Uncontrolled growth of tumour stromal fibroblasts in vitro.

The disturbance of the growth control mechanisms in tumour cells in vivo may be manifested as uncontrolled growth of the tumour stroma in vitro. Stromal fibroblast-like finite cell lines produced from benign or malignant human breast tissue specimens exhibited cell overlapping which ranged from multilayers to dense piling up colonies, while cells derived from normal tissues exhibited intense contact inhibition of growth and locomotion, under the same culture conditions. 6 out of 13 lines derived from malignant tissues and 2 out of 5 lines derived from benign lesions exhibited the phenomenon of 'periodic appearance of piling up colonies'.