A specific common chromosomal pathway for the origin of human malignancy. II.
A consistent chromosome abnormality exists in 17 human cell lines and in 11 fresh cancers, a finding strongly supportive of our original support of Boveri's concept of a chromosomal imbalance origin of human cancer. This abnormality is in the form of a marked excess of E16 chromosomes per cell, either absolute or in relationship to other chromosome classes. If the ratio of E16 chromosomes to those of other classes be the crucial parameter, several ratios involving E16 chromosomes must be considered as candidates. We feel the choice between such possible ratios might be better made when 100 or more human cancers have been studied, rather than now. It may be that imbalance in E16 chromosomes relative to certain other classes represents a necessary condition for malignant cell behavior, but that more than one such E16 imbalance may be a sufficient condition.