Supplementary Figures from Development of Circulating Tumor Cell-Endocrine Therapy Index in Patients with Hormone Receptor–Positive Breast Cancer

Supplementary Figures. Figure S1. Clinical trial study design. Figure S2. Examples of biomarker staining of cultured human breast cancer cell lines after spike and capture from normal human blood using the CellSearch® system. A semi-quantitative scale was established based on relative expression of each biomarker: negative (0), weak (1+), intermediate (2+), and high (3+). Footnote: *hormone depleted condition. Figure S3. Demonstration of appropriate antibody staining of cultured human breast cancer cells with known positive and negative biomarker expression after spike and capture from normal human blood using the CellSearch® System. A: ER staining for MCF-7 and Sk-Br-3. B: BCL- 2 staining for MCF-7 and Sk-Br-3. C: HER2 staining for Sk-Br-3 and MCF-7. D: Ki-67 staining for MCF-7. Figure S4. Composite "CTC-Bio-Score" for different cell lines. A: Hormone depleted MCF-7 cells (Luminal-type). B: MDA-MB-231 (Basal-like type). C: Sk-Br-3 (HER2 positive). Figure S5. Heterogeneity of ER expression within the cultured MCF-7 human breast cancer cell line. Cells were cultured in hormone depleted media for 48 hours, harvested, and spiked into 7.5 ml of normal human blood. The blood was then processed using CellSearch® and stained for DAPI, CK, CD45, and ER. Examples of strong (2+, 3+), weak (1+), and no staining (0) are displayed. Apparent staining in the bottom panel is due to high gain analysis by the automated fluorescent microscopy, as indicated by very high background. Figure S6. Coefficient of variation of CTC-enumeration by mean CTC count. Figure S7. Heterogeneity between primary tissue and CTC for patient #4. The CTC galleries displayed were selected from over 1,000 images to illustrate CTC-ER heterogeneity.