ABSTRACT
Identifying sensitive and specific biomarkers for early detection of cancer is immensely imperative for early diagnosis and treatment and better clinical outcome of cancer patients. This study aimed to construct a specific DNA methylation pattern of cancer suppressor genes and explore the feasibility of applying cell-free DNA based methylation as a biomarker for early diagnosis of esophageal squamous cell carcinoma (ESCC). We recruited early stage ESCC patients from Yangzhong County, China. The Illumina Infinium 450K Methylation BeadChip was used to construct a genome-wide DNA methylation profile. Then, differentiated genes were selected for the validation study using the Sequenom MassARRAY platform. The frequency of methylation was compared between cancer tissues, matched cell-free DNAs and normal controls. The specific methylation profiles were constructed, and the sensitivity and specificity were calculated. Seven CG sites in three genes CASZ1, CDH13 and ING2 were significantly hypermethylated in ESCC as compared with normal controls. A significant correlation was found between the methylation of DNA extracted from cancer tissues and matched plasma cell-free DNA, either for individual CG site or for cumulative methylation analysis. The sensitivity and specificity reached 100% at an appropriate cut-point using these specific methylation biomarkers. This study revealed that aberrant DNA methylation is a promising biomarker for molecular diagnosis of esophageal cancer. Hypermethylation of CASZ1, CDH13 and ING2 detected in plasma cell-free DNA can be applied as a potential noninvasive biomarker for diagnosis of esophageal cancer.
ABSTRACT
BACKGROUND & OBJECTIVE: This study was conducted to investigate the altered gene expression of MCF-7 cell before and after the treatment with beta-carotene using cDNA microarray and to investigate the mechanism which beta-carotene induce breast cancer cell apoptosis. METHODS: Two fluorescence cDNA probes were made using reverse transcriptional reaction from mRNA of beta-carotene untreated or treated MCF-7 cells (human estrogen receptor positive breast cancer cells), marked with two different fluorescence dyes (cy3 and cy5) respectively, hybridized with expressed cDNA microarray scanned and analyzed by computer system and finally the expressed gene was produced. RESULTS: A total of 21 genes related to cell apoptosis, cell signal transduction, protein translation and immunity were expressed differently after the treatment of beta-carotene, which 3/21 were up-regulated (AF040958, AK001555,g41894),18/21 were down- regulated(hshsp90r,U83857,AB014509,AF126028,AF053641,AF117386,AF050127,NM_012177,humtopi,AJ250915,U37547,U78798,NM_004849,NM_005346,AF004711,NM_006595,NM_001418,AB015051). CONCLUSION: beta-carotene may inhibit the growth of breast cancer cells through inducing apoptosis,breaking signal transduction,and blocking protein translation.
