New Doctor of Medical Sciences Proves the Role of Probiotics in Colon Cancer Prevention

Friday, July 1, 2022

Located in the third floor Postgraduate courtroom, the Doctoral Promotion exam was held offline with promovendus candidate dr. I Ketut Mariadi, Sp.PD.,K-GEH., FINASIM with the dissertation title "Probiotic Lactobacillus Rhamnosus SKG34 Causes Malondialdehyd Levels, Expression of Tumor Necrosis Factor Alpha Programmed Death Ligand-1 and Lower Incidence of Colorectal Cancer in Balb/c Mice with Induced with Azoxymethane and Dextran Sodium Sulfate."

Colorectal cancer (CRC) is still a global health problem, so prevention efforts need to be made. Oxidative stress and chronic inflammation play an important role in the initiation of CRC, whereas immunosuppression plays a role in the final phase of the transformation of adenomas to carcinomas. Inhibition of oxidative stress, inflammation and immunosuppression is a strategy for the prevention of CRC. Currently, there is no research that proves the role of the probiotic Lactobacillus rhamnosus SKG34 for the prevention of CRC. This study aims to determine whether L. rhamnosus SKG34 is able to inhibit oxidative stress, inflammation and immunosuppression so that it can reduce the incidence of CRC.

The results of the study showed that the administration of the probiotic L. rhamnosus SKG34 was able to inhibit oxidative stress, inflammation and inhibit immunosuppression as evidenced by lower MDA levels, lower TNF-alpha expression, and lower tumor PD-L1 expression and resulted in a lower incidence of CRC. lower than the positive control group. The mechanism of probiotics that has been shown to play a significant role in the carcinogenesis of CRC is through inhibition of the expression of TNF-alpha and PD-L1. Giving probiotic L. rhamnosus SKG34 was able to reduce the risk of CRC by 44%.

The development of new science (novelty) in this research is that Lactobacillus rhamnosus SKG34 is the first probiotic that has been proven to have the effect of inhibiting the expression of PD-L1 in colon tumors, thereby increasing antitumor immune activity. L. rhamnosus SKG34 has also recently been found to have the effect of suppressing TNF alpha expression. L. rhamnosus SKG34 was shown to be able to reduce the incidence of CRC through the mechanism of inhibition of tumor PD-L1 expression and TNF alpha expression. These findings complement the probiotic mechanism for the prevention of CRC, which is known from previous studies.

The implication of the results of this study is that L. rhamnosus SKG34 can be continued with clinical trial research on human subjects, especially in individuals who are at high risk to see the preventive effect in humans. Lactobacillus rhamnosus SKG34 can be developed as an additional immunotherapy agent to complement the main therapy in CRC because it has the effect of inhibiting tumor PD-L1 expression. The presence of anti-TNF-alpha effect can be used to be tested further in diseases related to intestinal inflammation.

The exam was led by the Coordinator of the Doctoral Study Program of the Faculty of Medicine, Udayana University, Prof. Dr. dr. I Made Jawi, M.Kes, with a team of examiners:


1. Prof. Dr. dr. I Dewa Nyoman Wibawa, Sp. PD-KGEH (Promoter)

2. Prof. Dr. dr. I Made Bakta, Sp. PD-KHOM (Copromotor I)

3. Prof. Dr. dr. I Dewa Made Sukrama, M.Sc., Sp.MK (K) (Copromotor II)

4. Prof. Dr. Ir. Ida Bagus Putra Manuaba, M.Phil

5. Prof. Dr. dr. Ketut Suega, Sp. PD-KHOM

6. Prof. Dr. dr. I Wayan Putu Sutirta Yasa, M.Si

7. Ir. I Nengah Sujaya, M. Agr. Sc,. Ph.D

8. dr. Ni Nengah Dwi Fatmawati, S.Ked., Sp. MK(K)., Ph.D

9. Dr. dr. Ida Ayu Ika Wahyuniari, S.Ked., M.Kes

While the academic invitations are:

1. Dr. dr. Yenny Kandarini, Sp. PD-KGH

2. Dr. dr. I Ketut Agus Somia, Sp. PD-KPTI, FINASIM

3. Dr. dr. Ni Made Linawati, M.Si

4. Dr. dr. Putu Ayu Asri Damayanti, M.Kes

5. Dr. dr. Ni Kadek Mulyantari, Sp. PK(K)

In this exam, Dr. dr. I Ketut Mariadi, Sp.PD., K-GEH., FINASIM graduated as the 349th Graduate Doctoral Study Program of the Doctoral Study Program, Faculty of Medicine, Udayana University with the predicate VERY SATISFACTORY