**4. Genome-wide E2 and P4 signalling**

There are hundreds of studies presenting how expression of a single gene could change upon E2 or P4 treatment in different cell culture. Knock out studies with transgenic animals have confirmed the importance of ERs and PRs in reproductive system and cancer development. To understand the broad role of steroid hormones in humans it is mandatory to study their action in genome-wide level. Recently, the development of large-scale genomic methods to analyse gene expression and factor binding to DNA enable us to study steroid hormone dependent gene expression changes and transcription regulation in the entire genome. As ERs and PRs are acting as TFs they have an ability to regulate the expression of proximal and distal genes by binding hormone responsive elements. Chromatin immunoprecipitation (ChIP) analysis has been broadly used for identification TF binding regions on DNA. ChIP assay can be followed by polymerase chain reaction (PCR), hybridization the probes on a microarray (ChIP-on-chip) or high throughput (HTP) sequencing (ChIP-Seq) to establish the genomic regions occupied by a specific TF. To understand whether TF binding has a positive or negative impact on gene expression microarrays, sequencing (RNA-Seq) and RT-qPCR are commonly used followed to mRNA extraction.
