Identification of homozygous deletion and expression of PIG7/LITAF. (A) Real-time RT-PCR analysis of PIG7/LITAF expression in samples from tonsil and spleen and in B-NHL cell lines (10 MCL cell lines; 11 diffuse large B-cell lymphoma cell lines with t14:18), 3 diffuse large B-cell lymphoma cell lines lacking t(14;18), and 6 Burkitt lymphoma cell lines. Data shown are the relative gene-expression levels normalized with GAPDH bars indicate standard deviations. The results are derived from 3 independent experiments. DLBCL indicates diffuse large B-cell lymphoma; BL, Burkitt lymphoma. (B) Affymetrix oligonucleotide microarrays and Western blot analyses of PIG7/LITAF and BCL6 in MCL cell lines. KHM10B cell line was used as a positive control for BCL6 expression. (C) Lymphochip cDNA microarrays and Western blot analyses of PIG7/LITAF and BCL6 in B-NHL cell lines of different origins. (D) Immunohistochemistry analysis for PIG7/LITAF and BCL6 protein on tissue microarrays. In nontumoral tissue samples (tonsils), PIG7/LITAF expression was cytoplasmatic and was shown to be expressed mostly in mantle, marginal, and interfollicular lymphocytes, whereas BCL6 was shown to be expressed in germinal center B cells.