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Biomedical subjects

Louis Guillou

Publications and source records attributed to Louis Guillou.

40 records · Page 3Linked to original sources
PubMed2002

Monophasic fibrous and poorly differentiated synovial sarcoma: immunohistochemical reassessment of 60 t(X;18)(SYT-SSX)-positive cases.

Diagnosing monophasic fibrous and poorly differentiated synovial sarcoma (SS) on morphology alone is often a source of problems for pathologists. SS bear the t(X;18)(p11.2,q11.2) translocation, which proved to be specific for this tumor type and is currently considered one of the most reliable diagnostic criteria. To evaluate the sensitivity of immunohistochemical techniques in diagnosing monophasic fibrous SS (MFSS) and poorly differentiated SS (PDSS), we examined 60 t(X;18)(SYT-SSX)-positive cases (47 MFSS and 13 PDSS) for cytokeratin AE1/AE3, cytokeratin KL1, epithelial membrane antigen, E-cadherin, CD34, S-100 protein, alpha-smooth muscle actin, desmin, h-caldesmon, CD99, bcl2, and C-kit (CD117) antibodies. Of the four epithelial markers tested, epithelial membrane antigen proved to be the most sensitive, reacting with 100% of MFSS and 92% of PDSS, followed by cytokeratin AE1/AE3 (70% of MFSS, 46% of PDSS), cytokeratin KL1 (49% of MFSS, 38% of PDSS), and E-cadherin (47% of MFSS, 54% of PDSS). A staining for cytokeratin AE1/AE3 and/or E-cadherin was observed in 79% of MFSS and 69% of PDSS, and a staining for cytokeratin KL1 and/or E-cadherin was observed in 74% of MFSS and 62% of PDSS. S-100 protein was positive in 38% of MFSS and 23% of PDSS, and alpha-smooth muscle actin in 21% of MFSS and 8% of PDSS. Tumor cells were rarely positive for CD34 (6% of MFSS, 0% of PDSS) and desmin (2% of MFSS, 0% of PDSS). Most SS were strongly positive for bcl-2 (91% of MFSS, 92% of PDSS) and CD99 (91% of MFSS, 100% of PDSS). A weak and focal cytoplasmic reactivity for CD117 was observed in 11% of MFSS (only one case had a strong immunoreactivity) and 8% of PDSS. Staining with h-caldesmon was consistently negative. In conclusion, in keeping with literature data, our results show that reactivity for epithelial membrane antigen, cytokeratin AE1/AE3, and E-cadherin, in combination with CD34 negativity, are the most useful and sensitive markers for diagnosing monophasic fibrous and poorly differentiated t(X;18)-positive SS. They also support the fact that about one third of MFSS and one fourth of PDSS are positive for S-100 protein, a finding of diagnostic relevance when considering their distinction from other spindle to round cell sarcomas, especially malignant peripheral nerve sheath tumors.

Adolescent↗
PubMed2002

Molecular detection of the synovial sarcoma translocation t(X;18) by real-time polymerase chain reaction in paraffin-embedded material.

The t(X;18) translocation is known to be a useful marker for the diagnosis of synovial sarcoma. In this study, the authors describe a new real-time reverse transcriptase-polymerase chain reaction (RT-PCR) method to detect SYT/SSX fusion transcripts using paraffin-embedded and frozen tumor specimens. A series of 38 soft tissue sarcomas were analyzed. Diagnosis was based on clinical, histologic, and immunohistochemical examination. The fusion transcripts were detected in 16 of 17 synovial sarcoma samples (the 17th sample was not suitable for molecular analysis). No t(X;18)-fusion transcript was PCR-amplified in the 21 nonsynovial sarcoma mesenchymal tumors. Therefore, real-time PCR amplification appears to be a powerful, rapid, specific, and sensitive technique that can be used routinely to diagnose the synovial sarcoma t(X;18) translocation. In addition, the t(X;18) can be detected not only on frozen but also on paraffin-embedded tumor samples.

Biomarkers, Tumor↗
PubMed2002

Radiation-associated synovial sarcoma: clinicopathologic and molecular analysis of two cases.

Development of a soft-tissue sarcoma is an infrequent but well-known long-term complication of radiotherapy. Malignant fibrous histiocytomas, extraskeletal osteosarcomas, fibrosarcomas, malignant peripheral nerve sheath tumors, and angiosarcomas are most frequently encountered. Radiation-associated synovial sarcomas are exceptional. We report the clinicopathologic, immunohistochemical, and molecular features of two radiation-associated synovial sarcomas. One tumor developed in a 42-year-old female 17 years after external irradiation was given for breast carcinoma; the other occurred in a 34-year-old female who was irradiated at the age of 7 years for a nonneoplastic condition of the left hand. Both lesions showed morphologic features of monophasic spindle cell synovial sarcoma, were immunoreactive for cytokeratins, epithelial membrane antigen, CD99, CD117 (c-kit), and bcl-2 and bore the t(X;18) (SYT-SSX1) translocation. We conclude that synovial sarcoma has to be added to the list of radiation-associated soft-tissue sarcomas.

Adult↗