BMC Cancer 2008, 8:379 http://www.biomedcentral.com/1471-2407/8/379 angioimmunoblastic T-cell lymphomas and 2 peripheral T-cell lymphomas, unspecified. Statistical analysis The correlation between expression of the proteins was determined by counting the positive cells in at least four medium power fields of serial sections, calculating and presenting as means ± SD. The statistical significance of association was assessed by Spearman's correlation coeffi- cient test, with SPSS15.0. A value of P less than 0.05 was accepted as statistically significant. Results Expressions of ID2, EBV-LMP1 and P16(INK4A) in classical Hodgkin lymphoma ID2 protein was expressed positively in 83.3% (50 out of 60) of the classical Hodgkin lymphomas (Table 1). It was strongly positive in both cytoplasm and nucleus of the HRS cells (Figure 1A, B), and also positive in plasma cells or lymphoplasmacytoid cells but negative or only mini- mally positive in reactive B and T lymphocytes in the background of Hodgkin lymphoma. It was noted that some HRS cells did not express ID2. In normal lymphatic tissues, ID2 expression was mainly restricted to a few GC and interfollicular cells. Based on morphology, the ID2- positive cells were dendritic cells and macrophages. Fibroblasts and endotheliocytes were positive for ID2 as Table 1: Expression of ID2, EBV-LMP1 and P16(INK4A) in classical Hodgkin lymphoma n ID2 EBV-LMP1 P16(INK4A) Lymphoma Classical HL Nodular sclerosis Mixed cullularity Lymphocyte-rich Lymphocyte-depleted Non-HL DLBCL MALT Burkitt's ALCL AILT NK/T(nasal type) Peripheral TCL Non-lymphomatous Tonsilla Lymph nodes 29 25 11 10 16 12 4 3 5 4 1 2 2 2 2 4 3 1 2 1 0 0 2 2* 10 2* 24 9 14 4 2 0 1 1 2 2 0 0 0 22 7 11 3 3 1 1 1 1 1 1 0 0 HL: Hodgkin lymphoma DLBCL: diffuse large B cell lymphoma MALT: extranodal marginal zone B-cell lymphoma of mucosa- associated lymphoid tissue Burkitt's: Burkitt's lymphoma ALCL: anaplastic large cell lymphoma AILT: angioimmunoblastic T-cell lymphoma *: restricted to a few GC and interfollicular cells EFHxiogpdurgerkseisni1olynmopfhI Dom2,aEBV-LMP1 and P16(INK4A) in classical Expression of ID2, EBV-LMP1 and P16(INK4A) in classical Hodgkin lymphoma. ID2 expression in HRS cells (A: 200×; B: 400×); EBV-LMP1 expression in HRS cells (C: 200×); P16(INK4A) expression in HRS cells (D: 400×). Page 3 of 5 (page number not for citation purposes)