Immunohistochemical Analyses of α1 and α3 Na+/K+-ATPase Subunit Expression in Medulloblastomas

Background: The levels of expression of the alpha 1 and alpha 3 subunits of the Na+/K+-ATPase (the NaK sodium pump) in medulloblastomas are unclear. Patients and Methods: This study investigated the expression of the NaK subunits using immunohistochemical methods in 29 medulloblastomas including 23 classic, three large-cell/anaplastic and three nodular/desmoplastic medulloblastomas, as well as in three atypical teratoid/rhabdoid tumors (AT/RTs). Results: There was overexpression of the alpha 1 or alpha 3 NaK subunits in more than half of the medulloblastomas and atypical AT/RTs, with about one-third of these tumours displaying overexpression of both subunits. Conclusion: These preliminary data suggest that targeting these subunits in AT/RTs and medulloblastomas that overexpress these proteins may lead to therapeutic benefit. These findings warrant confirmation in larger numbers of patents than those used in this study. Moreover, it should be determined whether inhibition of the alpha 1/alpha 3 NaK subunits can be integrated into the risk stratification schemes already in use for medulloblastoma patients.