Figure 1 - p53 Gene alterations detected by non-isotopic SSCP in standard silver-stained polyacrylamide gels. A, PCR products of exon 5 amplified from an HPV-positive cervical carcinoma with a single nucleotide substitution (GA) (lane 1), an HPV-negative cervical carcinoma with a normal exon 5 sequence (lane 2), a gastric carcinoma with a single nucleotide substitution (GA) (lane 3). B, PCR products of exon 6 from HPV-positive cervical carcinomas with single nucleotide substitutions (AG) (lanes 1, 2), an HPV-negative penile carcinoma with a single substitution (AG) (lane 3), a gastric carcinoma with a 3 nucleotide deletion in codon 181 (lane 4). C, PCR products of exon 7 from an HPV-negative penile carcinoma with two nucleotide substitutions (CA and CT) (lane 1), an HPV-negative cervical carcinoma with a normal exon 7 sequence (lane 2). D, PCR products of exons 8 and 9 from head and neck tumors with normal (lanes 3, 9) and altered nucleotide sequences (lanes 1, 2, 4, 5 6, 7, and 8). wt: Corresponds to the normal sequences amplified from the cervical carcinoma cell line HeLa (A,B,C) and from a head and neck tumor (D).