FOXA1

Forkhead box protein A1 (FOXA1), also known as hepatocyte nuclear factor 3-alpha (HNF-3A), is a is_associated_with::protein that in humans is encoded by the FOXA1 is_associated_with::gene.

Function
FOXA1 is a member of the forkhead class of DNA-binding proteins. These is_associated_with::hepatocyte nuclear factors are transcriptional activators for liver-specific transcripts such as is_associated_with::albumin and is_associated_with::transthyretin, and they also interact with is_associated_with::chromatin as a is_associated_with::pioneer factor. Similar family members in mice have roles in the regulation of metabolism and in the differentiation of the pancreas and liver.

Marker in breast cancer
FOXA1 in is_associated_with::breast cancer is highly correlated with ERα+, is_associated_with::GATA3+, and PR+ protein expression as well as is_associated_with::endocrine signaling. FOXA1 acts as a is_associated_with::pioneer factor for ERa in ERα+ breast cancer, and its expression might identify ERα+ cancers that undergo rapid reprogramming of ERa signaling that is associated with poor outcomes and treatment resistance. Conversely, in ERα− breast cancer FOXA1 is highly correlated with low-grade morphology and improved disease free survival. FOXA1 is a downstream target of is_associated_with::GATA3 in the mammary gland. Expression in ERα− cancers may identify a subset of tumors that is responsive to other endocrine therapies such as is_associated_with::androgen receptor antagonist treatment.

Role in prostate cancer
Mutations in this gene have been recurrently seen in instances of prostate cancer.