Gene expression profiling involves assessing the activity (expression) of thousands of genes simultaneously to create an overall snapshot of cellular function.

These profiles can identify differences between cells that are actively dividing and those that are not, or demonstrate how cells respond to specific treatments.

Often, such experiments measure the entire transcriptome at once, capturing the activity of every gene present in a particular cell.

This comprehensive measurement is known as the transcriptome, representing the complete set of RNA transcripts produced by the genome at any given time.