A composition and method are provided for detecting and isolating antigen associated cancer cells. The composition and method utilize an antigen specific, immunomagnetic composition as the detecting and isolating agent. An illustrative immunomagnetic composition comprises avidin or streptavidin conjugated to paramagnetic beads and further conjugated to antigen specific, biotinylated antibody. A fluidic admixture of the antigen associated cancer cells with the immunomagnetic composition in an affinity column disposed in a magnetic field produces a cancer cell immunomagnetic composition conjugate which is deposited onto the inner wall of the column.