Amplification analysis of clones 26-4, 96-5, and 129-1 in squamous cell lung carcinomas L115, L10, and L116 by comparative PCR. Three different concentrations of tumor and blood DNA were amplified each by PCR using primers specific for clones 26-4, 96-5, and 129-1 and the MUC gene. The PCR products were separated by gel electrophoresis and visualized by SYBR green I. While the signal intensities of tumor and peripheral blood DNA (PB) were comparable using primers specific for the MUC gene, the signals of all three clones 26-4, 96-5, and 129-1 were significantly increased in tumor DNA L10 versus normal DNA indicating amplification of the corresponding genes in tumor L10. This tumor was used to generate the cDNA expression library. Lower amplification levels or the absence of amplification are observed for tumors L115 and L116, respectively. Lane 1, DNA marker; lanes 2 through 4, three dilutions of blood DNA; lanes 5 through 7, three dilutions of tumor DNA L115; lanes 8 through 10, three dilutions of tumor DNA L10; lanes 11 through 13, three dilutions of tumor DNA L116; lane 14, no DNA.