GROWTH-PATTERNS AND CELL-KINETICS OF HUMAN OSTEOSARCOMA XENOGRAFTS INSERIAL PASSAGES IN NUDE-MICE ANALYZED BY IN-VIVO LABELING WITH IODODEOXYURIDINE

A human osteoblastic osteosarcoma was transplanted in nude mice and fo llowed in seven serial passages, Tumour growth, structure and cell pro liferation were studied in order to test the validity of the experimen tal tumour model. Tumour cell kinetics was analysed by in vivo labelli ng with the thymidine analogue iododeoxyuridine (IdUrd). Immunohistoch emistry was used to measure the IdUrd labelling index. Duration of S p hase (t(s)) was estimated by flow cytometry. From these two parameters potential doubling time (t(pot)) was calculated. Cell kinetic paramet ers showed low variations between passages and also between xenografts in the same passage. Smaller variations of t(s) compared to labelling index and t(pot) were found. t(pot) was generally short with an inter passageal mean of 1.3 days and CV = 14.8%. All xenografts showed DNA a neuploidy (mean DNA index = 1.6). Homogeneous tumour growth was indica ted by low variations of volume doubling time and lag time. There was no correlation between tumour growth and cell proliferation. Histopath ological characteristics of the donor patient's tumour were retained d uring serial transplantation.