Lack of correlation between clinical characteristics and serum soluble Fas ligand levels in patients with multiple myeloma

Immunohistochemical detection of CD 95 (Fas) & Fas ligand (Fas-L) in plasma cells of multiple myeloma and its correlation with survival

Multiple myeloma (MM) is a malignant disease resulting from an uncontrolled proliferation of a neoplastic plasma cell clone in the bone marrow, which might also be induced by the loss of control on apoptosis. Fas ligand (Fas-L), a member of the tumor necrosis factor family, induces apoptosis mediated via its transmembrane death receptor Fas (Apo-1/CD95) antigen. In the present study, immunostaining was performed on the initial diagnostic bone marrow biopsies of 36 MM patients (1 stage I, 5 stage II, 30 stage III), to evaluate the distribution of Fas receptor and Fas-L on malignant plasma cells. Both Fas and Fas-L were positive in 13 cases and negative in 3, whereas 10 cases were Fas-negative, Fas-L-positive and 10 were Fas-positive, Fas-L-negative. Although no association was found between the expression of Fas receptor or Fas-L and overall survival, Fas-L positivity was significantly associated with a shorter event-free survival (p = 0.0335). In this study, it has been shown that the expression of Fas-L, in malignant plasma cells of myeloma patients significantly shortens the event-free survival, indicating that the defect in apoptosis might be associated with disease progression in MM.

Apoptotic markers in cancer

In cancer, apoptotic processes occur both spontaneously and induced by antitumor therapies. Qualitative and quantitative changes in cancer cell death along with proliferative alterations are essential determinants in the pathogenesis and progression of malignant disease and its responsiveness to therapy. Besides detecting apoptosis by invasive means in tumor tissue, apoptotic products can be quantified in the circulation. Although circulating apoptotic products usually lack organ and tumor specificity, they contribute in the assessment of disease extent or aggressiveness. The ease of drawing blood facilitates the serial measurement of circulating apoptotic markers to monitor antitumor treatment and predict early response to therapy. This review describes the features of apoptotic and necrotic cell death along with the role the balance between the rates of cell death and cell proliferation plays in the progression of malignancy. The intracellular pathways mediating apoptosis are next summarized. The focus then shifts to the apoptotic markers found in the circulation and their diagnostic, prognostic, predictive, and management utility in cancer.

Role of Apo2L/TRAIL and Bcl-2-family proteins in apoptosis of multiple myeloma

Apo2 Ligand or Tumour Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (Apo2L/TRAIL) is a member of the TNF gene superfamily that selectively induces apoptosis in tumor cells of diverse origins through engagement of death receptors. We have recently demonstrated that Type I interferons (IFN-alpha and beta) induce apoptosis in multiple myeloma (MM) cell lines and in plasma cells from MM patients. Moreover, Apo2L selectively induces apoptosis of patient MM tumor cells while sparing non-malignant cells. Apo2L induction is one of the earliest events following IFN administration in these cells. IFNs activate Caspases and the mitochondrial-dependent apoptotic pathway mediated by Apo2L production. Cell death induced by IFNs and Apo2L can be blocked by a dominant-negative Apo2L receptor, DRS, and is regulated by members of the Bcl-2 family of proteins. This review is focused on the apoptotic signaling pathways regulated by Apo2L and Bcl-2-family proteins and summarizes what is known about their clinical role.