TY - JOUR
T1 - Automated brightfield dual-color in situ hybridization for detection of mouse double minute 2 gene amplification in sarcomas
AU - Zhang, Wenjun
AU - McElhinny, Abigail
AU - Nielsen, Alma
AU - Wang, Maria
AU - Miller, Melanie
AU - Singh, Shalini
AU - Rueger, Ruediger
AU - Rubin, Brian P.
AU - Wang, Zhen
AU - Tubbs, Raymond R.
AU - Nagle, Raymond B.
AU - Roche, Pat
AU - Wu, Ping
AU - Pestic-Dragovich, Lidija
PY - 2011/1
Y1 - 2011/1
N2 - Background: The human homolog of the mouse double minute 2 (MDM2) oncogene is amplified in about 20% of sarcomas. The measurement of the MDM2 amplification can aid in classification and may provide a predictive value for recently formulated therapies targeting MDM2. We have developed and validated an automated bright field dual-color in situ hybridization application to detect MDM2 gene amplification. DESIGN: A repeat-depleted MDM2 probe was constructed to target the MDM2 gene region at 12q15. A chromosome 12-specific probe (CHR12) was generated from a pα12H8 plasmid. The in situ hybridization assay was developed by using a dinitrophenyl-labeled MDM2 probe and a digoxigenin-labeled CHR12 probe on the Ventana Medical Systems' automated slide-staining platforms. The specificity of the MDM2 and CHR12 probes was shown on metaphase spreads and further validated against controls, including normal human tonsil and known MDM2-amplified samples. The assay performance was evaluated on a cohort of 100 formalin-fixed, paraffin-embedded specimens by using a conventional bright field microscope. Results: Simultaneous hybridization and signal detection for MDM2 and CHR12 showed that both DNA targets were present in the same cells. One hundred soft tissue specimens were stained for MDM2 and CHR12. Although 26 of 29 lipomas were nonamplified and eusomic, MDM2 amplification was noted in 78% of atypical lipomatous tumors or well-differentiated liposarcomas. Five of 6 dedifferentiated liposarcoma cases were amplified for MDM2. MDM2 amplification was observed in 1 of 8 osteosarcomas; 3 showed CHR12 aneusomy. MDM2 amplification was present in 1 of 4 chondrosarcomas. Nine of 10 synovial sarcomas displayed no evidence of MDM2 amplification in most tumor cells. In pleomorphic sarcoma, not otherwise specified (pleomorphic malignant fibrous histiocytoma), MDM2 was amplified in 38% of cases, whereas 92% were aneusomic for CHR12. One alveolar rhabdomyosarcoma and 2 embryonal rhabdomyosarcomas displayed low-level aneusomy of CHR12 without net MDM2 amplifications. Conclusions: These results show that the use of the ISH MDM2 and CHR12 assay allows simultaneous analyses of the 2 DNA targets within the context of tissue morphology. This method combines the advantages of a fully automated protocol with bright field microscopy and has the potential for routine application in surgical pathology.
AB - Background: The human homolog of the mouse double minute 2 (MDM2) oncogene is amplified in about 20% of sarcomas. The measurement of the MDM2 amplification can aid in classification and may provide a predictive value for recently formulated therapies targeting MDM2. We have developed and validated an automated bright field dual-color in situ hybridization application to detect MDM2 gene amplification. DESIGN: A repeat-depleted MDM2 probe was constructed to target the MDM2 gene region at 12q15. A chromosome 12-specific probe (CHR12) was generated from a pα12H8 plasmid. The in situ hybridization assay was developed by using a dinitrophenyl-labeled MDM2 probe and a digoxigenin-labeled CHR12 probe on the Ventana Medical Systems' automated slide-staining platforms. The specificity of the MDM2 and CHR12 probes was shown on metaphase spreads and further validated against controls, including normal human tonsil and known MDM2-amplified samples. The assay performance was evaluated on a cohort of 100 formalin-fixed, paraffin-embedded specimens by using a conventional bright field microscope. Results: Simultaneous hybridization and signal detection for MDM2 and CHR12 showed that both DNA targets were present in the same cells. One hundred soft tissue specimens were stained for MDM2 and CHR12. Although 26 of 29 lipomas were nonamplified and eusomic, MDM2 amplification was noted in 78% of atypical lipomatous tumors or well-differentiated liposarcomas. Five of 6 dedifferentiated liposarcoma cases were amplified for MDM2. MDM2 amplification was observed in 1 of 8 osteosarcomas; 3 showed CHR12 aneusomy. MDM2 amplification was present in 1 of 4 chondrosarcomas. Nine of 10 synovial sarcomas displayed no evidence of MDM2 amplification in most tumor cells. In pleomorphic sarcoma, not otherwise specified (pleomorphic malignant fibrous histiocytoma), MDM2 was amplified in 38% of cases, whereas 92% were aneusomic for CHR12. One alveolar rhabdomyosarcoma and 2 embryonal rhabdomyosarcomas displayed low-level aneusomy of CHR12 without net MDM2 amplifications. Conclusions: These results show that the use of the ISH MDM2 and CHR12 assay allows simultaneous analyses of the 2 DNA targets within the context of tissue morphology. This method combines the advantages of a fully automated protocol with bright field microscopy and has the potential for routine application in surgical pathology.
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U2 - 10.1097/PAI.0b013e3181ee8e14
DO - 10.1097/PAI.0b013e3181ee8e14
M3 - Article
C2 - 20881839
AN - SCOPUS:78650839507
SN - 1541-2016
VL - 19
SP - 54
EP - 61
JO - Applied Immunohistochemistry and Molecular Morphology
JF - Applied Immunohistochemistry and Molecular Morphology
IS - 1
ER -