Primed in situ labeling (PRINS) for evaluation of gene deletions in cancer

Rearrangements involving the 13q14 and 17p13 chromosomal regions are often observed in leukemias and lymphomas. These rearrangements are not always identifiable cytogenetically. In more than 50% of cases, deletions occur at the submicroscopic level and the karyotypes appear normal. Molecular cytogenetic techniques such as fluorescence in situ hybridization (FISH) have accordingly contributed to the identification of a variety of subtle rearrangements such as those involving submicroscopic deletions. However, FISH is expensive, time consuming, technically burdensome, and requires cloned DNA probes. A newer technique, primed in situ labeling (PRINS), has been tested as a possible alternative to FISH. To assess the utility and efficiency of the PRINS method in the detection of RB1 and p53 deletions, we evaluated 10 patients with hematological disorders and known rearrangements, i.e., deletions involving 13q14 and 17p13 regions. The data in these cases were validated against data obtained with standard FISH probes. Our results indicate that PRINS could be used with relative ease in cytogenetics laboratories and could serve as an alternative to conventional FISH for defining deletions involving unique sequences.