LABELLING INDEX OF HUMAN SQUAMOUS CELL CARCINOMAS.

Abstract

In vivo and in vitro labelling has been compared in 16 human solid squamous cell carcinomas (ENT [ear, nose, throat]). The median in vivo/in vitro LI ratio was 1 .cntdot. 2, but for 2/3 of the patients it was only 1 .cntdot. 1, suggesting a slight LI underestimation in vitro. Two factors can possibly explain the divergences: heterogeneity from one biopsy to another in the same tumor, and lower mean grain count in the deep cell layers of the in vitro labelled tumor samples. One must be cautious in considering in vitro LI as a valid result for a given patient. Even if the in vitro LI leads to a certain underestimate, it can provide useful data.