Relative expression of GAPDH. Total RNA was extracted from each of the 12 lung cancer cell lines and reverse-transcribed to produce cDNA. GAPDH expression was determined by qPCR in triplicate assays. Results are shown as the mean ± S.D. Numbers indicate cell lines, 1: MRC-9 [normal control], 2: A549 [AD], 3: ABC-1 [AD], 4: RERF-LC-MS [AD], 5: EBC-1 [SQ], 6: LK-2 [SQ], 7: LC-1-sq [SQ], 8: LU65 [LC], 9: LU99 [LC], 10: 86-2 [LC], 11: STC 1 [SC], 12: RERF-LC-MA [SC] and 13: MS-1-L [SC].