Nucleotide sequence of representative mutant P53 alleles. DNA from tumors scored positive on PCR-SSCP analysis were further characterized by nucleotide sequencing of both DNA strands. (a and b) Structural changes in exon 5. PCR product from these tumors was cloned into a TA-vector from which normal and mutant alleles were isolated and sequenced. Tumor no. 907 had a deletion and no. 1095 had a duplication.

(c, d, e, and f) Representative point mutations in exon 6. (g, h, i, and j) Representative point mutations in exon 7. PCR-amplified DNA from these tumors was sequenced directly. Note that both homologs of chromosome 17 were cytogenetically normal in nos. 323, 1095, and 1866; 1 copy of 17p was lost in nos. 459, 840, and 905; status of chromosome 17 was not known in nos. 629 and 2303.