Clinical value of fluorescence in situ hybridization with MDM2 and DDIT3 probe in diagnosis of liposarcoma / 北京大学学报(医学版)

OBJECTIVE@#To investigate the value of using MDM2 amplification probe and DDIT3 dual-color, break-apart rearrangement probe fluorescence in situ hybridization (FISH) technique in the diagnosis of liposarcoma.@*METHODS@#In the study, 62 cases of liposarcoma diagnosed in Peking University First Hospital from January 2015 to December 2019 were analysed for clinicopathological information. Of these 62 cases of liposarcoma, all were analysed for MDM2 amplification and 48 cases were analysed for DDIT3 rearrangement using a FISH technique. Our study aimed to evaluate the status of MDM2 and DDIT3 by FISH in liposarcoma and correlate it with diagnosis of different subtypes of liposarcoma. The subtypes of liposarcoma were classified according to the FISH results, combined with the relevant clinicopathological features.@*RESULTS@#The patients aged 31-89 years (mean: 59 years) with a 1.75:1 male to female ratio. Histologically, there were 20 cases of atypical lipomatous tumour/well-differentiated liposarcoma (ALT/WDLPS), 26 cases of dedifferentiated liposarcoma (DDLPS), 13 myxoid liposarcoma (MLPS) and 3 pleomorphic liposarcoma (PLPS). Tumors with DDLPS (23/26) and WDLPS (8/20) were localized retroperitoneally, while both tumours of MLPS and PLPS were localized extra-retroperitoneally, and the difference of sites among the four subtypes of liposarcoma was statistically significant (P < 0.05). Histologically, varied mucoid matrix could be observed in the four subtypes of liposarcoma, and the difference was statistically significant (P < 0.05). MDM2 gene amplification was demonstrated in all cases of ALT/WDLPS and DDLPS (100%, 20/20 and 26/26 respectively); DDIT3 gene rearrangement was noted only in MLPS (100%, 13/13); most cases of DDLPS (96.2%, 25/26) and ALT/WDLPS (83.3%, 5/6, 6 cases selected for detection) demonstrated the picture of amplification of the DDIT3 telomeric tag. According to the instructions of DDIT3 break-apart rearrangement probe, the 5' telomere probe and 3' centromere probe spanned but did not cover the DDIT3 gene itself, on the contrary, the 5' telomere probe covered the CDK4 gene, while the DDIT3 and CDK4 gene were located adjacent to each other on chromosome, therefore, when the amplification signal appeared on the telomeric tag of the DDIT3 rearrangement probe, it indeed indicated the CDK4 gene amplification rather than the DDIT3 gene rearrangement. Then the 10 cases with DDIT3 telomeric tag amplification were selected for CDK4 and DDIT3 gene amplification probe FISH tests, and all the cases showed CDK4 gene amplification (100%, 10/10) and two of the 10 cases demonstrated co-amplification of CDK4 and DDIT3 (20%, 2/10); DDIT3 polysomy detected by DDIT3 gene rearrangement probe was found in 1 case of DDLPS and 2 cases of PLPS (66.7%, 2/3) with morphology of high-grade malignant tumour and poor prognosis.@*CONCLUSION@#Our results indicate that a diagnosis of different subtype liposarcoma could be confirmed based on the application of MDM2 and DDIT3 FISH, combined with clinicopathological findings. It is also noteworthy that atypical signals should be correctly interpreted to guide correct treatment of liposarcomas.

Overexpression and amplification of Murine double minute 2 as a diagnostic tool in large lipomatous tumor and its correlation with Ki67 proliferation index: An institutional experience.

Context: Well-differentiated liposarcoma (WDLPS) is the most common type of liposarcoma and sometimes can be diffi cult to distinguish from large lipoma due to the similar morphology. Aims: This study proposed to evaluate the expression and amplifi cation of Murine double minute 2 (MDM2) gene and determine its correlation with Ki67 proliferation index. Settings and Design: This study used cross-sectional design. Materials and Methods: This study enrolled 37 cases of lipomatous tumors with >5 cm in size. Eighteen cases of WDLPS and 19 cases of lipoma were stained for MDM2 and Ki67 immunohistochemistry, followed by MDM2 in situ hybridization in 12 selected cases. Statistical Analysis Used: MDM2 overexpression and amplification status for both groups were compared using Chi-square test, with the alternative of Fisher’s exact test. Correlation test between MDM2 overexpression and clinical characteristics with the Ki67 proliferation index were performed using Pearson’s test with the alternative of Spearman’s rho test. Results: MDM2 overexpression was detected in all WDLPS cases and in 3 (16%) of lipoma cases with signifi cance difference (P = 0.000), whereas MDM2 amplifi cation was found in all WDLPS and in 1 of lipoma cases (P = 0.200). There was a strong correlation between MDM2 overexpression and higher Ki67 proliferation index (r = 0.645, P = 0.000). Conclusion: Evaluation of MDM2 overexpression can be used as a useful adjunct to differentiate WDLPS from large lipoma and seems to be related with Ki67 proliferation index.

MDM2 gene expression in nasopharyngeal carcinoma and its relationship with p53 protein expression and EB virus latent infection / 临床耳鼻咽喉头颈外科杂志

Objective:To define the expression levels of MDM2 gene in nasopharyngeal carcinoma (NPC)and its relationship with p53 protein expression and EB virus latent infection. Method :MDM2 gene expression atmRNA and protein levels,p53 protein and EB virus DNA were detected by nonradioactive in situ hybridization(ISH) ,immunohistochemistry(IHC) and polymerase chain reaction (PCR) separately in 46 cases of NPC tissuesand 12 cases of chronic inflammation of nasopharyngeal epithelium (CINE). Result: Fourteen cases of NPCshowed MDM2 mRNA and protein overexpression, 38 cases were p53 protein positive,and 43 cases were EBV-DNA positive. Neither MDM2 nor p53 protein was expressed in any case of CINE. MDM2 expression was signifi-cantly related to p53 protein expression ( P ＜0. 05), but not to EB virus latent infection in NPC. Conclusion:MDM2 gene may play an important role in the pathogenesis of NPC through interacting with p53 protein.

Leiomyosarcoma of the Esophagus: Report of two cases, one with associated squamous cell carcinoma

Two new cases of leiomyosarcoma of the esophagus, one with an associated squamous cell carcinoma, are presented with review of literature. lmmunohistochemical study of MDM2 gene is performed upon these cases, and one case revealed overexpression of the MDM2 protein, whereas the other case showed negative result. And the pathological significance of MDM2 gene expression in esophageal leimyosarcoma is discussed, as, to our knowlege, no esophageal leiomyosarcoma with confirmed MDM2 gene amplification has been reported in the literature, to date. Gross character of these tumors was polypoid. Microscopically, the tumors consisted of interlacing fascicles of elongated spindle-shaped cells. Mitoses could be found without difficulty, with more than five per 10 high power fields. The tumor cells of the both cases showed imunohistochemical reactivity for vimentin and actin. Electron microscopically parallel arrays of myofilaments with interspersed dense bodies in spindle cell components were confirmed. The itera-literature regarding the association of leiomyosarcoma with epithelial malignancy in the gastrointestinal tract as well as esophagus is reviewed, and we found that this is a highly unusual occurrences(3 cases reported so far).