滤泡型淋巴瘤中t(14;18)染色体易位的分析及其临床意义

目的探讨滤泡型淋巴瘤（FL）的分子遗传学特征及其在病理诊断中的意义。方法收集55例FL石蜡标本,对照组小B细胞淋巴瘤28例和反应性滤泡增生（RFH）10例,应用套式PCR技术检测FL中,免疫球蛋白重链基因（IgH）的克隆性重排;应用标准PCR技术检测55例FL中t（14;18）易位,以10例RFH做对照;采用双色荧光原位杂交（FISH）技术检测20例淋巴结FL中t（14;18）易位,以4例RFH作为对照;并与PCR检测结果进行比较。结果（1）55例FL中,结内49例,结外6例。男性33例,女性22例,男女比为1．5：1。发病年龄36—79岁（中位年龄57岁）;FL分级：FL1—3分别为25例、19例和11例。（2）55例中50例（90％）检出β-肌动蛋白（actin）,该50例中FR3A阳性24例（48％）,FR2阳性25例（50％）,其中15例（30％）呈FR3A和FR2双阳性,共34例（68％）IgH基因重排。对照组小B细胞淋巴瘤28例中,25例检出β—actin,其中FR3A阳性18例（64％）,FR2阳性17例（61％）,共24例（86％）可检测出克隆性IgH基因重排。4例RFH均未检出IgH基因重排。（3）在44例结内FL中检出15例（34％）t（14;18）易位,其中14例在MBR,1例在mcr。（4）20例中,有16例（80％）可检出t（14;18）易位。结论（1）IgH克隆性重排在FL中的检测率比其他小B淋巴细胞低。（2）FISH检测石蜡包埋组织中t（14;18）易位有助于FL的诊断。FISH比PCR的敏感性更好,操作简便,可用于检测石蜡包埋组织中的分子遗传学改变。

Detection of t (14; 18) chromosomal translocation in paraffin-embedded tissues of follicular lymphoma and its clinical significance

OBJECTIVE: To study the genetic aberrations and their pathologic significance in follicular lymphoma (FL). METHODS: Paraffin-embedded tissue samples of 55 cases of FL, 28 cases of other small B-cell lymphomas and 10 cases of reactive follicular hyperplasia were retrieved. Nested polymerase chain reaction (PCR) was used to detect clonal rearrangement of immunoglobulin heavy chain gene (IgH) in FL and other small B-cell lymphomas. The translocation t (14; 18) was studied by PCR and dual-color fluorescence in-situ hybridization (FISH) in FL. Cases of reactive follicular hyperplasia were used as controls. RESULTS: Amongst the 55 cases studied, 49 cases were nodal and 6 cases were extranodal. There were 33 males and 22 females. The male-to-female ratio was 1.5:1. The median age of the patients was 57 years. Twenty-five cases belonged to histologic grade 1, while 19 cases were grade 2 and 11 cases were grade 3. Beta-actin DNA was detected in 50 cases of FL. Amongst those 50 cases, clonal IgH rearrangement was present in 34 (68%). Twenty-four cases (48%) and 25 cases (50%) were positive for FR3A and FR2 respectively. Fifteen cases (30%) showed dual positivity for both FR3A and FR2. Thirty-four cases (68%) demonstrated clonal IgH rearrangement. As for other small B-cell lymphomas, 25 cases were positive for beta-actin. FR3A and FR2 were detected in 18 and 17 cases respectively. Clonal IgH rearrangement was demonstrated in 24 cases. In contrast, none of the 4 cases of reactive follicular hyperplasia showed the clonal rearrangement pattern. Amongst the 44 cases of nodal FL analyzed, t (14; 18) was detected in 15 cases (with 14 cases in MBR and 1 case in mcr). In general, FISH was superior to PCR in detecting t (14; 18) using paraffin-embedded tissue samples. CONCLUSIONS: The detection rate of clonal IgH rearrangement in FL is lower than that in other small B-cell lymphomas. Demonstration of t (14; 18) in paraffin-embedded tissue samples by FISH helps in diagnosis of FL. FISH is superior to PCR, as the technique is more sensitive and less labor intensive.