Skripsi

Efek Ekstrak Kacang Kedelai terhadap Ekspresi PD-L1 dalam Menghambat Jaringan Kanker Payudara Tikus yang diinduksi DMBA = Effect of Soybean Extract on PD-L1 Expression in Inhibiting DMBA-Induced Breast Cancer in Rats.

Latar Belakang: Kanker payudara merupakan kanker dengan insidensi tertinggi pada wanita di Indonesia. Ekspresi Programmed Death-Ligand 1 (PD-L1) berperan penting dalam mekanisme immune escape sel kanker. Kedelai mengandung senyawa bioaktif seperti isoflavon, flavonol, dan saponin yang berpotensi menurunkan ekspresi PD-L1 melalui modulasi berbagai jalur molekuler sehingga berpotensi sebagai agen kemopreventif alami. Metode: Penelitian ini menggunakan rancangan post-test only control group design pada 30 ekor tikus Sprague-Dawley betina yang dibagi menjadi lima kelompok: kontrol normal (KNo), kontrol negatif (KNe), serta perlakuan ekstrak kedelai dosis 250, 500, dan 1000 mg/kgBB (EK-D250, EK-D500, EK-D1000). Induksi kanker dilakukan dengan DMBA 20 mg/kgBB secara intragastrik dua kali seminggu. Ekspresi PD-L1 pada jaringan payudara diukur menggunakan imunohistokimia dan dianalisis dengan H-score. Analisis statistik dilakukan dengan Welch ANOVA diikuti uji post hoc Games-Howell. Hasil: Ekspresi PD-L1 ditemukan pada sitoplasma. Rerata H-score PD-L1 meningkat signifikan pada KNe (41,74 ± 21,90) dibanding KNo (1,14 ± 0,60). Pemberian ekstrak kedelai menurunkan ekspresi PD-L1 secara signifikan pada EK-D500 (3,28 ± 2,14), dan EKD1000 (2,77 ± 1,34) dibanding KNe. Tidak terdapat perbedaan bermakna antara kelompok perlakuan. Perbedaan signifikan juga ditemukan antara kelompok KNo dengan EK-D250. Kesimpulan: Ekstrak kedelai secara signifikan menurunkan ekspresi PD-L1 sitoplasma pada jaringan payudara yang diinduksi DMBA, meskipun efek dose-dependent tidak terlihat.
Kata Kunci: ekstrak kedelai, PD-L1, kanker payudara, DMBA, imunohistokimia


Introduction Breast cancer is the most common malignancy among women in Indonesia. The expression of Programmed Death-Ligand 1 (PD-L1) plays a crucial role in the immune escape mechanism of cancer cells. Soy contains bioactive compounds such as isoflavones, flavonols, and saponins, which have the potential to reduce PD-L1 expression through the modulation of multiple molecular pathways, making it a promising natural chemopreventive agent. Method This study employed a post-test only control group design using 30 female SpragueDawley rats, divided into five groups: normal control (KNo), negative control (KNe), and treatment groups receiving soy extract at doses of 250, 500, and 1000 mg/kgBW (EKD250, EK-D500, EK-D1000). Breast cancer induction was performed using DMBA (20 mg/kgBW) administered intragastrically twice a week. PD-L1 expression in mammary tissues was evaluated using immunohistochemistry and quantified by the H-score method. Statistical analysis was conducted using Welch ANOVA followed by the Games–Howell post hoc test. Results PD-L1 expression was found in cytoplasm. Mean PD-L1 H-scores were significantly higher in the KNe group (41.74 ± 21.90) compared to the KNo group (1.14 ± 0.60). Soy extract treatment significantly reduced PD-L1 expression in the EK-D500 (3.28 ± 2.14) and EK-D1000 (2.77 ± 1.34) groups compared to KNe. No significant difference was found among treatment groups, while a significant difference was also observed between KNo and EK-D250. Conclusion Soy extract significantly reduced cytoplasmic PD-L1 expression in DMBA-induced breast tissue although a clear dose-dependent effect was not observed.
Keywords: soy extract, PD-L1, breast cancer, DMBA, immunohistochemistry