Aberrant DNA Methylation of NPTX2 as an Indicator of Malignant Behavior in Thymic Epithelial Tumors.

Thymic epithelial tumors (TET) consist of thymomas, thymic carcinoma (TC), and neuroendocrine tumors of the thymus (NECTT). Genetic and epigenetic alterations in TET have been the focus of recent research. In the present study, genome-wide screening was performed on aberrantly methylated CpG islands in TET, and this identified neuronal pentraxin 2 (NTPX2) as a significantly hypermethylated CpG island in TC relative to thymomas. NPTX2 is released from pre-synaptic cells in response to neuronal activity/seizure, and plays a role in host immunity and acute inflammation. TET samples were obtained from 38 thymomas, 25 TC, and 6 NECTT. The DNA methylation, mRNA, and protein expression levels of NPTX2 were examined. The DNA methylation rate of the NPTX2 gene was significantly higher in TC than in the normal thymus and thymomas, except B3. The mRNA expression level of NPTX2 was lower in TC than in the normal thymus. An inverse relationship was observed between mRNA expression levels and methylation levels. Relapse-free survival was shorter in patients with high NPTX2 DNA methylation levels than in those with low DNA methylation levels. NECTT showed very high mRNA and protein expression levels and low DNA methylation levels of NPTX2. NPTX2 may function as a tumor suppressor in TC, and have an oncogenic function in NECTT.

Aberrant methylation of dipeptidyl peptidase­like 6 as a potential prognostic biomarker for lung adenocarcinoma.

We previously performed the genome-wide screening of aberrantly methylated CpG islands (CGIs) using the paired tumorous and non-tumorous tissues of 12 lung adenocarcinomas (LADC). In comparisons with paired normal lung tissues, dipeptidyl peptidase-like 6 (DPP6) has been identified as the most significantly hypermethylated CGI in LADC. DPP6 is a protein that modulates A-type potassium channels in the somatodendritic compartments of neurons, which play a role in synaptic plasticity. Previous studies have showed that DPP6 is downregulated in cancers, such as acute myeloid leukemia and melanoma, but upregulated in colon cancer, which is attributed to hyper- and hypomethylation, respectively. The present study investigated the methylation and expression levels of DPP6 and its prognostic value in patients with LADC. The DNA methylation and mRNA expression levels of DPP6 in surgically resected LADC tissues were examined by bisulfite pyrosequencing and reverse transcription-quantitative PCR, respectively. The DNA methylation and mRNA expression levels of DPP6 were both significantly higher in LADC tissues compared with in normal lung tissues (n=25; P<0.0001). Overall and disease-free survival rates were significantly higher in LADC with high mRNA expression levels compared with those with low levels. In conclusion, epigenetic alterations in DPP6 were significantly higher in LADC tissues compared with in normal lung tissues, which may contribute to the malignant features and worse prognosis of these patients.

Utility of cytopathological specimens and an automated image analysis for the evaluation of HER2 status and intratumor heterogeneity in breast carcinoma.

OBJECTIVES: Although updated HER2 testing guidelines have been improved by a collaboration between the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) in 2013, HER2 evaluation is still problematic because of issues involving CEP17 polysomy, heterogeneity, and HER2 score 2+ cases. The aim of this retrospective study was to evaluate the relationship between HER2 gene heterogeneity, or so called CEP17 polysomy, using breast carcinoma cells sampled by scraping and the IHC score graded by automated image analysis using whole slide image. MATERIAL AND METHODS: We randomly selected 23 breast carcinoma cases with a HER2 score 0, 24 cases with a HER2 score 1+, 24 cases with HER2 score 2+, and 23 cases with HER2 score 3+ from the records of patients with breast cancer at Hiroshima University Hospital. We compared the results of fluorescent in situ hybridization (FISH) using formalin-fixed, paraffin-embedded (FFPE) tissues and cytological samples and compared the HER2 score calculated using an automated image analysis using wholly scanned slide images and visual counting. RESULTS: We successfully performed the FISH assay in 78 of 94 cases (83%) using FFPE tissues and in all 94 (100%) cases using cytological samples. Frequency of both HER2 amplification and CEP17 polysomy was higher when cytological samples were used than when FFPE tissue was used. Frequency of HER2 heterogeneity using cytological samples was higher that than using FFPE tissue, except for the IHC score 3+ cases. CONCLUSIONS: When assessment of HER2 status based on FISH using FFPE tissue cannot be accomplished, FISH using cytological samples should be considered. When intensity of HER2 is heterogeneous in the tumor tissue, particularly in cases regarded as score 2+, they should be evaluated by automated image analysis using the whole slide image.

Methylation and expression profiles of MGMT gene in thymic epithelial tumors.

OBJECTIVES: A key challenge in diagnosis and treatment of thymic epithelial tumors (TET) is in improving our understanding of the genetic and epigenetic changes of these relatively rare tumors. METHODS: Methylation specific PCR (MSP) and immunohistochemistry were applied to 66 TET to profile the methylation status of DNA repair gene O6-methylguanine DNA methyltransferase (MGMT) and its protein expression in TET to clarify the association between MGMT status and clinicopathological features, response to chemotherapy and overall survival. RESULTS: MGMT methylation was significantly more frequent in thymic carcinoma than in thymoma (17/23, 74% versus 13/44, 29%; P<0.001). Loss of expression of MGMT protein was significantly more frequent in thymic carcinoma than in thymoma (20/23, 87% versus 10/44, 23%; P<0.0001). There is a significant correlation between of MGMT methylation and loss of its protein expression (P<0.0003). MGMT methylation and loss of expression were significantly more frequent in advanced thymic epithelial tumors (III/IV) than in early tumors (I/II). CONCLUSION: MGMT methylation plays a soul role in development of TET, especially in thymic carcinoma. Therefore, translation of our results from basic molecular research to clinical practice may have important implication for considering MGMT methylation as a marker and a target of future therapies in TET.

Among triple-negative breast cancers, HER2(0) breast cancer shows a strong tendency to be basal-like compared with HER2(1+) breast cancer: preliminary results.

BACKGROUND: Diagnosis of triple-negative breast cancer (ER-negative, PgR-negative, HER2-negative; TNBC) is performed by means of immunohistological staining. HER2-negative includes HER2(0) and HER2(1+), based on differences in the staining intensity, but there have been no reports on comparison of these two types in TNBC. Accordingly, this study was designed to investigate the possible differences in the biological characteristics of HER2(0) breast cancer and HER2(1+) breast cancer in TNBC. METHODS: Tissue specimens from 89 TNBC patients were immunohistochemically stained for CK5/6, EGFR, p53, Ki67, E-cadherin, TOP2A and Bcl-2. The expressions of these markers and the clinicopathological findings were compared between the HER2(0) patient group and the HER2(1+) patient group. When either CK5/6 or EGFR was positive, the specimen was judged to be the basal-like phenotype of breast cancer. RESULTS: The percentages of CK5/6- and/or EGFR-positive specimens in the HER2(0) and HER2(1+) groups were 44.9 and 16.8%, respectively, showing that there was a significantly greater number of basal-like phenotype patients in the HER2(0) group (p < 0.01). The percentage of E-cadherin-positive specimens in the HER2(0) group was 66.6%, which was significantly greater than the 40.0% recorded in the HER2(1+) group (p < 0.05). The respective percentages of TOP2A-positive specimens in the HER2(0) and HER2(1+) groups were 55.0 and 30.0%, and the difference was statistically significant (p < 0.05). CONCLUSION: In TNBC, HER2(0) breast cancer showed a strong tendency to include more of the basal-like phenotype compared with HER2(1+) breast cancer. The staining results indicated the possibility that HER2(0) breast cancer and HER2(1+) breast cancer have different characteristics.

Expression of p53, Ki-67, E-cadherin, N-cadherin and TOP2A in triple-negative breast cancer.

BACKGROUND: Elucidation of the biological features of triple negative breast cancer (TNBC) is important for deciding treatment strategies. The expression of a number of biomarkers in TNBC was analyzed to elucidate those features. PATIENTS AND METHODS: The subjects were 134 TNBC patients. Immunohistochemical staining was employed to analyze for eight biomarkers: cytokeratin 5/6 (CK5/6), epidermal growth factor receptor (EGFR), p53, Ki-67 antigen (Ki-67), E-cadherin, N-cadherin, topoisomerase 2 alpha (TOP2A) and B-cell lymphoma 2 (BCL-2), which were then correlated with the nuclear grade (NG), tumor diameter, and the presence/absence of lymph node metastasis, distant recurrence and lymphatic infiltration. RESULTS: Significantly more high than low NG TNBC exhibited positive p53, Ki-67, E-cadherin and TOP2A. High N-cadherin and TOP2A expression was shown significantly in TNBC with lymphatic infiltration, and N-cadherin was also significantly positively expressed in node metastasis-positive cases. EGFR and CK5/6 were positively expressed in high NG TNBC, but not significantly. CONCLUSION: Analysis for expression of p53, Ki-67, E-cadherin, N-cadherin and TOP2A is meaningful for deciding treatment strategies for TNBC.

Primary pulmonary malignant peripheral nerve sheath tumor: a case report.

BACKGROUND: Although the histologic features of malignant peripheral nerve sheath tumor (MPNST) have been described, the cytologic features of primary pulmonary MPNST have not been reported in the literature. CASE: We report a case of primary pulmonary MPNST in a 78-year-old man. Follow-up computed tomography of colon cancer, renal cancer, penile cancer and gingival cancer revealed a nodular lesion, 12 mm in diameter, in the right upper lobe of the lung. In frozen section, a diagnosis of malignant neoplasm, not otherwise specified, was rendered for the imprinting specimen and histologic specimen. Imprinting specimens were composed of small cellular aggregates and discohesive neoplastic cells with obvious malignant features. Histologically, spindle cells with pleomorphic nuclei arranged infascicular patterns and multinucleated tumor giant cells were also observed. More than 25 mitotic figures were observed per 10 high-power fields. Tumor cells were positive only for vimentin and S-100, and the Ki-67 labeling index was 10%. Clinical and imaging investigation failed to identify an alternative primary site. We histologically diagnosed this case as primary pulmonary MPNST. CONCLUSION: MPNST has a varied cytomorphology with frank nuclear atypia showing no definite differentiation. Multinucleated neoplastic giant cells with immunopositivity for S-100 may permit more accurate diagnosis of MPNST.