Furthermore, altered expression of several genes of the pathway, including DDX4, HENMT1, MAEL, PDL6, PRMT5, TDRD1, TDRD6, TDRD9, TDRKH and WDR77, suggesting that the piRNA pathway is functional in liver and its activity is modified in the liver cancer (Supplementary Figure S1). The gene discussed is TDRD9; the disease is liver cancer.