Little is known about the relationship between genetic recombination m
echanisms and loss of tumour suppressor genes in solid tumours. Here,
we demonstrate deletion and truncation of both p53 alleles in a primar
y human glioblastoma and a derived cell line as the combined result of
a t(17;20) reciprocal translocation and a 1.1 Mbp genomic deletion on
chromosome 17p, starting in intron 4 of the p53 gene and ending at th
e telomeric CA-repeat marker D17S960. These results (i) suggest that g
enetic instability can lead to loss of tumour suppressor function in s
olid cancers, (ii) provide mapping of one such recombination event at
the nucleotide level, and (iii) establish the orientation of the p53 g
ene on chromosome 17 as: centromere 5'-3'-telomere.