FOXM1 Induces a Global Methylation Signature That Mimics the Cancer Epigenome in Head and Neck Squamous Cell Carcinoma

The oncogene FOXM1 has been implicated in all major types of human cancer. We recently showed that aberrant FOXM1 expression causes stem cell compartment expansion resulting in the initiation of hyperplasia. We have previously shown that FOXM1 regulates HELLS, a SNF2/helicase involved in DNA methylation, implicating FOXM1 in epigenetic regulation. Here, we have demonstrated using primary normal human oral keratinocytes (NOK) that upregulation of FOXM1 suppressed the tumour suppressor gene p16INK4A (CDKN2A) through promoter hypermethylation. Knockdown of HELLS using siRNA re-activated the mRNA expression of p16INK4A and concomitant downregulation of two DNA methyltransferases DNMT1 and DNMT3B. The dose-dependent upregulation of endogenous FOXM1 (isoform B) expression during tumour progression across a panel of normal primary NOK strains (n = 8), dysplasias (n = 5) and head and neck squamous cell carcinoma (HNSCC) cell lines (n = 11) correlated positively with endogenous expressions of HELLS, BMI1, DNMT1 and DNMT3B and negatively with p16INK4A and involucrin. Bisulfite modification and methylation-specific promoter analysis using absolute quantitative PCR (MS-qPCR) showed that upregulation of FOXM1 significantly induced p16INK4A promoter hypermethylation (10-fold, P<0.05) in primary NOK cells. Using a non-bias genome-wide promoter methylation microarray profiling method, we revealed that aberrant FOXM1 expression in primary NOK induced a global hypomethylation pattern similar to that found in an HNSCC (SCC15) cell line. Following validation experiments using absolute qPCR, we have identified a set of differentially methylated genes, found to be inversely correlated with in vivo mRNA expression levels of clinical HNSCC tumour biopsy samples. This study provided the first evidence, using primary normal human cells and tumour tissues, that aberrant upregulation of FOXM1 orchestrated a DNA methylation signature that mimics the cancer methylome landscape, from which we have identified a unique FOXM1-induced epigenetic signature which may have clinical translational potentials as biomarkers for early cancer screening, diagnostic and/or therapeutic interventions

Multiple Pathway-Based Genetic Variations Associated with Tobacco Related Multiple Primary Neoplasms

BACKGROUND: In order to elucidate a combination of genetic alterations that drive tobacco carcinogenesis we have explored a unique model system and analytical method for an unbiased qualitative and quantitative assessment of gene-gene and gene-environment interactions. The objective of this case control study was to assess genetic predisposition in a biologically enriched clinical model system of tobacco related cancers (TRC), occurring as Multiple Primary Neoplasms (MPN). METHODS: Genotyping of 21 candidate Single Nucleotide Polymorphisms (SNP) from major metabolic pathways was performed in a cohort of 151 MPN cases and 210 cancer-free controls. Statistical analysis using logistic regression and Multifactor Dimensionality Reduction (MDR) analysis was performed for studying higher order interactions among various SNPs and tobacco habit. RESULTS: Increased risk association was observed for patients with at least one TRC in the upper aero digestive tract (UADT) for variations in SULT1A1 Arg²¹³His, mEH Tyr¹¹³His, hOGG1 Ser³²⁶Cys, XRCC1 Arg²⁸⁰His and BRCA2 Asn³⁷²His. Gene-environment interactions were assessed using MDR analysis. The overall best model by MDR was tobacco habit/p53(Arg/Arg)/XRCC1(Arg³⁹⁹His)/mEH(Tyr¹¹³His) that had highest Cross Validation Consistency (8.3) and test accuracy (0.69). This model also showed significant association using logistic regression analysis. CONCLUSION: This is the first Indian study on a multipathway based approach to study genetic susceptibility to cancer in tobacco associated MPN. This approach could assist in planning additional studies for comprehensive understanding of tobacco carcinogenesis

Extraskeletal Myxoid Chondrosarcomaof the Left Buccal Mucosa

Extraskeletal chondrosarcoma (ECS) is a rare malignant neoplasm of bone or soft-tissue origin, characterized by the presence of spindle cells admixed with well-differentiated cartilage or chondroid stroma. A case of ECS is reported in a 102-year-old woman who presented with a painful swelling of 2 cm in the left buccal vestibular area. Orthopantomography was insignificant. Biopsy and histopathological examination revealed a tumor composed of an undifferentiated small round cell component that surrounded a myxoid matrix of malignant cartilage. Immunohistochemical studies showed the tumor cells to be positive for nuclear S-100 protein immunostaining, focally positive for vimentin and synaptophysin, and negative for epithelial membrane antigen, desmin, chromogranin, Leu-7, glial fibrillary acid protein, actin muscle-specific, cytokeratin, carcinoembryonic antigen, and CD99 (MIC2). The proliferative index (MIB-1) was 20%. The tumor was treated by surgery with wide margins. There was no evidence of disease at one-year follow-up. This report presents a very rare case of ECS of the left buccal mucosa of the maxilla, and describes the histological characteristics and the immunoprofile

Ectomesenchymal chondromyxoid tumour of the tongue. A review of histological and immunohistochemical features.

Background: Ectomesenchymal chondromyxoid tumour (ECT) is a rare, benign neoplasm of uncertain histogenesis, which appears to exclusively involve the oral cavity, particularly the tongue. Case Report: We report the case of a 27-year-old woman with a 0.7 cm tumoral lesion of 3 months' duration on the dorsum of the tongue. Histologically, it comprised well-circumscribed, unencapsulated lobular proliferations of fusiform and polygonal cells, with varying degrees of cellularity, with neoplastic cells often set in a myxoid, chondroid or hyalinized background. Immunohistochemistry revealed positivity of the neoplastic cells for antibodies directed against S-100, glial fibrillary acidic protein and vimentin, plus negativity for CD-57(leu-7), epithelial membrane antigen, smooth muscle actin, desmin and cytokeratin AE1-AE3. The diagnosis was consistent with ECT. Total excision was performed and there has been no recurrence after 10 months' follow-up. Conclusion: This is the 37th case reported in the English language literature; ECT is characterized microscopically by a biphasic myxoid and chondroid pattern. Immunohistochemical expression of S100, glial fibrillary acidic protein and vimentin, very helpful in confirming diagnosis, suggest a probable mesenchymal and neural origin of this rare entity

Metastatic embryonal carcinoma in the maxillary gingiva.

Gingival metastases from embryonal carcinoma are very rare and often associated with widespread disease and poor prognosis. Because of their indistinct clinical appearance, they may be difficult to discriminate from more frequent gingival hyperplastic or reactive lesions. The case of a 35-year-old man who presented with a swelling in the left maxillary gingiva, extending from the first premolar to the second molar is reported. This medical history revealed that, 2 years previously, he had been diagnosed with a testicular mixed germ cell tumor (GCTs), for which he had undergone right inguinal orchidectomy and chemotherapy, leading to complete remission. Histology revealed a metastatic embryonal carcinoma. Imaging of the chest and abdomen showed this was the only site of metastasis. He is currently undergoing chemotherapy and responding well. This case draws attention to the multiple diseases that may present as gingival masses and stresses the difficulty of making a correct diagnosis. It is emphasized that in some mixed cases of testicular GCT it may be the more aggressive component that metastasizes, without being clearly apparent

Hyalinizing clear cell carcinoma arising on the anterior palatoglossal arch.

Hyalinizing clear cell carcinoma (HCCC) is very rare in the oral cavity, arising more frequently in the minor salivary glands. We present the case of a 57-year-old woman with a swelling on the anterior palatoglossal arch of 2x1 cm size. An incisional biopsy was taken and histological examination revealed typical clear cells arranged in anastomosing trabeculae, cords, nests, and solid sheets with a hyalinizing stroma. These clear cells were strongly positive to periodic acid-Schiff stain (PAS) but were negative for mucicarmine. Immunohistochemically, the neoplastic cells were immunoreactive to pancytokeratin, focally positive to EMA, but negative for smooth muscle actin (SMA), vimentin and S-100 protein, HMB45, CD68, carcinoembryonic antigen (CEA) and glial fibrillary acid protein (GFAP). These findings allowed us to define this tumor as a clear cell tumor of the anterior palatoglossal arch. The tumor was subjected to radical excision and the patient is doing well at twelve months after surgery. This report focuses on the heterogeneous group of clear cell neoplasms with the intent of pointing out some aspects that may contribute to forming a diagnosis of HCCC, and which, above all enable us to distinguish this neoplasm from other very similar forms occurring in the oral cavity