Anchorage independent growth of SV40 transformed human epithelial cells from amniotic fluids: differences within and among cell donors.

Cells from seven individuals were cultured separately for the induction of morphological transformation by SV40. Sixty-three transformed colonies were tested for anchorage independent growth in soft agar at various passage levels. Colony formation was consistent for all clones of respective cell donors. Four donors yielded clones that grew in soft agar in the first passage. Clones from three donors were similar to controls and formed no colonies. The size of the agar colonies was constant in the early passages. Size differences were observed in later passages and for negative clones that gained anchorage independence during time in culture. The early passage positive type of anchorage independence is expressed concomitantly with morphological transformation. Considering that the clonal isolates were genetically homogeneous within cell donors and heterogeneous among cell donors, it is concluded that the phenotype of anchorage independence is determined by at least two genetic mechanisms; namely, the genotype of the cell donor (the hereditary type) or by culturally derived new genetic variability, or both. Family history on cancer incidence showed that one grandparent for each of the four positive donors for the hereditary type of anchorage independence had cancer, whereas the grandparents of the three negative donors were asymptomatic. The incidence of cancer did not appear to be age related. Chromosome analyses of two morphologically transformed colonies from each of the cell donors by the in situ technique, showed diploid and tetraploid cells and a small number of cells with rearrangements. It is concluded as previously that the progenitor transformed cell to the colony of cells is normal diploid.