Detection of t (14; 18) chromosomal translocation in paraffin-embedded tissues of follicular lymphoma and its clinical significance / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the genetic aberrations and their pathologic significance in follicular lymphoma (FL).</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Analysis of bcl-6 protein expression and gene rearrangement in diffuse large B-cell lymphoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate bcl-6 protein expression and gene rearrangement patterns in diffuse large B-cell lymphoma (DLBCL) and their clinicopathologic significance.</p><p><b>METHODS</b>Immunohistochemical studies for bcl-6 and CD10 proteins were performed on 51 cases of DLBCL paraffin-embedded tissues (including 22 nodal samples and 29 extranodal samples) and 10 cases of reactive lymphoid hyperplasia (RLH) paraffin-embedded tissues. Interphase fluorescence in-situ hybridization (FISH) with dual color breakapart probe was also used to identify rearrangement of bcl-6 gene in 32 cases of nodal DLBCL tissues (including 22 paraffin-embedded samples and 10 fresh samples) and 5 cases of RLH paraffin-embedded tissues.</p><p><b>RESULTS</b>(1) The rates of bcl-6 protein expression in nodal DLBCL, extranodal DLBCL and RLH were 72.7% (16/22), 75.9% (22/29) and 100.0% (10/10) respectively. The rates of CD10 expression were 40.9% (9/22), 41.4% (12/29) and 100.0% (10/10) respectively. All lymphoma samples which expressed CD10 also showed co-expression of bcl-6 protein. (2) The co-expression of bcl-6 and CD10 was observed in 40.9% (9/22) nodal DLBCL and 41.4% (12/29) extranodal DLBCL. Low clinical stage (stage I and II) was more frequently observed in cases with co-expression of bcl-6 and CD10 (P < 0.05). (3) The rates of bcl-6 gene rearrangement in nodal DLBCL was 28.1% (9/32), with 27.3% (6/22) in paraffin-embedded tissues and 30.0% (3/10) in fresh tissues. There was no statistically significant difference found between the two groups (P > 0.05). Bcl-6 gene rearrangement was not found in all the 5 cases of RLH, and there was a significant difference between RLH and DLBCL (P < 0.05).</p><p><b>CONCLUSIONS</b>The rate of bcl-6 protein expression is high in DLBCL cases, and the detection of bcl-6 and CD10 protein co-expression may help in the diagnosis and differential diagnosis of DLBCL. Those DLBCL cases with co-expression of bcl-6 and CD10 may also have a better prognostic implication. On the other hand, bcl-6 gene rearrangement can be identified by interphase FISH with dual color breakapart probe in both paraffin-embedded and fresh lymphoma tissues.</p>

Study of mutations in 5'-noncoding region of BCL-6 gene in B-cell non-Hodgkin's lymphomas / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate BCL-6 gene mutations in B-cell non-Hodgkin lymphomas (B-NHL) and their implications in lymphoma pathogenesis.</p><p><b>METHODS</b>Polymerase chain reaction (PCR) and direct DNA sequencing methods were used to identify mutations in the 5'-noncoding region of BCL-6 gene in 135 cases of B-NHL, 5 cases of T-NHL, 5 cases of nodular lymphocyte predominance Hodgkin's lymphoma (NLPHL) and 10 cases of reactive hyperplasia of lymph node.</p><p><b>RESULTS</b>Mutations were identified in 6 cases of nodal DLBCL (27.3%), 4 cases of FL (22.2%), 4 cases of MALT lymphoma (22.2%), 4 cases of extranodal DLBCL (20.7%) and 2 cases of LRH (20%). No mutations were detected in T-NHL and NLPHL (P < 0.05). There were no significant differences in incidences of BCL-6 gene mutations between nodal and extranodal DLBCL (P > 0.05). All mutations were base substitutions and the frequency of single-base change was 0.14 x 10(-2)/bp approximately 0.68 x 10(-2)/bp.</p><p><b>CONCLUSIONS</b>Mutations of the 5'non-coding region of BCL-6 gene may be involved in the pathogenesis and progression of B-NHL. Molecular demonstration of such mutations may provide a marker of lymphomas derived from the germinal center-related B cells.</p>

Clinicopathological, immunohistochemical and molecular genetic study of intra-abdomen extra-gastrointestinal stromal tumors / 中华病理学杂志

<p><b>OBJECTIVE</b>To explore the clinicopathological, immunohistochemical and molecular genetic features of intra-abdomen extra-gastrointestinal stromal tumors (EGISTs) and their differential diagnosis.</p><p><b>METHODS</b>Nine cases of EGISTs from the abdominal cavity or retroperitoneum which were previously diagnosed as leiomyoma, leiomyoblastoma, or leiomyosarcoma etc. by a panel of antibodies such as CD117, CD34, alpha-SMA, MSA, desmin, S-100, and PGP9.5 from which five cases were detected for c-kit gene mutation.</p><p><b>RESULTS</b>The tumors occurred in 5 men and 4 women, the age ranged from 38 to 72 years (mean 61.7 years). Four cases arose from the mesentery, two from omentum, two from retroperitoneum and one located at the hilus of the spleen. The size of tumors ranged from 5 cm to 23 cm (mean 12.9 cm) in diameter and the tumor cell components varied: mainly spindle cells (seven cases), epithelioid cells (one case), mixed cells (one case). Tumors expressed CD117 (8/9), CD34 (5/9), alpha-SMA (3/9), MSA (4/9), desmin (0), S-100 protein (1/9) and PGP9.5 (1/9). Of the five cases examined for heterozygous deletion mutation of 11 exon of the c-kit gene two were found positive. Two borderline cases showed long-term survival of 8 years and 11 years, respectively. In seven malignant cases, two showed adverse outcome, one survived 4 years without recurrence, two were lost in follow up and two new cases were still being in followed.</p><p><b>CONCLUSIONS</b>GIST-type stromal tumors can also occur in the abdomen, most cases were borderline or malignant, tumor coagulative necrosis, mitoses >or= 5 per 50 high-power fields and obvious nuclear atypia indicating malignancy. Differential diagnosis of EGIST including benign or malignant smooth muscle tumors, benign or malignant nerve sheath tumors etc.</p>