Different Recurrence and Growth Pattern of Gliomatous Foci after Mesenchymal Stem Cell Harbouring the Herpes Simplex Thymidine Kinase Gene Transplantation in Multifocal Glioblastoma Multiform: A Clinical Case Report

Background: Glioblastoma multiform (GBM) as a malignant brain tumor has poor prognosis despite the current therapies. Suicide gene therapy is one of the most widespread cancer gene therapies which requires mRNA encoding a pro-drug activating enzyme transduced into the vector such as Mesenchymal Stem Cells (MSCs) that injects into the tumor tissue and leads to tumor suppression. Case presentation: In this case report, the authors describe a 37-year-old man with two obvious foci of glioblastoma multiform at left frontal and left parietal lobes. After the resection of the foci, the patient received stem cell-mediated herpes simplex virus thymidine kinase (HSV-TK) gene at frontal focus of tumor besides ganciclovir as prodrug for 14 days after injection. Then he was followed up with regular magnetic resonance imaging (MRI). The growth and recurrence pattern of foci was assessed. After the injection on Feb 09, 2019, the patient’s follow-up revealed recurrence of parietal focus on Dec 19, 2019; however, frontal focus had a slight and unremarkable enhancement. Until our last radiological follow-up (on Mar 18, 2020) left frontal focus had no prominent recurrence and the size of the left parietal focus increased and extended to the contralateral hemisphere through the corpus callosum. Eventually patient has passed away on July 16, 2020 (PFS=293 days, OS=657 days).Conclusions: It seems that the gliomatous focus that undergone administration of bone marrow MSC containing the HSV-TK gene, had a different pattern of growth and recurrence compared to a non-treated one.