Figure 5. Significant molecular factors involved in the spleen for tumor bearing and non-tumor bearing old hosts.

A. – C. & E. – G. Gene network analysis for key genes involved in age-dependent splenic changes for old mice compared to all other age groups. Pathway analysis was done with Ingenuity Pathway Analysis (IPA) software. IFNG, IL5, and TNF were added to the network to provide relations and connections between all genes. Predicted activity due to other genes is also shown for these two genes. Log₂ fold changes to the gene expression were used to obtain different shades of green for regulation levels for 1.2 fold change in down-regulated genes, while different shades of red depict regulation levels for 1.2 fold change in up-regulated genes. The darker the shade of green or red, the greater the fold change. D. & H. A schematic of the significant genes (Table 4), determined to be key in regulating many functions at older ages, illustrating the balance between the tumor promoters (text in yellow) and tumor suppressors (text in white and underlined) with the Log₂ fold change color coded as before. Genes that have no determined effect on tumor progression appear in white text.