(A) Slide with 10 reaction fields as used for the study. Each reaction field contained 9 biochips with HEK293 cells expressing Delta/Notch-like epidermal growth factor-related receptor (DNER), CDR2/Yo, or CDR2L, and mock-transfected control cells fixed with either acetone or formalin as well as cryosections of monkey cerebellum. (B) Binding of serum IgG of a patient with paraneoplastic cerebellar degeneration and Hodgkin lymphoma (a–c) to Purkinje cell somata and dendritic trees (anti-Tr) pattern on monkey cerebellum (a, d) and to DNER-expressing cells (b, e) but not control cells used as internal control (c, f). None of these reactivities were seen with serum from controls (d–f). (C) Preincubation with a lysate of HEK293 expressing DNER (a, b) completely abolished the anti-Tr/DNER fluorescence (a, c: monkey cerebellum; b, d: DNER-expressing cells), but it was not abolished following incubation with a similar lysate from wild-type HEK293 (c, d).