The purpose of this study is to collect blood and tissue to help develop tests that might be able to detect cancer earlier. The investigator will be collecting these samples and reviewing test results from participants who have had an area of concern found on breast imaging, as well as from participants who are scheduled to have a routine breast cancer screening mammogram.

Inclusion Criteria:

• Females with one or more BI-RADS 4 radiographic lesions who are undergoing ultrasound, stereotactic or MRI-guided breast biopsy at MSKCC or at an MSK Alliance Member Site. If multiple imaging modalities were employed (mammogram, ultrasound, MRI) and no integrated score is provided, then the highest BI-RADS score will be used.
• Age ≥ 18 years at the time of breast biopsy
• Willing to provide blood samples for research purposes before biopsy.
• Able to provide written informed consent

Exclusion Criteria:

• Women with a BI-RADS 4 lesion who had the lesion previously biopsied
• Females with a current active malignancy other than non-melanoma skin cancers. Females are considered not to have a "current active" malignancy if they have completed therapy and have no evidence of systemic disease for at least three years from the initial diagnosis
• Currently pregnant women
• History of bilateral mastectomy.
• Participant has or is currently participating in another GRAIL-sponsored protocol

Breast cancer

Females with one or more BI-RADS 4 radiographic lesion who are undergoing ultrasound, stereotactic or MRI-guided breast biopsy at a participating study center.