PHORBOL-12,13-DIBUTYRATE IMPROVES THE QUALITY OF CYTOGENETIC PREPARATION IN LYMPHOID MALIGNANCIES

In cytogenetic preparation of lymphoid malignancies we investigated th e quantitative and qualitative impact of phorbol-12,-13-dibutyrate (P) and of this tumor promoter in combination with the calcium ionophore A23187 (PA). Using parallel cultures of unstimulated and stimulated pr eparations, the effect was examined in 13 patients with malignant lymp homas and six patients with acute lymphoblastic leukemias (ALL). Focus ing on high-quality analyzable metaphases, the best results were found in seven of 13 cases with lymphomas and five of six patients with ALL in the cultures supplemented with phorbol-12,13-dibutyrate. The yield of metaphases of good quality regarding length, spreading, and bandin g of chromosomes was regularly better in P-stimulated 24-hour culture (p < 0.05), followed by 48-hour cultures stimulated with P alone. Addi tion of the calcium-ionophore was of no further benefit. The yield of the unstimulated direct harvest was rather poor in nearly all patients investigated. Because no mutagenic effect of P was observed, the use of this mitogen may offer interesting perspectives in cytogenetic anal ysis of lymphoid malignancies and perhaps also in other tumors with lo w mitotic indexes.