Nested Mechanical Architecture in Archival Neuroblastic Tumors Revealed by Atomic Force Microscopy

Neuroblastic tumors are classified by neuroblastic differentiation and Schwannian stromal development, but corresponding mechanical phenotypes remain unclear. We evaluated compartment-resolved elastic and viscoelastic properties in archival FFPE neuroblastic tumors using atomic force microscopy (AFM). Nine biologically independent tumors, three each of neuroblastoma (NB), ganglioneuroblastoma intermixed (GNB-I), and ganglioneuroma (GN), were analyzed in two sections per block, yielding a total of 18 specimens. Apparent Young’s-modulus endpoints were aggregated hierarchically to the patient level; dynamic microrheology provided a complementary viscoelastic readout, and patient-level exact permutation tests were used for inference. Mean patient endpoints increased from NB neuroblastic regions (0.759 MPa) to GNB-I stroma (0.991 MPa) and GN stroma (1.171 MPa; exact p = 0.0107). Neuroblastic clusters and ganglion-cell-centered regions were stiffer than matched stroma in all patients of GNB-I and GN. A lineage-oriented comparison across cell-rich compartments of all three histotypes yielded p = 0.025, and microrheology showed a stable GN, GNB-I, and then NB storage-modulus ordering from 3 to 300 Hz (p = 0.0179, exploratory after multiplicity correction). AFM results are consistent with a nested mechanical architecture in archival neuroblastic tumors, in which a histotype-related stromal gradient coexists with distinct cell-rich microdomains. These findings extend morphology-based classification with a quantitative physical phenotype, while remaining exploratory given the small sample and FFPE processing effects.