In previous DREAM-High activities, we studied cancer patient data from TCGA. Here we switch to a different kind of cancer model: **human cancer cell lines**. Cancer cell lines are cells that can grow in the laboratory. Researchers use them to study cancer biology and to test hypotheses about cancer behavior. In this activity, we will compare two breast cancer cell lines: - T-47D - MDA-MB-231 We will ask: Do differences in cell movement correspond to differences in gene expression? This is a core idea in systems biology: we connect a measurable behavior, or **phenotype**, to molecular data. Learning goals By the end of this activity, you should be able to: - load cell line motility and gene expression data - inspect data frames and matrices - subset a data frame using biological criteria - match sample IDs across two datasets - calculate log-transformed expression values - calculate differential gene expression between two cell lines - interpret genes in the tails of a distribution - connect gene expression patterns to cell behavior

August 3, 2026 AM