PVT1 and acute promyelocytic leukemia: High expression of PTV1 was detected in patients with acute promyelocytic leukemia (APL) and experiments done on NB4 (human APL cell line) have shown that knockdown of c-MYC causes decrease in PVT1 expression and knockdown of PVT1 results in the decrease of c-MYC protein, causing inhibition of cell proliferation.