Real-time PCR analysis of selected clones. Expression of 5 selected large-cell clones and 3 selected small-cell clones was measured by real-time PCR relative to GAPDH in the small- and large-cell populations. The procedure involved analysis of 0.2 to 4 ng small- and large-cell total RNA in triplicate. Data are expressed as the fold expression of each gene in large cells relative to small cells (A) or small cells relative to large cells (B). Histograms represent the fold expression calculated as 2^–ΔΔCt, including the range [2^{–(ΔΔCt +1.96 SE)}, 2^{–(ΔΔCt –1.96 SE)}]. Gene expression levels in one cell population versus another are significantly different if the range does not overlap the normalized value of 1 (2-sided Z test; P = .05).