Methods, Systems and Devices for Separating Tumor Cells

A method of separating circulating tumor cells from blood cells in a bodily fluid using a filter membrane that has a first side, a second side opposite the first side, and a plurality of pores extending from the first side to the second side, the blood cells including leukocytes, the method comprising:

• contacting the bodily fluid with the first side of the filter membrane;
• and
• applying a pressure differential across the filter membrane such that at least a majority of leukocytes in the bodily fluid pass through the pores to produce a filtrate at the second side of the filter and such that at least 75% of the circulating tumor cells are retained at the first side of the filter membrane,
• wherein the leukocytes that pass through the filter membrane retain their vitality,
• each of the pores of the filter membrane has a minimum dimension, in a plane of the first side, of between 3 μm and 8 μm,
• the filter membrane has a thickness in a direction from the first side to the second side that is less than the minimum dimension of each pore.

A method comprising:

• contacting with a first side of a filter membrane a fluid containing blood cells and circulating tumor cells from a patient, the blood cells comprising non-lysed whole cells,
• the filter membrane having a second side opposite the first side and a plurality of pores extending from the first side to the second side, each of the pores having a minimum dimension, in a plane of the first side, of between 3 μm and 8 μm,
• the filter membrane having a thickness in a direction from the first side to the second side that is less than the minimum dimension of each pore,
• applying a pressure differential across the filter membrane such that blood cells pass through the pores to produce a filtrate at the second side of the filter and such that at least 75% of the circulating tumor cells are retained at the first side of the filter membrane;
• and
• returning the blood cells without the retained circulating tumor cells to the patient, the blood cells retaining their vitality after the applying a pressure differential.