Detection of somatic DNA alterations in ovarian cancer by DNA fingerprint analysis. The M13 phage single-strand DNA probe which recognizes highly polymorphic loci was applied to HinfI-digested DNA isolated from tumor tissue and peripheral leukocytes from 20 patients with ovarian cancer. An average of 22 minisatellite-containing DNA fragments were observed per individual. DNA fingerprint analysis revealed a change in restriction-fragment-length patterns in the DNA from 12 of 20 (60%) tumors compared with the patient's constitutional DNA. Deletion of one or more bands from the tumor was recognized by the probe in seven cases, new bands were identified in two, and intensity shift was demonstrated in eight. The authors conclude that the unmapped M13 minisatellite probe is a useful method for identifying cancer-related somatic DNA alterations. 