Jae Hwan Oh's research while affiliated with National Cancer Center Korea and other places

Aim The aim of this study was to compare the clinicopathological and oncological characteristics of sporadic colorectal cancer (CRC) between young and elderly patients without any genetic mutations that cause hereditary CRC. Method In this cross‐sectional, retrospective study conducted at three tertiary referral hospitals, we enrolled 1599 patients with CRC who underwent surgery between January 2010 and December 2017, including 157 young patients (age ≤ 40 years; yCRC) and 1442 elderly patients (age ≥ 70 years; eCRC). The clinicopathological and oncological outcomes were compared between the two groups. Results The median age at diagnosis was 37 years in the yCRC group (range 33.0–39.2 years) and 76 years in the eCRC group (range 72.0–79.0 years). The yCRC group did not present with advanced stages at diagnosis compared with the eCRC group, and the distribution of tumour stages was similar between the two groups. Microsatellite instability (MSI) testing revealed no difference in the frequency of tumours with high MSI (7.8% in yCRC, 5.8% in eCRC), and the frequency of mutations in the KRAS , NRAS and BRAF genes was also similar. The 3‐year overall survival was better in the yCRC group than in the eCRC group (97.4% vs. 83.5%, p < 0.001); however, no such difference was observed in cancer‐specific survival. Conclusion Genetically proven sporadic CRCs did not differ significantly between young and elderly patients in terms of tumour stage, tumour location and various molecular features. Clinical Trial Registration Number The study was retrospectively registered with Clinical Trials.gov (no. NCT05601609).

Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.

Although there is evidence of an association between the fecal microbiota and colorectal cancer (CRC) risk in epidemiologic studies, there is a lack of data from large-scale population-based studies. To address this gap, we assessed the dysbiosis of the fecal microbiome in a large-scale study in Korea. We recruited 287 CRC patients from the Center for Colorectal Cancer, National Cancer Center Hospital, Korea to perform 16S rRNA gene sequencing of fecal samples. A total of 287 age- and sex-matched healthy participants were selected from 890 cohort of healthy Koreans that are publicly available (PRJEB33905). The microbial dysbiosis index (MDI) was calculated based on the differentially abundant species. The association between MDI and CRC risk was observed using conditional logistic regression. Alpha-diversity indices were not significantly different between CRC cases and controls. The first three principal coordinates derived by a principal coordinate analysis (PCoA) based on weighted UniFrac distance explained 41.24% of the overall microbial diversity, with a significant divergence of the microbial composition between CRC patients and controls (PERMANOVA p=0.001). Three enterotypes were found based on CRC patients’ microbial composition. Those who were in the third tertile of the MDI showed a significantly increased risk of CRC in the total population (OR: 6.59, 95% CI: 3.83-11.33, p-trend<0.001) compared to those in the lowest tertile. Similar results were found for men (OR: 6.58, 95% CI: 3.17-13.63, p-trend<0.001) and women (OR: 6.69, 95% CI: 2.91-15.37, p-trend<0.001). Dysbiosis in the fecal microbiota may be associated with an increased risk of CRC. Due to the potentially modifiable nature of the gut microbiota, our findings may have implications for CRC prevention among Koreans. Key words: Fecal microbiome, 16S rRNA gene sequencing, Microbial dysbiosis, Colorectal cancer Citation Format: Jeongseon Kim, Madhawa Gunathilake, Hyun Yang Yeo, Jae Hwan Oh, Byung Chang Kim, Nayoung Han, Bun Kim, Hyojin Pyun, Mi Young Lim, Young-Do Nam, Hee Jin Chang. Fecal microbial dysbiosis is associated with colorectal cancer risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 755.

The importance of selenium in human health has received much attention due to its antioxidant properties when it is consumed at an appropriate level. However, the existing evidence is limited to obtain an effective conclusion for colorectal cancer (CRC). Notably, an adequate intake of selenium was reported for Koreans. Furthermore, cytokine secretion and immune function may be affected by dietary selenium. Our study aimed to explore whether selenium potentially reduces CRC risk and whether the IL10 rs1800871 polymorphism has an effect on this association. We designed a case‒control study with 1,420 cases and 2,840 controls. A semiquantitative food frequency questionnaire was used to obtain information on selenium intake. We determined IL10 rs1800871 through genetic analysis. Different models were developed to explore selenium intake related to CRC risk by calculating odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression. A reduced risk of CRC was found as selenium intake increased, with an OR (95% CI) of 0.44 (0.35–0.55) (p for trend <0.001). However, this association seems to be allele specific and only present among risk variant allele carriers (GA/GG) with a significant interaction between dietary selenium and IL10 rs1800871 (P interaction=0.043). We emphasized that a reduction in CRC risk is associated with appropriate selenium intake. However, the IL10 rs1800871 polymorphism has an impact on this reduction, with a greater effect on variant allele carriers. These findings suggest the importance of considering an individual’s genetic characteristics when developing nutritional strategies for CRC prevention.

Dietary patterns may be a crucial modifiable factor in colorectal cancer (CRC) risk. This study aimed to examine the associations of dietary patterns derived from two methods with CRC risk in Korea. In a study of 1420 CRC patients and 2840 control participants, we obtained dietary patterns by principal component analysis (PCA) and reduced rank regression (RRR) using 33 predefined food groups. The associations between dietary patterns and CRC risk were assessed using unconditional logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals (CIs). We identified two similar dietary patterns, derived from PCA 1 (prudent) and RRR (healthy), characterized by higher consumption of green/yellow vegetables, light-colored vegetables, fruits, eggs, and milk in both men and women. In women, higher prudent and healthy pattern scores were significantly associated with a lower risk of CRC (prudent, ORQ4 vs. Q1 = 0.59, 95% CI 0.40–0.86, P for trend = 0.005; healthy, ORQ4 vs. Q1 = 0.62, 95% CI 0.43–0.89, P for trend = 0.007). In men, a significant inverse association between dietary pattern and risk of rectal cancer was found only for the healthy dietary pattern (ORQ4 vs. Q1 = 0.66, 95% CI 0.45–0.97, P for trend = 0.036). Compared with the dietary pattern derived by PCA, the RRR dietary pattern had a slightly stronger association with a lower risk of distal colon cancer (ORQ4 vs. Q1 = 0.58, 95% CI 0.35–0.97, P for trend = 0.025) and rectal cancer (ORQ4 vs. Q1 = 0.29, 95% CI 0.15–0.57, P for trend < 0.001) in women. Our findings suggest cancer prevention strategies focusing on a diet rich in vegetables, fruits, eggs, and milk. Moreover, the use of both PCA and RRR methods may be advantageous to explore the associations between dietary patterns and risk of CRC.

Objectives: We explored whether the association between vitamin B2 and colorectal cancer (CRC) risk could be modified by the MTRR rs1801394 and MTR rs1805087 genetic polymorphisms and examined whether the interaction effects are sex-specific. Methods: We performed a case‒control study involving 1,420 CRC patients and 2,840 controls from the Korea National Cancer Center. Dietary vitamin B2 intake was assessed using a semiquantitative food frequency questionnaire, and the association with CRC was evaluated. Genotyping was performed using an Illumina MEGA-Expanded Array. For gene-nutrient interaction analysis, pre-matched (1,081 patients and 2,025 controls) and matched (1,081 patients and 1,081 controls) subsets were included. Unconditional and conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Results: A higher intake of vitamin B2 was associated with a significantly lower CRC risk (OR=0.65; 95% CI, 0.51-0.82; p<0.001). Carriers of at least 1 minor allele of MTRR rs1801394 showed a significantly higher CRC risk (OR=1.43; 95% CI, 1.12-1.83). Men homozygous for the major allele (A) of MTRR rs1801394 and who had a higher intake of vitamin B2 had a significantly lower CRC risk (OR=0.31; 95% CI, 0.18-0.54; p-interaction=0.02). In MTR rs1805087, men homozygous for the major allele (A) and who had a higher vitamin B2 intake had a significantly lower CRC risk (OR=0.38; 95% CI, 0.25-0.60; p-interaction<0.001). Conclusion: The MTRR rs1801394 and MTR rs1805087 genetic polymorphisms may modify the association between vitamin B2 and CRC risk, particularly in men. However, further studies are warranted to confirm these interaction.

Purpose: This study aimed to evaluate the long-term clinical outcomes based on the ligation level of the inferior mesenteric artery (IMA) in patients with rectal cancer.Methods: This was a retrospective analysis of a prospectively collected database that included all patients who underwent elective low anterior resection for rectal cancer between January 2013 and December 2019. The clinical outcomes included oncological outcomes, postoperative complications, and functional outcomes. The oncological outcomes included overall survival (OS) and relapse-free survival (RFS). The functional outcomes, including defecatory and urogenital functions, were analyzed using the Fecal Incontinence Severity Index, International Prostate Symptom Score, and International Index of Erectile Function questionnaires.Results: In total, 545 patients were included in the analysis. Of these, 244 patients underwent high ligation (HL), whereas 301 underwent low ligation (LL). The tumor size was larger in the HL group than in the LL group. The number of harvested lymph nodes (LNs) was higher in the HL group than in the LL group. There were no significant differences in complication rates and recurrence patterns between the groups. There were no significant differences in 5-year RFS and OS between the groups. Cox regression analysis revealed that the ligation level (HL vs. LL) was not a significant risk factor for oncological outcomes. Regarding functional outcomes, the LL group showed a significant recovery in defecatory function 1 year postoperatively compared with the HL group.Conclusion: LL with LNs dissection around the root of the IMA might not affect the oncologic outcomes comparing to HL; however, it has minimal benefit for defecatory function.

Magnesium may have a significant impact on the development of cancer. However, the relationship between magnesium intake and the risk of colorectal cancer (CRC) is unclear. Therefore, we evaluated the association between magnesium intake and the risk of CRC, and we investigated how the insulin receptor (INSR) rs1799817 variant impacts this relationship. Data from 1,420 CRC patients and 2,840 controls from the Korean National Cancer Centre were analysed. A higher intake of magnesium was associated with a reduced risk of CRC in the total population (odds ratio (OR) = 0.65, 95% confidence interval (CI) = 0.52-0.81). We found that G + carriers of INSR rs1799817 with higher magnesium intake had a significantly lower risk of CRC (p for interaction = 0.003). Our findings indicated that high magnesium intake could be associated with a decreased risk of CRC, and this association could be modified by the INSR rs1799817 variant.

Background Glucose is a main source of energy for tumor cells. Thus, a low-carbohydrate diet (LCD) is thought to make a significant contribution to cancer prevention. In addition, LCD and HECT domain E3 ubiquitin protein ligase 4 (HECTD4) gene may be related to insulin resistance. Objectives We explored whether LCD score and HECTD4 rs11066280 are etiological factors for colorectal cancer (CRC) and whether LCD score interacts with HECTD4 rs11066280 to modify CRC risk. Methods We included 1457 controls and 1062 cases in a case-control study. The LCD score was computed based on the proportion of energy obtained from carbohydrate, protein, and fat, as determined by a semiquantitative food frequency questionnaire. We used unconditional logistic regression models to explore the association of HECTD4 with CRC prevention and interaction of LCD score and HECTD4 polymorphism with CRC preventability. Results Individuals with AA/AT genotypes who carried a minor allele (A) of HECTD4 rs11066280 exhibited a decreased CRC risk [odds ratio (OR) = 0.75, 95% confidence interval (CI): 0.62, 0.91]. In addition, a protective effect of high LCD score against CRC development was identified (OR = 0.52, 95% CI: 0.40, 0.68, P for trend <0.001). However, the effect of LCD depended on individual’s genetic background, which appears only in participants with TT genotype of HECTD4 rs11066280 [OR = 0.49 (0.36–0.68), P interaction = 0.044]. Conclusions Our findings suggest a protective effect of LCD and a minor allele of HECTD4 rs11066280 against CRC development. In addition, we provide an understanding of the interaction effect of LCD and HECTD4 rs11066280 on CRC, which may be helpful for establishing diet plans regarding cancer prevention.