STEM-22. UPTAKE OF P-BORONO-PHENYLALANINE BY BRAIN TUMOR STEM LIKE CELLS ANALYZED BY MASS CYTOMETRY

INTRODUCTION Because of chemo- and radio-resistance of brain tumor stem cells, they could be the origins of recurrent malignant glioma. We have used boron neutron capture therapy (BNCT) to treat patients with either recurrent or newly diagnosed malignant glioma resulting in a significant increase in median survival of patients. BNCT is a form of tumor-selective particle radiation therapy consisting of two components. First, a boron-10 (10B)-containing drug is administered, followed by irradiation with epithermal neutrons. The resulting 10B(n,α)7Li capture reaction produces alpha particles whose short path length (5–9 µm) results in the selective killing of tumor cells with a concomitant sparing of adjacent normal tissues. P-borono-phenylalanine (BPA) is a chemical compound used in clinical trials in BNCT. BPA accumulates preferentially in growing cells rather than in quiescent cells of the tumor. Here, we investigate whether brain tumor stem like cells take up BPA or not using mass cytometry (Cytof).