Cell proliferation in neuroblastoma

Abstract

In a patient with generalized neuroblastoma labeling index and median grain-count determinations on tumor cells in mitosis and interphase were performed autoradiographically after pulse-labeling with tritiated thymidine. The tumor-cell samples were removed from different parts of a superficially growing metastasis. The mitotic index was 0·57%. Labeled mitoses data indicated a minimum G 2 time of 1–2 hr and a mean DNA synthesis time of approximately 27–28 hr. Mitotic-time calculations yielded a value of 1·4 hr. The initial labeling index of all neuroblastoma cells in interphase was 11%. Classification of tumor cells according to relative nuclear size permitted to distinguish at least two cell compartments: one of cells with large, initially labeled and one of cells with small, initially unlabeled nuclei. The data are compatible with the assumption that there is a continuous reciprocal exchange of cells between these compartments and that the majority of the tumor cells retain the ability to divide.