Department of Pathology, Shantou University Medical College, Shantou, China.
Cancer. 2010 Apr 15;116(8):1953-63. doi: 10.1002/cncr.24892.
The traditional view that immunoglobulin (Ig) is produced only by B lymphocytes has been challenged, because it has been demonstrated that Ig genes and proteins are expressed in epithelial cancer cells. However, whether Ig expression in nonlymphoid cells is limited to epithelial cells is unclear. Because sarcomas differ distinctly from carcinomas in their biologic and clinical features, the authors investigated the question of nonlymphoid IgG expression in soft tissue lesions.
Immunohistochemistry, in situ hybridization, and polymerase chain reaction (PCR) were used to demonstrate IgG expression in 80 soft tissue lesions. The correlation between Ig expression and proliferation markers (proliferating cell nuclear antigen [PCNA], Ki-67, and cyclin D1) in sarcomas was investigated by immunohistochemical and statistical analyses.
Igkappa was identified in 97.4% of sarcomas and in 31.7% of benign lesions by immunohistochemistry. The difference was statistically significant (P < .01). Messenger RNA from the IgG1 heavy-chain constant region was also detected by in situ hybridization. Variable-diversity-joining recombination sequences of both heavy and light chains were obtained by PCR and sequencing. Moreover, the labeling index of PCNA, Ki-67, and cyclin D1 was much higher in sarcomas with high Igkappa expression than in sarcomas with low Igkappa expression (P < .01 for PCNA and cyclin D1; P < .001 for Ki-67). There were more grade 3 sarcomas with high Igkappa expression compared with grade 1 and 2 sarcomas (P < .05).
IgG was identified in a wide variety of soft tissue tumors and correlated well with proliferation markers and tumor grades. IgG may be a useful marker for cell proliferation in sarcomas.
免疫球蛋白（Ig）仅由 B 淋巴细胞产生的传统观点受到了挑战，因为已经证明 Ig 基因和蛋白在上皮癌细胞中表达。然而，非淋巴细胞中 Ig 的表达是否仅限于上皮细胞尚不清楚。由于肉瘤在生物学和临床特征上与癌明显不同，作者研究了软组织病变中非淋巴细胞 IgG 表达的问题。
作者使用免疫组织化学、原位杂交和聚合酶链反应（PCR）来证明 80 例软组织病变中的 IgG 表达。通过免疫组织化学和统计学分析研究了 Ig 表达与肉瘤中增殖标志物（增殖细胞核抗原[PCNA]、Ki-67 和 cyclin D1）之间的相关性。
免疫组织化学鉴定出 97.4%的肉瘤和 31.7%的良性病变中存在 Igkappa。差异具有统计学意义（P<.01）。还通过原位杂交检测到 IgG1 重链恒定区的信使 RNA。通过 PCR 和测序获得了重链和轻链的可变多样性连接重组序列。此外，高 Igkappa 表达的肉瘤中 PCNA、Ki-67 和 cyclin D1 的标记指数明显高于低 Igkappa 表达的肉瘤（PCNA 和 cyclin D1 的 P<.01；Ki-67 的 P<.001）。与 1 级和 2 级肉瘤相比，高 Igkappa 表达的 3 级肉瘤更多（P<.05）。
在多种软组织肿瘤中鉴定出 IgG，与增殖标志物和肿瘤分级密切相关。IgG 可能是肉瘤细胞增殖的有用标志物。
