Department of Pathology, Tokai University School of Medicine, Isehara, Japan.
Pathol Int. 2013 Jul;63(7):339-44. doi: 10.1111/pin.12076.
The basic region-leucine zipper (bZip) factor BTB, CNC homology 2 (BACH2) is known to have important roles in class switch recombination and somatic hypermutation (SHM) of the immunoglobulin (Ig) gene. In this study, we investigated the relationship between the expression of BACH2 and the status of SHM of the Ig heavy chain gene variable region (IgHV) for SHM in diffuse large B-cell lymphoma (DLBCL). We examined 20 cases of DLBCL, 13 of which were germinal center B-cell (GCB) DLBCL and 7 were non-GCB DLBCL. Seven cases were negative, 6 were positive (cytoplasmic expression) and 7 were strongly positive (both nuclear and cytoplasmic expression) for BACH2. Confirmed mutation (CM) was identified in 8 cases and the CM index (number of confirmed mutations per 10 subclones) was distributed from 0 to 5. A CM index of 7 strongly positive (over-expression) cases with BACH2 were distributed from 0 to 5, and that of 7 negative and 6 positive cases were distributed from 0 to 1. Over-expression of BACH2 was statistically related to CM index (P = 0.008). In conclusion, over-expression of BACH2 is critical for ongoing SHM of IgHV in DLBCL, and our data suggest that BACH2 may play an essential role for SHM of the Ig gene in B-cell lymphoma.
BTB、CNC 同源 2 (BACH2) 碱性亮氨酸拉链因子已知在免疫球蛋白 (Ig) 基因的类别转换重组和体细胞高频突变 (SHM) 中具有重要作用。在这项研究中，我们研究了 BACH2 的表达与弥漫性大 B 细胞淋巴瘤 (DLBCL) 中 Ig 重链基因可变区 (IgHV) 的 SHM 状态之间的关系。我们检查了 20 例 DLBCL，其中 13 例为生发中心 B 细胞 (GCB) DLBCL，7 例为非 GCB DLBCL。7 例为 BACH2 阴性，6 例为 BACH2 阳性 (细胞质表达)，7 例为 BACH2 强阳性 (核质表达)。8 例为证实突变 (CM)，CM 指数 (每 10 个子克隆的确认突变数) 分布为 0 至 5。BACH2 强阳性 (过表达) 的 7 例 CM 指数分布为 0 至 5，而 7 例阴性和 6 例阳性的 CM 指数分布为 0 至 1。BACH2 的过表达与 CM 指数呈统计学相关 (P = 0.008)。总之，BACH2 的过表达对 DLBCL 中 IgHV 的持续 SHM 至关重要，我们的数据表明 BACH2 可能在 B 细胞淋巴瘤中 Ig 基因的 SHM 中发挥重要作用。
