gram-negative fusiform rod, is implicated in several types of oral anaerobic infections. Most gram-negative bacteria have OmpA-like proteins that are homologous to the OmpA protein in Escherichia coli. We identified an OmpA-like protein in T. forsythia encoded by the tf1331 gene as one of the major proteins by mass spectrometric analysis. Two-dimensional, diagonal electrophoresis showed that the OmpA-like protein formed a dimeric or trimeric structure via intermolecular disulfide bonds. A biotin labeling experiment revealed that a portion of the protein was exposed on the cell surface, even though T. forsythia possesses an S-layer at the outermost cell surface. Using a tf1331-deletion mutant, we showed that the OmpA-like protein affected cell morphology. The length of the mutant cell was reduced almost by half. Cell swelling was observed in more than 40% of the mutant cells. Moreover, the mutant exhibited decreased adhesion to fibronectin, retarded autoaggregation, and reduced cell surface hydrophobicity. These results suggest that the OmpA-like protein in T. forsythia plays an important role in cellular integrity and adhesive function.

Impact of CRTC1/3-MAML2 fusions on histological classification and prognosis of mucoepidermoid carcinoma

AIMS

The aim of study was to evaluate the impact of CRTC1-MAML2 and CRTC3-MAML2 fusions on the histological classification of mucoepidermoid carcinoma (MEC) of the salivary glands and on the prognosis of patients.

METHODS AND RESULTS

MEC cases (n = 111) were screened for CRTC1-MAML2 and CRTC3-MAML2 fusions by reverse transcription polymerase chain reaction. We developed a system of 'molecular Armed Forces Institute of Pathology (AFIP) classification' that combined the AFIP histological classification proposed by Goode et al. and the presence of CRTC1-MAML2 or CRTC3-MAML2 fusions. MEC cases positive for CRTC1-MAML2 or CRTC3-MAML2 fusion formed a favourable tumour subset that was distinct from fusion-negative cases. When positive for the fusions, 'high-risk' patients, including those with a higher histological grade or an advanced clinical stage, showed an excellent prognosis. For overall survival, 'molecular AFIP classification' was selected as a powerful independent prognostic factor (P=0.0038), as was the clinical stage (P =0.0032). For disease-free survival, 'molecular AFIP classification' was also selected as an independent prognostic factor (P = 0.0006).

CONCLUSIONS

Molecular AFIP classification may be useful in predicting the prognosis of patients with MEC.

Imaging features contributing to the diagnosis of ameloblastomas and keratocystic odontogenic tumours: logistic regression analysis

OBJECTIVE

The aim of this study was to clarify the characteristic imaging features that can be used to differentiate ameloblastomas from keratocystic odontogenic tumours and to examine the significant imaging features contributing to a correct diagnosis.

METHODS

60 observers (39 specialists in oral and maxillofacial radiology and 21 non-specialists) examined CT and/or panoramic images of 10 ameloblastomas and 10 keratocystic odontogenic tumours shown on a webpage and made diagnoses. Their correct answer ratios were then calculated. The imaging features of the tumours were evaluated and expressed as binary numbers or quantitative values. The imaging features that contributed to a correct diagnosis were elucidated using logistic regression analysis.

RESULTS

The mean correct answer ratio was 61.3% ± 17.2% for the diagnosis of ameloblastomas and keratocystic odontogenic tumours. CT images produced higher correct answer ratios for diagnosis of keratocystic odontogenic tumours by specialists. The significantly different imaging features between ameloblastomas and keratocystic odontogenic tumours were the degree of bone expansion and the presence of high-density areas. The significant imaging features contributing to a correct imaging diagnosis were the number of locules, the presence of high-density areas and the inclusion of impacted teeth.

CONCLUSION

The presence of high-density areas is the most useful feature in the differential diagnosis of ameloblastomas and keratocystic odontogenic tumours based on comparison of the imaging features of both tumours and examination of the diagnostic contributions of these features.

Two missense mutations of the IRF6 gene in two Japanese families with popliteal pterygium syndrome

Mutations in the interferon regulatory factor 6 gene (IRF6) cause either popliteal pterygium syndrome (PPS) or Van der Woude syndrome (VWS), allelic autosomal dominant orofacial clefting conditions. To further investigate the IRF6 mutation profile in PPS, we performed mutation analysis of patients from two unrelated Japanese families with PPS and identified mutations in IRF6: c.251G>T (R84L) and c.1271C>T (S424L). We also found R84L, which together with previous reports on R84 mutations, provided another line of evidence that both syndromes could result from the same mutation probably under an influence of a modifier gene(s). This supports the idea that the R84 residue in the DNA binding domain of IRF6 is a mutational hot spot for PPS. A luciferase assay of the S424L protein in the other family demonstrated that the mutation decreased the IRF6 transcriptional activity significantly to 6% of that of the wild-type. This finding suggests that the C-terminus region of IRF6 could have an important function in phosphorylation or protein interaction. To our knowledge, this is the first report of mutations observed in Japanese PPS patients.

A novel mutation in the C-terminal region of RUNX2/CBFA1 distal to the DNA-binding runt domain in a Japanese patient with cleidocranial dysplasia

Cleidocranial dysplasia (CCD) is an autosomal dominant inherited skeletal disease with high penetrance and variable expressivity. Although many mutations in RUNX2/CBFA1, an osteoblast-specific transcription factor, have been identified as causes of CCD, it is unclear whether these mutation genotypes relate to various symptoms. Heterogeneous mutations of RUNX2/CBFA1 result in disease characterized by abnormal skeletal genesis and dental disorders. There are few reports describing the relation between detailed orofacial pathology and the RUNX2/CBFA1 genotype. The case of a Japanese patient with severe orofacial dysplasia who was clinically thought to have CCD is described here. The authors performed mutation analysis on the RUNX2/CBFA1 gene and identified a novel frameshift mutation (722delT), which produces a mutant RUNX2/CBFA1 with a truncating C-terminus distal to the runt domain.

Analysis of VH gene rearrangement and somatic hypermutation in Sjogren's syndrome and IgG4-related sclerosing sialadenitis

IgG4-related sclerosing sialadenitis is currently considered as an autoimmune disease distinct from Sjogren's syndrome (SS) and responds extremely well to steroid therapy. To further elucidate the characteristics of IgG4-related sclerosing sialadenitis, we analysed VH fragments of IgH genes and their somatic hypermutation in SS (n = 3) and IgG4-related sclerosing sialadenitis (n = 3), using sialolithiasis (n = 3) as a non-autoimmune control. DNA was extracted from the affected inflammatory lesions. After PCR amplification of rearranged IgH genes, at least 50 clones per case (more than 500 clones in total) were sequenced for VH fragments. Monoclonal IgH rearrangement was not detected in any cases examined. When compared with sialolithiasis, there was no VH family or VH fragment specific to SS or IgG4-related sclerosing sialadenitis. However, rates of unmutated VH fragments in SS (30%) and IgG4-related sclerosing sialadenitis (39%) were higher than that in sialolithiasis (14%) with statistical significance (P = 0.0005 and P < 0.0001, respectively). This finding suggests that some autoantibodies encoded by germline or less mutated VH genes may fail to be eliminated and could play a role in the development of SS and IgG4-related sclerosing sialadenitis.

Massive immature teratoma in a neonate

Teratomas are embryonal tumours composed of diverse tissues from three germinal layers with variable levels of maturity. The authors report a female patient with a large immature epignathus. Prenatal diagnosis permitted a caesarean section and tracheotomy to be planned under ex utero intrapartum treatment for airway obstruction. The tumour was successfully controlled, even though it was impossible to distinguish from normal tissue because it lacked a pedicle and capsule, using multidisciplinary therapy, including a series of surgical treatments and adjuvant chemotherapy. This case suggested that the level of serum alpha fetoprotein might be a useful indicator after surgery. At present, after 4 years, no regrowth has been observed and the patient has no problems with respiration or swallowing.

Clinicopathological significance of the CRTC3-MAML2 fusion transcript in mucoepidermoid carcinoma

Mucoepidermoid carcinoma is the most common primary malignancy of the salivary gland. We and others showed that CRTC1-MAML2 gene fusion was associated with favorable clinicopathological tumor features. Recently, a novel gene fusion, CRTC3-MAML2, was reported as a rare gene alteration in a case of mucoepidermoid carcinoma. However, its frequency and clinicopathological significance remains unclear. In all, 101 cases of mucoepidermoid carcinoma and 89 cases of non-mucoepidermoid carcinoma of the salivary gland were analyzed, and RNA was extracted from formalin-fixed, paraffin-embedded specimens. In the CRTC family, there have been three genes, CRTC1, CRTC2, and CRTC3. We developed reverse transcription-polymerase chain reaction (RT-PCR) assays for CRTC1-MAML2, CRTC2-MAML2, and CRTC3-MAML2 fusions. Clinicopathological data of the patients were obtained from their clinical records. Of 101 cases of mucoepidermoid carcinoma, 34 (34%) and 6 (6%) were positive for CRTC1-MAML2 and CRTC3-MAML2 fusion transcripts. However, in the 89 cases of non-mucoepidermoid carcinoma, neither transcript was noted. In the former cases, CRTC1-MAML2 and CRTC3-MAML2 fusions were mutually exclusive. The other fusion, CRTC2-MAML2, was not detected. We confirmed that the clinicopathological features of CRTC1-MAML2-positive mucoepidermoid carcinomas indicated an indolent course. CRTC3-MAML2-positive mucoepidermoid carcinomas also had clinicopathologically favorable features; all cases showed a less advanced clinical stage, negative nodal metastasis, no high-grade tumor histology, and no recurrence or tumor-related death after surgical resection of the tumor. It is interesting to note that patients with CRTC3-MAML2-positive tumors (mean 36 years of age) were significantly younger that those with the CRTC1-MAML2 fusion (55 years) and those with fusion-negative tumors (58 years). In conclusion, CRTC3-MAML2 fusion, which is mutually exclusive with CRTC1-MAML2 fusion and specific to mucoepidermoid carcinoma, may be detected more frequently than previously expected. Mucoepidermoid carcinomas possessing CRTC3-MAML2 fusion may be associated with favorable clinicopathological features and patients may be younger than those with CRTC1-MAML2 fusion or those with no detectable gene fusion.