In conclusion, these findings contribute to the understanding of PRG4’s biological activity in the previously uninvestigated area of breast cancer, and provide the framework for future investigation to target not only breast cancer but potentially other cancers which are dependent on TGFβ and HA-CD44 signalling for their survival, proliferation and metastatic ability [40,50]. The gene discussed is TGFB1; the disease is breast carcinoma.