Salivary Duct Cyst

Salivary duct cysts (SDCs) are true cysts caused by obstruction of salivary ducts and are rare in minor salivary glands. Intraoral SDCs and mucoceles represent clinically salivary gland neoplasms, making diagnosis difficult and subject to errors in treatment. It is important for Oral and Maxillofacial Surgeons to include SDC in the differential diagnosis of swelling affecting buccal mucosa

Exploring Targets of TET2-mediated Methylation Reprogramming as Potential Therapeutic Targets and Discriminators of Prostate Cancer Progression

Aberrant cytosine methylation is one of the most common alterations in cancer, with global hypomethylation and regional hypermethylation characterizing many different malignancies, including prostate cancer. In normal cells, master methylation regulators, the ten-eleven translocase (TET) family of enzymes, demethylate genes by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine. Although lowered expression of all three TETs is common in prostate cancer, TET2 in particular plays a central role through its interaction with – and repression by – the androgen receptor. Loss of TET2 is associated with decreased cancer-specific survival, while missense alterations of TET2 are linked to metastatic disease. In this thesis, genome-wide targets of TET2 were examined via integrative (hydroxy)methylation and expression analysis to first identify how locus-specific epigenetic patterns affect prostate cancer cells and phenotype. Subsequently, genes regulated by TET2 were assessed to determine their individual and combinatorial utility as potential tumor suppressors or oncogenic factors in disease. In contrast to the paradigm of universal hydroxymethylation loss in cancer, locus-specific intronic retention in genes related to basic cellular function and intergenic gain of hydroxymethylcytosine marks proximal to androgen-related genes was observed in 22Rv1 prostate cancer cell lines. CRISPR-Cas9 based TET2 knockout in prostate cells identified high-confidence genes specifically mediated by TET2 methylation reprogramming. Expression loss of three such genes – ASB2, NUDT10, and SRPX – or increased promoter methylation of NRG1 was significantly (pPh.D

A 38-gene model comprised of key TET2-associated genes shows additive utility to high-risk prostate cancer cases in the prognostication of biochemical recurrence

Abstract Background Early treatment of patients at risk for developing aggressive prostate cancer is able to delay metastasis and reduce mortality; as such, up-front identification of these patients is critical. Several risk classification systems, including CAPRA-S, are currently used for disease prognostication. However, high-risk patients identified by these systems can still exhibit wide-ranging disease outcomes, leading to overtreatment of some patients in this group. Methods The master methylation regulator TET2 is downregulated in prostate cancer, where its loss is linked to aggressive disease and poor outcome. Using a random forest strategy, we developed a model based on the expression of 38 genes associated with TET2 utilizing 100 radical prostatectomy samples (training cohort) with a 49% biochemical recurrence rate. This 38-gene model was comprised of both upregulated and downregulated TET2-associated genes with a binary outcome, and was further assessed in an independent validation (n = 423) dataset for association with biochemical recurrence. Results 38-gene model status was able to correctly identify patients exhibiting recurrence with 81.4% sensitivity in the validation cohort, and added significant prognostic utility to the high-risk CAPRA-S classification group. Patients considered high-risk by CAPRA-S with negative 38-gene model status exhibited no statistically significant difference in time to recurrence from low-risk CAPRA-S patients, indicating that the expression of TET2-associated genes is able to separate truly high-risk cases from those which have a more benign disease course. Conclusions The 38-gene model may hold potential in determining which patients would truly benefit from aggressive treatment course, demonstrating a novel role for genes linked to TET2 in the prognostication of PCa and indicating the importance of TET2 dysregulation among high-risk patient groups

Exploring targets of TET2-mediated methylation reprogramming as potential discriminators of prostate cancer progression

Abstract Background Global DNA methylation alterations are hallmarks of cancer. The tumor-suppressive TET enzymes, which are involved in DNA demethylation, are decreased in prostate cancer (PCa); in particular, TET2 is specifically targeted by androgen-dependent mechanisms of repression in PCa and may play a central role in carcinogenesis. Thus, the identification of key genes targeted by TET2 dysregulation may provide further insight into cancer biology. Results Using a CRISPR/Cas9-derived TET2-knockout prostate cell line, and through whole-transcriptome and whole-methylome sequencing, we identified seven candidate genes—ASB2, ETNK2, MEIS2, NRG1, NTN1, NUDT10, and SRPX—exhibiting reduced expression and increased promoter methylation, a pattern characteristic of tumor suppressors. Decreased expression of these genes significantly discriminates between recurrent and non-recurrent prostate tumors from the Cancer Genome Atlas (TCGA) cohort (n = 423), and ASB2, NUDT10, and SRPX were significantly correlated with lower recurrence-free survival in patients by Kaplan-Meier analysis. ASB2, MEIS2, and SRPX also showed significantly lower expression in high-risk Gleason score 8 tumors as compared to low or intermediate risk tumors, suggesting that these genes may be particularly useful as indicators of PCa progression. Furthermore, methylation array probes in the TCGA dataset, which were proximal to the highly conserved, differentially methylated sites identified in our TET2-knockout cells, were able to significantly distinguish between matched prostate tumor and normal prostate tissues (n = 50 pairs). Except ASB2, all genes exhibited significantly increased methylation at these probes, and methylation status of at least one probe for each of these genes showed association with measures of PCa progression such as recurrence, stage, or Gleason score. Since ASB2 did not have any probes within the TET2-knockout differentially methylated region, we validated ASB2 methylation in an independent series of matched tumor-normal samples (n = 19) by methylation-specific qPCR, which revealed concordant and significant increases in promoter methylation within the TET2-knockout site. Conclusions Our study identifies seven genes governed by TET2 loss in PCa which exhibit an association between their methylation and expression status and measures of PCa progression. As differential methylation profiles and TET2 expression are associated with advanced PCa, further investigation of these specialized TET2 targets may provide important insights into patterns of carcinogenic gene dysregulation

Dynamic interplay between locus-specific DNA methylation and hydroxymethylation regulates distinct biological pathways in prostate carcinogenesis

Abstract Background Despite the significant global loss of DNA hydroxymethylation marks in prostate cancer tissues, the locus-specific role of hydroxymethylation in prostate tumorigenesis is unknown. We characterized hydroxymethylation and methylation marks by performing whole-genome next-generation sequencing in representative normal and prostate cancer-derived cell lines in order to determine functional pathways and key genes regulated by these epigenomic modifications in cancer. Results Our cell line model shows disruption of hydroxymethylation distribution in cancer, with global loss and highly specific gain in promoter and CpG island regions. Significantly, we observed locus-specific retention of hydroxymethylation marks in specific intronic and intergenic regions which may play a novel role in the regulation of gene expression in critical functional pathways, such as BARD1 signaling and steroid hormone receptor signaling in cancer. We confirm a modest correlation of hydroxymethylation with expression in intragenic regions in prostate cancer, while identifying an original role for intergenic hydroxymethylation in differentially expressed regulatory pathways in cancer. We also demonstrate a successful strategy for the identification and validation of key candidate genes from differentially regulated biological pathways in prostate cancer. Conclusions Our results indicate a distinct function for aberrant hydroxymethylation within each genomic feature in cancer, suggesting a specific and complex role for the deregulation of hydroxymethylation in tumorigenesis, similar to methylation. Subsequently, our characterization of key cellular pathways exhibiting dynamic enrichment patterns for methylation and hydroxymethylation marks may allow us to identify differentially epigenetically modified target genes implicated in prostate cancer tumorigenesis

Additional file 1: of Dynamic interplay between locus-specific DNA methylation and hydroxymethylation regulates distinct biological pathways in prostate carcinogenesis

Co-occurrence of methylation and hydroxymethylation in pathway regulation. This file lists all pathways found to be co-occurrent between 5mC- and 5hmC-enriched regions within each cell line, providing the genomic features and gene lists associated with enrichment for each mark