Isolating epidermal growth factor receptor overexpressing carcinoma cells from human whole blood by bio-ferrography

Background: The epidermal growth factor receptor (EGFR) is overexpressed in carcinoma. In some cases, including in colorectal cancer, it is used as a therapeutic target. Bio-Ferrography is a nondestructive method for isolating magnetized cells and tissues from a fluid onto a glass slide based on their interaction with an external, strong, and focused magnetic field. Methods: Here, we implement Bio-Ferrography to separate EGFR-positive cancer cells from EGFRnegative noncancer cells, mixed at a ratio of 1 to 1 × 10⁶, from either phosphate-buffered saline or human whole blood. Incubation of the cells with an anti-EGFR antibody and magnetic microbeads coupled to a secondary antibody was used to magnetize the target cells prior to the ferrographic analysis. Results: A procedure was developed for "a proof of concept" isolation. Recovery values as high as 78% for 1 mL phosphate-buffered saline, and 53% for 1 mL human whole blood, with a limit-ofdetection of 30 and 100 target cells, respectively, were achieved. Conclusions: These capture efficiency values are considered significant and, therefore, warrant further study on isolation of real circulating tumor cells from blood samples of patients, aiming at early diagnosis of EGFR-overexpressing tumor types.