gms | German Medical Science

Objective: The aim of this study was to unravel cancer stem cells (CSC) in a large series of craniopharyngiomas (CP), which is a benign, epithelial tumor originating from the sellar region. Early disease onset, clinical manifestation, histology, and frequent relapse distinguish the adamantinomatous subtype (adaCP) from the more favorable papillary variant (papCP). A molecular hallmark of adaCP is an activated Wnt signaling pathway, characterized by whirl like cell formations displaying nuclear beta-catenin accumulations. The peculiar growth pattern and molecular pathogenesis may thus be related to a specific CSC population, as recently shown in colorectal or prostate cancer using surface markers CD44 and CD133.

Methods: We analyzed the expression of CD44 and CD133 in a cohort of 20 CP (6 papCP and 14 adaCP) using immunohistochemistry. To unravel the correlation between potential CSC and beta-catenin accumulating tumor cell clusters, double immunofluorescence staining was also conducted.

Results: CD44 and CD133 staining patterns were differentially distributed between both CP subtypes. PapCP tumor cells revealed only CD44 expression, predominantly at the cell membrane, whereas CD133 labeling was hardly detectable. In contrast, both markers consistently labeled whirl-like tumor cell clusters in adaCP. Furthermore, double immunofluorescence staining revealed co-expression of CD44 and CD133 in tumor cells with aberrant nuclear b-catenin accumulation.

Conclusion: The presented results suggest stem cell - like characteristics of adaCP tumor cells with nuclear beta-catenin accumulations. This observation is compatible with the increased potential of recurrence observed in adaCP, but not in papCP. Notwithstanding, the impact of tumorigenicity of these cells will be further evaluatedin vitroandin vivo, i.e., using stem cell specific cell culture experiments or intracranial transplantation into nude mice.