Cobalt Induced Oxidative Stress Contributes to Alveolar/Bronchiolar Carcinogenesis in B6C3F1/N Mice

To identify differentially expressed transcripts between control samples and spontaneous tumors, or control samples and cobalt treated tumors, we collected RNA from male and female B6C3F1 mice from a 2-year inhalation NTP bioassay exposed to 0 or 5 mg/m3 cobalt metal dust. These samples were interrogated with the Affymetrix Mouse Genome 430 2.0 GeneChip Array. A total of 11557 gene transcripts were differentially expressed between control samples and spontaneous tumors, and 12420 gene transcripts were differentially expressed between control samples and treated cobalt tumors (false discovery rate (FDR) < 0.05). There were 3 groups and 6x replication for each group, for 18 total samples. The groups were (1) vehicle control, (2) spontaneous tumors, (3) tumors present with cobalt treatment. We compared vehicle control vs spontaneous tumor and control vs treated tumor using ORIOGEN software. The permutation based p-values for each test were significant for FDR≤5%.