Expression Profiling of Hepatocellular Carcinomas Arising Either Spontaneously or due to Chronic Exposure to Ginkgo biloba Extract (GBE) in B6C3F1/N Mice [Expression]

In a recent NTP study, chronic exposure of B6C3F1/N mice to Ginkgo biloba extract (GBE) resulted in a high incidence of hepatocellular carcinomas (HCC). Genome-wide promoter methylation profiling and Expression profiling on GBE-exposed HCC (2000 mg/kg group), spontaneous HCC (vehicle-control group) and age-matched vehicle control liver was performed to identify differentially methylated genes and differentially expressed genes in GBE-exposed HCC and spontaneous HCC. DNA methylation alterations were correlated to the corresponding global gene expression changes to identify differentially methylated promoter regions of relevant cancer genes altered in GBE-exposed HCC compared to spontaneous HCC. Male and female B6C3F1/N mice were exposed to 0, 200, 600, and 2000 mg/kg GBE by corn-oil gavage, 5 days a week for 104 weeks . Upon examination of the hematoxylin and eosin stained slides made out of FFPE sections representing the frozen counterpart, five CNTL liver (3 males and 2 females), five SPNT-HCC (4 males and 1 female), and five GBE-HCC from high dose 2000 mg/kg group (4 males and 1 female) frozen tissue samples were selected for DNA isolation for methylation array study. Six control liver (4 males and 2 females), six SPNT-HCC (5 males and 1 female) and six GBE-HCC (5 males and 1 female) from 2000 mg/kg are used for RNA isolation for microarray experiments.