Fig. 2.

Effects of overexpressing individually or combinatorially the 14q13.3 amplicon genes on the proliferation of premalignant lung epithelial cells. (A) Colony formation of BEAS-2B retroviral transfectants stably expressing individual genes (single transfectant) or pairwise combinations of the three candidate driver genes (double transfectant). The assay was initiated by plating 1,000 cells per well in six-well plates. After 12 days, cells were fixed and stained with crystal violet. Representative pictures of experiments performed in triplicate are shown. (B) The crystal violet stain in A was dissolved in 0.1% SDS solution and quantified by absorbance at 595 nm according to Scragg and Ferreira (20). V, vector only; N, NKX2-8; T, TTF1; P, PAX9; V-V, vector-vector; T-P; TTF1-PAX9; N-P, NKX2-8-PAX9; T-N, TTF1-NKX2-8.