A novel interleukin-2 (IL-2)-dependent cell line, HANK1, was established from a patient with CD56+ NK/T-cell lymphoma arising in the retroperitoneum. Morphologically, HANK1 is a pleomorphic large cell line with irregular nuclei, which contains azurophilic granules in the cytoplasm. Immunophenotypic analysis showed that HANK1 expressed CD2, CD3epsilon, CD56, TIA-1, granzyme B, and HLA-DR, but no other T-lineage markers. These features were the same as seen in the original tumour, and are highly characteristic of nasal and 'nasal-type' NK/T-cell lymphoma as described in the proposed W.H.O. classification. Genotypically, this cell line also demonstrated the germline configuration of the T-cell receptor beta, gamma and the immunoglobulin heavy chain genes and clonal integration of the Epstein-Barr virus (EBV) together with antigen expression with a type II latency pattern (LMP-1+ and EBNA2-). Furthermore, Southern blot analysis using the EBV termini as probes confirmed its derivation from the original lymphoma, and revealed that it contained multiple copies of the EBV genome. Dose-dependent growth on IL-2 was observed in an in vitro study with a doubling time of 3 d at maximal stimulation. These data indicate that HANK1 seemed to preserve the biological characteristics of the original tumour and therefore may serve as a good model for the further analysis of unusual 'nasal-type' NK/T-cell lymphoma.