You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Protein", "Chemical"].

Please return the output as a JSON object of the format: {"Chemical" : ["Dexamethasone", ...], "Protein" : ["BRCA-1", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Fulvestrant: a unique antiendocrine agent for estrogen-sensitive breast cancer.
IMPORTANCE OF THE FIELD: The role of estrogen deprivation for the treatment of breast cancer has been understood since the 1800s. Pharmacologic advances in the field in the past decades, including tamoxifen and the aromatase inhibitors, have contributed significantly to the reduced mortality of estrogen-sensitive breast cancer. However, this subtype of breast cancer still presents with relapses and, once metastatic, progression to hormone-refractory state and loss of disease control remain an expected disease course. Fulvestrant, a pure estrogen receptor downregulator, is a new addition to the antiestrogen therapeutic armamentarium since its FDA approval in 2002. Its unique mechanism of action offers potential advantages over other estrogen targeted therapies. AREAS COVERED IN THIS REVIEW: Published scientific literature, including presented abstracts, on fulvestrant from 1985 to the present were reviewed with selected publications included. WHAT THE READER WILL GAIN: This review addresses current issues and therapies for estrogen-sensitive breast cancer, highlights the role of fulvestrant in current treatment guidelines and outlines some of the ongoing investigations of this compound. TAKE HOME MESSAGE: Fulvestrant is an effective and well-tolerated drug for treatment of metastatic estrogen-sensitive breast cancer. Work is underway to enhance its clinical benefit to patients as a single agent and in combination with other therapies.
{"Chemical": ["estrogen", "tamoxifen", "fulvestrant", "Fulvestrant"], "Protein": ["aromatase", "estrogen receptor"]}