Positive correlation of BCL6 and BACH2 expression in human GC B cell. (A) Immunoblot and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis of BCL6, BACH2, and MAFK expression in naïve B cells (NB) and GC B cells (GB) purified from human tonsils. For qRT-PCR analysis, data are shown as mean ± standard error of the mean from 3 different sets of NBs and GBs. *P < .01; ns, not significant; 2-tailed Student t test. (B) Immunohistochemistry analysis of BCL6 (blue) and BACH2 (brown) in human tonsil sections. Bars represent 200 μm.