Differences of protein expression profiles, KRAS and BRAF mutation, and prognosis in right-sided colon, left-sided colon and rectal cancer

Colorectal adenocarcinoma in Uganda: are right-sided and left-sided colon cancers two distinct disease entities?

INTRODUCTION

In Western countries, right-sided colon cancers (RSCC) present at an older age and advanced stage. Researchers believe that there is a difference between left-sided colon cancer (LSCC) and RSCC. In Uganda, however, it is unknown whether differences exist in the pathological profile between RSCC and LSCC. The aim of this study was to determine the differences in clinicopathological characteristics between RSCC and LSCC in Ugandan patients.

METHODOLOGY

A cross-sectional study was conducted in which colorectal adenocarcinoma formalin-fixed paraffin-embedded tissue (FFPE) blocks were obtained from 2008 to 2021. Colorectal specimens were obtained from prospectively recruited patients. In the retrospective study arm, FFPE blocks and data were obtained from the archives of pathology laboratory repositories. Parameters studied included age, sex, location of the tumour, grade, stage, lymphovascular (LVI) status, and histopathological subtype between LSCC and RSCC.

RESULTS

Patients with RSCC were not older than those with LSCC (mean age, 56.3 years vs 53.5 years; p = 0.170). There was no difference in the stage between RSCC and LSCC. Poorly differentiated tumours were more commonly found in RSCC than in LSCC (18.7% vs 10.1%; p = 0.038). Moderately and poorly differentiated colonic tumours were more common with RSCC (89.3%) than with LSCC (75.1%) (p = 0.007). Younger patients had more poorly differentiated tumours than older patients (19.6% versus 8.6%; p = 0.002). LVI was more common with RSCC than with LSCC (96.8% vs 85.3%; p = 0.014). Mucinous adenocarcinoma (MAC) was more common with RSCC (15.8%) compared with LSCC (8.5%) (p = 0.056) although statistical significance was borderline.

CONCLUSIONS

Clinicopathological features of RSCCs tend to be different from those of LSCCs. RSCCs tend to be associated with MAC, a higher grade and LVI status compared to LSCC. LSCC and RSCC present predominantly with an advanced stage; therefore, national screening programmes for the early detection of CRC are necessary to reduce mortality in our Ugandan population.

The Prognostic Significance of RIMKLB and Related Immune Infiltrates in Colorectal Cancers

RimK-like family member B (RIMKLB) is an enzyme that post-translationally modulates ribosomal protein S6, which can affect the development of immune cells. Some studies have suggested its role in tumor progression. However, the relationships among RIMKLB expression, survival outcomes, and tumor-infiltrating immune cells (TIICs) in colorectal cancer (CRC) are still unknown. Therefore, we analyzed RIMKLB expression levels in CRC and normal tissues and investigated the correlations between RIMKLB and TIICs as well as the impact of RIMKLB expression on clinical prognosis in CRC using multiple databases, including the Tumor Immune Estimation Resource (TIMER), Gene Expression Profiling Interactive Analysis (GEPIA), PrognoScan, and UALCAN databases. Enrichment analysis was conducted with the cluster Profiler package in R software to explore the RIMKLB-related biological processes involved in CRC. The RIMKLB expression was significantly decreased in CRC compared to normal tissues, and correlated with histology, stage, lymphatic metastasis, and tumor status (p < 0.05). Patients with CRC with high expression of RIMKLB showed poorer overall survival (OS) (HR = 2.5,p = 0.00,042), and inferior disease-free survival (DFS) (HR = 1.9,p = 0.19) than those with low expression of RIMKLB. TIMER analysis indicated that RIMKLB transcription was closely related with several TIICs, including CD4⁺ and CD8⁺ T cells, B cells, tumor-associated macrophages (TAMs), monocytes, neutrophils, natural killer cells, dendritic cells, and subsets of T cells. Moreover, the expression of RIMKLB showed significant positive correlations with infiltrating levels of PD1 (r = 0.223, p = 1.31e-06; r = 0.249, p = 1.25e-03), PDL1 (r = 0.223, p = 6.03e-07; r = 0.41, p = 5.45e-08), and CTLA4 (r = 0.325, p = 9.68e-13; r = 0.41, p = 5.45e-08) in colon and rectum cancer, respectively. Enrichment analysis showed that the RIMKLB expression was positively related to extracellular matrix and immune inflammation-related pathways. In conclusion, RIMKLB expression is associated with survival outcomes and TIICs levels in patients with CRC, and therefore, might be a potential novel prognostic biomarker that reflects the immune infiltration status.

Comprehensive analysis of R-spondin fusions and RNF43 mutations implicate novel therapeutic options in colorectal cancer

PURPOSE

Gene fusions involving R-spondin (RSPOfp) and RNF43 mutations have been shown to drive Wnt-dependent tumor initiation in colorectal cancer (CRC). Herein, we aimed to characterize the molecular features of RSPOfp/RNF43 mutated (mut) compared to wildtype CRCs to gain insights into potential rationales for therapeutic strategies.

EXPERIMENTAL DESIGN

A discovery cohort was classified for RSPOfp/RNF43 status using DNA/RNA sequencing and immunohistochemistry. An independent cohort was used to validate our findings.

RESULTS

The discovery cohort consisted of 7,245 CRC samples. RSPOfp and RNF43 mutations were detected in 1.3% (n=94) and 6.1% (n=443) of cases. We found 5 RSPO fusion events that had not previously been reported (e.g. IFNGR1-RSPO3). RNF43-mut tumors were associated with right-sided primary tumors. No RSPOfp tumors had RNF43 mutations. In comparison to wildtype CRCs, RSPOfp tumors were characterized by a higher frequency of BRAF, BMPR1A and SMAD4 mutations. APC mutations were observed in only a minority of RSPOfp-positive compared to wildtype cases (4.4 vs. 81.4%). Regarding RNF43 mutations, a higher rate of KMT2D and BRAF mutations were detectable compared to wildtype samples. While RNF43 mutations were associated with a microsatellite instability (MSI-H)/mismatch repair deficiency (dMMR) phenotype (64.3%), and a TMB {greater than or equal to}10 mt/Mb (65.8%), RSPOfp was not associated with MSI-H/dMMR. The validation cohort replicated our genetic findings.

CONCLUSIONS

This is the largest series of RSPOfp/RNF43-mut CRCs reported to date. Comprehensive molecular analyses asserted the unique molecular landscape associated with RSPO/RNF43 and suggested potential alternative strategies to overcome the low clinical impact of Wnt-targeted agents and immunotherapy.

Construction of Novel Prognostic Nomogram for Mucinous and Signet Ring Cell Colorectal Cancer Patients with a Survival Longer Than 5 Years

Purpose

Patients and Methods

Results

Conclusion

Construction and characterization of rectal cancer-related lncRNA-mRNA ceRNA network reveals prognostic biomarkers in rectal cancer

Rectal cancer is an important cause of cancer‐related deaths worldwide. In this study, the differentially expressed (DE) lncRNAs/mRNAs were first identified and the correlation level between DE lncRNAs and mRNAs were calculated. The results showed that genes of highly correlated lncRNA‐mRNA pairs presented strong prognosis effects, such as GPM6A, METTL24, SCN7A, HAND2‐AS1 and PDZRN4. Then, the rectal cancer‐related lncRNA‐mRNA network was constructed based on the ceRNA theory. Topological analysis of the network revealed that the network was maintained by hub nodes and a hub subnetwork was constructed, including the hub lncRNA MIR143HG and MBNL1‐SA1. Further analysis indicated that the hub subnetwork was highly related to cancer pathways, such as ‘Focal adhesion’ and ‘Wnt signalling pathway’. Hub subnetwork also had significant prognosis capability. A closed lncRNA‐mRNA module was identified by bilateral network clustering. Genes in modules also showed high prognosis effects. Finally, a core lncRNA‐TF crosstalk network was identified to uncover the crosstalk and regulatory mechanisms of lncRNAs and TFs by integrating ceRNA crosstalks and TF binding affinities. Some core genes, such as MEIS1, GLI3 and HAND2‐AS1 were considered as the key regulators in tumourigenesis. Based on the authors’ comprehensive analysis, all these lncRNA‐mRNA crosstalks provided promising clues for biological prognosis of rectal cancer.

Blood lipids and risk of colon or rectal cancer: a Mendelian randomization study

PURPOSE

Recent Mendelian randomization (MR) studies derived inconsistent results of blood lipids' effect on colorectal cancer, and whether the blood lipids' effect on colon and rectal cancer is different is still unknown. Here, we sought to answer these questions.

METHODS

Primarily, we employed univariable MR to explore the blood lipids' effect on colon and rectal cancer, including high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol and triglycerides. Then, multivariable MR was also employed to reassess each blood lipid's effect on the two cancers with adjustment of the other lipids. Reverse MR analysis was adopted to determine whether colon or rectal cancer could affect the levels of blood lipids. The Cochrane's Q value was used to evaluate the heterogeneity, and MR-PRESSO was used to appraise the pleiotropy.

RESULTS

Generally, we did not find any significant result between blood lipids and the colon/rectal cancer after Bonferroni correction in the univariable MR analysis. The multivariable MR analysis also obtained the same results. However, it should be noted that higher total cholesterol level might increase the risk of colon cancer (OR = 1.15 [1.01, 1.31], IVW p value = 0.029) but not rectal cancer (OR = 1.02 [0.85, 1.21], IVW p value = 0.853). Such causal relationship turned insignificant in the multivariable MR. The reverse MR analysis suggested that either colon or rectal cancer could increase the levels of blood lipids.

CONCLUSION

We found no association between blood lipids and risk of colon or rectal cancer, except for a positive association between total cholesterol and colon cancer risk.

SPARCL1 exhibits different expressions in left- and right-sided colon cancer and is downregulated via DNA methylation

Aim: The authors previously found that SPARCL1 functions to suppress colorectal cancer metastasis. Here, the epigenetic mechanism of SPARCL1 regulation and its relationship with clinicopathological features in colon cancer were investigated. Materials & methods: SPARCL1 expression was evaluated by immunohistochemistry staining in a tissue array containing 271 left-sided colon cancer samples and 257 right-sided colon cancer samples. In vivo and in vitro DNA methylation states were measured by biochemical sulfide potential assay. The transcription and DNA methylation states in cells were altered by siRNA or decitabine treatment, respectively. Cellular motility properties were compared through transwell assay. Results & conclusion: SPARCL1, mediated by its DNA methylation, may arrest colorectal carcinoma motility. Furthermore, SPARCL1 expression is higher and may have a specific prognostic value in left-sided colon cancer.

Clinicopathological Features and Survival of Signet-Ring Cell Carcinoma and Mucinous Adenocarcinoma of Right Colon, Left Colon, and Rectum

Histological subtype plays an important role in the different clinical characteristics and survival outcomes of patients with colorectal carcinoma (CRC). However, in previous studies, the influences of tumor locations and tumor stages have not been strictly controlled. This study focused on the assessment of the prognostic value of each histological subtype in different tumor locations and tumor stages of CRC. We used the Surveillance, Epidemiology, and End Results (SEER) database (1973-2011) to analyze 818,229 CRC patients with different clinical and pathological features, and analyzed the prognostic value of each histological subtype. Under the condition of stratification by tumor stage, signet-ring cell carcinoma (SRCC) presented the worst survival in each stage of right colon cancer (stage I, log-rank, p = 0.002, stages II, III, and IV, log-rank, p < 0.001), rectal cancer (RC) (log-rank, p < 0.001), and in stages II, III, and IV of left colon cancer (log-rank, p < 0.001). Multivariate survival analysis suggested SRCC subtype, male gender, age ≥ 70 years, tumor size ≥ 5 cm, stage progression, and poor differentiation were all significant factors worsening survival in CRC (p < 0.001, respectively). Mucinous adenocarcinoma (MC) histological subtype proved to be an independent protective factor for the prognosis of right colon cancer (p = 0.003). Overall, in our study, the results suggested SRCC had the worst survival among the three histological subtypes of CRC. MC was associated with favorable prognosis in right colon cancer but not with other tumor locations.

Construction and Comprehensive Prognostic Analysis of a lncRNA-miRNA-mRNA Regulatory Network and Tumor Immune Cell Infiltration in Colorectal Cancer

Colorectal cancer (CRC) is a malignant tumor with high morbidity and mortality worldwide. Recent studies have shown that long noncoding RNAs (lncRNAs) play an important role in almost all human tumors, including CRC. Competitive endogenous RNA (ceRNA) regulatory networks have become hot topics in cancer research. Tumor-infiltrating immune cells (TICs) have also been reported to be closely related to the survival and prognosis of CRC patients. In this study, we used the lncRNA–miRNA–mRNA regulatory network combined with tumor immune cell infiltration to predict the survival and prognosis of 598 CRC patients. First, we downloaded the lncRNA, mRNA, and miRNA transcriptome data of CRC patients from The Cancer Genome Atlas (TCGA) database and identified differentially expressed genes through “limma” package of R software. The ceRNA regulatory network was established by using the “GDCRNATools” R package. Then, univariate Cox analysis and least absolute shrinkage and selection operator analysis were performed to identify the optimal prognostic network nodes, including SRPX, UST, H19, SNHG7, hsa-miR-29b-3p, and TTYH3. Next, we analyzed the differences in 22 types of TICs between 58 normal subjects and 206 CRC patients and included memory CD4 T cells, dendritic cells and neutrophils in the construction of a prognostic model. Finally, we identified the relationship between the ceRNA prognostic model and the infiltrating immune cell prognostic model. In conclusion, we constructed two prognostic models that provide insights on the prognosis and treatment strategy of CRC.

Serum Tumor Markers Combined With Clinicopathological Characteristics for Predicting MMR and KRAS Status in 2279 Chinese Colorectal Cancer Patients: A Retrospective Analysis

Although serum tumor markers (STMs), clinicopathological characteristics and the status of KRAS and MMR play an important role in optimizing the treatment and prognosis of colorectal cancer, their interrelationships remain largely unknown. A retrospective analysis of 2279 patients who tested for KRAS and MMR status, and STM measurements prior to treatment over the past four years was conducted. Of the 784 patients tested for KRAS and 2279 patients tested for MMR status, KRAS mutations and dMMR were identified in 276 patients (35.20%) and 177 patients (7.77%), respectively. Logistic regression analysis demonstrated that right colon, well and moderate differentiation and negative CA19-9 were independent predictors for KRAS mutations. The ROC curve yielded an AUC of 0.609 through the combination of these three factors. Age < 65 was an independent predictive factor for dMMR, along with tumor size > 4.6 cm, right colon, poor differentiation, harvested lymph nodes ≥ 22, no lymph node metastasis, no perineural invasion, negative CEA and positive CA72-4. When the nine criteria were used together, the AUC was 0.849. In summary, both STMs and clinicopathological characteristics were found to be significantly associated with the status of KRAS and MMR. The combination of these two factors possessed a strong predictive power for KRAS mutations and dMMR among CRC patients.

High-Grade Inflammation Attenuates Chemosensitivity and Confers to Poor Survival of Surgical Stage III CRC Patients

Background: Heterogeneous clinical and molecular characteristics are reported in colorectal cancer (CRC) with different tumor laterality. However, the outcome of left- and right-sided patients with stage I–III CRC and the role of chronic inflammation in survival differences between them remain unclear.

Method: A prospective study including 1,181 surgical patients with stage I–III CRC was carried out to investigate the involvement of circulating fibrinogen-to-pre-albumin (Alb) ratio (FPR) and primary tumor sidedness in the clinical outcome of those patients. We further investigated the effect of FPR on adjuvant chemotherapy response and recurrence in stage III patients.

Results: Our study showed that the right tumor location was significantly associated with poor recurrence-free survival (RFS) (p = 0.04, adjusted HR = 1.41, 95% CI = 1.02–1.94) and overall survival (OS) (p = 0.04, adjusted HR = 1.55, 95% CI = 1.01–2.38) only in the stage III disease. In these patients, T4 stage distribution (83.39 vs. 70.94%, p < 0.01) within right-sided cases was significantly higher than left-sided patients. Moreover, preoperative FPR within right-sidedness (p < 0.01), T4 stage (p < 0.05), and large cancer bulk (≥5 cm) (p < 0.05) subgroups was significantly elevated compared to their counterparts, and it was gradually rising following the increased cancer bulk (p trend < 0.01). High-FPR distribution (52.30 vs. 27.00%, p < 0.01) within right-sided patients with the stage III disease was significantly higher than that in the left-sided cases. RFS (p_log−rank < 0.01) and OS (p_log−rank < 0.01) of the high-FPR patients were extremely inferior to the low-FPR cases, and the significant associations were observed when they were adjusted by other confounders including primary tumor location (p < 0.01, adjusted HR = 1.96, 95% CI = 1.42–2.70 for RFS; p < 0.01, adjusted HR = 2.44, 95% CI = 1.59–3.75 for OS). Additionally, RFS of adjuvant chemotherapy-treated high-FPR patients was superior to the patients without chemotherapy (p_log−rank = 0.01) but was inferior to the low-FPR patients undergoing the treatment, especially in the 5-FU- and XELOX-treated subgroup.

Conclusion: These findings indicate that chronic high-grade inflammation weakens chemotherapy efficacy and contributes to the poor prognosis of stage III surgical CRC patients.

Epidural analgesia does not impact recurrence or mortality in patients after rectal cancer resection

The relationship between epidural analgesia and rectal cancer outcome is not fully clarified. We aimed to investigate the putative effect of epidural analgesia on the risks of recurrence and mortality after rectal tumour resection. In this monocentric cohort study, we consecutively enrolled patients with stage I-III rectal cancer who underwent tumour resection from 2005 to 2014. Patients received epidural analgesia or intravenous opioid-based analgesia for postoperative pain control. Primary endpoint was first cancer recurrence. Secondary endpoints were all-cause mortality and cancer-specific mortality. We collected 1282 patients in the inverse probability of treatment weighting analyses, and 237 (18.5%) used epidurals. Follow-up interval was median 46.1 months. Weighted Cox regression analysis showed the association between epidural analgesia and recurrence-free survival was non-significant (adjusted hazard ratio [HR] 0.941, 95% CI 0.791-1.119, p = 0.491). Similarly, the association between epidural analgesia and overall survival (HR 0.997, 95% CI 0.775-1.283, p = 0.984) or cancer-specific survival (HR 1.113, 95% CI 0.826-1.501, p = 0.482) was non-significant either. For sensitivity tests, quintile stratification and stepwise forward model selection analyses showed similar results. We did not find a significant association between epidural analgesia and risk of recurrence, all-cause mortality, or cancer-specific mortality in patients with rectal cancer undergoing tumour resection.

Myosteatosis Differentially Affects the Prognosis of Non-Metastatic Colon and Rectal Cancer Patients: An Exploratory Study

Body composition performed by computed tomography (CT) impacts on cancer patients' prognoses and responses to treatment. Myosteatosis has been related to overall survival (OS) and disease-specific survival in colorectal cancer (CRC); however, the independent impact of the association of myosteatosis with prognosis in colon cancer (CC) and rectal cancer (RC) is still unclear. CT was performed at the L3 level to assess body composition features in 227 patients with CRC. Clinical parameters were collected. Overall survival (OS) was the primary outcome, and the secondary outcome was disease-free survival (DFS). Skeletal muscle attenuation and intramuscular adipose tissue area were associated with DFS (p = 0.003 and p = 0.011, respectively) and OS (p < 0.001 and p < 0.001, respectively) in CC patients but not in RC patients. Only the skeletal muscle area was associated with better prognosis related to OS in RC patients (p = 0.009). When CC and RC were analyzed separately, myosteatosis influenced survival negatively in CC patients, worsening DFS survival (hazard ratio [HR], 2.70; 95% confidence interval [CI], 1.07-6.82; p = 0.035) and OS (HR, 5.76; 95% CI, 1.31-25.40; p = 0.021). By contrast, the presence of myosteatosis did not influence DFS (HR, 1.02; 95% CI, 0.52-2.03; p = 0.944) or OS (HR, 0.76; 95% CI, 0.33-1.77; p = 0.529) in RC patients. Our study revealed the interference of myosteatosis in the therapy and survival of patients with CC but not in those with RC, strengthening the value of grouping the two types of cancer in body composition analyses.

GAPDH and PUM1: Optimal Housekeeping Genes for Quantitative Polymerase Chain Reaction-Based Analysis of Cancer Stem Cells and Epithelial-Mesenchymal Transition Gene Expression in Rectal Tumors

Background

The overwhelming majority of published articles have taken colon and rectal cancer as a single group, i.e., colorectal cancer, when normalizing gene expression data with housekeeping genes (HKG) in quantitative polymerase chain reaction (qPCR) experiments though there are published reports that suggest the differential expression pattern of genes between the colon and rectal cancer groups and hence the current experiment was attempted to find out the optimal set of housekeeping genes from the list of common HKG for rectal tumor gene expression analysis.

Methods

The expression of five potential housekeeping genes GAPDH, RPNI, PUM1, B2M, and PMM1 was analyzed through qPCR and Bestkeeper software (http://www.wzw.tum.de/gene-quantification/bestkeeper.html) in 20 stage II-IV rectal cancer samples to check for uniformity in their expression pattern. Cancer stem cell (CSC) marker ALDH1 and epithelial-mesenchymal transition marker (EMT) markers E cadherin, vimentin, Twist, and SNAI2 expression were evaluated in conjunction with the two optimal reference genes in 10 rectal cancers as part of validation.

Results

The standard deviation of the cycle threshold value of GAPDH was found the lowest at 0.65 followed by RPN1 at 0.88, PUM1 at 0.94, PMM1 at 0.94, and B2M at 1.21 when analyzed with BestKeeper software. Using GAPDH and PUM1 as the reference gene for the validation phase, rectal cancer patients with stage III/IV showed a 4.79-fold change (P=0.006) in ALDH1 expression, and an 11.76-fold change in Twist expression (P=0.003) with respect to stage II rectal tumor when normalized with GAPDH and PUM1.

Conclusion

GAPDH and PUM1 can be used as an optimal set of housekeeping genes for gene expression-related experiments in rectal tumors. ALDH1 and Twist were found significantly overexpressed in stage III/IV rectal tumors in comparison to stage II rectal cancer. Genes associated with cancer stem cells and EMT markers could be optimally analyzed by normalizing them with GAPDH and PUM1 as housekeeping genes.

Microbial Community Profiling Distinguishes Left-Sided and Right-Sided Colon Cancer

The difference between left- and right-sided colon cancer has become the focus of global attention, and researchers have found differences in the morbidity, molecular biological characteristics, and response to targeted drug therapy between left- and right-sided colon cancer. Therefore, the identification of more effective predictive indicators is critical for providing guidance to future clinical work. We collected samples from different colon sites and regions and analyzed the identities and distributions of differentially expressed species in the microbiota in the left and right sides of the colon to better explore the pathogenesis of colon cancer and provided a basis for individualized drug therapy. We collected samples from different regions in the body of 40 patients with colon cancer, including stool and tissues. The Subjects were classified into four groups, and this classification was mainly based on the colon cancer distribution. The microbiota composition of the left-sided and right-sided colon samples was assessed by specifically amplifying the V3-V4 region of the 16S rDNA gene from DNA extracts from the samples. These amplicons were examined by Illumina HiSeq 2500 sequencing. The microbial taxa in the left-sided colon samples are more abundant than those in the right-sided colon samples. The flora in the left-sided colon samples, such as Clostridium perfringens and Fusobacterium nucleatum, might be associated with VEGF expression and are more likely to promote colon cancer. The microbiota distribution in the right-sided colon samples is less invasive and harmful and particularly rich in Bifidobacterium dentium. In addition, Streptococcus, which is the target of EGFR, was found to be expressed in both the left- and right-sided colon samples but was found at a higher level in the left-sided colon samples. Additionally, the differential pathways involved in the left-sided colon samples mainly mediate DNA damage, methylation, and histone modifications, whereas those in the right-sided colon samples are dominated by DNA synthesis. The comparison of only the geographical differences revealed a significant difference in the distribution of the microbial population. The adherent microbiota composition and structural changes between the left- and right-sided colon samples might contribute to the development of colon cancer, lead to different morbidities, and further affect the prognosis of patients and their sensitivity to targeted drugs. Therefore, the identification of the differential flora in the colon could be used as an indicator for predicting the occurrence and development of colon cancer, which is also beneficial for future individualized drug therapy.

MicroRNA Expression and Correlation with mRNA Levels of Colorectal Cancer-Related Genes

INTRODUCTION

MicroRNAs (miRNAs), as a family of non-coding RNAs, have opened a new window in cancer biology and transcriptome. It has been revealed that miRNAs post-transcriptionally regulate the gene expression and involve in colorectal cancer (CRC) development and progression. Our aim was to examine the differential expression of miRNAs in a CRC and to correlate their expression levels with mRNA levels of CRC-related genes (K-ras, APC, p53).

MATERIALS AND METHODS

Seventy-two colorectal tumor tissues from patients with newly diagnosed CRC and 72 matched normal adjacent tissues were analyzed. Relative expression of seven CRC-related miRNAs (miR-21, miR-31, miR-20a, miR-133b, and miR-145, miR-135b and let-7g) and three CRC-related genes (K-ras, APC, p53) was detected using the SYBR Green quantitative real-time PCR technique. The correlation between gene expression levels and clinicopathological features was evaluated.

RESULTS

Our results showed a significant difference between the two groups for the expression level of miR-21, miR-31, miR-145, and miR-20a (P < 0.001). Also, a significant difference between the two groups for the expression level of K-ras was found (P < 0.001). Further analysis revealed an inverse significant correlation between miR-145 and K-ras (R² = 0.662, P < 0.001), while a positive correlation was observed between miR-21 and K-ras (R² = 0.732, P < 0.001).

CONCLUSION

Dysregulation of miRNAs and correlation with molecular signaling pathways designated a biological role for miRNAs in various cellular mechanisms underlying CRC. On the other hand, the pattern of miRNAs expression and its correlation with transcriptional status are helpful to discovery biomarkers and design therapeutics for CRC.

BMI May Be a Prognostic Factor for Local Advanced Rectal Cancer Patients Treated with Long-Term Neoadjuvant Chemoradiotherapy

Objective

This study aims to develop feasible nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of the local advanced rectal cancer (LARC) patients who were treated with neoadjuvant chemoradiotherapy (nCRT) and operation.

Methods

A total of 243 LARC patients undergoing nCRT followed by total mesorectal excision (TME) were enrolled. Preoperative clinical features and postoperative pathological characteristics were collected. A Cox regression analysis was performed, and Cox-based nomograms were developed to predict the OS and CSS. We assessed the predictive performance of the nomogram with concordance index and calibration plots.

Results

A total of 243 patients were included with a median follow-up period of 46 months (range from 9 to 86 months). Cox regression analysis showed that low BMI (BMI < 18.5, HR= 21.739, P < 0.05), high level of preoperative CA19-9 (HR = 3.369, P = 0.036), high ypStage (HR = 19.768, P < 0.001), positive neural invasion (HR = 4.218, P = 0.026) and no adjuvant chemotherapy (HR = 5.495, P < 0.001) were independent predictors of poor OS. Age ≥70 (HR = 2.284, P <0.001), low BMI (BMI < 18.5, HR = 3.906, P < 0.05), positive preoperative CA19-9 (HR = 1.920, P = 0.012), high ypStage (HR = 5.147, P <0.001) and positive neural invasion (HR = 2.873, P = 0.022) were independent predictors of poor CSS. The predictive nomograms were developed to predict the OS and CSS with a C-index of 0.837 and 0.760. Good statistical performance on internal validation was shown by calibration plots.

Conclusion

In conclusion, this study demonstrated that BMI was an independent prognostic factor for OS and CSS in LARC patients treated with nCRT followed TME. A nomogram incorporating BMI, neural invasion, pre-CA19-9, ypStage, age, and adjuvant chemotherapy could be helpful to predict the OS and CSS.

Discovering the molecular differences between right- and left-sided colon cancer using machine learning methods

Background

In recent years, the differences between left-sided colon cancer (LCC) and right-sided colon cancer (RCC) have received increasing attention due to the clinicopathological variation between them. However, some of these differences have remained unclear and conflicting results have been reported.

Methods

From The Cancer Genome Atlas (TCGA), we obtained RNA sequencing data and gene mutation data on 323 and 283 colon cancer patients, respectively. Differential analysis was firstly done on gene expression data and mutation data between LCC and RCC, separately. Machine learning (ML) methods were then used to select key genes or mutations as features to construct models to classify LCC and RCC patients. Finally, we conducted correlation analysis to identify the correlations between differentially expressed genes (DEGs) and mutations using logistic regression (LR) models.

Results

We found distinct gene mutation and expression patterns between LCC and RCC patients and further selected the 30 most important mutations and 17 most important gene expression features using ML methods. The classification models created using these features classified LCC and RCC patients with high accuracy (areas under the curve (AUC) of 0.8 and 0.96 for mutation and gene expression data, respectively). The expression of PRAC1 and BRAF V600E mutation (rs113488022) were the most important feature for each model. Correlations of mutations and gene expression data were also identified using LR models. Among them, rs113488022 was found to have significance relevance to the expression of four genes, and thus should be focused on in further study.

Conclusions

On the basis of ML methods, we found some key molecular differences between LCC and RCC, which could differentiate these two groups of patients with high accuracy. These differences might be key factors behind the variation in clinical features between LCC and RCC and thus help to improve treatment, such as determining the appropriate therapy for patients.

Impact of Primary Tumor Location on Survival After Curative Resection in Patients with Colon Cancer: A Meta-Analysis of Propensity Score-Matching Studies

BACKGROUND

Recent retrospective subgroup analyses of patients with unresectable colon cancer (CC) receiving systemic chemotherapy have demonstrated that there is a significant difference in treatment outcome between patients with right-sided CC (RSCC) and those with left-sided CC (LSCC). However, it is impossible to divide patients with CC randomly into RSCC and LSCC groups before surgery. Therefore, the aim of this study is to explore the impact of primary tumor location (PTL) on survival after curative surgery for patients with CC using propensity score-matching (PSM) studies instead of randomization.

MATERIALS AND METHODS

We performed a comprehensive electronic search of the literature up to January 2019 to identify studies that had used databases allowing comparison of postoperative survival between patients with RSCC and those with LSCC. To integrate the impact of PTL on 5-year overall survival (OS) after curative surgery, a meta-analysis was performed using random-effects models to calculate the risk ratio (RR) and 95% confidence interval (CI) for the selected PSM studies.

RESULTS

Five studies involving a total of 398,687 patients with CC were included in this meta-analysis. Among 205,641 patients with RSCC, 69,091 (33.6%) died during the observation period, whereas among 193,046 patients with LSCC, 63,380 (32.8%) died during the same period. These results revealed that patients with RSCC and those with LSCC had almost the same 5-year OS (RR, 0.98; 95% CI, 0.89-1.07; p = .64; I² = 97%).

CONCLUSION

This meta-analysis has demonstrated that there was no significant difference in 5-year OS between patients with RSCC and those with LSCC after curative resection.

IMPLICATIONS FOR PRACTICE

To integrate the impact of primary tumor location (PTL) on 5-year overall survival (OS) after curative surgery, five propensity score-matching (PSM) studies involving a total of 398,687 patients with colon cancer (CC) were included in this meta-analysis. Among 205,641 patients with right-sided CC (RSCC), 69,091 (33.6%) died during the observation period, whereas among 193,046 patients with left-sided CC (LSCC), 63,380 (32.8%) died during the same period. These results revealed that patients with RSCC and those with LSCC had almost the same 5-year OS (risk ratio, 0.98; 95% confidence interval, 0.89-1.07; p = .64; I² = 97%).

Genetic predisposition and prediction protocol for epithelial neoplasms in disease-free individuals: A systematic review

Background

Epithelial neoplasm is an important global health-care problem, with high morbidity and mortality rates. Early diagnosis and appropriate treatment are essential for increased life survival. Prediction of occurrence of malignancy in a disease-free individual by any means will be a great breakthrough for healthy living.

Aims and Objectives

The aims and objectives were to predict the genetic predisposition and propose a prediction protocol for epithelial malignancy of various systems in our body, in a disease-free individual.

Methods

We have searched databases both manually and electronically, published in English language in Cochrane group, Google search, MEDLINE and PubMed from 2000 to 2019. We have included all the published, peer-reviewed, narrative reviews; randomized controlled trials; case-control studies; and cohort studies and excluded the abstract-only articles and duplicates. Specific words such as "etiological factors," "pathology and mutations," "signs and symptoms," "genetics and IHC marker," and "treatment outcome" were used for the search. A total of 1032 citations were taken, and only 141 citations met the inclusion criteria and were analyzed.

Results

After analyzing various articles, the etiological factors, clinical signs and symptoms, genes and the pathology involved and the commonly used blood and tissue markers were analyzed. A basic investigation strategy using immunohistochemistry markers was established.

Conclusion

The set of proposed biomarkers should be studied in future to predict genetic predisposition in disease-free individuals.

Unique clinicopathologic and genetic alteration features in early onset colorectal carcinoma compared with age-related colorectal carcinoma: a large cohort next generation sequence analysis

Colorectal carcinoma (CRC) is the third most common cancer type in the United States. While the incidence of CRC is decreasing among an older population undergoing screening, the incidence of early-onset CRC is rising. There is a growing understanding that the molecular underpinnings of colorectal carcinoma vary by age. In this study, we report the genetic alterations and clinicopathologic features of a single-institution colorectal carcinoma cohort over a 2-year period using a next-generation sequencing (NGS) approach and microsatellite stability (MS) status determined by immunohistochemical staining. Forty cases were identified in an early-onset colorectal carcinoma cohort (eCRC) defined by age <40 years, and 164 cases were identified in an age-related colorectal carcinoma cohort (arCRC) defined by age >70 years. eCRC was more often-left-sided/rectal and more likely to present high rates of lymph node positivity with metastatic disease. NGS mutational analysis revealed distinct differences between eCRC and arCRC, with eCRC being characterized by low frequency of PIK3CA mutations, elevated frequency of KRAS and CTNNB1 mutations in microsatellite instability high tumors, and very low frequency of BRAF mutations.

Racial disparity in survival of patients diagnosed with early-onset colorectal cancer

Background: Survival is reduced in African–Americans (AAs) diagnosed with colorectal cancer (CRC), especially in those <50 years old, when compared with Caucasian Americans (CAs). Yet, the role of clinicopathologic features of CRCs on racial differences in survival needs further study. Materials & methods: Over 1000 individuals (CA 709, AA 320) diagnosed with CRC were studied for survival via the Cox proportional hazards regression analysis based on race and risk of death in two age groups (<50 or 50+). Results: Risk of death for younger AAs (<50) was elevated compared with younger CAs (hazard ratio [HR] 1.98 [1.26–3.09]). Yet no racial differences in survival was observed in older cohort (50+ years), HR 1.07 (0.88–1.31); p for interaction = 0.01. In younger AAs versus CAs only, colonic location attenuated the risk of death. Conclusion: The tumor location and histology influence the poorer survival observed in younger AAs suggesting these may also influence treatment responses.

Adjuvant Chemotherapy after Neoadjuvant Chemotherapy and Long-term Outcomes of CAPOX Plus Bevacizumab Followed by TME for High-risk Localized Rectal Cancer

Objectives:

We previously reported the feasibility of neoadjuvant capecitabine and oxaliplatin plus bevacizumab as a treatment for locally advanced rectal cancer (UMIN000003219). The aim of this study is to investigate the prognostic relevance of neoadjuvant chemotherapy followed by total mesorectal resection (TME).

Methods:

Twenty-five patients of our prior multicenter prospective study of neoadjuvant chemotherapy followed by TME enrolled to this study. We analyzed the adjuvant chemotherapy regimen, and the duration between surgery and initial chemotherapy treatment. Five-year progression-free survival and overall survival were estimated using the Kaplan-Meier method.

Results:

Among survivors, the median follow-up time was 66 months. Recurrence occurred in six patients, all of whom had suboptimal tumor regression after neoadjuvant chemotherapy. Five patients died from other causes. The rate of local recurrence and distant metastasis was 17.4% and 8.7%, respectively. Five-year progression-free survival was 70.0%, and 5 year overall survival was 84.0%.

Conclusions:

We report the long-term survival of patients who received neoadjuvant chemotherapy without radiation followed by TME, revealing a generally favorable prognosis.

Differences in the immunosurveillance pattern associated with DNA mismatch repair status between right-sided and left-sided colorectal cancer

Tumor location and immunity play important roles in the progression of colorectal cancer (CRC). This study aimed to investigate the differences in the immunosurveillance pattern between right‐ and left‐sided CRC and analyze their association with clinicopathologic features, including mismatch repair (MMR) status. We included surgically resected stage II/III CRC cases and evaluated the immunohistochemical findings of HLA class I, HLA class II, programmed cell death‐ligand 1 (PD‐L1), PD‐1, CTLA‐4, CD3, CD4, CD8, TIA‐1, T‐bet, GATA3, RORγT, Foxp3, and CD163. A total of 117 patients were included in the analyses; of these, 30 and 87 had right‐ and left‐sided cancer, respectively. Tumor immunity varied according to the tumor location in the overall cohort. Analysis of the tumors excluding those with DNA mismatch repair (MMR) deficiency also revealed that tumor immunity differed according to the tumor location. In right‐sided colon cancer (CC), high expression of Foxp3 (P = .0055) and TIA‐1 (P = .0396) were associated with significantly better disease‐free survival (DFS). High CD8 (P = .0808) and CD3 (P = .0863) expression tended to have better DFS. Furthermore, in left‐sided CRC, only high PD‐L1 expression in the stroma (P = .0426) was associated with better DFS. In multivariate analysis, high Foxp3 expression in right‐sided CC was an independent prognostic factor for DFS (hazard ratio, 7.6445; 95% confidence interval, 1.2091‐150.35; P = .0284). In conclusion, the immunosurveillance pattern differs between right‐ and left‐sided CRC, even after adjusting for MMR deficiency.

Clinicopathological Characteristics and Mutation Spectrum of Colorectal Adenocarcinoma With Mucinous Component in a Chinese Cohort: Comparison With Classical Adenocarcinoma

Background: Colorectal adenocarcinoma with mucinous component (AWMC) is a special entity of colorectal cancer. The study is aimed at analyzing the clinicopathological characteristics, mutation spectrum, and prognosis of AWMC and comparing it with classical adenocarcinoma (AC) in a Chinese cohort. Methods: One hundred eight AMWC and 204 AC patients were included. Targeted next-generation sequencing (NGS) was performed on formalin-fixed paraffin-embedded (FFPE) tissues. AWMC was further divided into two groups: AWMC with signet ring cell component and AWMC without signet ring cell component. Clinicopathological features, mismatch repair protein (MMR) status, genetic alterations, and survival outcomes were analyzed after tumor location was taken into consideration. Results: AWMC had larger tumor size (p = 0.014) and showed predilection for proximal colon (p < 0.001) compared with AC. Regardless of primary sites, AWMC was associated with less metastasis (p < 0.001) and earlier AJCC stage (p < 0.001). Mismatch repair protein deficiency (dMMR) was more commonly detected in AWMC than in AC for right-sided colon (p < 0.001), but the difference was not significant for left-sided colon (p = 0.081). The five most commonly mutated genes in AWMC were KRAS (45.4%), TP53 (39.8%), APC (22.2%), PIK3CA (22.2%), and SMAD4 (10.2%). AWMC showed a significantly lower mutation rate of TP53 than AC, both in right-sided colon and in left-sided colon (p < 0.001 and p = 0.033, respectively). In left-sided colon, AWMC with signet ring cell component had a significantly smaller size than tumors with signet ring cell component (p = 0.034). No dMMR cases were detected in AWMC with signet ring cell component (n = 7). Moreover, AWMC with signet ring cell component had a significantly lower KRAS mutation rate than AWMC without signet ring cell component, both in right-sided colon and in left-sided colon (p = 0.036 and p = 0.012, respectively). The disease-specific survival (DSS) for AWMC and AC were not statistically different (p = 0.0587). Multivariate analysis showed that AWMC was not an independent predictor of prognosis. Conclusion: Regardless of primary sites, AWMC demonstrates less metastasis, earlier stages, more frequent dMMR, and lower TP53 mutation rate than AC. Our results indicate that different molecular pathogenesis might underlie mucinous morphology in colorectal carcinoma. Mucinous component is not an independent factor of outcome.

Contrasting Prognostic Effects of Tumor-Infiltrating Lymphocyte Density in Cardia and Non-cardia Gastric Adenocarcinomas

PURPOSE

This study sought to investigate the prognostic significance of tumor-infiltrating lymphocytes (TILs) in relation to tumor location within the stomach.

MATERIALS AND METHODS

The densities and prognostic significance of TIL subsets were evaluated in 542 gastric cancer patients who underwent gastrectomy. Immunohistochemical staining for CD3, CD4, CD8, forkhead/winged helix transcription factor (Foxp3), and granzyme B was performed.

RESULTS

Cardia cancer was associated with significantly lower densities of CD8 T-cells and higher densities of Foxp3 and granzyme B T-cells than non-cardia tumors. Multivariate analysis showed that advanced age (hazard ratio [HR], 1.023; 95% confidence interval [CI], 1.006-1.040), advanced T classification (HR, 2.029; 95% CI, 1.106-3.721), lymph node metastasis (HR, 3.319; 95% CI, 1.947-5.658), low CD3 expression (HR, 0.997; 95% CI, 0.994-0.999), and a high Foxp3/CD4 ratio (HR, 1.007; 95% CI, 1.001-1.012) were independent predictors of poor overall survival in cardia cancer patients. In non-cardia cancer patients, total gastrectomy (HR, 2.147; 95% CI, 1.507-3.059), advanced T classification (HR, 2.158; 95% CI, 1.425-3.266), lymph node metastasis (HR, 1.854; 95% CI, 1.250-2.750), and a low Foxp3/CD4 ratio (HR, 0.978; 95% CI, 0.959-0.997) were poor prognostic factors for survival.

CONCLUSIONS

The densities and prognostic effects of TILs differed in relation to the location of tumors within the stomach. The contrasting prognostic effects of Foxp3/CD4 ratio in cardia and non-cardia gastric cancer patients suggests that clinicians ought to consider tumor location when determining treatment strategies.

Screening and Identification of Differentially Expressed Genes Expressed among Left and Right Colon Adenocarcinoma

Purpose

Colon adenocarcinoma (COAD) is the third most common malignancy globally and is further categorized as left colon adenocarcinoma (LCOAD) or right colon adenocarcinoma (RCOAD) depending on the location of the primary tumor. The therapeutic outcome and long-term prognosis for patients with COAD are less than satisfactory, and this may be associated with tumor location. Therefore, it is important to investigate the genetic differences in COAD at different sites. Patients and Methods. Public data associated with COAD were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using R software (version 3.5.3), and functional annotation of DEGs was performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. A protein-protein interaction network was constructed, hub genes were identified and analyzed, and data mining using Gene Expression Profiling Interactive Analysis (GEPIA) was conducted.

Results

A total of 286 DEGs were identified between LCOAD and RCOAD. Additionally, 10 hub genes associated with COAD at different locations were screened, namely, CDKN2A, IGF1R, MDM2, SMAD3, SLC2A1, GRM5, PLCB4, FGFR1, UBE2V2, and TNFRSF10B. The expression of cyclin-dependent kinase inhibitor 2A (CDKN2A) and solute carrier family 2 member 1 (SLC2A1) was significantly associated with pathological stage (P < 0.05). COAD patients with high expression levels of CDKN2A exhibited poorer overall survival (OS) times than those with low expression levels (P < 0.05).

Conclusion

CDKN2A expression was significantly different between LCOAD and RCOAD and was closely related to the prognosis of COAD. It is of great value for further understanding of the pathogenesis of LCOAD and RCOAD.

Comparative mutational analysis of distal colon cancer with rectal cancer

Distal colon and rectal cancer are associated with each other but display distinct clinical behavior; however, the genetic basis for these differences is poorly understood. In the present study, a systematic comparison of mutational profiles between 137 distal colon and 125 rectal cancer samples was performed based on the data from the Memorial Sloan Kettering Cancer Center. Tumor mutational burden analysis showed that distal colon and rectal cancer harbored a similar burden of ~5.9 mutations/megabase, irrespective of the mismatch repair status. Comparison of significantly mutated genes between the groups determined that B-Raf proto-oncogene serine/threonine kinase mutations were enriched in distal colon cancer, whilst RAS and SMAD family member 4 (SMAD4) mutations were significantly more frequent in rectal cancer. Furthermore, two novel and potentially targetable hotspot mutations (APC regulator of WNT signaling pathway R876* and SMAD4 R361) were identified, which were enriched in rectal cancer compared with distal colon cancer. Overall, the results of the present study showed that the mutation profiles of distal colon and rectal cancer were largely similar, but distinct in specific key genetic events, which may provide valuable information for improving the management of patients with the disease.

Prognostic and predictive values of CXCL10 in colorectal cancer

BACKGROUND

The role of CXCL10 in progression and prognosis of colorectal cancer (CRC) has been studied for years, yet results remain controversial.

AIM

This study aims to explore the relationship between CXCL10 and CRC progression and prognosis.

METHODS

We evaluated plasma CXCL10 in CRC patients using ELISA. We also performed a meta-analysis of the associations between CXCL10 and overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), relapse-free survival (RFS), and clinicopathological features. Finally, correlations between CXCL10 and methylation or immune infiltration were performed using TCGA data.

RESULTS

ELISA analysis showed that CXCL10 was associated with age, red blood cells, blood platelets, and blood urea nitrogen. A separate analysis of 3,763 patients from 24 studies revealed that there were significant associations between low CXCL10 expression and OS (HR 1.25, 95% CI 1.01-1.53), DFS (HR 1.65, 95% CI 1.17-2.34), and RFS (HR 1.43, 95% CI 1.20-1.71) in CRC. Additionally, downregulated CXCL10 expression was significantly correlated with age [odds ratio (OR) 1.31, 95% CI 1.13-1.52], metastasis (OR 1.34, 95% CI 1.11-1.63), recurrence (OR 1.46, 95% CI 1.16-1.83), tumor location (OR 1.88, 95% CI 1.58-2.24), differentiation (OR 0.57, 95% CI 0.35-0.93), microsatellite instability (OR 0.23, 95% CI 0.15-0.35), BRAF mutation (OR 1.62, 95% CI 1.25-2.08), p53 mutation (OR 0.28, 95% CI 0.16-0.47), and CIMP (OR 0.27, 95% CI 0.17-0.43). Furthermore, significant associations were observed between CXCL10 and methylation and immune infiltration.

CONCLUSIONS

The study suggests that CXCL10 might be a potential target for the treatment of CRC.

TRIAL REGISTRATION

NCT03189992. Registered 4 June 2017, https://www.clinicaltrials.gov/ct2/show/study/NCT03189992?term=NCT03189992&rank=1 .

Tumor sidedness influences prognostic impact of lymph node metastasis in colon cancer patients undergoing curative surgery

This study aimed to evaluate prognostic impacts of the number of lymph nodes (LNs) examined and LN ratio on cancer-specific mortality after surgery in patients with right-sided colon cancer (RCC) or left-sided colon cancer (LCC) using the Surveillance, Epidemiology, and End Results database. Number of LNs examined and LN ratio were treated as categorical and/or continuous. Competing risks proportional hazards regressions adjusted by propensity score were performed. All included patients had stage I, II, or III disease, and 45.1% of them had RCC. RCC and LCC patients with high level of LNs examined had better prognosis after segmental resection or hemicolectomy. RCC and LCC patients with higher LN ratio had worse prognosis regardless of surgery. Survival benefit of having high level of LNs examined was observed in RCC patients with stage I, II, or III disease, but only in LCC patients with stage II disease. Both higher LN ratio and high level of LN were negative prognostic factors for cancer-specific mortality in stage III patients regardless of tumor sidedness. In conclusion, RCC patients in various conditions had worse or comparable prognosis compared to their LCC counterparts, which reflected the severity of LN metastasis.

Influence of primary tumour and patient factors on survival in patients undergoing curative resection and treatment for liver metastases from colorectal cancer

Background

Resection of the primary tumour is a prerequisite for cure in patients with colorectal cancer, but hepatic metastasectomy has been used increasingly with curative intent. This national registry study examined prognostic factors for radically treated primary tumours, including the subgroup of patients undergoing liver metastasectomy.

Methods

Patients who had radical resection of primary colorectal cancer in 2009–2013 were identified in a population‐based Swedish colorectal registry and cross‐checked in a registry of liver tumours. Data on primary tumour and patient characteristics were extracted and prognostic impact was analysed.

Results

Radical resection was registered in 20 853 patients; in 38·7 per cent of those registered with liver metastases, surgery or ablation was performed. The age‐standardized relative 5‐year survival rate after radical resection of colorectal cancer was 80·9 (95 per cent c.i. 80·2 to 81·6) per cent, and the rate after surgery for colorectal liver metastases was 49·6 (46·0 to 53·2) per cent. Multivariable analysis identified lymph node status, multiple sites of metastasis, high ASA grade and postoperative complications after resection of the primary tumour as strong risk factors after primary resection and following subsequent liver resection or ablation. Age, sex and primary tumour location had no prognostic impact on mortality after liver resection.

Conclusion

Lymph node status and complications have a negative impact on outcome after both primary resection and liver surgery. Older age and female sex were underrepresented in the liver surgical cohort, but these factors did not influence prognosis significantly.

Unique characteristics of CpG island methylator phenotype (CIMP) in a Chinese population with colorectal cancer

Background

Molecular characteristics of CpG island methylator phenotype (CIMP) in colorectal cancer (CRC) have been well documented in Western, but not in Chinese, populations.

Methods

We investigated the incidence of CIMP, BRAF/KRAS mutation, and microsatellite instability (MSI) in a Chinese population with CRC (n = 401) and analysed associations between CIMP status and clinicopathological and molecular features.

Results

A total of 41 cases, 310 cases, and 40 cases were classified as CIMP-high, CIMP-low, and CIMP-negative, respectively. We detected a significantly low incidence of BRAF mutation in adenomas (2%) and CRC (0.7%), and a relatively low incidence of KRAS mutation (24.9%) compared with that in other populations. We also detected a relatively low incidence of CIMP-high (10.2%), which was significantly associated with younger age (≤49 years of age), female sex, and proximal tumour location.

Conclusions

This study revealed unique characteristics of CIMP in a Chinese population with colorectal cancer. Developing specific CIMP markers based on unique populations or ethnic groups will further help to fully elucidate CIMP pathogenesis.

LINC00365 promotes colorectal cancer cell progression through the Wnt/β-catenin signaling pathway

In the past decade, substantial evidence established that long noncoding RNAs are serious about mediating the evolution of malignancies. In previous studies, LINC00365, which has not been reported in colorectal cancer (CRC), was selected using the bioinformatics analysis in GSE109454 and GSE41655 data sets. However, the function and mechanism of LINC00365 are still obscure. In our study, LINC00365 was found upregulated in CRC specimens and intimately connected with the prognosis of patients with CRC. In addition, LINC00365 overexpression enhances the cell abilities of proliferation, migration, and invasion in vitro. Meanwhile, mechanistic studies showed that LINC00365 might involve in CRC cell progression by mediating the Wnt/β-catenin pathway. Furthermore, LINC00365 upregulation increased CDK1 protein expression. In conclusion, this study suggests that LINC00365 acts as a vital part in facilitating CRC progression and might play as a therapeutic target for patients with CRC.

Comprehensive characterization of RAS mutations in colon and rectal cancers in old and young patients

Colorectal cancer (CRC) is increasingly appreciated as a heterogeneous disease, with factors such as microsatellite instability (MSI), cancer subsite within the colon versus rectum, and age of diagnosis associated with specific disease course and therapeutic response. Activating oncogenic mutations in KRAS and NRAS are common in CRC, driving tumor progression and influencing efficacy of both cytotoxic and targeted therapies. The RAS mutational spectrum differs substantially between tumors arising from distinct tissues. Structure-function analysis of relatively common somatic RAS mutations in G12, Q61, and other codons is characterized by differing potency and modes of action. Here we show the mutational profile of KRAS, NRAS, and the less common HRAS in 13,336 CRC tumors, comparing the frequency of specific mutations based on age of diagnosis, MSI status, and colon versus rectum subsite. We identify mutation hotspots, and unexpected differences in mutation spectrum, based on these clinical parameters.

Activating oncogenic mutations in KRAS and NRAS are common in colorectal cancer, which is a heterogenous disease. Here, the authors show that the RAS mutation spectrum is markedly different between colon and rectal cancer, and also different based on age of diagnosis and microsatellite instability.

MicroRNA 32 promotes cell proliferation, migration, and suppresses apoptosis in colon cancer cells by targeting OTU domain containing 3

Colorectal cancer is considered as the fourth leading reason of cancer-linked deaths worldwide. However, our knowledge about its pathogenic mechanism remains inadequate. MicroRNA 32 (miR-32), a member of small noncoding RNAs, has been found vital roles in tumorigenesis. This study studied its functions and underlying mechanism in colorectal cancer. The experiment revealed the obvious upregulation of miR-32 in colorectal cancer tissues and six cancer cell lines, compared with normal tissues and cells. Moreover, miR-32 upregulation reduced cell apoptosis and promoted cell proliferation and migration, while its downregulation displayed opposite effects. Dual luciferase reporter assays proved that miR-32 bound to the 3'-untranslated region (3'-UTR) of OTU domain containing 3 (OTUD3), suggesting that miR-32 directly targeted OTUD3. Further experiments demonstrated that overexpression of miR-32 could reduce the expression level of OTUD3. Furthermore, OTUD3 silence promoted proliferation and motility and decreased apoptosis for HCT116 cells and restored partly miR-32-mediated cell proliferation, migration, and antiapoptosis for colon cancer. Therefore, our study indicated that miR-32 enhanced cell proliferation and motility abilities, and inhibited apoptosis by directly targeting OTUD3 in colon cancer cells, which implied that miR-32 was hopeful to be a biomarker or target used for diagnosis and therapy of colon cancer.

Impact of primary colorectal Cancer location on the KRAS status and its prognostic value

BACKGROUND

Colorectal cancer (CRC) originating from the right-sided or left-sided colon is distinct clinicopathological entity. The KRAS status and its prognostic value in CRC remain controversial. This study aimed to investigate the association of KRAS status with clinicopathological features and prognostic value in CRC.

METHODS

178 colon cancer and 145 rectal cancer patients were enrolled. KRAS mutation test was performed on paraffin-embedded tumor samples using PCR methods. The colon cancer was divided into right-sided colon cancer (RCC) and left-sided colon cancer (LCC). Studies that reported the association of KRAS mutation with CRC clinical features and prognosis in databases were searched prior to 2018. The data of the present study was combined with the data of published studies using meta-analysis methods.

RESULTS

No significant difference between colon cancer and rectal cancer regarding the KRAS status. The KRAS mutation was much frequent in RCC than in LCC (p = 0.010). 17 studies with 11,385 colon cancer patients were selected, the pooled results of our data and previous published data showed that KRAS mutation was more frequent in RCC compared with in LCC (p < 0.01); KRAS mutation was not associated with the prognosis in RCC patient; however, KRAS mutation indicated a poor prognosis in LCC patients compared with KRAS wild type (p < 0.01).

CONCLUSION

KRAS status has no difference between colon cancer and rectal cancer. KRAS mutation was more frequent in RCC than in LCC, and associated with a poor prognosis in LCC patients, but not in RCC patients.

Mechanisms of PTEN loss in cancer: It's all about diversity

PTEN is a phosphatase which metabolises PIP₃, the lipid product of PI 3-Kinase, directly opposing the activation of the oncogenic PI3K/AKT/mTOR signalling network. Accordingly, loss of function of the PTEN tumour suppressor is one of the most common events observed in many types of cancer. Although the mechanisms by which PTEN function is disrupted are diverse, the most frequently observed events are deletion of a single gene copy of PTEN and gene silencing, usually observed in tumours with little or no PTEN protein detectable by immunohistochemistry. Accordingly, with the exceptions of glioblastoma and endometrial cancer, mutations of the PTEN coding sequence are uncommon (<10%) in most types of cancer. Here we review the data relating to PTEN loss in seven common tumour types and discuss mechanisms of PTEN regulation, some of which appear to contribute to reduced PTEN protein levels in cancers.

Laparoscopic approach for left-sided T4 colon cancer is a safe and feasible procedure, compared to open surgery

BACKGROUND

A laparoscopic approach can be attempted for pathologic T4 (pT4) colon cancer. Our aim was to evaluate the clinico-oncologic outcomes following laparoscopic versus open surgery for right and left-sided pT4 colon cancer.

METHODS

From a multicentric collaborative database, we enrolled 245 patients with right-sided colon cancer (RCC, 128 laparoscopy and 117 open) and 338 with left-sided colon cancer (LCC, 176 laparoscopy and 162 open). All patients underwent intended curative surgery for histologically proven T4 adenocarcinoma, between 2004 and 2013. The primary end-point of our analysis was the oncologic outcome, including the 5-year disease-free survival (5 year-DFS) and the 5-year overall survival (5 year-OS). The secondary end-points included the R0 resection rate and postoperative complications.

RESULTS

Our study group included 224 T4N0 and 359 T4N+ tumors. The median follow-up was 53 months. For patients with RCC, the rate of postoperative morbidities was lower for the laparoscopy than that for the open surgery group (12.5 vs. 22.2%, p = 0.044). There was no difference in the R0 resection rate (94.5 vs. 96.6%, p = 0.425) between the groups. The 5 year-DFS and 5 year-OS rates were lower for the laparoscopy than that in the open group (48.9% vs. 59.2%, p = 0.093; 60.0% vs. 70.0%, p = 0.284, respectively), but this difference was not statistically significant. Among patients with LCC, there were no differences in the rate of postoperative complication and R0 resection (15.3 vs. 21.0%, p = 0.307; 96.0 vs. 95.7%, p = 0.875, respectively). Both groups had comparable 5 year-DFS and 5 year-OS rates (62.7% vs. 61.1%, p = 0.552; 72.0% vs. 71.8%, p = 0.611, respectively).

CONCLUSIONS

Laparoscopic surgery appears to be a safe procedure for patients with pT4 LCC, but requires careful consideration for patients with pT4 RCC.

Brain metastases in colorectal cancer: prognostic factors and survival analysis

PURPOSE

Colorectal cancer (CRC) brain metastases (BM) are an uncommon and late event. We aim to investigate the impact of clinical factors, treatment modalities and RAS/BRAF status on the outcomes of CRC patients with BM.

PATIENTS

We retrospectively analysed CRC patients who developed BM in our centre between January 1997 and June 2017. Clinical factors, treatment modalities, RAS/BRAF status and survival were evaluated.

RESULTS

Twenty-eight patients were recorded; 82% had left-sided (LS) CRC and 71% had lung metastases. Median time to BM diagnosis was 36 months (m) and 93% of patients received local treatment of BM (43% whole brain radiotherapy, 50% surgery). Right-sided (RS) CRC showed shorter time to BM, not previously described (9.3 vs 46.6 m for RS and LS CRC, respectively; HR = 4.7, p = 0.006). Median overall survival (mOS) from BM treatment was 9.5 m, better in patients who underwent surgery than those treated with radiotherapy alone (12.1 vs 4.6 m, respectively; HR = 0.3, p = 0.019) and in those without progressive metastatic extracranial disease (7.2 vs 20.9 m, for progressive and non-progressive, respectively; HR = 0.3, p = 0.056). Patients with two or more metastatic extracranial locations showed worse prognosis (5.9 vs 16.3 m, for > 2 vs 0-1, respectively; HR = 3.7, p = 0.015). RAS/BRAF status did not showed prognostic value.

CONCLUSIONS

Time to BM diagnosis is shorter in RS CRC. The presence of two or more metastatic extracranial locations and progressive metastatic extracranial disease at the time of BM diagnosis could be bad prognosis factors for CRC BM patients.

LncRNA DLEU1 contributes to colorectal cancer progression via activation of KPNA3

Background

Accumulating evidences show that long noncoding RNAs (lncRNA) play essential roles in the development and progression of various malignancies. However, their functions remains poorly understood and many lncRNAs have not been defined in colorectal cancer (CRC). In this study, we investigated the role of DLEU1 in CRC.

Methods

Quantitative real-time PCR was used to detect the expression of DLEU1 and survival analysis was adopted to explore the association between DLEU1 expression and the prognosis of CRC patients. CRC cells were stably transfected with lentivirus approach and cell proliferation, migration, invasion and cell apoptosis, as well as tumorigenesis in nude mice were performed to assess the effects of DLEU1 in BCa. Biotin-coupled probe pull down assay, RNA immunoprecipitation and Fluorescence in situ hybridization assays were conducted to confirm the relationship between DLEU1 and SMARCA1.

Results

Here we revealed that DLEU1 was crucial for activation of KPNA3 by recruiting SMARCA1, an essential subunit of the NURF chromatin remodeling complex, in CRC. DLEU1 was indispensible for the deposition of SMARCA1 at the promoter of KPNA3 gene. Increased expression of DLEU1 and KPNA3 was observed in human CRC tissues. And higher expression of DLEU1 or KPNA3 in patients indicates lower survival rate and poorer prognosis. DLEU1 knockdown remarkably inhibited CRC cell proliferation, migration and invasion in vitro and in vivo while overexpressing KPNA3 in the meantime reversed it.

Conclusions

Our results identify DLEU1 as a key regulator by a novel DLEU1/SMARCA1/KPNA3 axis in CRC development and progression, which may provide a potential biomarker and therapeutic target for the management of CRC.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0873-2) contains supplementary material, which is available to authorized users.

Difference between right and left colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant tumors around the world. The incidence of CRC has increasing, but the prognosis is quite different. In recent years, the impact of tumor site on the treatment and prognosis of CRC has attracted widespread attention, and the research for differences between tumors provides a theoretical basis for precise treatment. This review aims to summarize the difference between right and left CRC.

First Biologic Drug in the Treatment of RAS Wild-Type Metastatic Colorectal Cancer: Anti-EGFR or Bevacizumab? Results From a Meta-Analysis

Introduction: We performed a meta-analysis in order to analyze and quantify the effect on survival of starting therapy in RAS wild-type (wt) metastatic colorectal cancer (mCRC) patients with anti-EGFR agents or bevacizumab.

Patients and Methods: Randomized, phase II or III, clinical trials reporting overall survival (OS) in RAS wt mCRC patients treated with first-line chemotherapy (CT) associated with bevacizumab or anti-EGFR agents were selected. The primary end-point of this meta-analysis was OS; findings were depicted in classical Forest plots.

Results: Seven studies met the criteria for meta-analysis including 3,805 patients. The pooled second-line cross-over rate to bevacizumab was 36.6%, to anti-EGFR 33.2%. Only one study was selected reporting comparison between CT vs. CT plus bevacizumab in RAS wt patients with a HR of 1.13 in favor of CT (CI: 0.89–1.43, p = 0.317). The pooled HRs were 0.89 (95% CI: 0.79–1.00) for CT plus anti-EGFR vs. CT and 0.81 (95% CI: 0.71–0.92) in favor of CT plus anti-EGFR vs. CT plus bevacizumab. Subgroup analysis showed a positive prognostic impact of starting CT plus anti-EGFR in left colon cancer (pooled HR: 0.70; CI: 0.54–0.85) while a positive trend of starting CT plus bevacizumab was observed in right colon cancer (pooled HR: 1.29; CI: 0.81–1.77).

Conclusions: This meta-analysis shows that starting therapy in RAS wt mCRC patients with an anti-EGFR agent improves OS when the primary tumor location is in the left colon but a strong limitation of previous studies is the very low rate of biologic drug therapy cross-over.

Challenging a dogma: five-year survival does not equal cure in all colorectal cancer patients

BACKGROUND

The current study tried to evaluate the factors affecting 10- to 20- years' survival among long term survivors (>5 years) of colorectal cancer (CRC).

METHODS

Surveillance, Epidemiology and End Results (SEER) database (1988-2008) was queried through SEER*Stat program.Univariate probability of overall and cancer-specific survival was determined and the difference between groups was examined. Multivariate analysis for factors affecting overall and cancer-specific survival was also conducted.

RESULTS

Among node positive patients (Dukes C), 34% of the deaths beyond 5 years can be attributed to CRC; while among M1 patients, 63% of the deaths beyond 5 years can be attributed to CRC. The following factors were predictors of better overall survival in multivariate analysis: younger age, white race (versus black race), female gender, Right colon location (versus rectal location), earlier stage and surgery (P <0.0001 for all parameters). Similarly, the following factors were predictors of better cancer-specific survival in multivariate analysis: younger age, white race (versus black race), female gender, Right colon location (versus left colon and rectal locations), earlier stage and surgery (P <0.0001 for all parameters).

CONCLUSION

Among node positive long-term CRC survivors, more than one third of all deaths can be attributed to CRC.