Gene Expression Profile of a Single Organ
at Different Points in Time

Gene expression also varies within a certain type of cell at different points in time.

For example, the gene expression profiles of an organ might differ between normal and cancerous states, as shown here.

One goal of the National Cancer Institute's (NCI) Cancer Genome Anatomy Project is to identify the human genes expressed in different cancerous states, based on cDNA (EST) libraries, and to determine the molecular profiles of normal, precancerous, and malignant cells.