Because the effect of PLD2 knockdown on KIT levels in GIST-R9 and GIST430 cells was less than that in GIST-T1 cells, these imatinib-resistant GIST cells may compensate for the loss of PLD1 and PLD2 proteins and restore PA levels in PLD1/PLD2-knocked cells. The gene discussed is PLD1; the disease is gastrointestinal stromal tumor.