Diagnostic significance of DOG-1 and PKC-θ expression and c-Kit/PDGFRA mutations in gastrointestinal stromal tumours.

OBJECTIVE: To investigate discovered on gastrointestinal stromal tumor (GIST)-1 (DOG-1) and protein kinase C-θ (PKC-θ) expression in a series of GISTs and determine the sensitivity, specificity, and diagnostic value of these two antigens. METHODS: Immnunohistochemistry (IHC) was used to detect CD117, DOG-1, PKC-θ, CD34, Ki-67, α-smooth muscle actin (SMA), S100, and Desmin expression in 147 GISTs and 51 non-GISTs. c-Kit gene (exons 9, 11, 13, and 17) and platelet-derived growth factor receptor-alpha (PDGFRA) gene (exons 12 and 18) mutations were also detected. RESULTS: About 94.5% GISTs were CD117 positive, 96% were DOG-1 positive, and 90.5% were PKC-θ positive. DOG-1 had a specificity of 100%, while CD117 and PKC-θ had a specificity of 90% and 80%, respectively. There was no significant difference between DOG-1 and PKC-θ expressions when compared to CD117 expression. In 30 out of 42 (71.5%) GISTs, a c-Kit gene mutation was found, and in 3 out of 42 cases (7%), PDGFRA was mutated. Wild-type c-Kit/PDGFRA genes accounted for 21.5% (9/42). Most c-Kit gene mutations were found to be located at exon 11, mainly as in-frame deletions. Mutations in exon 9 were all missense mutations. Most PDGFRA gene mutations were found in exon 18, codon 842. c-Kit gene mutations in exons 13 and 17, and the PDGFRA gene mutation in exon 12 were not detected. CONCLUSIONS: Compared to CD117, DOG-1 is a biomarker with higher sensitivity and specificity. The combination of CD117 and DOG-1 can be used to improve the diagnosis of GIST. Although PKC-θ has a lower specificity than DOG-1, it can be a useful biomarker, especially in CD117(-) and/or DOG-1(-) cases.

[Detection of antigen-receptor gene rearrangement clonality for diagnosis of lymphoma].

This study was aimed to investigate the significance of detecting the antigen-receptor gene rearrangement clonality in the diagnosis of lymphoma. Paraffin-embedding and HE staining of samples from 31 patients with lymphomas were performed for morphologic observation by light microscope. Immunophenotype was analyzed by the immunohistochemistry (IHC) method. The clonality of antigen-receptor gene rearrangement was detected by BIOMED-2 Assay Kit. The results showed that among the 31 cases, 12 cases were suspected to be T-cell lymphoma, 1 case was suspected to be T-cell reactive hyperplasia, and 16 cases were suspected to be B-cell lymphoma, 2 cases were B-cell reactive hyperplasia. The detection results showed that the positivity of Ig gene rearrangement clonality was 94.44% (17/18), the positivity of TCR gene rearrangement clonality was 92.31% (12/13), the other two cases were negative. Finally, 12 cases were diagnosed to be T-cell lymphoma and 17 cases were B-cell lymphoma. The other two cases were reactive lymphoid proliferations. And the positivity rate in the 31 patients with lymphomas was 93%. It is concluded that the detection of antigen-receptor gene rearrangement clonality is a useful assistant method in the diagnosis of lymphoma.

[Expression of dendritic cell marker CD21 is a positive prognostic factor in diffuse large B-cell lymphoma].

OBJECTIVE: To analyze CD21 expression in diffuse large B cell lymphoma (DLBCL) and to explore its relationship with the clinicopathological characteristics and prognosis. METHODS: The clinical data from 80 DLBCL patients who were treated in First Hospital of Jilin University from June 2005 to September 2011 were retrospectively analyzed. The cases were subjected to immunohistochemical staining (SP method) for Ki-67, CD20, CD79a, CD3, CD43, CD5, cyclin D1, bcl-2, CD10, bcl-6, GCET-1, FOXP-1 and MUM-1 protein expression in the tumor tissue. Immunohistochemistry was also used to detect CD21 expression in the tumor tissue. SPSS 18.0 was used to analyze the relationship between CD21 expression and various clinical factors, and the relationship between various clinical factors including CD21 and overall survival. RESULTS: In the patients aged under 60 years, the incidence of CD21(+) lymphoma (64.0%, 16/25) was significantly higher than that of CD21(-) lymphoma (38.2%, 21/55). There were more CD21(+) lymphoma patients who were at clinical stages I-II (52.0%, 13/25) than patients with CD21(-)lymphomas (23.6%, 13/55). There were also more CD21(+) lymphoma patients (68.0%, 17/25) having less than two extranodal sites involvement than CD21(-)lymphoma patients (41.8%, 23/55). In addition, there were more CD21(+) lymphoma patients with IPI 0-2 (68.0%, 17/25) than CD21(-)lymphoma patients (41.8%, 23/55). There were more CD21(+) lymphoma patients with GCB subtype (60.0%, 15/25) than CD21(-)lymphoma patients (23.6%, 13/55). Death related to DLBCL was less in CD21(+) lymphoma patients (32.0%, 8/25) than CD21(-) lymphoma patients (56.4%, 31/55). Univariate analysis showed that these clinical pathological characteristics affected the overall survival of DLBCL patients, including age, ECOG score, LDH, extranodal involvement, IPI index, CD21 expression, treatment option and efficacy (P < 0.05) . Cox multivariate analysis showed that ECOG score, LDH, extranodal involvement, CD21 expression were closely related to prognosis, and the difference was statistically significant (P < 0.05). Among the 80 patients, the overall survival (OS) of CD21(+) lymphoma patients was significantly higher than that of CD21(-) lymphoma patients. CONCLUSIONS: The expression of CD21 is associated with young age at onset, early clinical stage, small number of involvement and low IPI index. The OS and median overall survival of CD21(+) lymphoma patients are significantly higher than those of CD21(-) patients. CD21 expression, ECOG score, LDH, extranodal involvement are independent prognostic factors in DLBCL, and in particular, the expression of CD21 is more significant in the prognosis of DLBCL patients.