Predicting mechanism of immune response in microsatellite instability colorectal cancer.

Colorectal cancer (CRC), also known as colon cancer, is the third most common cancer and the fourth most cause of cancer-related death in the world. CRC can be classified into two major subtypes, including microsatellite instability (MSI) and microsatellite stability (MSS), which showed different characteristics in immunotherapy. Low sensitivity of diagnostic biomarkers and metastasis are still the principal cause of mortality, especially in MSI. Here, applying computational programs, we identified recurring expression programs based on single cell RNA sequencing (scRNA-Seq) data of CRC cell lines. Notably, three MSI specific recurring modules were identified by non-negative matrix factorization (NMF). High NMF score genes enriched in the function of metabolism and inflammatory response. Focusing on top specific active transcription factor (TF), RUNX3 (Runt-related transcription factor 3), our results suggest that T cell infiltration was increased in RUNX3 high MSI CRC samples. Unbiased Gene Set Enrichment Analysis (GSEA) showed that RUNX3 was strongly associated with immune and metastasis related functions, such as Interferon Gamma (IFN-γ) and EPITHELIAL MESENCHYMAL TRANSITION (EMT). In addition, RUNX3 shows specific highly activated at epigenetic level in MSI compared with other gastrointestinal carcinomas. Positive correlation between RUNX3 and most immune checkpoints further confirmed RUNX3 might have crucial roles in MSI cancer progression and immunotherapy. Taken together, these results indicate significant tumor heterogeneity of two CRC subtypes at single-cell level and epigenetic modification level. These results also linked transcriptional dysregulation with immune infiltration at single-cell level in MSI, which may advance the application of scRNA-Seq technology in immunotherapy and contribute to developing novel biomarkers of this malignancy.

D3 Lymph Node Dissection Improves Survival Outcomes in Patients With cT2 Colorectal Non-well-differentiated Adenocarcinoma.

BACKGROUND/AIM: The extent of lymphadenectomy appropriate for patients with cT2 colorectal cancer (CRC) remains controversial. This study was conducted to compare the survival outcomes of patients with cT2 CRC after D3 or D2 lymph node dissection (LND). PATIENTS AND METHODS: Qualifying subjects (N=590) had undergone radical colorectal resections for cT2 CRC and were grouped according to tumor histological type as either well-differentiated (WDA) or non-well-differentiated (nWDA) adenocarcinoma. Each group was further stratified into D3 or D2 LND according to the extent of lymph node dissection. Propensity score matching (PSM) was applied to balance potential confounding factors, and identify independent prognostic risk factors using Cox regression analysis. Primary outcome measures were overall survival (OS), cancer-specific survival, (CSS) and relapse-free survival rate (RFS). RESULTS: Prior to PSM, OS and CSS differed significantly (p=0.001 and p=0.021, respectively) for D3 and D2 LND subsets in the nWDA group. Estimated hazard ratios (HRs) for OS and CSS were 3 [95% confidence interval (CI)=1.3-6.8; p=0.0084] and 3.2 (95%CI=1-10; p=0.047), respectively, in the D3 LND subset. After matching, significant differences in OS (p=0.007) and CSS (p=0.012) were also observed, with corresponding estimated HRs of 4 (95%CI=1.2-14; p=0.028) and 16 (95%CI=1.2-220; p=0.034). In the WDA group, D2 and D3 LND procedures displayed similar favorable prognoses before and after matching. Postoperative complications emerged as independent risk factors for prognosis in the WDA group of patients with cT2 CRC. CONCLUSION: D3 LND improved survival outcomes in patients with non-well-differentiated cT2 CRC. In patients with well-differentiated cT2 adenocarcinoma, D3 LND was preferred to reduce perioperative complications.

LINC00858 facilitates formation of hepatic metastases from colorectal cancer via regulating the miR-132-3p/IGF2BP1 axis.

Hepatic metastasis is a major cause of colorectal cancer (CRC)-related deaths. Presently, the role of long non-coding RNAs (lncRNAs) in hepatic metastases from CRC is elusive. We dissected possible interplay between LINC00858/miR-132-3p/IGF2BP1 via bioinformatics approaches. Subsequently we analyzed mRNA expression of LINC00858, miR-132-3p and IGF2BP1 through qRT-PCR. Western blot was used to detect protein expression of IGF2BP1. RNA immunoprecipitation chip and dual-luciferase assay validated interaction between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Cell viability, invasion, and migration were examined via CCK-8, colony formation, transwell and wound healing assays. Effect of LINC00858 on CRC hepatic metastases was validated via in vivo assay. Upregulated LINC00858 and IGF2BP1, and downregulated miR-132-3p were predicted in tumor tissues of patients with hepatic metastases from CRC. There were targeting relationships between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Besides, LINC00858 facilitated progression of CRC cells. Rescue assay suggested that silencing LINC00858 suppressed CRC cell progression, while further silencing miR-132-3p or overexpressing IGF2BP1 reversed such effects. LINC00858 could facilitate CRC tumor growth and hepatic metastases. LINC00858 induced CRC hepatic metastases via regulating miR-132-3p/ IGF2BP1, and this study may deliver a new diagnostic marker for the disease.

The Significance of Skip Lymph Node Metastasis in Colorectal Cancer.

BACKGROUND/AIM: The purpose of this study was to elucidate the status and clinical significance of skip lymph node metastasis (LNM) in colorectal cancer. PATIENTS AND METHODS: This is a retrospective cohort study from a high-volume cancer center in Japan. A total of 1,060 patients with primary stage III colorectal cancer (CRC) underwent radical resection were included in the study and divided into skip LNM (LNM) (skip+) and non-skip LNM (skip-) groups. Propensity score matching was used to balance potential confounding factors. The cancer-specific survival (CSS) and relapse-free survival rate (RFS) between the two groups before and after matching were evaluated. RESULTS: Before matching, patients in the skip+ group had a greater number of LNM (pN2: 48.3% vs. 31.1%; p<0.001), more pathological stage IIIC (43.2% vs. 17.6%; p<0.001), and a higher rate of recurrence (38.1% vs. 25.8%; p=0.0045). Consequently, the CSS (p=0.034) and RFS (p=0.005) were worse compared to the skip- group. However, after matching, there were no significant differences in prognosis for CSS (p=0.529) and RFS (p=0.515). In multivariate analysis, skip+ was not an independent risk factor for prognosis. However, the skip+ LNM group was more likely to have local lymph node recurrence. CONCLUSION: Skip+ LNM was more likely to happen in later stage CRCs, leading to significantly poorer survival outcomes. However, when all background factors were matched, the prognosis of the skip+ group was not worse. Surgeons need to be more alert to the possibility of local recurrence in patients with skip LNM.

D3 lymph node dissection improves the survival outcome in patients with pT2 colorectal cancer.

BACKGROUND: The extent of lymphadenectomy in patients with pT2 colorectal cancer (CRC) remains controversial. This study aimed to elucidate the effects of D3 and D2 lymph node dissection (LND) on survival in patients diagnosed with pT2 CRC. METHODS: This was a retrospective cohort study from a high-volume cancer center in Japan. From April 2007 to December 2020, 6273 patients with primary CRC were included in the study; among these, 616 patients diagnosed with pT2 CRC underwent radical colorectal resection. Propensity score matching (PSM) was applied to balance potential confounding factors, and a total of 104 matched pairs were extracted from the entire cohort. Independent risk factors associated with prognosis were determined by Cox regression analysis. The main outcome measures were overall survival (OS) and cancer-specific survival (CSS). RESULTS: Before PSM, there was a statistically significant difference across the cohort in OS and CSS (p = 0.000 and 0.013) between D3 and D2 LND groups; the estimated hazard ratio (HR) was 2.2 (95% confidence interval (CI), 1.1-4.4, p = 0.031) for OS in the D3 LND and 4.4 (95% CI, 1.7 to 11, p = 0.0027) for CSS (p = 0.013). There was also a significant difference (p = 0.024) in OS between the D3 and D2 LND groups in the matched cohort, with an estimated HR for OS of 3.3 (95% CI, 1.2 to 9.1, p = 0.024) and an estimated HR for CSS of 7.2 (95% CI, 1.6 to 33, p = 0.011). CONCLUSIONS: D3 LND had a significant survival advantage in the treatment of pT2 CRC. The results of this study provide a theoretical basis for the application of D3 LND in radical surgery for preoperative T2 CRC.

Prognostic Factors in Stage IV Colorectal Cancer Patients With Resection of Liver and/or Pulmonary Metastases: A Population-Based Cohort Study.

Importance: Currently, surgical resection of distant metastatic lesions has become the preferred treatment for select colorectal cancer (CRC) patients with liver metastasis (LM) and/or pulmonary metastasis (PM). Metastasectomy is the most common curative method. However, evidence of the factors affecting the prognosis of CRC patients after resection of LM and/or PM is still insufficient. Objective: To explore the prognostic factors of CRC patients with LM and/or PM who have undergone resection of metastatic tumors and to provide reliable selection factors for surgical treatment in patients affected by LM and/or PM from CRC. Methods: The SEER database was used to identify eligible CRC LM and/or PM patients who underwent resection of the primary tumor and distant metastases from January 1, 2010, to December 31, 2018. The Kaplan-Meier method was used to calculate survival, and comparisons were performed using the log-rank test for univariate analysis. A Cox proportional hazards regression model was used to identify prognostic factors for the multivariate analysis. The outcomes included overall survival (OS) and cancer-specific survival (CSS). Results: A total of 3,003 eligible colorectal cancer patients with LM and/or PM were included in this study. The 3-year and 5-year OS rates were 53% and 33.6%, respectively, and the 3-year and 5-year CSS rates were 54.2% and 35.3%, respectively. In the adjusted multivariate analysis, age < 65 years (OS: p=0.002, CSS: p=0.002) was associated with better long-term outcomes, and primary tumors located on the left side of the colon (OS: p=0.004, CSS: p=0.006) or rectum (OS: p=0.004, CSS: p=0.006), T3 stage (OS: p<0.001, CSS: p<0.001), number of regional lymph nodes examined ≥ 12 (OS: p<0.001, CSS: p=0.001), and CRC LM (OS: p<0.001, CSS: p<0.001) were positive prognostic factors for survival after resection of metastatic tumors. Conclusion: Age < 65 years is associated with better long-term outcomes in colorectal cancer patients with LM and/or PM, analogously to the left sided primary tumor, T3 stage, number of regional lymph nodes examined ≥ 12 and liver metastases.