NOTCH4 and adenoid cystic carcinoma: Our previous study showed that NOTCH1, NOTCH3, and NOTCH4 were upregulated in ACC-M cells, an adenoid cystic carcinoma cell line with high metastatic potential, compared with ACC-2 cells, which have low metastatic potential, and knockdown of NOTCH4 in ACC-M cells inhibited the migratory and invasive abilities of the cells, indicating a pro-metastasis role of Notch4 in SACC [13].