RET and infection: While analysis of c-Myb transcription levels resulted in expected findings (high constitutive transcription of c-Myb and its variants from integrated retroviruses, downregulation of endogenous c-Myb mRNA during cultivation of cells in DM, reducing of c-Myb mRNA levels in miR-150-RET infected cells), the analysis of c-Myb protein levels by Western blotting (Figure 4A) resulted in one unexpected finding: c-Myb-RET (and c-Mybm-RET as well) infection did not increase c-Myb protein levels in GM.