Elevated phospho-AKT1 and Patched 1 levels in zebrafish tumors. A, B, a 3-week-old transgenic fish with trunk tumor (B) and its age-matched tumor-free fish (A). C, D, a 12-week-old fish with an eye tumor (D) and its age-matched tumor free fish (C). Immunofluorescence was done on cryosections for the above fish. E-H, an astrocytoma from a double transgenic fish showed elevated levels of both Patched 1 (F) and phosphorylated AKT (H). Immunofluoresence was done on paraffin sections for this tumor. Negative controls for Patched 1 (E) and phosphorylated AKT (G) were treated the same way except no primary antibodies were added. N, Notochord; AKT-P, phosphorylated AKT. Scale bars, 100 μm for A-D, 50 μm for E-H.