in vitro studies showed that when quiescent ( ki-67-negative ) nih 3t3 fibroblasts or bovine peripheral blood lymphocytes were induced to proliferate , the appearance of ki-67-positive cells paralleled the induction of cell proliferation caused by addition of fetal calf serum or pha , respectively , to the cultures , and in both human and rat proliferating cells the ki-67 expression closely paralleled the incorporation of [ 3h ] -thymidine .
C0016030
fibroblasts
C0007634
cells