[The incidence of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements in diffuse large B-cell lymphoma].

Objective: To investigate the incidence of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangement in Chinese diffuse large B-cell lymphoma (DLBCL) . Methods: From January 2013 to August 2020, 922 DLBCL cases were collected. C-MYC and BCL2 protein expression levels were analyzed by immunohistochemistry staining. Fluorescence in situ hybridization was used to detect the structural abnormalities of MYC, BCL2, and BCL6, including gene breaks and copy number changes. Results: MYC and BCL2 and/or BCL6 gene breaks were found in 29 out of 922 DLBCL cases (3.15%) , including 25 cases of double-hit lymphoma (DHL; 14 cases involving MYC and BCL2 rearrangements and 11 cases involving MYC and BCL6 rearrangements) and four cases involving MYC, BCL2, and BCL6 rearrangements, referring to triple-hit lymphoma. According to the threshold of C-MYC ≥40% and BCL2 ≥50%, 541 cases (58.68%) overexpressed C-MYC and BCL2 proteins, including 22 DHL cases. Moreover, according to the threshold of C-MYC ≥70% and BCL2 ≥50%, 52 cases (5.64%) overexpressed C-MYC and BCL2 proteins, including nine DHL cases. The P53 protein expression was detected by immunohistochemistry staining. The mutant P53 expression pattern was shown in 101 out of 709 cases (14.25%) , whereas 13 cases (1.83%) were negative, likely indicating P53 gene fragment deletion. Conclusion: The incidence of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements was low in DLBCLs, and no significant correlation between gene abnormality and protein overexpression was shown. The correct diagnosis of DHL depends on molecular genetic detection.

[Implication of BRAF V600E and CTNNB1 gene mutations in the pathological classification of craniopharyngioma].

Objective: To investigate the clinicopathological significance of BRAF V600E and CTNNB1 gene mutations in adamantinomatous craniopharyngiomas (ACP) and papillary craniopharyngiomas (PCP). Methods: The retrospective study included a total of 67 craniopharyngiomas diagnosed from October 2009 to August 2018 at Xuanwu Hospital, Capital Medical University. The immunohistochemical staining for ß-catenin and BRAF V600E expression, Sanger sequencing of exon 3 of CTNNB1, BRAF mutation analysis by scorpions amplification refractory mutation system (ARMS) fluorescence quantitative PCR were performed. Univariate survival analysis was used to correlate with tumor recurrence. Results: Of the 67 patients, 53 were ACPs and 14 were PCPs. Four patients underwent multiple operations and one of them presented with malignant transformation into squamous cell carcinoma. Histologically, ACPs were characterized by whorl-like cell clusters, peripheral palisaded layer, stellate reticulum, finger-shaped protrusions, ghost cells and wet keratinous substances. While PCPs usually consisted of mature squamous epithelium associated with fibrovascular stroma resulting in papillary appearance. The nuclear immunopositivity for ß-catenin was observed in 73.6% (39/53) of ACPs, and it was absent in PCPs (0/14). The nuclear translocation of ß-catenin usually presented at whorl-like structures or around ghost cells. Of all the cases, mutations analysis in exon 3 of ß-catenin gene CTNNB1 were successful in 46 cases and 42.1% (16/38) of ACP showed CTNNB1 gene mutation, while none of the PCPs harbored CTNNB1 gene mutation (0/8). The cytoplasmic immunopositivity for BRAF V600E mutant protein was found in all PCPs (14/14) and negative in all ACPs (0/53). ARMS-PCR results showed that BRAF V600E mutations were observed in 13/14 of PCPs but not seen in ACPs (0/53). Follow-up data were available in 35 patients with duration of 2 to 120 months. Ten patients experienced recurrences after the first surgery. Upon univariate survival analysis, only subtotal excision was found to be associated with increased recurrence (P=0.032), while pathological type, postoperative radiotherapy and CTNNB1 gene mutation were not (P>0.05). Conclusions: There is significant difference in the expression of BRAF V600E and CTNNB1 genes between ACP and PCP, and their immunohistochemical and molecular detection therefore can be used in the diagnosis and differential diagnoses of craniopharyngiomas.

[BRAF V600E mutation and clinicopathologic characteristics in 250 cases of brain tumors associated with epilepsy].

Objective: To investigate the clinicopathologic characteristics and BRAF V600E mutation of brain tumors associated with epilepsy. Methods: Totally 250 patients with brain tumors associated with epilepsy were included from March 2008 to August 2017 retrospectively at Sanbo Brain Hospital, Capital Medical University.The clinical manifestations, histological features and BRAF V600E mutation results were collected and analyzed. Results: There were 132 males and 118 females, and the male to female ratio was 1.1∶1.0. The age of patients ranged from 2 to 67 years(mean 22 years). The tumors had obvious local space occupying effect on MRI. The temporal lobe was the most common site (44.4%, 111/250). There were 58.4% (146/250) of ganglioglioma (GG), 24.0% (60/250) of dysembryoplastic neuroepithelial tumor (DNT), 12.8% (32/250) of pleomorphic xanthoastrocytoma(PXA), 4.0% (10/250) of angiocentric glioma (AG) and 0.8% (2/250) of papillary glioneuronal tumor (PGNT). Mixed GG, PXA and DNT morphological structures were found in 9 of patients. Among 250 cases, 35 cases were accompanied by focal cortical dysplasia(FCD). BRAF V600E was seen in 43 of 74 (58.1%) GG and 13 of 28 (46.4%) PXA. The most common pathologic grade of GG, DNT, AG and PGNT was WHO I. Some of the tumor cells from GG (34 cases) showed higher proliferative activity (WHO Ⅱ/Ⅲ). Most cases of PXA were WHOⅡand high proliferative activity was seen in nine cases. Conclusions: The association of low-grade glioneuronal tumors with intractable epilepsy was well-recognized. The most common low-grade glioneuronal tumors were GG.GG may occur in any part of the central nervous system, with a predilection for temporal lobe. Each type of low-grade glioneuronal tumors has its own unique histological morphology, but some may show complex features with 2 or 3 mixed components. The occurrence of BRAF V600E mutations in GG is common, and their detection may be valuable for the diagnosis and treatment in GG.

[Value of PET/CT in the prognosis of extranodal NK/T cell lymphoma].

Objective: To explore the value of Positron-Emission Tomography/Computed Tomography (PET/CT) in the prognosis of extranodal NK/T cell lymphoma. Methods: The patients of NK/T cell lymphoma diagnosed from January 2007 to July 2016 in Department of Pathology of Beijing Tongren Hospital were enrolled in this study. Seventy-two in-hospital patients were examined on the invasion of adjecent tissue or organ by PET/CT. The PET/CT results were analyzed retrospectively. Kaplan-Meier method was used to analyze the prognostic value of the positive results by PET/CT on overall survival (OS). Results: There were 54 males and 18 females with median age of 44.5 years (13-75 years). According to Ann Arbor staging system, there were 16 cases (22.2%) in stage Ⅰ, 29 cases (40.3%) in stage Ⅱ, 6 cases (8.3%) in stage Ⅲ and 21 cases (29.2%) in stage Ⅳ. According to the IPI scoring system, there were 34 cases (47.2%) in the low risk group (0-1 point), 21 cases (29.2%) in the low-middle risk group (2 points), 16 cases (22.2%) in the middle-high risk group (3 points), and 1 case (1.4%) in the high risk group (4-5 points) . The median follow-up time was 29.2 months (1-118 months). The disease occured in unilateral nasal cavity in 26 cases (36.1%), bilateral nasal cavities in 36 cases (50.0%), nasopharynx, oropharynx and pharynx in 10 cases (13.9%). The tumors of 51 cases involved the surrounding tissue, including nasal wings in 29 cases (40.3%), nasal sinus in 29 cases (40.3%), maxillofacial soft tissue in 18 cases (25.0%), orbital in 12 cases (16.7%), maxilla and skull base in 8 cases (11.1%), eyelid in 6 cases (8.3%), brain tissue in 3 cases (4.2%), eyeball in 2 cases (2.8%). In addition, cervical and inguinal lymphadenopathy were found in 54 cases (75.0%) . Splenomegaly and hepatomegaly were found in 10 cases (13.9%) and 2 cases (2.8%), respectively. Survival analysis showed that the clinical stage and IPI were significantly associated the clinical prognosis (P=0.000, 0.001, respectively). Involvement of the maxillofacial soft tissue, eyelid, orbital, maxilla and skull base and brain tissue were significantly related to reduced the overall survival time (P=0.006, 0.000, 0.024, 0.001 and 0.015, respectively). Involvement of palate or tonsil, the nosewingand nasal sinus did not show significant shorter overall survival (P=0.091, 0.063, and 0.139, respectively). Cox regression multivariate analysis showed maxilla and skull base involvement was independent adverse prognostic factor (P=0.047). Conclusions: The PET/CT examination can accurately detect the extent of adjacent and distant tissues of tumor involvement of NK/T cell lymphoma by showing the tumor structure and metabolic status, thus has important value in the clinical staging and prognosis predication.

[Abnormality of TOP2A expression and its gene copy number variations in neuroblastic tumors].

Objective: To detect TOP2A protein expression and gene copy number alterations, and to analyze related clinical and pathological implications in pediatric neuroblastic tumors (NT). Methods: Immunohistochemistry was used to detect TOP2A protein expression. Fluorescence in situ hybridization (FISH) was used to detect numerical aberrations of TOP2A. Results: TOP2A protein was expressed in 59.1%(52/88) of cases, which was associated with differentiation (P=0.006), Ki-67 index (P<0.01) and MKI (P=0.001). Twenty-eight cases (35.0%, 28/88) showed TOP2A gene amplification, which was correlated with the age (P<0.01), clinical stage (P=0.028), high risk group (P=0.001), Ki-67 index (P=0.040) and differentiation (P=0.014). Survival analysis showed that TOP2A expression was related to survival rate. Multivariate analyses showed that TOP2A expression was an independent predictor for poor prognosis (P=0.010). Conclusions: More than half of the cases show TOP2A expression, which is more likely associated with NB, high Ki-67 index and high MKI. Cases with TOP2A expression have shorter survivals and poorer prognosis. TOP2A amplification is seen in 35% and likely occurs in patients older than 18 months and at advanced INSS stages (Ⅲ and Ⅳ). As a target of the anthracycline-based adjuvant drugs, TOP2A test can be used to select patient with NT for the therapy.