DROSHA and neoplasm: The study of gene expression after in vitro exposure of tumour cells to native and DEPC-inactivated RNase A showed that the incubation of tumour cells with RNase A for 48 h resulted in a significant increase in the expression of Drosha and xpo5 (Figure 5B), whereas the inactivated RNase A did not affect the miRNA biogenesis machinery.