Objective: To investigate the characteristic of ALK protein expression in anaplastic large cell lymphoma (ALCL) and the relationship between ALCL and Epstein-Barr virus (EBV).
Methods: Histopathological method was used to study the morphological characteristic. Immunohistochemical staining was used to detect ALK protein and other antigen. EBV-encoded EBER was detected by in situ hybridization.
Results: All 2 cases of primary cutaneous ALCL were ALK protein negative. 20 cases of systemic ALCL were found to be ALK protein positive in 12 cases (60%), which included 8 cases of common variant, 3 cases of lymphohistiocytic variant and 1 case of small cell variant; the expression of ALK protein showed no significant difference between these 3 variants (P>0.05). The ALK protein expression pattern was characterized by the brown-stained nucleus and cytoplasm of the cells, but in 2 cases only the cytoplasm was stained. The patients with ALK protein expression were younger than those without ALK protein expression (P<0.05); all 22 cases were EBER negative.
Conclusion: High incidence of the expression of ALK protein was seen in ALCL, especially in ALCL of younger patients. No relationship was observed between EBV and ALCL in this study.