When optimizing parameters for high recovery of PDX cells and minimal collection of CD34+/PBPCs in the center fraction (“tumor cell outlet”), relative recovery rates of up to 92.5 ± 14.5% for PDX-1 cells were achieved with the short chip (Fig. 2, left, 21% voltage setting), compared to 96.8 ± 3.5% when using the long chip (Fig. 2, right, + 11% voltage setting). Here, CD34 is linked to neoplasm.