Evaluation of an in vitro invasion assay for use on solid tissue samples and cultured cells.

An invasion assay, developed for monitoring the in vitro penetration of reconstituted basement membrane, matrigel, was modified and successfully applied to solid tumours, normal tissues as well as a variety of normal and tumour cell lines. However, we found that some normal fibroblasts were capable of in vitro invasion whilst some malignant cell lines with invasive capacity in vivo did not penetrate the matrigel. Nevertheless, this method can distinguish invasive capacity within a tumour model, and as a consequence may be used to elucidate some of the biochemical mechanisms in the invasion process comparing cells grown both in vitro and in vivo. Since the method does not always correlate with invasion in vivo the results must be interpreted with caution.