Infection of cultured Cdkn2a∆/∆ renal cells with lentiviruses expressing shRNA-Tsc1 or shRNA-Tsc2 increased the rate of proliferation (Fig. 1a) and allowed the formation of colonies in soft-agar (Fig. 1a and Supplementary Fig. 2d), indicative of cellular transformation. This evidence concerns the gene TSC1 and infection.