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AIMS Mucoepidermoid carcinoma (MEC) is one of the most common salivary gland carcinomas. Epidermal growth factor receptor (EGFR) signalling pathway gene mutations are important in predicting a patient's prognosis, selecting molecularly targeted drugs and estimating the efficacy of a molecular therapy. However, their significance in MEC have been poorly clarified. CRTC1/3-MAML2 fusions are specific to MEC and may be associated with favourable characteristics in these patients. METHODS AND RESULTS We looked for CRTC1/3-MAML2 fusions and gene alterations in the EGFR, RAS family (KRAS, HRAS and NRAS), PIK3CA, BRAF and AKT1 in 101 MEC cases. We also examined mutations in TP53. CRTC1/3-MAML2 fusions were found in 62.4% of the cases. KRAS, HRAS and PIK3CA mutations were detected in 6.9%, 2.0% and 6.9%, respectively, but other EGFR pathway genes were not mutated. In total, gene mutations (RAS/PIK3CA) in the EGFR pathway were detected in 14.9% of the cases. TP53 mutations were found in 20.8%. CRTC1/3-MAML2 fusions were associated with a better prognosis and RAS/PIK3CA mutations a worse prognosis of the patients, respectively, and both were selected as independent prognostic factors for the overall survival of the patients. TP53 mutations had no prognostic impact. CRTC1/3-MAML2 fusion-positive rates were inversely associated with the patients' age and the fusions were found in 82% of patients aged

Aims Thymic carcinoma is rare and usually has a fatal outcome. Gene mutations in the epidermal growth factor receptor (EGFR) signalling pathway and TP53 have not been well analysed in thymic carcinoma. Methods and results We examined a large cohort of thymic carcinoma and thymoma type A/B3 and looked for gene mutations in the RAS family, EGFR, PIK3CA, AKT1, BRAF and TP53. Among 54 thymic carcinoma cases, RAS family mutations were detected in 10 cases, EGFR in two, PIK3CA in one, AKT1 in one, BRAF in none and TP53 in five. Among 33 thymoma type A/B3 cases, HRAS gene mutation were found in one, PIK3CA in two and AKT1 in one. All these mutations were those of missense type activating mutations. RAS family mutations were significantly more frequent in thymic carcinoma than in thymoma type A/B3 (P = 0.0461). A prognostic analysis focusing on thymic squamous cell carcinoma cases (n = 44) showed that the overall survival was significantly shorter in patients with EGFR pathway mutations (n = 9) than in those without in a univariate analysis (P = 0.0173). Subsequently, EGFR pathway mutations were selected as an independent factor for a poor overall survival in a multivariate analysis (P = 0.0389). Conclusions Mutations in the EGFR pathway and TP53 in thymic carcinoma may be frequent, and the EGFR pathway mutations may be associated with a poor prognosis in thymic squamous cell carcinoma patients. The therapeutic significance of gene mutations in thymic carcinoma should be further clarified.

Aims Cancer/testis antigens (CTAs) are detected in cancer cells but not in healthy normal tissues, with the exception of gametogenic tissues. CTAs are highly immunogenic proteins, and thus represent ideal targets for cytotoxic T-lymphocyte-mediated specific immune therapy. The aim of this study was to screen CTA expression in various types of salivary gland carcinoma and to clarify clinicopathological significance of MAGE-A and NY-ESO-1 expression in adenoid cystic carcinomas (AdCCs) of the salivary gland, which is one of the most common salivary gland carcinomas, and usually has a fatal outcome. Methods and results We used immunohistochemistry to examine the expression of four CTAs (MAGE-A, NY-ESO-1, CT7, and GAGE7) in various types of salivary gland carcinoma (n = 95). When carcinoma cases were divided into low-grade and intermediate/high-grade types, NY-ESO-1 and CT7 were expressed more frequently in intermediate/high-grade carcinomas. We then focused on MAGE-A and NY-ESO-1 expression in a large cohort of adenoid cystic carcinomas (AdCCs) (n = 46). MAGE-A and NY-ESO-1 were frequently expressed in AdCC; specifically, MAGE-A was expressed in >60% of the AdCC cases. MAGE-A expression and tumour site (minor salivary gland) were identified as independent risk factors for locoregional tumour recurrence. Conclusions These findings suggest that CTAs may be expressed in a variety of salivary gland carcinomas, especially in those with higher histological grades. In addition, MAGE-A, which is frequently expressed in AdCC cases, may be a useful prognostic factor for poorer locoregional recurrence-free survival.

Aims Adenoid cystic carcinoma (AdCC) is one of the most common salivary gland malignancies and the long-term prognosis is poor. In this study, we examined alterations of AdCC-associated genes, MYB, MYBL1, MYBL2 and NFIB, and their target molecules, including MYC. The results were correlated to clinicopathological profile of the patients. Methods and results Using paraffin tumour sections from 33 cases of salivary gland AdCC, we performed a detailed fluorescence in-situ hybridization (FISH) analysis for gene splits and fusions of MYB, MYBL1, MYBL2 and NFIB. We found that 29 of 33 (88%) AdCC cases showed gene splits in either MYB, MYBL1 or NFIB. None of the cases showed an MYBL2 gene alteration. AdCCs were divided genetically into six gene groups, MYB–NFIB (n = 16), MYB–X (n = 4), MYBL1–NFIB (n = 2), MYBL1–X (n = 1), NFIB–X (n = 6) and gene-split-negative (n = 4). AdCC patients showing the MYB or MYBL1 gene splits were associated with microscopically positive surgical margins (P = 0.0148) and overexpression of MYC (P = 0.0164). MYC expression was detected in both ductal and myoepithelial tumour cells, and MYC overexpression was associated with shorter disease-free survival of the patients (P = 0.0268). Conclusions The present study suggests that (1) nearly 90% of AdCCs may have gene alterations of either MYB, MYBL1 or NFIB, suggesting the diagnostic utility of the FISH assay, (2) MYB or MYBL1 gene splits may be associated with local aggressiveness of the tumours and overexpression of MYC, which is one of the oncogenic MYB/MYBL1 targets and (3) MYC overexpression may be a risk factor for disease-free survival in AdCC.

Aims Malignant thymic tumour histologically resembling a soft tissue sarcoma is extremely rare and defined as sarcomatoid carcinoma in the recent World Health Organization (WHO) classification. We report two such cases in which the tumour cells showed a prominent rhabdomyoblastic differentiation and analyse whether these tumours retain an epithelial nature at least in part. Methods and results One tumour occurred in a 51-year-old man (Case 1) and the other in a 40-year-old woman (Case 2). Microscopically, both tumours consisted essentially of two types of tumour cells: spindle and large round cells, with no apparent epithelial components. Osteosarcomatous small foci were also found in Case 2. Immunohistochemically, desmin and muscle-specific actin were positive in the majority of both types of tumour cells, whereas myogenin was predominant in the spindle cells and myoglobin in the large round cells. Some of both types of cells expressed cytokeratin with co-expression of myoglobin in the large round cells, but with no myogenin in the spindle cells. Some cytokeratin-positive spindle cells were also negative for desmin. Ultrastructural examination of a recurrent tumour in Case 2 revealed some epithelial features among the spindle cells. Cytogenetic study of the same tumour showed a complex abnormality including der(16)t(1;16)(q12;q12.1), an identical pattern previously reported in a case of thymic squamous cell carcinoma. Conclusions The findings support the definition in the WHO classification of sarcomatoid carcinoma that includes purely sarcomatous tumour as in the present cases. Occurrence of this type of tumour may indicate a relationship between thymic epithelial cells and myoid cells and/or a potential for divergent differentiation in thymic epithelial tumours.

Aims : Autoimmune pancreatitis (AIP), characterized by raised serum IgG4 levels, is frequently complicated by disorders of extrapancreatic organs. The aim of the present study was to examine immunohistochemically which extrapancreatic organs are affected, and whether an autoantibody to such organs is present in the serum of AIP patients. Methods : Various tissues/organs obtained from AIP patients were studied immunohistochemically with an anti-IgG4 antibody. To examine the presence of an autoantibody in the serum of AIP patients, sera were incubated with various normal organs/tissues extracted for other diseases, followed by detection with an anti-IgG4 antibody. Sera were also examined before and after glucocorticoid therapy. Results : Marked infiltration of IgG4+ plasma cells was observed in the pancreas, liver, bile duct and salivary gland of many of the AIP patients examined. The normal epithelia of the pancreatic ducts, bile ducts, gallbladder and salivary gland ducts reacting with the patients' sera were detectable by the anti-IgG4 antibody. Following glucocorticoid therapy the IgG4 antibody from the patients' sera showed decreased reactivity with these tissues. Conclusions : AIP may also affect extrapancreatic organs, the serum of AIP patients may contain an IgG4 autoantibody to various organs and glucocorticoid therapy may improve such disorders.