COEXISTING CLONES IN DIPLOID AND NEAR-DIPLOID CELL-LINES

The karyotypic characteristics and clonal composition of human normal diploid MRC-5 (46,XY) and tumorigenic SK-UT-1 (45,XX,-13) and SK-UT-1B (46,XX) cell lines were studied. In MRC-5, 45, XY, -6; 45,X; 46, XY,t (7;14)(p11;q24) and 47, XY; M(1) clones were identified. Other karyoty pic characteristics included 2.4% polyploidy, 4.8% breaks/gaps, 4.1% s tructural anomalies, 1.4% hyperdiploidy, and 5.4% hypodiploidy. In SK- UT-1, 45, XX, -13, and clones with t(18;22) (q22.2;q11.23) and 46, XX, 4p+ occurred at 56.6%, 39.3%, and 4.1%, respectively. The t(18;22) ka ryotypes differed by either paired N13, one N13 plus one i(13q), or on e i(13q). The significance of single chromosome amplification relating to the outgrowth in one culture by the t(18;22) clone is discussed. S tructural aberrations occurred at high frequencies in N3, N6, and N7, and breaks from these chromosomes were clustered at 3p12 3q21, 6q21, 6 q23, and 7q11.2. The highly malignant SK-UT-1B had the stable karyotyp e and one 46X, f clone only. Clearly, the cell population was basicall y mosaic, containing more than one co-existing clone plus the polyploi dy of each clone.