Oncolytic Viruses: A Promising Solution for Relapse Prevention after Autologous Hematopoietic Stem Cell Transplantation

Autologous hematopoietic stem cell transplantation (AHSCT) is widely used as a successful treatment in many hematopoietic cancers. However, one of the main challenges of AHSCT is the relapse of the disease which occurs mainly due to tumor contamination of autologous grafts or remaining cancer cells in bone marrow niches. So far, several strategies are suggested to purge tumor contamination in autografts, including chemotherapy, positive selection of hematopoietic stem cells via CD34, removal of cancer cells in graft with cytotoxic agents or monoclonal antibodies, and using allreoactive T cells. Nevertheless, these methods are not sufficiently specific and are associated with long-term cytopenia and damage the hematopoietic progenitors and ultimately cause transplant failure. One recent promising solution in this field is using oncolytic viruses (OV) which can target malignant cells without any harmful effect on normal hematopoietic stem cells. Although the OV therapy has been receetly emerged in AHSCT, the promising ex vivo results and the capacity of OVs in discrimination between malignant and healthy cells provides an opportunity to use OVs as tumor purging agents in AHSCT. In this review, we focused on the role of OV therapy as a purging agent in decreasing post-AHSCT relapses.