67 kDa laminin receptor (67LR) in normal and neoplastic hematopoietic cells: is its targeting a feasible approach?

The 67 kDa laminin receptor (67LR) is a non-integrin cell surface receptor for laminin (LM) that derives from a 37 kDa precursor (37LRP). 67LR expression is increased in neoplastic cells and correlates with an enhanced invasive and metastatic potentialin many human solid tumors, recommending this receptor as a new promising target for cancer therapy. This is supported by in vivo studies showing that 67LR downregulation reduces tumour cell proliferation and tumour formation by inducing apoptosis. 67LR association with the anti-apoptotic protein PED/PEA-15 activates a signal transduction pathway, leading to cell proliferation and resistance to apoptosis. However, the main function of 67LR is to enhance tumor cell adhesion to the LM of basement membranes and cell migration, two crucial events in the metastasis cascade. Thus, inhibition of 67LR binding to LM has been proved to be a feasible approach to block metastatic cancer cell spread. Despite accumulating evidences on 67LR overexpression in hematologic malignancies, 67LR role in these diseases has not been clearly defined. Here, we review 67LR expression and function in normal and malignant hematopoietic cells, 67LR role and prognostic impact in hematological malignancies and first attempts in targeting its activity.