Establishment of aspiration biopsy nucleic acid diagnosis of malignant lymphoma

甲状腺恶性淋巴瘤和淋巴细胞性甲状腺炎（桥本甲状腺炎）的鉴别是相当困难和有问题的。B细胞淋巴瘤显示克隆性免疫球蛋白重链（IgH）基因重排，Southern印迹杂交（SBH）常用于检测IgH基因的单克隆性。然而，SBH通常是有问题的，因为它需要大量的样品。Vectorrette PCR是一种扩增5'端序列未知的DNA片段的方法，使用修饰的接头以促进靶序列的特异性扩增，并且它仅需要200 ng基因组DNA即可开始，这很容易通过细针抽吸活检获得。本研究以200 ng的甲状腺恶性淋巴瘤组织或肿瘤组织中的基因组DNA为模板，采用载体PCR法检测甲状腺恶性淋巴瘤IgH基因的单克隆性。在使用组织样本的分析中，在47例恶性淋巴瘤中的36例（76.6%）中检测到单克隆性，而在10例桥本甲状腺炎组织样本中未检测到单克隆性。其敏感性与SBH法相近，SBH法在45例恶性淋巴瘤中检出单克隆抗体33例（73.3%）。此外，1例抽吸的肿瘤细胞通过vectorette PCR显示IgH基因的单克隆性，经开放活检后组织病理学诊断为弥漫性大细胞B细胞淋巴瘤。这些结果表明，vectorette PCR可能是SBH的替代品，因为它只需要少量的样品，它也被用于分析抽吸活检。

Distinguishing between thyroid malignant lymphoma and lymphocytic thyroiditis (Hashimoto's thyroiditis) is quite difficult and problematic. B-cell lymphomas display clonal immunoglobulin heavy chain (IgH) gene rearrangement, and Southern blot hybridization (SBH) is often used for detection of the monoclonality of the IgH gene. However, SBH is often problematic, since it requires a large volume of samples. Vectorette PCR is a method for amplifying DNA fragments of which the 5' sequences are unknown, using a modified linker to facilitate specific amplification of the targeted sequence, and it requires only 200 ng of genomic DNA to start with, which is easily obtainable by fine needle aspiration biopsy. We examined the efficiency in detecting the monoclonality of IgH gene in thyroid malignant lymphomas by vectorette PCR, which we started with 200 ng of genomic DNA obtained either from tissue samples or tumor aspirates. In the analysis using tissue samples, monoclonality was detected in 36 (76.6%) of 47 malignant lymphomas, whereas it was not detected in 10 samples of tissue of Hashimoto's thyroiditis. The sensitivity was almost the same as that with SBH in which monoclonality was detected in 33 (73.3%) of 45 malignant lymphomas. Further, one case in which aspirated tumor cells showed monoclonality in the IgH gene by vectorette PCR revealed to be diffuse large cell B-cell lymphoma by histopathological diagnosed after open biopsy. These results suggest that vectorette PCR may be a substitute for SBH, and since it requires only a small volume of samples, it is also used in the analysis of aspiration biopsies.