Our investigation on the role of the PBX1 transcription factor continues. After revealing its role as a pioneer factor for the oestrogen receptor in 2011, now we find that PBX1 is frequently amplified in breast cancer. Amplification can be spotted in primary cancers as well as in the blood of patient with metastatic disease.
PBX1 amplification correlates with poor survival. Finally, we discovered that PBX1 also contribute to an alternative form of oestrogen receptor activation. The Epidermal Growth Factor (EGF) can act as an alternative to women’s hormones in the process of activation of the oestrogen receptor. We found that removing PBX1 from breast cancer cells blocks this activation mechanisms and kills breast cancer cells.
Interestingly, PBX1 is a target gene of DMXL2, the other factor we had previously characterised in our 2015 campaign.