Stromal Involvement In Malignant Growth

Abstract

This chapter describes various modes of interaction between malignant cells and stroma. Malignant cells are shown to produce various lytic enzymes, which attack the stroma or to induce fibroblasts to synthesize collagenolytic, elastolytic, and glycosaminoglycan-degrading enzymes. In some cancers tumor cells stimulate fibroblasts to produce stromal components—collagen, elastin, and glycosaminoglycans. Migration of tumor cells is partly determined by versatile adhesive glycoproteins in the stroma. Wound healing and especially fibrosis (scars) appear to be possible auxiliary factors in carcinogenesis. Stromal cells (local or generalized) may exhibit subtle alterations similar to transformed cells. Stromal alterations preceding manifest malignancy contribute to carcinogenesis. In vitro data point to intricate interdependencies between cancer cells and fibroblasts resulting in synthesis of collagenolytic enzymes. Normal ontogenesis depends on a complex of interactions between various tissues among which the stroma plays an essential role. Epithelial–stromal interactions are also important in the adult organism. In cancer growth, the microenvironmental signals constitute an essential category of influences contributing to malignancy.