Abstract

The metastatic potential of a solid tumor is dependent upon its ability to interact with the extracellular matrix. The integrin superfamily is a group of proteins that are fundamental in such interactions and play a major role in cell-cell and cell-matrix adhesion. Localization of the integrin proteins was performed in normal ovary, primary epithelial ovarian tumors and metastatic tumor cells in ascitic samples. Expression of α₁, α₃, α₆ and β₄ was observed on normal ovarian epithelium with variable expression of α₅. Loss of α₁ expression by malignant cells in the primary tumors was noted. β₄, a component of the laminin receptor which was strongly expressed by both normal ovary and solid tumor, was absent from the ascitic tumor cells in the majority of cases. There was an associated loss of α₆ expression, indicating a deficiency of hemidesmosomes in the ascitic tumor cells. This alteration of integrin expression by metastatic malignant epithelial ovarian tumor cells may therefore represent one important mechanism by which metastatic disease occurs.