Joining of recombination signals on the der 14q- chromosome in T-cell acute leukemia with t(10;14) chromosome translocation.

Sequence analysis of the translocation breakpoint junctions on the der(14q-) chromosome in six patients carrying a t(10;14) chromosome translocation revealed that the breakpoint occurred 5' to the HOX11 protooncogene at the breakpoint cluster region. HOX11 coding sequence was not effected. The translocation resulted in the joining of the V-(D)-J recombination signals 5' to the T-cell receptor D delta 2 segment on chromosome 14 with chromosome 10 at a location within a heptamer-like sequence. At the breakpoint junctions, the insertion of extra nucleotides, N-nucleotides, including P-nucleotides, was evident. The mechanism involved in this process is discussed.

Homozygous deletions at 8p22 and 8p21 in prostate cancer implicate these regions as the sites for candidate tumor suppressor genes.

Frequent loss of an allele at specific chromosomal regions implicates these regions as sites of tumor suppressor genes (TSG) that become inactivated during tumor progression. We have studied chromosome 8p allele losses in 32 primary human prostate carcinomas with 16 polymorphic microsatellite sequences. Overall, 22 of 32 (69%) informative specimens showed loss of allele in at least one locus. The most frequent losses of heterozygosity (LOH) occurred at the LPL locus (46%) on chromosome 8p22 and at the D8S360 (45%) and NEFL (43%) loci on chromosome 8p21. Homozygous deletions were detected at the LPL and NEFL loci at 8p22 and 8p21, respectively. The minimal region with frequent LOH and homozygous deletion, around the LPL locus, was restricted between the MSR locus and the D8S258 marker, separated by less than 9 cM. The second region was restricted between markers D8S1128 and D8S131 separated by 12 cM. The results suggest the existence of two chromosome 8p sites for candidate TSGs in prostate cancer.