CAV1 and soft tissue sarcoma: However, all of the malignant mesenchymal tumors which are poorly differentiated and dedifferentiated, including leiomyosarcoma and liposarcoma, showed weak immunoreactivity or failed to stain with CAV1 [17], suggesting that loss of CAV1 might be a necessary step towards a differentiation block typical of malignancy and visible in most soft tissue sarcomas.