Differential influence of stromal fibroblasts from different breast tissues on human breast tumour cell growth in nude mice.

The influence of human stromal fibroblasts cultured from normal, non-malignant and malignant breast tissues on in vivo growth of human breast tumour cells was studied. Earlier appearance and increased incidence were observed when low cell inocula of breast MDA-MB 231 tumour cells were coinjected with fibroblasts from either normal or non-malignant mammary tissue. However, at higher cell inoculations the appearance of MDA-MB tumours was delayed while the incidence was reduced. Coinjected fibroblasts derived from breast tumours did not modify MDA-MB tumour growth. The tumourigenic MCF-7 and non-tumourigenic NPM14-T4/9 breast cell lines were not affected by the presence of normal breast fibroblasts. These results indicate that fibroblasts can influence the behavior of tumour cells in vivo but the effects depend on the type and the proportions of coinoculated cells.