Both semi-quantitative and quantitative PCR analysis demonstrated that Epidermal Growth Factor (EGF), Fibroblast Growth Factor (FGF), and Insulin-like Growth Factor (IGF-1) (factors known to support growth of cancer cells) were expressed by both primary tumor and brain metastasis CAFs (Fig. 1d and Supplemental Fig. 2). The gene discussed is IGF1; the disease is cancer.