Cytogenetic studies in 77 patients with chronic lymphocytic leukemia: correlations with clinical, immunologic, and phenotypic data.

Cytogenetic analyses by G-banding and/or Q-banding techniques of polyclonal B cell mitogen-stimulated peripheral blood lymphocytes in 77 patients with chronic lymphocytic leukemia were carried out in the present study. Adequate metaphases were obtained in 65 patients (84%). Of 29 patients with abnormal karyotypes, ten (34%) had trisomy 12 as the sole abnormality, eight (28%) had trisomy 12 in combination with other karyotypic changes, and the remaining 11 had various karyotypic changes other than trisomy 12. There was a significant relationship between the abnormal karyotype and disease status, clinical stage, lymphocyte count, bone marrow infiltration pattern, monoclonal IgM gammopathy, and urinary monoclonal-free light chain status. Six of seven patients (87%) with trisomy 12 only had stage 0-11 disease, whereas all eight patients with trisomy 12 with other changes had stage III or IV disease (P less than .02). However, of nine patients with other karyotypic changes without trisomy 12, five had stage 0-II and four had stage III or IV disease. These observations suggest that trisomy 12 may be the primary or the earliest karyotypic change in a majority of aneuploid patients with chronic lymphocytic leukemia, and that other karyotypic changes in addition to trisomy 12 may develop as a result of clonal evolution, dedifferentiation, or therapy. Of nine patients in whom autopsy studies were carried out, four were found to have diffuse histiocytic lymphoma or Richter's syndrome (three with trisomy 12 in combination with other chromosome changes and one with normal karyotype). Our findings clearly demonstrate that cytogenetic study may be of value in the clinical and prognostic evaluation of patients with chronic lymphocytic leukemia.