BRAF Mutated Colorectal Cancer: New Treatment Approaches

The Influence of Betulin and Its Derivatives on Selected Colorectal Cancer Cell Lines' Viability and Their Antioxidant Systems

Oxidative stress is considered one of the main reasons for the development of colorectal cancer (CRC). Depending on the stage of the disease, variable activity of the main antioxidant enzymes, i.e., superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), is observed. Due to limited treatment methods for CRC, new substances with potential antitumor activity targeting pathways related to oxidative stress are currently being sought, with substances of natural origin, including betulin, leading the way. The betulin molecule is chemically modified to obtain new derivatives with improved pharmacokinetic properties and higher biological activity. The aim of this study was to evaluate the effects of betulin and its new derivatives on viability and major antioxidant systems in colorectal cancer cell lines. The study showed that betulin and its derivative EB5 affect the antioxidant enzyme activity to varying degrees at both the protein and mRNA levels. The SW1116 cell line is more resistant to the tested compounds than RKO, which may be due to differences in the genetic and epigenetic profiles of these lines.

High Probability of Lynch Syndrome Among Colorectal Cancer Patients Is Associated With Higher Occurrence of KRAS and PIK3CA Mutations

Background

In Indonesia, early-onset colorectal cancer (EOCRC) rates are higher in patients < 50 years old compared to Western populations, possibly due to a higher frequency of Lynch syndrome (LS) in CRC patients. We aimed to examine the association of KRAS and PIK3CA mutations with LS.

Methods

In this retrospective cross-sectional single-center study, the PCR-HRM-based test was used for screening of microsatellite instability (MSI) mononucleotide markers (BAT25, BAT26, BCAT25, MYB, EWSR1), MLH1 promoter methylation, and oncogene mutations of BRAF (V600E), KRAS (exon 2 and 3), and PIK3CA (exon 9 and 20) in FFPE DNA samples.

Results

All the samples (n = 244) were from Dr. Sardjito General Hospital Yogyakarta, Indonesia. KRAS and PIK3CA mutations were found in 151/244 (61.88%) and 107/244 (43.85%) of samples, respectively. KRAS and PIK3CA mutations were significantly associated with MSI status in 32/42 (76.19%) and 25/42 (59.52%) of samples, respectively. KRAS mutation was significantly associated with LS status in 26/32 (81.25%) of samples. The PIK3CA mutation was present in a higher proportion in LS samples of 19/32 (59.38%), but not statistically significant. Clinicopathology showed that KRAS mutation was significantly associated with right-sided CRC and higher histology grade in 39/151 (25.83%) and 24/151 (16.44%) samples, respectively. PIK3CA mutation was significantly associated with female sex and lower levels of tumor-infiltrating lymphocytes in 62/107 (57.94%) and 26/107 (30.23%) samples, respectively. KRAS and PIK3CA mutations did not significantly affect overall survival (120 months) in LS and non-LS patients.

Conclusions

The high probability of LS in Indonesian CRC patients is associated with KRAS and PIK3CA mutations.

Isovaleryl Sucrose Esters from Atractylodes japonica and Their Cytotoxic Activity

Cancer represents one of the most significant health challenges currently facing humanity, and plant-derived antitumour drugs represent a prominent class of anticancer medications in clinical practice. Isovaleryl sucrose esters, which are natural constituents, have been identified as having potential antitumour effects. However, the mechanism of action remains unclear. In this study, 12 isovaleryl sucrose ester components, including five new (1-5) and seven known compounds (6-12), were isolated from the roots of Atractylodes japonica. The structures of the compounds were elucidated using 1D and 2D-NMR spectroscopy, complemented by HR-ESI-MS mass spectrometry. The cytotoxic activities of all the compounds against human colon cancer cells (HCT-116) and human lung adenocarcinoma cells (A549) were also evaluated using the CCK8 assay. The results demonstrated that compounds 2, 4, and 6 were moderately inhibitory to HCT-116 cells, with IC50 values of 7.49 ± 0.48, 9.03 ± 0.21, and 13.49 ± 1.45 μM, respectively. Compounds 1 and 6 were moderately inhibitory to A549, with IC50 values of 8.36 ± 0.77 and 7.10 ± 0.52 μM, respectively. Molecular docking revealed that compounds 1-9 exhibited a stronger affinity for FGFR3 and BRAF, with binding energies below -7 kcal/mol. Compound 2 exhibited the lowest binding energy of -10.63 kcal/mol to FGFR3. We screened the compounds with lower binding energies, and the protein-ligand complexes already obtained after molecular docking were subjected to exhaustive molecular dynamics simulation experiments, which simulated the dynamic behaviour of the molecules in close proximity to the actual biological environment, thus providing a deeper understanding of their functions and interaction mechanisms. The present study provides a reference for the development and use of iso-valeryl sucrose esters in the antitumour field.

Colorectal cancer: a comprehensive review of carcinogenesis, diagnosis, and novel strategies for classified treatments

Colorectal cancer is the third most common and the second deadliest cancer worldwide. To date, colorectal cancer becomes one of the most important challenges of the health system in many countries. Since the clinical symptoms of this cancer appear in the final stages of the disease and there is a significant golden time between the formation of polyps and the onset of cancer, early diagnosis can play a significant role in reducing mortality. Today, in addition to colonoscopy, minimally invasive methods such as liquid biopsy have received much attention. The treatment of this complex disease has been mostly based on traditional treatments including surgery, radiotherapy, and chemotherapy; the high mortality rate indicates a lack of success for current treatment methods. Moreover, disease recurrence is another problem of traditional treatments. Recently, new approaches such as targeted therapy, immunotherapy, and nanomedicine have opened new doors for cancer treatment, some of which have already entered the market, and many methods have shown promising results in clinical trials. The success of immunotherapy in the treatment of refractory disease, the introduction of these methods into neoadjuvant therapy, and the successful results in tumor shrinkage without surgery have made immunotherapy a tough competitor for conventional treatments. It seems that the combination of those methods with such targeted therapies will go through promising changes in the future of colorectal cancer treatment.

Evaluation of the Immunohistochemical Scoring System of CDX2 Expression as a Prognostic Biomarker in Colon Cancer

Encoded by the CDX2 homeobox gene, the CDX2 protein assumes the role of a pivotal transcription factor localized within the nucleus of intestinal epithelial cells, orchestrating the delicate equilibrium of intestinal physiology while intricately guiding the precise development and differentiation of epithelial tissue. Emerging research has unveiled that positive immunohistochemical expression of this protein shows that the CDX2 gene exerts a potent suppressive impact on tumor advancement in colorectal cancer, impeding the proliferation and distant dissemination of tumor cells, while the inhibition or suppression of CDX2 frequently correlates with aggressive behavior in colorectal cancer. In this study, we conducted an immunohistochemical assessment of CDX2 expression on a cohort of 43 intraoperatively obtained tumor specimens from patients diagnosed with colon cancer at Colțea Clinical Hospital in Bucharest, between April 2019 and December 2023. Additionally, we shed light on the morphological diversity within colon tumors, uncovering varying differentiation grades within the same tumor, reflecting the variations in CDX2 expression as well as the genetic complexity underlying these tumors. Based on the findings, we developed an innovative immunohistochemical scoring system that addresses the heterogeneous nature of colon tumors. Comprehensive statistical analysis of CDX2 immunohistochemical expression unveiled significant correlations with known histopathological parameters such as tumor differentiation grades (p-value = 0.011) and tumor budding score (p-value = 0.002), providing intriguing insights into the complex involvement of the CDX2 gene in orchestrating tumor progression through modulation of differentiation processes, and highlighting its role in metastatic predisposition. The compelling correlation identified between CDX2 expression and conventional histopathological parameters emphasizes the prognostic significance of the CDX2 biomarker in colon cancer. Moreover, our novel immunohistochemical scoring system reveals a distinct subset of colon tumors exhibiting reserved prognostic outcomes, distinguished by their "mosaic" CDX2 expression pattern.

Variation in KRAS/NRAS/BRAF-Mutation Status by Age, Sex, and Race/Ethnicity Among a Large Cohort of Patients with Metastatic Colorectal Cancer (mCRC)

BACKGROUND

Racial/ethnic disparities in metastatic colorectal cancer (mCRC) survival are well documented as is the impact that tumor mutation of KRAS and BRAF has on prognosis. It has been suggested that frequency differences of KRAS- and BRAF-mutated tumors may partially explain this disparity. Demographic differences in mutation frequency are not well established nor whether mutation and microsatellite instability (MSI) differentially impact survival among groups.

METHODS

Using data for 11,117 patients diagnosed with de-novo mCRC from an electronic health record-derived database we estimated adjusted odds ratios (aOR) to characterize the association between demographics and MSI and KRAS/NRAS/BRAF-mutation status. Stratified Cox models were used to identify differences in overall survival (OS), adjusting for treatment and demographics.

RESULTS

Being female, compared to male, (aORKRAS:1.33 (1.23-1.44); aORBRAF:1.84 (1.56-2.16)), and non-Hispanic Black race (NHB), compared to non-Hispanic White (NHW) (aORKRAS:1.62 (1.42-1.85); aORBRAF: 0.55 (0.38-0.77)) were associated with KRAS- or BRAF-mutant tumors. MSI prevalence was similar across race/ethnicity but higher in women. BRAF-mutant tumors were associated with poorer prognosis overall, especially among non-white patients. Among patients who had KRAS/NRAS/BRAF-WT tumors we observed no difference in OS by race or MSI. Among patients with KRAS-mutant tumors, Hispanic patients had more favorable prognosis adjusted hazards ratio (aHR) = 0.76 (0.65-0.89)) than their NHW counterparts. Among those with BRAF-mutant tumors, NHB patients had poorer prognosis than NHW patients (aHR:1.78 (1.08-2.93)).

CONCLUSION

MSI and frequency of KRAS and BRAF mutations differed by demographics. Racial/ethnic disparities in OS differed by mutation. Future studies should explore biological and/or social determinants underlying these differences.

The Clinical, Genomic, and Transcriptomic Landscape of BRAF Mutant Cancers

BACKGROUND

BRAF mutations are classified into four molecularly distinct groups, and Class 1 (V600) mutant tumors are treated with targeted therapies. Effective treatment has not been established for Class 2/3 or BRAF Fusions. We investigated whether BRAF mutation class differed according to clinical, genomic, and transcriptomic variables in cancer patients.

METHODS

Using the AACR GENIE (v.12) cancer database, the distribution of BRAF mutation class in adult cancer patients was analyzed according to sex, age, primary race, and tumor type. Genomic alteration data and transcriptomic analysis was performed using The Cancer Genome Atlas.

RESULTS

BRAF mutations were identified in 9515 (6.2%) samples among 153,834, with melanoma (31%), CRC (20.7%), and NSCLC (13.9%) being the most frequent cancer types. Class 1 harbored co-mutations outside of the MAPK pathway (TERT, RFN43) vs. Class 2/3 mutations (RAS, NF1). Across all tumor types, Class 2/3 were enriched for alterations in genes involved in UV response and WNT/β-catenin. Pathway analysis revealed enrichment of WNT/β-catenin and Hedgehog signaling in non-V600 mutated CRC. Males had a higher proportion of Class 3 mutations vs. females (17.4% vs. 12.3% q = 0.003). Non-V600 mutations were generally more common in older patients (aged 60+) vs. younger (38% vs. 15% p < 0.0001), except in CRC (15% vs. 30% q = 0.0001). Black race was associated with non-V600 BRAF alterations (OR: 1.58; p < 0.0001).

CONCLUSIONS

Class 2/3 BRAFs are more present in Black male patients with co-mutations outside of the MAPK pathway, likely requiring additional oncogenic input for tumorigenesis. Improving access to NGS and trial enrollment will help the development of targeted therapies for non-V600 BRAF mutations.

p53-armed oncolytic adenovirus induces autophagy and apoptosis in KRAS and BRAF-mutant colorectal cancer cells

Colorectal cancer (CRC) cells harboring KRAS or BRAF mutations show a more-malignant phenotype than cells with wild-type KRAS and BRAF. KRAS/BRAF-wild-type CRCs are sensitive to epidermal growth factor receptor (EGFR)-targeting agents, whereas KRAS/BRAF-mutant CRCs are resistant due to constitutive activation of the EGFR-downstream KRAS/BRAF signaling pathway. Novel therapeutic strategies to treat KRAS/BRAF mutant CRC cells are thus needed. We recently demonstrated that the telomerase-specific replication-competent oncolytic adenoviruses OBP-301 and p53-armed OBP-702 exhibit therapeutic potential against KRAS-mutant human pancreatic cancer cells. In this study, we evaluated the therapeutic potential of OBP-301 and OBP-702 against human CRC cells with differing KRAS/BRAF status. Human CRC cells with wild-type KRAS/BRAF (SW48, Colo320DM, CACO-2), mutant KRAS (DLD-1, SW620, HCT116), and mutant BRAF (RKO, HT29, COLO205) were used in this study. The antitumor effect of OBP-301 and OBP-702 against CRC cells was analyzed using the XTT assay. Virus-mediated modulation of apoptosis, autophagy, and the EGFR-MEK-ERK and AKT-mTOR signaling pathways was analyzed by Western blotting. Wild-type and KRAS-mutant CRC cells were sensitive to OBP-301 and OBP-702, whereas BRAF-mutant CRC cells were sensitive to OBP-702 but resistant to OBP-301. Western blot analysis demonstrated that OBP-301 induced autophagy and that OBP-702 induced autophagy and apoptosis in human CRC cells. In BRAF-mutant CRC cells, OBP-301 and OBP-702 suppressed the expression of EGFR, MEK, ERK, and AKT proteins, whereas mTOR expression was suppressed only by OBP-702. Our results suggest that p53-armed oncolytic virotherapy is a viable therapeutic option for treating KRAS/BRAF-mutant CRC cells via induction of autophagy and apoptosis.

BRAF Inhibitors in Metastatic Colorectal Cancer and Mechanisms of Resistance: A Review of the Literature

Metastatic colorectal cancer (mCRC) with mutated BRAF exhibits distinct biological and molecular features that set it apart from other subtypes of CRC. Current standard treatment for these tumors involves a combination of chemotherapy (CT) and VEGF inhibitors. Recently, targeted therapy against BRAF and immunotherapy (IT) for cases with microsatellite instability (MSI) have been integrated into clinical practice. While targeted therapy has shown promising results, resistance to treatment eventually develops in a significant portion of responsive patients. This article aims to review the available literature on mechanisms of resistance to BRAF inhibitors (BRAFis) and potential therapeutic strategies to overcome them.

Classification of patients with metastatic colorectal cancer into consensus molecular subtypes into real-world: A pilot study

BACKGROUND

Colorectal cancer is a complex disease with high mortality rates. Over time, the treatment of metastatic colorectal cancer (mCRC) has gradually improved due to the development of modern chemotherapy and targeted therapy regimens. However, due to the inherent heterogeneity of this condition, identifying reliable predictive biomarkers for targeted therapies remains challenging. A recent promising classification system-the consensus molecular subtype (CMS) system-offers the potential to categorize mCRC patients based on their unique biological and molecular characteristics. Four distinct CMS categories have been defined: immune (CMS1), canonical (CMS2), metabolic (CMS3), and mesenchymal (CMS4). Nevertheless, there is currently no standardized protocol for accurately classifying patients into CMS categories. To address this challenge, reverse transcription polymerase chain reaction (RT-qPCR) and next-generation genomic sequencing (NGS) techniques may hold promise for precisely classifying mCRC patients into their CMSs.

AIM

To investigate if mCRC patients can be classified into CMS categories using a standardized molecular biology workflow.

METHODS

This observational study was conducted at the University of Chile Clinical Hospital and included patients with unresectable mCRC who were undergoing systemic treatment with chemotherapy and/or targeted therapy. Molecular biology techniques were employed to analyse primary tumour samples from these patients. RT-qPCR was utilized to assess the expression of genes associated with fibrosis (TGF-β and β-catenin) and cell growth pathways (c-MYC). NGS using a 25-gene panel (TumorSec) was performed to identify specific genomic mutations. The patients were then classified into one of the four CMS categories according to the clinical consensus of a Tumour Board. Informed consent was obtained from all the patients prior to their participation in this study. All techniques were conducted at University of Chile.

RESULTS

Twenty-six patients were studied with the techniques and then evaluated by the Tumour Board to determine the specific CMS. Among them, 23% (n = 6), 19% (n = 5), 31% (n = 8), and 19% (n = 5) were classified as CMS1, CMS2, CMS3, and CMS4, respectively. Additionally, 8% of patients (n = 2) could not be classified into any of the four CMS categories. The median overall survival of the total sample was 28 mo, and for CMS1, CMS2, CMS3 and CMS4 it was 11, 20, 30 and 45 mo respectively, with no statistically significant differences between groups.

CONCLUSION

A molecular biology workflow and clinical consensus analysis can be used to accurately classify mCRC patients. This classification process, which divides patients into the four CMS categories, holds significant potential for improving research strategies and targeted therapies tailored to the specific characteristics of mCRC.

BRAF Non-V600 Mutations in Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Despite advancements in detection and therapeutic options, patients with metastatic CRC continue to face poor survival rates. The heterogeneity of oncogenic alterations, including BRAF mutations, poses a substantial challenge in identifying optimal treatment approaches. Notably, BRAF non-V600 mutations, encompassing class II and class III mutations, exhibit the distinct patterns of the signaling pathways and responses to targeted therapies compared to BRAF V600 mutations (class I). Nevertheless, the current classification system may underestimate the complexity and heterogeneity of BRAF-mutant CRC. Ongoing clinical trials are actively investigating targeted therapies for BRAF non-V600 mutations, but they are being confronted with patient recruitment obstacles due to the genetic diversity of these alterations. Continued research is needed to refine mutation subtyping, identify effective treatment strategies, and improve outcomes for patients with BRAF non-V600-mutant CRC. Enhancing our understanding and management of this specific subgroup of CRC is crucial for developing personalized treatment approaches and advancing patient care. This manuscript provides a comprehensive overview of the recent advances in and perspectives on BRAF non-V600 alterations in colorectal cancer, including relevant ongoing clinical trials.

Clinical, Pathological and Molecular Insights on KRAS, NRAS, BRAF, PIK3CA and TP53 Mutations in Metastatic Colorectal Cancer Patients from Northeastern Romania

Mutations in RAS, BRAF, PIK3CA, and TP53 are well-established genetic abnormalities in metastatic colorectal cancer (mCRC). However, limited information is available for patients from Eastern Europe, including Romania. In this retrospective analysis, we investigated 104 mCRC patients from the Northeastern region of Romania to determine the frequency, distribution, coexistence, and clinicopathological and molecular correlations of these mutations. TP53 was the most frequently mutated gene (73.1%), followed by KRAS (45.2%) and PIK3CA (6.7%). Patients with KRAS mutant tumors and wild-type TP53 genotype were found to have no personal history of gastrointestinal cancer (p = 0.02, p = 0.007). KRAS mutations in exon 3 were associated with the female gender (p = 0.02) and the absence of lymph node invasion (p = 0.02). PIK3CA mutations were linked to the absence of lymph node invasion (p = 0.006). TP53 mutations were associated with KRAS mutations in exon 2 (p = 0.006), ulcerated histopathologic type (p = 0.04), and G2 differentiation (p = 0.01). It provides novel insights into genetic variations specific to the population from Northeastern Romania, which has been underrepresented in previous studies within Eastern Europe. Furthermore, our findings enable the development of genetic profiles in a developing country with limited access to specialized genetic tests and facilitate comparisons with other populations.

The role of curcumin on apoptosis and NLRP3 inflammasome-dependent pyroptosis on colorectal cancer in vitro

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers worldwide. Many factors such as stress, lifestyle, and dietary habits are known to play a role in the initiation and progression of the disease. Herbal therapeutic agents including curcumin can hold a great potential against cancer treatment; however, their efficacy on CRC is still under investigation. Herein, we evaluated the anticancer mechanism of curcumin on four different CRC cell lines.

METHODS

Cells were treated with curcumin for 24, 48 and 72 h, and IC50 doses for each cell line were calculated. Mechanistic studies were conducted with the lowest IC50 dose determined for each cell line by evaluating apoptosis and necrosis, cell division, and NLRP3-mediated pyroptosis.

RESULTS

Curcumin treatment significantly decreased viability while increasing the SubG1 phase in all cell lines tested, indicating apoptosis is the main programmed cell death pathway activated upon curcumin treatment in CRC. In terms of pyroptosis, components of NLRP3 inflammasome were found to be elevated in SW480 and HCT116 cell lines, although to a lesser extent in the latter, and NLRP3 inflammasome activation was not observed in LoVo and HT29 cells.

DISCUSSION

Our results reveal that while curcumin effectively induces apoptosis, its effects on NLRP3-inflammasome mediated pyroptosis vary. Our results underline the need for further research focusing on the other inflammasome complexes to confirm the differential effects of curcumin on CRC.

Novel heavily fucosylated glycans as a promising therapeutic target in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is highly prevalent and lethal globally, and its prognosis remains unsatisfactory. Drug resistance is regarded as the main cause of treatment failure leading to tumor recurrence and metastasis. The overexpression of fucosylated epitopes, which are usually modifications of glycoproteins, was reported to occur in various epithelial cancers. However, the effects of treatments that target these antigens in colorectal cancer remain unclear.

METHODS

This study investigated the expression of heavily fucosylated glycans (HFGs) in 30 clinical samples from patients with CRC and other normal human tissues. The complement-dependent cytotoxicity was explored in vitro through treatment with anti-HFG monoclonal antibody (mAb) alone or in combination with chemotherapeutic agents. In vivo inhibitory effects were also examined using a xenograft mouse model.

RESULTS

Immunohistochemistry staining and western blotting revealed that HFG expression was higher in human colorectal cancer tissues than in normal tissues. In DLD-1 and SW1116 cells, which overexpress fucosylated epitopes, anti-HFG mAb produced observable cytotoxic effects, especially when it was combined with chemotherapeutic agents. The xenograft model also demonstrated that anti-HFG mAb had potent and dose-dependent inhibitory effects on colorectal tumor growth.

CONCLUSIONS

As a novel cancer antigen, HFGs are a promising treatment target, and the implementation of anti-HFG mAb treatment for CRC warrants further investigation.

Biomarker testing in colorectal cancer

Christopher Lieu, co-director of gastrointestinal medical oncology and the associate director for clinical research at the University of Colorado Cancer Center (Aurora, CO, USA) discusses the importance of biomarker testing in metastatic colorectal cancer to inform personalized patient care.

Microsatellite Instability with BRAF V600E Associated with Delayed Presentation but Poor Survival in Stage III Colorectal Cancer

Colorectal cancer (CRC) has tremendous molecular and genetic heterogeneity, making it a difficult cancer to treat. Two of the key prognostic indicators of CRC include microsatellite instability (MSI) and BRAF V600E mutation. Here, we performed a retrospective survival analysis on 145 stage II and III CRC patients treated at the University of Kansas Cancer Center between 2009 and 2020. Of the 145 patients, BRAF V600E was observed in 15% patients and MSI in 28% patients. Median survival was not reached for stage II. For stage III, patients with BRAF V600E showed poor overall survival, which worsened with concurrent presence of MSI [χ2=6.4, p=0.01]. Eighty-five percent of this group was found to have right-sided CRC. For stage III, overall survival (OS) was 27 months, 37 months, 87 months and not reached for MSI-H/BRAF V600E, MSS/BRAF V600E, MSS/BRAF WT and MSI-H/BRAF WT, respectively. Although associated with poor prognosis, presence of MSI in BRAF V600E patients was associated with delayed disease presentation (mean age 77) compared to those with stable microsatellite (mean age 63) [p=0.01]. Although median survival between the groups could not be assessed for stage II due to very few deaths and/or inadequate length of study, comparison of survival trend suggests that BRAF V600E, rather than MSI, is what drives prognosis in stage II CRC. Our findings suggest that prognostic value of MSI is more relevant for stage III than stage II CRC. Patients with MSI-H and BRAF V600E have advantage of late presentation, although at the cost of poor overall prognosis.

Endoscopic polypectomy for malignant polyps: Should tumor location (right versus left side) guide clinical decisions?

BACKGROUND

Current guidelines consider endoscopic resection appropriate treatment for malignant colon polyps with negative margins, low-grade histology, and no lymphovascular invasion. While increasing literature demonstrates a worse prognosis for advanced stage right- versus left-sided colon cancers after curative treatment, there is paucity of data regarding prognostic effect of location in patients undergoing endoscopic resection of T1 polyps. We hypothesized the more aggressive biologic behavior observed in advanced right-sided cancers would be similarly represented in malignant polyps, and this location would be associated with lower overall survival.

METHODS

The National Cancer Database was queried for adults with T1NxMx tumors who underwent endoscopic polypectomy (2004-2017). Patients with positive margins or without follow-up information were excluded.

RESULTS

A total of 2,337 patients met inclusion criteria; 22% had right-sided polyps. Endoscopically excised proximal tumors were more common in elderly, and those with public insurance and more comorbidities (all P < .01). Among patients with complete pathologic data, there were no statistical differences between right- and left-sided polyps with 1 cm median size, >92% without lymphovascular invasion, and 100% without tumor deposits. Univariate analysis showed 73% vs 86% 5-year overall survival for right versus left polyps (P < .01). After adjustment for available confounders, right-sided location remained significantly associated with worse overall survival (hazard ratio 1.49, 95% confidence interval 1.21-1.83).

CONCLUSION

In this national cohort of patients with endoscopically excised malignant polyps, we identified right colon location as an independent prognostic factor associated with increased risk of mortality. Our data suggest polyp location should be taken into consideration when making clinical decisions regarding treatment and/or surveillance.

Survival improvement for patients with metastatic colorectal cancer over twenty years

Over the past two decades of successive clinical trials in metastatic colorectal cancer (CRC), the median overall survival of both control and experimental arms has steadily improved. However, the incremental change in survival for metastatic CRC patients not treated on trial has not yet been quantified. We performed a retrospective review of 1420 patients with de novo metastatic CRC who received their primary treatment at the University of Texas M.D. Anderson Cancer Center (UTMDACC) from 2004 through 2019. Median OS was roughly stable for patients diagnosed between 2004 and 2012 (22.6 months) but since has steadily improved for those diagnosed in 2013 to 2015 (28.8 months), and 2016 to 2019 (32.4 months). Likewise, 5-year survival rate has increased from 15.7% for patients diagnosed from 2004 to 2006 to 26% for those diagnosed from 2013 to 2015. Notably, survival improved for patients with BRAFV600E mutant as well as microsatellite unstable (MSI-H) tumors. Multivariate regression analysis identified surgical resection of liver metastasis (HR = 0.26, 95% CI, 0.19-0.37), use of immunotherapy (HR = 0.44, 95% CI, 0.29-0.67) and use of third line chemotherapy (regorafenib or trifluridine/tipiracil, HR = 0.74, 95% CI, 0.58-0.95), but not year of diagnosis (HR = 0.99, 95% CI, 0.98-1), as associated with better survival, suggesting that increased use of these therapies are the drivers of the observed improvement in survival.

Current Landscape and Potential Challenges of Immune Checkpoint Inhibitors in Microsatellite Stable Metastatic Colorectal Carcinoma

Colorectal cancer (CRC) is the third most frequent cancer and the second most common cause of cancer-related death in Europe. High microsatellite instability (MSI-H) due to a deficient DNA mismatch repair (dMMR) system can be found in 5% of metastatic CRC (mCRC) and has been established as a biomarker of response to immunotherapy in these tumors. Therefore, immune checkpoint inhibitors (ICIs) in mCRC with these characteristics were evaluated with results showing remarkable response rates and durations of response. The majority of mCRC cases have high levels of DNA mismatch repair proteins (pMMR) with consequent microsatellite stability or low instability (MSS or MSI-low), associated with an inherent resistance to ICIs. This review aims to provide a comprehensive analysis of the possible approaches to overcome the mechanisms of resistance and evaluates potential biomarkers to establish the role of ICIs in pMMR/MSS/MSI-L (MSS) mCRC.

Resistin-like beta reduction is associated to low survival rate and is downregulated by adjuvant therapy in colorectal cancer patients

Colorectal Cancer (CRC) is one of the most common cancers accounting for 1.8 million new cases worldwide every year. Therefore, the identification of new potential therapeutic targets represents a continuous challenge to improve survival and quality of CRC patient's life. We performed a microarray analysis dataset consisting of colon biopsies of healthy subjects (HS) and CRC patients. These results were further confirmed in a clinical setting evaluating a series of CRC patients to assess the expression of Resistin-Like Beta (RETNLB) and to correlate it with their clinical data. Our results showed a significant reduction of RETNLB expression in CRC biopsies compared to the HS mucosa. Furthermore, such reduction was significantly associated with the TNM grade and patients' age. Furthermore, a significantly positive correlation was found within mutated subjects for KRAS, TP53, and BRAF. In particular, patients with poor prognosis at 5 years exhibited RETNLB lower levels. In-silico analysis data were confirmed by histochemical analysis in a series of CRC patients recruited by our group. The results obtained provided that RETNLB low levels are associated with an unfavorable prognosis in CRC patients and its expression is also dependent on adjuvant therapy. Further studies are warranted in order to evaluate the molecular mechanisms underlying the role of RETNLB in CRC progression.

Diagnosis and functional prediction of microbial markers in tumor tissues of sporadic colorectal cancer patients associated with the MLH1 protein phenotype

Objective

Most patients with sporadic colorectal cancer (SCRC) develop microsatellite instability because of defects in mismatch repair (MMR). Moreover, the gut microbiome plays a vital role in the pathogenesis of SCRC. In this study, we assessed the microbial composition and diversity of SCRC tumors with varying MutL protein homolog 1 (MLH1) status, and the effects of functional genes related to bacterial markers and clinical diagnostic prediction.

Methods

The tumor microbial diversity and composition were profiled using high-throughput sequencing of the 16S ribosomal RNA (rRNA) gene V4 region. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) software and BugBase tool were used to predict the functional roles of the microbiome. We aimed to construct a high-accuracy model to detect and evaluate the area under the receiver operating characteristic curve with candidate biomarkers.

Results

The study included 23 patients with negative/defective MLH1 (DM group) and 22 patients with positive/intact MLH1 (IM group). Estimation of alpha diversity indices showed that the Shannon index (p = 0.049) was significantly higher in the DM group than in the controls, while the Simpson index (p = 0.025) was significantly lower. At the genus level, we observed a significant difference in beta diversity in the DM group versus the IM group. Moreover, the abundance of Lachnoclostridium spp. and Coprococcus spp. was significantly more enriched in the DM group than in the IM group (q < 0.01 vs. q < 0.001). When predicting metagenomes, there were 18 Kyoto Encyclopedia of Genes and Genomes pathways and one BugBase function difference in both groups (all q < 0.05). On the basis of the model of diagnostic prediction, we built a simplified optimal model through stepwise selection, consisting of the top two bacterial candidate markers (area under the curve = 0.93).

Conclusion

In conclusion, the genera Lachnoclostridium and Coprococcus as key species may be crucial biomarkers for non-invasive diagnostic prediction of DM in patients with SCRC in the future.

Targeting BRAF V600E in metastatic colorectal cancer: where are we today?

Colorectal cancer (CRC) is the second most frequent cause of direct cancer death worldwide. The study of the molecular state of oncogenes has predictive and prognostic value in metastatic CRC (mCRC). The B-raf proto-oncogene (BRAF) gene mutation represents the 8%-12% of all mutations in mCRC. The BRAF V600E mutation, considered the most common alteration of BRAF, corresponds to a constitutive kinase with a high activating capacity of the RAS/RAF/MEK/ERK pathway after a cascade of successive phosphorylations in the transcription of genes. BRAF V600E mutation is more prevalent in women, elderly, right-sided colon cancer and Caucasian population. Unfortunately, it is considered a poor predictive and prognosis biomarker. Patients with mCRC BRAF V600E mutated (BRAFm) are generally associated with poor response to chemotherapy and short progression-free survival and overall survival. Recently, randomised clinical trials have studied the combination of different chemotherapy regimens with angiogenic inhibitors in mCRC BRAFm. In addition, new anti-BRAF and immunotherapy agents have also been studied in this population, with positive results. The objective of this review is to acknowledge the biology and molecular pathway of BRAF, critically analyse the clinical trials and the therapy options published until today and evaluate the options of treatment according to the patient's clinical presentation.

BRAF Testing in Melanoma and Colorectal Cancer in Latin America: Challenges and Opportunities

The incidence of colorectal cancer in Argentina and Brazil has reached levels comparable to those in higher-income countries. Similarly, the incidence of melanoma in Latin America has increased during the past decades. BRAFmutation is seen frequently in melanomas and colorectal cancer. Discovering the expression of this specific biomarker in both cancers has unleashed the potential for targeted molecular therapies.In patients with BRAF-mutated melanoma, adopting a combined targeted treatment approach has shown a dramatic increase in overall survival. However, several barriers impede the development of early BRAF testing in Latin America, jeopardizing the potential for personalized therapies and care. To address this, the Americas Health Foundation convened a virtual meeting of Latin American oncologists to address the barriers to BRAF testing in melanoma and colorectal cancer. During a three-day conference, expert oncologists used literature reviews and personal experience to detail the barriers to early BRAF testing in their region. They proposed actionable steps to overcome the barriers identified, which included deficiencies in knowledge, treatment options, equitable distribution, timely results, and local data on BRAF mutations. Oncologists proposed several actions to overcome barriers, including raising public and healthcare awareness about the importance of BRAF testing, expanding treatment options in clinics across the region, developing centers in underserved areas, and increasing affordable treatment options for patients who test positive for BRAF mutations.

Incidence of BRAF V600E Gene Mutation Among Lebanese Population in Melanoma and Colorectal Cancer: A Retrospective Study Between 2010 and 2019

Introduction: Cancers arise owing to the accumulation of mutations in critical genes that leads to uncontrolled cell division and the avoidance of apoptosis. Among these oncogenes, BRAF is a potent mitogen-activated protein kinase (MAPK) pathway activator known to be somatically mutated by a glutamic acid to valine substitution at codon 600 (V600E). It is a common finding in various types of human cancers, including malignant melanoma and colorectal cancer (CRC), and is considered a poor prognostic factor and a predictive biomarker. The study aims to determine the incidence of BRAF V600E gene mutation in Lebanese patients with melanoma and CRC and its correlation with gender and age.

Methods: We conducted a retrospective cohort design study in which 210 and 132 patients diagnosed to have melanoma and CRC, respectively, were recruited from 2010 to 2019 from "L’Institut National de Pathologie," where a specific polymerase chain reaction is used to detect BRAF mutations. Data from digitized records were collected, including demographic characteristics (age and gender), cancer type, and BRAF mutation. The collected data were analyzed using SPSS Statistics version 20.0 (IBM Corp., Armonk, NY). A p-value < 0.05 was considered significant.

Results: The incidence of BRAF mutation in melanoma is 88.10%. There is female predominance with a ratio of 2.6:1 (p = 0.240) and the majority of patients aged between 40 and 60 years (51.2%) with a mean age of 53.74 years. While in CRC, BRAF is mutated in 7.5% with a ratio of 1.2:1 of male predominance (p = 0.999). The majority of patients (54.8%) were between the ages of 60 and 80 years, with a mean age of 65.5 years.

Conclusion: BRAF is a frequent oncogenic mutation that is found in lethal tumors. Targeted therapies for these cancers interfere with developing more effective therapeutic strategies, which affect the treatment response in BRAF mutants and improve the prognosis of the patients.

Genetic analysis of Japanese patients with small bowel adenocarcinoma using next-generation sequencing

BACKGROUND

Small bowel adenocarcinomas (SBAs) are rare and there is little comprehensive data on SBA genomic alterations for Asian patients. This study aimed to profile genomic alterations of SBA in Japanese patients using targeted next-generation sequencing (NGS).

METHODS

We examined 22 surgical resections from patients with primary SBA. SBA genomic alterations were analyzed by NGS. Mismatch repair (MMR) status was determined by immunohistochemical analysis. Mucin phenotypes were classified as gastric (G), intestinal (I), gastrointestinal (GI), and null (N) types on MUC2, MUC5AC, MUC6, and CD10 immunostaining.

RESULTS

The most common genomic alterations found in SBA tumors were TP53 (n = 16), followed by KRAS (n = 6), APC (n = 5), PIK3CA (n = 4), CTNNB1 (n = 3), KIT (n = 2), BRAF (n = 2), CDKN2A (n = 2), and PTEN (n = 2). Deficient MMR tumors were observed in 6 out of 22 patients. Tumor mucin phenotypes included 2 in G-type, 12 in I-type, 3 in GI-type, and 5 in N-type. APC and CTNNB1 mutations were not found in G-type and GI-type tumors. KRAS mutations were found in all tumor types except for G-type tumors. TP53 mutations were found in all tumor types. Although no single gene mutation was associated with overall survival (OS), we found that KRAS mutations were associated with significant worse OS in patients with proficient MMR tumors.

CONCLUSIONS

SBA genomic alterations in Japanese patients do not differ significantly from those reports in Western countries. Tumor localization, mucin phenotype, and MMR status all appear to impact SBA gene mutations.

Clonal evolution and expansion associated with therapy resistance and relapse of colorectal cancer

Colorectal cancer (CRC) arises by a continuous process of genetic diversification and clonal evolution. Multiple genes and pathways have a role in tumor initiation and progression. The gradual accumulation of genetic and epigenetic processes leads to the establishment of adenoma and cancer. The important 'driver' mutations in tumor suppressor genes (such as TP53, APC, and SMAD4) and oncogenes (such as KRAS, NRAS, MET, and PIK3CA) confer selective growth advantages and cause CRC advancement. Clonal evolution induced by therapeutic pressure, as well as intra-tumoral heterogeneity, has been a great challenge in the treatment of metastatic CRC. Tumors often develop resistance to treatments as a result of intra-tumor heterogeneity, clonal evolution, and selection. Hence, the development of a multidrug personalized approach should be prioritized to pave the way for therapeutics repurposing and combination therapy to arrest tumor progression. This review summarizes how selective drug pressure can impact tumor evolution, resulting in the formation of polyclonal resistance mechanisms, ultimately promoting cancer progression. Current strategies for targeting clonal evolution are described. By understanding sources and consequences of tumor heterogeneity, customized and effective treatment plans to combat drug resistance may be devised.

A Systematic Review and Meta-analysis on the Occurrence of Biomarker Mutation in Colorectal Cancer among the Asian Population

Globally, colorectal carcinoma (CRC) is the third most common cancer and the third major cause of cancer-related death in both sexes. KRAS and BRAF mutations are almost mutually exclusively involved in the pathogenesis of CRC. Both are major culprits in treatment failure and poor prognosis for CRC. Method. A systematic review and meta-analysis of various research was done following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. This trial is registered with PROSPERO CRD42021256452. The initial search included 646 articles; after the removal of noneligible studies, a total of 88 studies was finally selected. Data analysis was carried out using OpenMeta Analyst and Comprehensive Meta-Analysis 3.0 (CMA 3.0) software to investigate the prevalence of KRAS and BRAF mutations among patients with CRC in Asia. Results. The meta-analysis comprises of 25,525 sample sizes from Asia with most being male 15,743/25525 (61.7%). Overall prevalence of KRAS mutations was (59/88) 36.3% (95% CI: 34.5-38.2) with I 2 = 85.54% (P value < 0.001). In 43/59 studies, frequency of KRAS mutations was majorly in codon 12 (76.6% (95% CI: 74.2-78.0)) and less in codon 13 (21.0% (95% CI: 19.1-23.0)). Overall prevalence of BRAF mutations was 5.6% (95% CI: 3.9-8.0) with I 2 = 94.00% (P value < 0.001). When stratified according to location, a higher prevalence was observed in Indonesia (71.8%) while Pakistan has the lowest (13.5%). Conclusion. Total prevalence of KRAS and BRAF mutations in CRC was 36.6% and 5.6%, respectively, and the results conformed with several published studies on KRAS and BRAF mutations.

Can Natural Products be Used to Overcome the Limitations of Colorectal Cancer Immunotherapy?

Colorectal cancer (CRC) is a common cancer of the digestive system that endangers human health. Immunotherapy is widely used in the treatment of patients with cancer. Some patients with dMMR/MSI-H CRC benefit from treatments that use immune checkpoint inhibitors, but most CRC patients are not sensitive to immunotherapy. Furthermore, internal resistance and immune escape lead to a reduced immunotherapy response. Therefore, the development of an effective combination therapy to improve the response rate to immunotherapy is a goal of cancer research. Natural products are potential candidates for comprehensive cancer treatments due to their wide range of immunomodulatory effects through multifactorial underlying mechanisms. In this review, we summarize the challenges in the treatment of CRC and assess the immunomodulatory effects of natural products and their active components. Our work suggests that natural products represent potential options for combined CRC immunotherapy.

Integrated Analysis of Necroptosis-Related Genes for Prognosis, Immune Microenvironment Infiltration, and Drug Sensitivity in Colon Cancer

Background

Necroptosis, is intimately linked to tumor development and prognosis and has been considered as a target for anticancer therapy. However, the role of necroptosis-related genes (NRGs) in colon cancer is unclear.

Methods

In the present study, we screened 76 NRGs from previous studies and described the landscape of transcriptomic and genetic variation of NRGs in colon cancer (CC) patient samples. Molecular subtypes of necroptosis in colon cancer were identified by clustering analysis, and these molecular subtypes were linked to patient prognosis and TME cell infiltration characteristics. Then, the NRS-score for predicting overall survival (OS) was built based on the TCGA database and validated in the GSE39582 cohort for its predictive power in CC patients. Besides, the ESTIMATE and CIBERSORT algorithms were applied to explore the relationship between NRS-score and tumor immune microenvironment.

Results

We identified two molecular subtypes associated with necroptosis in CC, which have diverse prognosis and immune microenvironment characteristics. Based on the differentially expressed genes between the two molecular subtypes, we further developed a necroptosis risk score signature, referred to as NRS-score. High NRS-score was associated with poor prognosis in CC through immunosuppressive microenvironment and immune escape mechanisms. The nomogram based on NRS-score showed excellent ability to predict prognosis. In addition, NRS-score presented a positive correlation with tumor mutational burden (TMB) and immune checkpoint blockade (ICB) expression and was closely correlated with multiple anticancer agent susceptibility.

Conclusion

This work revealed a close relationship between necroptosis and the prognosis and immune microenvironment of colon cancer. The NRS-score based on the 8-gene signature may be used to predict the sensitivity of immunotherapy and chemotherapy in colon cancer patients, and provides a foundation for future studies targeting necroptosis and its immune microenvironment.

Pancreatic Neuroendocrine Neoplasms: Updates on Genomic Changes in Inherited Tumour Syndromes and Sporadic Tumours Based on WHO Classification

Pancreatic neuroendocrine neoplasms (PanNENs) are the neuroendocrine neoplasms with greatest rate of increase in incidence. Approximately 10% of PanNENs arise as inherited tumour syndromes which include multiple endocrine neoplasia type 1, multiple endocrine neoplasia type 4, von Hippel-Lindau syndrome, neurofibromatosis type1, tuberous sclerosis complex 1/2, Cowden syndrome, and Glucagon cell hyperplasia and neoplasia as well as familial insulinomatosis. In sporadic PanNENs, driver mutations in MEN1, DAXX/ATRX and mTOR pathway genes are associated with development and progression in pancreatic neuroendocrine tumours. The other changes are in VEGF pathway, Notch pathway, germline mutations in MUTYH, CHEK2, BRCA2, PHLDA3 as well as other genetic alterations. On the other hand, pancreatic neuroendocrine carcinomas share similar genetic alterations with ductal adenocarcinomas, e.g., TP53, RB1 or KRAS. In addition, microRNA and changes in immune microenvironment were noted in PanNENs. Updates on these genetic knowledges contribute to the development of management strategies for patients with PanNENs.

Association between Altered Oncogenic Signaling Pathways and Overall Survival of Patients with Metastatic Colorectal Cancer

Systemic characterization of genomic alterations into signaling pathways helps to understand the molecular pathogenies of colorectal cancer; however, their clinical implications remain unclear. Here, 128 patients with metastatic colorectal cancer (mCRC) receiving targeted next generation sequencing were retrospectively enrolled to analyze the impact of altered oncogenic pathways on clinical outcome. The datasets from Memorial Sloan Kettering Cancer Center were used for validation. In 123 patients with non-MSI-high tumor, the most common mutated gene was TP53 (84.6%), followed by APC (78.0%), KRAS (49.6%), and SMAD4 (22.8%). When mutated genes were allocated into signaling pathways defined as The Cancer Genome Atlas Pan-Cancer Analysis Project, alterations of cell cycle, Wnt, p53, RTK-RAS, PI3K, TGF-β, Notch, and Myc pathways were identified in 88%, 87%, 85%, 75%, 28%, 26%, 17%, and 10% of mCRC tissues, respectively. The survival analyses revealed that Myc and TGF-β pathway alterations were associated with a shorter overall survival (OS) (hazard ratio [HR]: 2.412; 95% confidence interval [CI]: 1.139–5.109; p = 0.018 and HR: 2.754; 95% CI: 1.044–7.265; p = 0.033, respectively). The negative prognostic impact of altered TGF-β pathway was maintained in patients receiving an anti-EGFR antibody. The OS of patients with mCRC carrying MYC and BRAF mutation was shorter than those with either MYC or BRAF mutation (HR: 4.981, 95% CI: 0.296–83.92; p = 0.02). These findings have clinical implications, such as prognosis prediction, treatment guidance, and molecular-targeted therapy development.

Prognostic Immunity and Therapeutic Sensitivity Analyses Based on Differential Genomic Instability-Associated LncRNAs in Left- and Right-Sided Colon Adenocarcinoma

Background: The purpose of our study was to develop a prognostic risk model based on differential genomic instability-associated (DGIA) long non-coding RNAs (lncRNAs) of left-sided and right-sided colon cancers (LCCs and RCCs); therefore, the prognostic key lncRNAs could be identified.

Methods: We adopted two independent gene datasets, corresponding somatic mutation and clinical information from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Identification of differential DGIA lncRNAs from LCCs and RCCs was conducted with the appliance of “Limma” analysis. Then, we screened out key lncRNAs based on univariate and multivariate Cox proportional hazard regression analysis. Meanwhile, DGIA lncRNAs related prognostic model (DRPM) was established. We employed the DRPM in the model group and internal verification group from TCGA for the purpose of risk grouping and accuracy verification of DRPM. We also verified the accuracy of key lncRNAs with GEO data. Finally, the differences of immune infiltration, functional pathways, and therapeutic sensitivities were analyzed within different risk groups.

Results: A total of 123 DGIA lncRNAs were screened out by differential expression analysis. We obtained six DGIA lncRNAs by the construction of DRPM, including AC004009.1, AP003555.2, BOLA3-AS1, NKILA, LINC00543, and UCA1. After the risk grouping by these DGIA lncRNAs, we found the prognosis of the high-risk group (HRG) was significantly worse than that in the low-risk group (LRG) (all p < 0.05). In all TCGA samples and model group, the expression of CD8⁺ T cells in HRG was lower than that in LRG (all p < 0.05). The functional analysis indicated that there was significant upregulation with regard to pathways related to both genetic instability and immunity in LRG, including cytosolic DNA sensing pathway, response to double-strand RNA, RIG-Ⅰ like receptor signaling pathway, and Toll-like receptor signaling pathway. Finally, we analyzed the difference and significance of key DGIA lncRNAs and risk groups in multiple therapeutic sensitivities.

Conclusion: Through the analysis of the DGIA lncRNAs between LCCs and RCCs, we identified six key DGIA lncRNAs. They can not only predict the prognostic risk of patients but also serve as biomarkers for evaluating the differences of genetic instability, immune infiltration, and therapeutic sensitivity.

The prognostic and predictive impact of BRAF mutations in deficient mismatch repair/microsatellite instability-high colorectal cancer: systematic review/meta-analysis

Aims: The authors present a systematic review/meta-analysis of the impact of BRAF mutations on prognosis and immune checkpoint inhibitor (ICI) response in deficient mismatch repair/microsatellite instability-high colorectal cancer. Methods: Hazard ratios for overall survival and odds ratios for objective response rate to ICIs were calculated in BRAF-mutated versus BRAF wild-type patients. Results: After screening, nine and three studies, respectively, were included for analysis of prognosis (analysis A) and ICI response (analysis B). Analysis A showed worse overall survival in BRAF-mutated compared with BRAF wild-type stage I-IV patients (hazard ratio: 1.57; 95% CI: 1.23-1.99), and analysis B showed no difference in objective response rate (odds ratio: 1.04; 95% CI: 0.48-2.25). Conclusion: BRAF mutations are associated with worse overall survival but not differential response to ICIs in deficient mismatch repair/microsatellite instability-high colorectal cancer.

BRAF Mutation as a Potential Therapeutic Target for Checkpoint Inhibitors: A Comprehensive Analysis of Immune Microenvironment in BRAF Mutated Colon Cancer

BRAF mutated colon cancer presents with poor survival, and the treatment strategies are controversial. The tumor microenvironment, which plays a key role in tumorigenesis as well as responses to treatments, of this subtype is largely unknown. In the present study, we analyzed the differences of immune microenvironments between BRAF mutated and BRAF wild-type colon cancer utilizing datasets from The Cancer Genome Atlas and Gene Expression Omnibus and confirmed the findings by tissue specimens of patients. We found that BRAF mutated colon cancer had more stromal cells, more immune cell infiltration, and lower tumor purity. Many immunotherapeutic targets, including PD-1, PD-L1, CTLA-4, LAG-3, and TIM-3, were highly expressed in BRAF mutated patients. BRAF mutation was also correlated with higher proportions of neutrophils and macrophages M1, and lower proportions of plasma cells, dendritic cells resting, and T cells CD4 naïve. In conclusion, our study demonstrates a different pattern of the immune microenvironment in BRAF mutated colon cancer and provides insights into the future use of checkpoint inhibitors in this subgroup of patients.

CXCL12-CXCR4/CXCR7 Axis in Colorectal Cancer: Therapeutic Target in Preclinical and Clinical Studies

Chemokines are chemotactic cytokines that promote cancer growth, metastasis, and regulate resistance to chemotherapy. Stromal cell-derived factor 1 (SDF1) also known as C-X-C motif chemokine 12 (CXCL12), a prognostic factor, is an extracellular homeostatic chemokine that is the natural ligand for chemokine receptors C-X-C chemokine receptor type 4 (CXCR4), also known as fusin or cluster of differentiation 184 (CD184) and chemokine receptor type 7 (CXCR7). CXCR4 is the most widely expressed rhodopsin-like G protein coupled chemokine receptor (GPCR). The CXCL12–CXCR4 axis is involved in tumor growth, invasion, angiogenesis, and metastasis in colorectal cancer (CRC). CXCR7, recently termed as atypical chemokine receptor 3 (ACKR3), is amongst the G protein coupled cell surface receptor family that is also commonly expressed in a large variety of cancer cells. CXCR7, like CXCR4, regulates immunity, angiogenesis, stem cell trafficking, cell growth and organ-specific metastases. CXCR4 and CXCR7 are expressed individually or together, depending on the tumor type. When expressed together, CXCR4 and CXCR7 can form homo- or hetero-dimers. Homo- and hetero-dimerization of CXCL12 and its receptors CXCR4 and CXCR7 alter their signaling activity. Only few drugs have been approved for clinical use targeting CXCL12-CXCR4/CXCR7 axis. Several CXCR4 inhibitors are in clinical trials for solid tumor treatment with limited success whereas CXCR7-specific inhibitors are still in preclinical studies for CRC. This review focuses on current knowledge of chemokine CXCL12 and its receptors CXCR4 and CXCR7, with emphasis on targeting the CXCL12–CXCR4/CXCR7 axis as a treatment strategy for CRC.

The Effects of Autophagy-Related Genes and lncRNAs in Therapy and Prognosis of Colorectal Cancer

Cellular autophagy plays an important role in the occurrence and development of colorectal cancer (CRC). Whether autophagy-related genes and lncRNAs can be used as ideal markers in CRC is still controversial. The purpose of this study is to identify novel treatment and prognosis markers of CRC. We downloaded transcription and clinical data of CRC from the GEO (GSE40967, GSE12954, GSE17536) and TCGA database, screened for differentially autophagy-related genes (DEAGs) and lncRNAs, constructed prognostic model, and analyzed its relationship with immune infiltration. TCGA and GEO datasets (GSE12954 and GSE17536) were used to validate the effect of the model. Oncomine database and Human Protein Atlas verified the expression of DEAGs. We obtained a total of 151 DEAGs in three verification sets collaboratively. Then we constructed a risk prognostic model through Lasso regression to obtain 15 prognostic DEAGs from the training set and verified the risk prognostic model in three verification sets. The low-risk group survived longer than the high-risk group. Age, gender, pathological stage, and TNM stage were related to the prognostic risk of CRC. On the other hand, BRAF status, RFS event, and tumor location are considered as most significant risk factors of CRC in the training set. Furthermore, we found that the immune score of the low-risk group was higher. The content of CD8 + T cells, active NK cells, macrophages M0, macrophages M1, and active dendritic cells was noted more in the high-risk group. The content of plasma cells, resting memory CD4 + T cells, resting NK cells, resting mast cells, and neutrophil cells was higher in the low-risk group. After all, the Oncomine database and immunohistochemistry verified that the expression level of most key autophagy-related genes was consistent with the results that we found. In addition, we obtained six lncRNAs co-expressed with DEAGs from the training set and found that the survival time was longer in the low-risk group. This finding was verified in the verification set and showed same trend to the results mentioned above. In the final analysis, these results indicate that autophagy-related genes and lncRNAs can be used as prognostic and therapeutic markers for CRC.

Molecular characterization of long-term survivors of hepatocellular carcinoma

Hepatocellular carcinoma is one of the most fatal cancers, and the majority of patients die within three years. However, a small proportion of patients overcome this fatal disease and survive for more than five years. To determine the molecular characteristics of long-term survivors (survival ≥ 5 years), we analyzed the genomic and clinical data of hepatocellular carcinoma patients from The Cancer Genome Atlas and the International Cancer Genome Consortium databases, and identified molecular features that were strongly associated with the patients' prognosis. Genes involved in the cell cycle were expressed at lower levels in tumor tissues from long-term survivors than those from short-term survivors (survival ≤ 1 years). High levels of positive regulators of the G₁/S cell cycle transition (cyclin-dependent kinase 2 [CDK2], CDK4, Cyclin E2 [CCNE2], E2F1, E2F2) were potential markers of poor prognosis. Hepatocellular carcinoma patients with TP53 mutations were mainly belonged to the short-term survivor group. Abemaciclib, an FDA-approved selective inhibitor of CDK4/6, inhibited the cell proliferation and tumor growth of hepatocellular carcinoma cells in vitro and in vivo. Thus, high G₁/S transition-related gene levels and TP53 mutations are promising diagnostic biomarkers for short-term survivals, and abemaciclib may be a potential targeted drug for hepatocellular carcinoma.