MUTATION-RATE OF NORMAL AND MALIGNANT HUMAN-LYMPHOCYTES

Abstract

The genetic stability of normal and neoplastic lymphocytes was compared by using base-line mutation frequency and mutation rate/cell generation. Mutations at the hypoxanthine-guanine phosphoribosyltransferase locus were studied by enumerating thioguanine-resistant cells in a clonogenic assay. The base-line ("spontaneous") mutation frequency was 152 .times. 10-6, 6.38 .times. 10-6 and 1.06 .times. 10-6 for normal cells from three individuals and was 1.16 .times. 10-3, 6.08 .times. 10-5, and 3.06 .times. 10-5 for the three malignant cell lines, Jurkat (JM), HRIK, FMC-Hu1B, respectively. The mutation cell/generation rate was 24.6 .times. 10-8, 15 .times. 10-8, and 5.5 .times. 10-8 for lymphocytes from the three normal individuals, and 666.4 .times. 10-8, 52.8 .times. 10-8, and 131 .times. 10-8 for the three malignant cell lines. The results suggest that neoplastic lymphocytes are more genetically unstable than normal lymphocytes.