Similar to HIFU, low-intensity low-frequency ultrasound (LILFU) may downregulate the expression levels of ABC transporters by inhibiting a specific cell-signalling pathway to improve the effect of chemotherapy and reverse tumour drug resistance in gemcitabine-resistant cells in pancreatic cancer, as demonstrated by QUI et al. [84]. Here, ABCG2 is linked to familial pancreatic carcinoma.