Annele Sainio and Hannu Järveläinen
Cancer cells create their own microenvironment via dynamically interacting with the surrounding non-malignant stromal cells and various Extracellular Matrix (ECM) macromolecules as well as with a large number of other proteins within the ECM. The term desmoplastic reaction is used to describe a phenomenon in which ECM macromolecules including specific species of proteoglycans and hyaluronan variously accumulate around the tumour mass. The precise role of the desmoplastic reaction is not known. However, it has been proposed to represent either a defense mechanism by non-malignant host cells against invading cancer cells or to be a tumourigenesis promoting phenomenon induced by cancer cells to assist their propagation. Even an idea that desmoplastic reaction precedes the development of cancer has been introduced, further emphasizing the importance of ECM macromolecules in tumourigenesis. Here, we will discuss ECM macromolecules in tumour microenvironment focusing particularly on desmoplastic reaction and ECM proteoglycans and hyaluronan. We will also present examples of strategies how ECM macromolecules involved in desmoplastic reaction could be considered in the development of innovative oncological pharmacotherapies in the future.