Patients with EBV-associated lymphoproliferative disorders show identical LMP-1 gene deletions in spontaneous LCLs and neoplastic cells. Polyacrylamide gel electrophoresis (PAGE) analysis of radioactive PCR products corresponding to the carboxy terminus of the LMP-1 gene. For each case, the results of the analysis of pathologic biopsy specimens (T) and of spontaneous LCLs derived from the lesion (L) or PBMCs (P) are reported. B95.8-induced LCLs were also investigated in cases HD-2 and HD-3 (B). B_d , DNA from an LCL derived from a healthy donor by transformation with the B95.8 EBV strain; (D) DNA from an EBV⁺ HD carrying a deleted LMP-1 gene. Sizes are in base pairs.