Elraiyah, Tarig A

Abstract The antimetabolite 5-fluorouracil (5-FU) is one of the most widely used chemotherapy drugs. Dihydropyrimidine dehydrogenase (DPD) is a major determinant of 5-FU response and toxicity. Although DPYD variants may affect 5-FU metabolism, they do not completely explain the reported variability in DPD function or the resultant differences in treatment response. Here, we report that H3K27 trimethylation (H3K27me3) at the DPYD promoter regulated by Ezh2 and UTX suppresses DPYD expression by inhibiting transcription factor PU.1 binding, leading to increased resistance to 5-FU. Enrichment of H3K27me3 at the DPYD promoter was negatively correlated with both DPYD expression and DPD enzyme activity in peripheral blood specimens from healthy volunteers. Lastly, tumor expression data suggest that DPYD repression by Ezh2 predicts poor survival in 5-FU–treated cancers. Collectively, the findings of the present article suggest that a previously uncharacterized mechanism regulates DPD expression and may contribute to tumor resistance to 5-FU. Cancer Res; 76(21); 6362–73. ©2016 AACR.

Abstract Background There is growing attention towards increasing patient and service user engagement ( PSUE ) in biomedical and health services research. Existing variations in language and design inhibit reporting and indexing, which are crucial to comparative effectiveness in determining best practices. Objective This paper utilizes a systematic review and environmental scan to derive an evidence‐based framework for PSUE . Design A metanarrative systematic review and environmental scan/manual search using scientific databases and other search engines, along with feedback from a patient advisory group ( PAG ). Eligible sources English‐language studies, commentaries, grey literature and other sources (including systematic and non‐systematic reviews) pertaining to patient and public involvement in biomedical and health services research. Data extracted Study description (e.g. participant demographics, research setting) and design, if applicable; frameworks, conceptualizations or planning schemes for PSUE ‐related endeavours; and methods for PSUE initiation and gathering patients'/service users' input or contributions. Results Overall, 202 sources were included and met eligibility criteria; 41 of these presented some framework or conceptualization of PSUE . Sources were synthesized into a two‐part framework for PSUE: (i) integral PSUE components include patient and service user initiation, reciprocal relationships, colearning and re‐assessment and feedback, (ii) sources describe PSUE at several research stages, within three larger phases: preparatory, execution and translational. Discussion and Conclusions Efforts at developing a solid evidence base on PSUE are limited by the non‐standard and non‐empirical nature of much of the literature. Our proposed two‐part framework provides a standard structure and language for reporting and indexing to support comparative effectiveness and optimize PSUE .