RESUMO
Colorectal cancer (CRC) is characterized by genome-wide alterations to DNA methylation that influence gene expression and genomic stability. Less is known about the extent to which methylation is disrupted in the earliest stages of CRC development. In this study, we have combined laser-capture microdissection with reduced representation bisulfite sequencing to identify cancer-associated DNA methylation changes in human aberrant crypt foci (ACF), the earliest putative precursor to CRC. Using this approach, methylation profiles have been generated for 10 KRAS-mutant ACF and 10 CRCs harboring a KRAS mutation, as well as matched samples of normal mucosa. Of 811 differentially methylated regions (DMRs) identified in ACF, 537 (66%) were hypermethylated and 274 (34%) were hypomethylated. DMRs located within intergenic regions were heavily enriched for AP-1 transcription factor binding sites and were frequently hypomethylated. Furthermore, gene ontology analysis demonstrated that DMRs associated with promoters were enriched for genes involved in intestinal development, including homeobox genes and targets of the Polycomb repressive complex 2. Consistent with their role in the earliest stages of colonic neoplasia, 75% of the loci harboring methylation changes in ACF were also altered in CRC samples, though the magnitude of change at these sites was lesser in ACF. Although aberrant promoter methylation was associated with altered gene expression in CRC, this was not the case in ACF, suggesting the insufficiency of methylation changes to modulate gene expression in early colonic neoplasia. Altogether, these data demonstrate that DNA methylation changes, including significant hypermethylation, occur more frequently in early colonic neoplasia than previously believed, and identify epigenomic features of ACF that may provide new targets for cancer chemoprevention or lead to the development of new biomarkers for CRC risk.
Assuntos
Neoplasias do Colo/genética , Metilação de DNA , Lesões Pré-Cancerosas/genética , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias do Colo/patologia , Estudo de Associação Genômica Ampla , Humanos , Microdissecção e Captura a Laser , Lesões Pré-Cancerosas/patologiaAssuntos
Atenção à Saúde , Veteranos , Idoso , Enfermagem Geriátrica , Serviços de Assistência Domiciliar , HumanosRESUMO
The Autohaler actuator is a breath-actuated device designed by 3M Pharmaceuticals. The objective of this study was to measure and improve the effectiveness of the device's package insert instructions (PII). Using only the PII for guidance, 5 of 20 (25%) subjects failed to trigger the device. The PII were revised based on the subject's performance and suggestions. Using the revised PII, only 1 of 20 (5%) different subjects failed to trigger the device. These results indicate that relatively minor modifications to instructions can result in significant improvements in patient use. Eighty-five percent of the participants thought the device was easier to use than a metered-dose inhaler.