Tesis

Analisis Ekspresi H3K27me3 pada Malignant Peripheral Nerve Sheath Tumor (MPNST) dan Sarkoma Sel Spindle Lain yang Menyerupai MPNST = Analysis of H3K27me3 Expression on Malignant Peripheral Nerve Sheath Tumor (MPNST) and Other Spindle Cell Sarcoma Resembling MPNST.

Latar Belakang: Malignant peripheral nerve sheath tumor (MPNST) merupakan jenis sarkoma sel spindle dengan insidensi sekitar 5% dari seluruh total sarkoma. Tidak adanya penanda imunohistokimia yang spesifik untuk MPNST turut mempunyai andil didalam sulitnya menegakkan diagnosis MPNST. Belakangan ini diketahui penanda imunohistokimia H3K27me3 yang diduga merupakan penanda spesifik untuk MPNST. Tujuan: Menilai ekspresi H3K27me3 pada MPNST dan sarkoma lain yang menyerupai MPNST serta MPNST derajat rendah dan MPNST derajat tinggi. Bahan dan Cara Kerja: Penelitian analitik potong lintang dilakukan terhadap 13 kasus MPNST, 14 kasus sinovial sarkoma, 13 kasus dermatofibrosarkoma protuberans (DFSP), 10 kasus leiomiosarkoma yang berasal dari Departemen Patologi Anatomik FKUI/RSCM selama Januari 2013 sampai Desember 2021. Dilakukan pulasan H3K27me3 pada semua kasus dan dikategorikan sebagai complete loss apabila lebih dari 95% sel tumor tidak terpulas. Hasil: Terdapat loss of expression H3K27me3 yang lebih tinggi pada MPNST dibandingkan sarkoma lain menyerupai MPNST, p = 0,021. Terdapat loss of expression H3K27me3 yang lebih tinggi pada MPNST derajat tinggi dibandingkan MPNST derajat rendah,p = 0,105. Kesimpulan: Loss of expression H3K27me3 dapat digunakan untuk membantu menegakkan diagnosis MPNST terutama MPNST derajat tinggi. Terdapat perbedaan ekspresi H3K27me3 pada MPNST dan sarkoma lain menyerupai MPNST (sinovial sarkoma, DFSP, leiomiosarkoma).
Kata kunci: MPNST, non MPNST, H3K27me3.



Background: Malignant peripheral nerve sheath tumors (MPNST) are a rare type of spindle cell sarcoma that are found in only about 5% of all sarcomas. The lack of specific immunohistochemical markers for MPNSTs has also contributed to the difficulty in making a diagnosis. Recently, the immunohistochemical marker H3K27me3 has been identified as a potential specific marker for MPNST. Aim: To analyze H3K27me3 expression in MPNST and other sarcoma that have histologic features similar to MPNST also in low grade MPNST and high grade MPNST. Method: A cross-sectional analytical study was conducted on 13 cases of MPNST, 14 cases of synovial sarcoma, 13 cases of dermatofibrosarcoma protuberans (DFSP), and 10 cases of leiomyosarcoma from anatomical pathology department ofUniversitas Indonesia Faculty of Medicine/RSCM from January 2013 to December 2021. H3K27me3 staining was performed on all cases and was categorized as complete loss if more than 95% of tumor cells were not stained. Result: There was a higher loss of expression of H3K27me3 in MPNST compared to other sarcomas resembling MPNST, p = 0.021. There was a higher loss of expression of H3K27me3 in high-grade MPNSTs compared to low-grade MPNST but this result is not statistically significant, p = 0.105. Conclusion: Loss of expression of H3K27me3 can be used to establish a diagnosis of MPNST especially high grade MPNST. There is a difference in the expression of H3K27me3 between MPNST and other sarcomas resembling MPNST (synovial sarcoma, DFSP, leiomyosarcoma).
Key Word: MPNST, non MPNST, H3K27me3.