For decades, cancer medicine has read the genome as if it were the whole story, yet the proteins that genes produce—the molecules that drugs must ultimately confront—have followed their own logic, invisible to sequencing alone. Proteogenomics now attempts to reconcile these two languages of the cell, layering genomic, transcriptomic, and proteomic data into a single, composite portrait of a tumor. The approach is already reshaping how researchers classify breast, colorectal, and lung cancers, and it carries the quiet promise that treatment decisions may soon be guided not by what a tumor's gen