Prognostic role of KRAS and BRAF in stage II and III resected colon cancer: results of the translational study on the PETACC-3, EORTC 40993, SAKK 60-00 trial

Precision Oncology and Systemic Targeted Therapy in Pseudomyxoma Peritonei

PURPOSE

Pseudomyxoma peritonei (PMP) is a rare and poorly understood malignant condition characterized by the accumulation of intra-abdominal mucin produced from peritoneal metastases. Currently, cytoreductive surgery remains the mainstay of treatment but disease recurrence and death after relapse frequently occur in patients with PMP. New therapeutic strategies are therefore urgently needed for these patients.

EXPERIMENTAL DESIGN

A total of 120 PMP samples from 50 patients were processed to generate a collection of 50 patient-derived organoid (PDO) and xenograft (PDX) models. Whole exome sequencing, immunohistochemistry analyses, and in vitro and in vivo drug efficacy studies were performed.

RESULTS

In this study, we have generated a collection of PMP preclinical models and identified druggable targets, including BRAFV600E, KRASG12C, and KRASG12D, that could also be detected in intra-abdominal mucin biopsies of patients with PMP using droplet digital PCR. Preclinical models preserved the histopathological markers from the original patient sample. The BRAFV600E inhibitor encorafenib reduced cell viability of BRAFV600E PMP-PDO models. Proof-of-concept in vivo experiments showed that a systemic treatment with encorafenib significantly reduced tumor growth and prolonged survival in subcutaneous and orthotopic BRAFV600E-PMP-PDX mouse models.

CONCLUSIONS

Our study demonstrates for the first time that systemic targeted therapies can effectively control PMP tumors. BRAF signaling pathway inhibition represents a new therapeutic opportunity for patients with BRAFV600E PMP who have a poor prognosis. Importantly, our present data and collection of preclinical models pave the way for evaluating the efficacy of other systemic targeted therapies toward extending the promise of precision oncology to patients with PMP.

The impact of preoperative treatments on the immune environment of rectal cancer

To improve local disease control, the use of preoperative radiotherapy either alone or combined with chemotherapy has become standard practice in rectal cancer, but it is unclear how these treatments modify the antitumoral immune response. We aimed to evaluate tumor histopathologic features and the prognostic effect of host immune response in rectal cancer with variable treatment modalities. Ninety-five rectal cancers with short-course radiotherapy (SRT), 97 with long-course chemoradiotherapy (CRT), and 154 without preoperative treatments, were evaluated for histopathologic features including Crohn's-like reaction (CLR). CD3+ and CD8+ immunohistochemistry and tumor cells were analyzed from tumor tissue microarray samples to calculate T-cell densities and G-cross function values to estimate cancer cell-T-cell co-localization (proximity score). We found that lymphocyte densities were diminished after SRT, but CLR was scarcer after CRT. Proximity score and CLR density were prognostic for survival in cancer without preoperative treatments and could be combined into an enhanced prognostic score (immune grade). In the irradiated tumors, CLR density remained prognostic while the impact of T-cell infiltration was insufficient alone. In multivariable analysis, the immune grade proved to be an independent prognostic factor for survival. In conclusion, the immune contexture of rectal cancer harbors prognostic significance even after preoperative radiotherapy.

Effect of RAS and BRAF mutations on peritoneal metastasis risk and cytoreductive surgery/hyperthermic intraperitoneal chemotherapy efficacy in colorectal cancer: A systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) patients with peritoneal metastasis (CRC-PM) have a worse prognosis than those with liver and lung metastases. Cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is an effective locoregional treatment for CRC-PM. To date, the prognostic analysis of CRS/HIPEC mostly focuses on clinical and pathological characteristics; however, genetic characteristics, such as RAS/BRAF mutation status, are not sufficient. This study aimed to systematically assess the correlation between RAS/BRAF status and PM risk, as well as the prognostic efficacy of CRS/HIPEC for CRC.

METHOD

This study was written in accordance with the 2020 guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols. We searched PubMed, EMBASE, and the Cochrane library with the following keywords: "Peritoneal Neoplasms," "raf Kinases" and "ras Proteins". The fixed-effects model and inverse variance method were used for analysis. Odds ratios (OR) and 95 % confidence intervals (CI) were used to reflect the risk of PM associated with RAS/BRAF mutations. Hazard ratios (HR) and 95 % CI were used to evaluate the effects of RAS/BRAF mutations on the prognosis of CRS/HIPEC.

RESULT

Eighteen articles included 5567 patients. In the risk analysis of PM, patients with BRAF mutation were more likely to have PM than those with wild-type BRAF (OR = 2.28, 95 % CI = 1.73-3.01, P < 0.001, I2 = 0 %). In contrast, there was no significant difference in the effect of RAS mutation and wild-type on PM of CRC (OR = 1.28, 95 % CI = 0.99-1.66, P = .06, I2 = 0 %). In a prognostic analysis of CRS/HIPEC, RAS mutation predicted poor overall survival (HR = 1.68, 95 % CI = 1.39-2.02, P < 0.001, I2 = 1 %) and disease-free survival (HR = 1.61, 95 % CI = 1.34-1.94, P < 0.001, I2 = 42 %). The results for BRAF mutation was consistent with the prognostic impact of RAS mutation's overall survival (HR = 2.57, 95 % CI = 1.93-3.44, P < 0.001, I2 = 0 %) and disease-free survival (HR = 1.90, 95 % CI = 1.40-2.56, P < 0.001, I2 = 82 %).

CONCLUSION

BRAF mutation, rather than RAS mutation, was a high-risk factor for CRC-PM. And both BRAF and RAS mutations negatively affected the prognosis of CRS/HIPEC in CRC-PM patients. Our results could provide suggestions for the selection of comprehensive treatment for CRC-PM with RAS/BRAF mutations.

Clinical Calculator for Predicting Freedom From Recurrence After Resection of Stage I-III Colon Cancer in Patients With Microsatellite Instability

PURPOSE

Outcome for patients with nonmetastatic, microsatellite instability (MSI) colon cancer is favorable: however, high-risk cohorts exist. This study was aimed at developing and validating a nomogram model to predict freedom from recurrence (FFR) for patients with resected MSI colon cancer.

PATIENTS AND METHODS

Data from patients who underwent curative resection of stage I, II, or III MSI colon cancer in 2014-2021 (model training cohort, 384 patients, 33 events; median follow-up, 38.8 months) were retrospectively collected from institutional databases. Variables associated with recurrence in multivariable analysis were selected for inclusion in the clinical calculator. The calculator's predictive accuracy was measured with the concordance index and validated using data from patients who underwent treatment for MSI colon cancer in 2007-2013 (validation cohort, 164 patients, eight events; median follow-up, 84.8 months).

RESULTS

T category and number of positive lymph nodes were significantly associated with recurrence in multivariable analysis and were selected for inclusion in the clinical calculator. The calculator's concordance index for FFR in the model training cohort was 0.812 (95% CI, 0.742 to 0.873), compared with 0.759 (95% CI, 0.683 to 0.840) for the staging schema of the eighth edition of the American Joint Committee on Cancer Staging Manual. The concordance index for the validation cohort was 0.744 (95% CI, 0.666 to 0.822), confirming robust predictive accuracy.

CONCLUSION

Although in general patients with nonmetastatic MSI colon cancer had favorable outcome, patients with advanced T category and multiple metastatic lymph nodes had higher risk of recurrence. The clinical calculator identified patients with MSI colon cancer at high risk for recurrence, and this could inform surveillance strategies. In addition, the model could be used in trial design to identify patients suitable for novel adjuvant therapy.

Clinicopathological, molecular, and prognostic features of colorectal carcinomas with KRAS c.34G>T (p.G12C) mutation

Evidence indicates that combinations of anti-EGFR antibodies and KRAS p.G12C (c.34G>T) inhibitors can be an effective treatment strategy for advanced colorectal cancer. We hypothesized that KRAS c.34G>T (p.G12C)-mutated colorectal carcinoma might be a distinct tumor subtype. We utilized a prospective cohort incident tumor biobank (including 1347 colorectal carcinomas) and detected KRAS c.34G>T (p.G12C) mutation in 43 cases (3.2%) and other KRAS mutations (in codon 12, 13, 61, or 146) in 467 cases (35%). The CpG island methylator phenotype (CIMP)-low prevalence was similarly higher in KRAS c.34G>T mutants (52%) and other KRAS mutants (49%) than in KRAS-wild-type tumors (31%). KRAS c.34G>T mutants showed higher CIMP-high prevalence (14%) and lower CIMP-negative prevalence (33%) compared with other KRAS mutants (6% and 45%, respectively; p = 0.0036). Similar to other KRAS mutants, KRAS c.34G>T-mutated tumors were associated with cecal location, non-microsatellite instability (MSI)-high status, BRAF wild type, and PIK3CA mutation when compared with KRAS-wild-type tumors. Compared with BRAF-mutated tumors, KRAS c.34G>T mutants showed more frequent LINE-1 hypomethylation, a biomarker for early-onset colorectal carcinoma. KRAS c.34G>T mutants were not associated with other features, including the tumor tissue abundance of Fusobacterium nucleatum (F. animalis), pks+ Escherichia coli, Bifidobacterium, or (enterotoxigenic) Bacteroides fragilis. Among 1122 BRAF-wild-type colorectal carcinomas, compared with KRAS-wild-type tumors, multivariable-adjusted colorectal cancer-specific mortality hazard ratios (95% confidence interval) were 1.82 (1.05-3.17) in KRAS c.34G>T (p.G12C)-mutated tumors (p = 0.035) and 1.57 (1.22-2.02) in other KRAS-mutated tumors (p = 0.0004). Our study provides novel evidence for clinical and tumor characteristics of KRAS c.34G>T (p.G12C)-mutated colorectal carcinoma.

Cellular and molecular events in colorectal cancer: biological mechanisms, cell death pathways, drug resistance and signalling network interactions

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide, affecting millions each year. It emerges from the colon or rectum, parts of the digestive system, and is closely linked to both genetic and environmental factors. In CRC, genetic mutations such as APC, KRAS, and TP53, along with epigenetic changes like DNA methylation and histone modifications, play crucial roles in tumor development and treatment responses. This paper delves into the complex biological underpinnings of CRC, highlighting the pivotal roles of genetic alterations, cell death pathways, and the intricate network of signaling interactions that contribute to the disease's progression. It explores the dysregulation of apoptosis, autophagy, and other cell death mechanisms, underscoring the aberrant activation of these pathways in CRC. Additionally, the paper examines how mutations in key molecular pathways, including Wnt, EGFR/MAPK, and PI3K, fuel CRC development, and how these alterations can serve as both diagnostic and prognostic markers. The dual function of autophagy in CRC, acting as a tumor suppressor or promoter depending on the context, is also scrutinized. Through a comprehensive analysis of cellular and molecular events, this research aims to deepen our understanding of CRC and pave the way for more effective diagnostics, prognostics, and therapeutic strategies.

Serum Uric Acid Level May Be a Predictive Factor for BRAF V600E Mutation in Older Patients with Metastatic Colorectal Cancer: An Exploratory Analysis

INTRODUCTION

This study aimed to show the relationship between the serum uric acid level measured at diagnosis and the BRAF mutation status in the primary tumor tissue in patients with metastatic colorectal cancer.

METHODS

In this retrospective cross-sectional study, 264 patients (64% male) whose serum uric acid level was measured at the time of diagnosis and whose BRAF mutation status in the primary tumor was determined were included.

RESULTS

The BRAF mutation rate was 14% (n = 37). The median serum uric acid levels of all patients were 6.9 mg/dL (25%, 75% percentile range 3.7, 8.2). The serum uric acid level cut-off value was 6.6 mg/dL. Sensitivity and specificity for BRAF mutated patients were 84% and 27%, respectively. These rates were calculated as 85% and 70% in BRAF-mutated patients aged 65 and over. There was a significant correlation between BRAF mutation and high serum uric acid level, female gender, tumor located in the ascending colon, and multiple metastatic sites. The independent factors affecting BRAF mutation were age 65 and over, tumor in the ascending colon, and high serum uric acid level.

CONCLUSION

As a result, we concluded that high serum uric acid level measured during diagnosis in metastatic colorectal cancer is an accessible and economical biomarker that can predict BRAF mutation in patients aged 65 and over.

RBM5 suppresses proliferation, metastasis and glycolysis of colorectal cancer cells via stabilizing phosphatase and tensin homolog mRNA

BACKGROUND

RNA binding motif 5 (RBM5) has emerged as crucial regulators in many cancers.

AIM

To explore more functional and mechanistic exploration of RBM5 since the lack of research on RBM5 in colorectal cancer (CRC) dictates that is essential.

METHODS

Through Gene Expression Profiling Interactive Analysis, we analyzed RBM5 expression in colon adenocarcinoma and rectum adenocarcinoma tissues. For detecting the mRNA expression of RBM5, quantitative real time-polymerase chain reaction was performed. Protein expression levels of RBM5, hexokinase 2, lactate dehydrogenase A, phosphatase and tensin homolog (PTEN), phosphoinositide 3-kinase (PI3K), phosphorylated-protein kinase B (p-AKT), and AKT were determined via Western blot. Functionally, cell counting kit-8 and 5-ethynyl-2'-deoxyuridine (EDU) assay were performed to evaluate proliferation of CRC cells. Invasiveness and migration of CRC cells were evaluated through conducting transwell assays. Glucose consumption, lactate production and adenosine-triphosphate (ATP) production were measured through a glucose assay kit, a lactate assay kit and an ATP production assay kit, respectively. Besides, RNA immunoprecipitation assay, half-life RT-PCR and dual-luciferase reporter assay were applied to detect interaction between RBM5 and PTEN. To establish a xenotypic tumor mice, CRC cells were subcutaneously injected into the right flank of each mouse. Protein expression of RBM5, Ki67, and PTEN in tumor tissues was examined using immunohistochemistry staining. Haematoxylin and eosin staining was used to evaluate tumor liver metastasis in mice.

RESULTS

We discovered down-regulation of RBM5 expression in CRC tissues and cells. RBM5 overexpression repressed proliferation, migration and invasion of CRC cells. Meantime, RBM5 impaired glycolysis in CRC cells, presenting as decreased glucose consumption, decreased lactate production and decreased ATP production. Besides, RBM5 bound to PTEN mRNA to stabilize its expression. PTEN expression was positively regulated by RBM5 in CRC cells. The protein levels of PI3K and p-AKT were significantly decreased after RBM5 overexpression. The suppressive influences of RBM5 on glycolysis, proliferation and metastasis of CRC cells were partially counteracted by PTEN knockdown. RBM5 suppressed tumor growth and liver metastasis in vivo.

CONCLUSION

This investigation provided new evidence that RBM5 was involved in CRC by binding to PTEN, expanding the importance of RBM5 in the treatment of CRC.

Construction and validation of a deep learning prognostic model based on digital pathology images of stage III colorectal cancer

BACKGROUND

TNM staging is the main reference standard for prognostic prediction of colorectal cancer (CRC), but the prognosis heterogeneity of patients with the same stage is still large. This study aimed to classify the tumor microenvironment of patients with stage III CRC and quantify the classified tumor tissues based on deep learning to explore the prognostic value of the developed tumor risk signature (TRS).

METHODS

A tissue classification model was developed to identify nine tissues (adipose, background, debris, lymphocytes, mucus, smooth muscle, normal mucosa, stroma, and tumor) in whole-slide images (WSIs) of stage III CRC patients. This model was used to extract tumor tissues from WSIs of 265 stage III CRC patients from The Cancer Genome Atlas and 70 stage III CRC patients from the Sixth Affiliated Hospital of Sun Yat-sen University. We used three different deep learning models for tumor feature extraction and applied a Cox model to establish the TRS. Survival analysis was conducted to explore the prognostic performance of TRS.

RESULTS

The tissue classification model achieved 94.4 % accuracy in identifying nine tissue types. The TRS showed a Harrell's concordance index of 0.736, 0.716, and 0.711 in the internal training, internal validation, and external validation sets. Survival analysis showed that TRS had significant predictive ability (hazard ratio: 3.632, p = 0.03) for prognostic prediction.

CONCLUSION

The TRS is an independent and significant prognostic factor for PFS of stage III CRC patients and it contributes to risk stratification of patients with different clinical stages.

Predicting prognosis in colorectal cancer patients with curative resection using albumin, lymphocyte count and RAS mutations

Colorectal cancer (CRC) poses a significant global health challenge, demanding reliable prognostic tools to guide treatment decisions. This study introduces a novel prognostic scoring system, the albumin-total lymphocyte count-RAS index (ALRI), integrating serum albumin, lymphocyte count, and RAS gene mutations. A cohort of 445 stage I-III CRC patients undergoing curative resection was analyzed, revealing ALRI's association with clinicopathological factors, including age, tumor location, and invasion depth. The ALRI demonstrated superior prognostic value, with a cutoff value of 2 distinguishing high and low-risk groups. The high-ALRI group exhibited elevated rates of recurrence. Univariate and multivariate analyses identified ALRI as an independent predictor for both 5 year recurrence-free survival (RFS) and overall survival (OS). Kaplan-Meier curves illustrated significant differences in RFS and OS between high and low-ALRI groups, emphasizing ALRI's potential as a prognostic marker. Importantly, ALRI outperformed existing nutritional indices, such as controlling nutritional status and neutrophil-to-lymphocyte ratio, in predicting overall survival. The study underscores the comprehensive insight provided by ALRI, combining inflammatory, nutritional, and genetic information for robust prognostication in CRC patients. This user-friendly tool demonstrates promise for preoperative prognosis and personalized treatment strategies, emphasizing the crucial role of inflammation and nutrition in CRC outcomes.

The relationship of KRAS expression with KRAS status, prognosis, and tumor-infiltrated T lymphocytes in colorectal cancer

Background

The significance of Kirsten rat sarcoma viral oncogene (KRAS) mutation in colorectal cancer (CRC) is well established; yet, its association with KRAS expression and prognosis warrants further investigation. While high KRAS expression is commonly linked with poorer prognosis in other cancers, its role in CRC remains relatively understudied.

Objective

To explore the correlation between KRAS expression, KRAS status, prognosis, and tumor-infiltrating T lymphocyte density in CRC.

Design

Single-center retrospective study.

Methods

Conducted between 2010 and 2020, this study utilized tumor samples to assess KRAS expression and quantify CD3+/CD8+ T lymphocytes. The Cox proportional hazards model and linear regression analysis were employed to examine the relationship between KRAS expression, prognosis, and tumor-infiltrating T lymphocytes.

Results

This study included 265 CRC patients who underwent radical surgery. No significant association was observed between KRAS expression and KRAS status (p > 0.05). High KRAS expression was associated with poorer overall survival and disease-free survival (p < 0.05). Subgroup analysis revealed that high KRAS expression remained indicative of a worse prognosis in the group with mismatch repair-deficient (dMMR) and KRAS mutant type (p < 0.05). Multivariate analysis confirmed KRAS expression as an unfavorable prognostic factor (p < 0.05). However, the significance of KRAS expression was lost in the dMMR and KRAS mutant-type group regarding overall survival (p > 0.05). Notably, KRAS expression showed a negative correlation with the density of CD8+ T lymphocytes in tumor tissue (p < 0.05), a finding also observed in the dMMR group (p < 0.05).

Conclusion

No association was found between KRAS expression and KRAS mutation status in CRC. Higher KRAS expression was indicative of poorer prognosis for CRC patients, except for those with proficient mismatch repair and KRAS wild type. In addition, in patients with dMMR, KRAS expression was associated with a lower density of CD8+ T lymphocytes in tumor tissue.

Unraveling the Interplay of KRAS, NRAS, BRAF, and Micro-Satellite Instability in Non-Metastatic Colon Cancer: A Systematic Review

Microsatellite Instability (MSI-H) occurs in approximately 15% of non-metastatic colon cancers, influencing patient outcomes positively compared to microsatellite stable (MSS) cancers. This systematic review focuses on the prognostic significance of KRAS, NRAS, and BRAF mutations within MSI-H colon cancer. Through comprehensive searches in databases like MEDLINE, EMBASE, and others until 1 January 2024, we selected 8 pertinent studies from an initial pool of 1918. These studies, encompassing nine trials and five observational studies involving 13,273 patients, provided insights into disease-free survival (DFS), survival after recurrence, and overall survival. The pooled data suggest that while KRAS and BRAF mutations typically predict poorer outcomes in MSS colorectal cancer, their impact is less pronounced in MSI contexts, with implications varying across different stages of cancer and treatment responses. In particular, adverse effects of these mutations manifest significantly upon recurrence rather than affecting immediate DFS. Our findings confirm the complex interplay between genetic mutations and MSI status, emphasizing the nuanced role of MSI in modifying the prognostic implications of KRAS, NRAS, and BRAF mutations in colon cancer. This review underscores the importance of considering MSI alongside mutational status in the clinical decision-making process, aiming to tailor therapeutic strategies more effectively for colon cancer patients.

HER2 targeted therapy in colorectal Cancer: Current landscape and future directions

Colorectal cancer (CRC) is one of the most common causes of tumor-related deaths globally. Despite recent improvements in the comprehensive therapy of malignancy, metastatic CRC continues to have a poor prognosis. Human epidermal growth factor receptor 2 (HER2) is an established oncogenic driver, which is successfully targeted for breast and gastric cancers. Approximately 5% of CRC patients carry somatic HER2 mutations or gene amplification. In 2019, the U.S. Food and Drug Administration have approved trastuzumab and pertuzumab in combination with chemotherapy for the treatment of HER2-positive metastatic CRC. This approval marked a significant milestone in the treatment of CRC, as HER2-positive patients now have access to targeted therapies that can improve their outcomes. Yet, assessment for HER2 overexpression/ amplification in CRC has not been standardized. The resistance mechanisms to anti-HER2 therapy have been not clearly investigated in CRC. Although many unknowns remain, an improved understanding of these anti-HER2 agents will be essential for advanced CRC. In this review, we provide an overview of the role of HER2 in CRC as an oncogenic driver, a prognostic and predictive biomarker, and a clinically actionable target, as well as the current progress and challenges in the field.

Unraveling the role of tumor sidedness in prognosis of stage II colon cancer

Background

Stage II colon cancer has varying risks for metastasis, and treatment strategies depend on molecular and clinicopathological features. While tumor-sidedness is a well-accepted prognostic factor for stage III/IV colon cancer, its role in stage II is controversial. Understanding its effect in stage II is crucial for improving treatment strategies.

Methods

We analyzed clinical and follow-up data of colon cancer from the Surveillance, Epidemiology, and End Results database (2004-2017). Patients were divided into a primary study cohort (2010-2017) and a validation cohort (2004-2009). The baseline characteristics between right-sided colon cancer (RCC) and left-sided colon cancer (LCC) groups were compared. Moreover, the effect of tumor size on cancer-specific survival (CSS) was evaluated using Kaplan-Meier analysis.

Results

The study involved 87,355 patients in the study cohort and 65,858 in the validation cohort. Of the study cohort, 52.3% were diagnosed with RCC. The median age was 64 years old, with 48.5% females and 76.8% of white people. In addition, stage II RCC showed better CSS compared with LCC (5-year CSS 88.0% vs 85.5%, P < 0.001), while stage III/IV RCC demonstrated poorer outcomes. Multivariate Cox regression analysis identified that the right-sidedness was a positive prognostic factor in stages I/II but negative in stages III (HR 1.10, P < 0.001) and IV (HR 1.26, P < 0.001). Chemotherapy rates decreased in RCC, particularly in stage II (RCC vs LCC: 16.2% vs 28.5%, P < 0.001). Subgroup analysis, stratified by T3/T4 stages and chemotherapy status, further highlighted better survival outcomes in RCC.

Conclusions

RCC is associated with a significantly better prognosis in stage II. The importance of considering tumor-sidedness in clinical decision-making and the design of future clinical trials should be emphasized.

Prognostic value of specific KRAS mutations in patients with colorectal peritoneal metastases

BACKGROUND

There is little evidence on KRAS mutational profiles in colorectal cancer (CRC) peritoneal metastases (PM). This study aims to determine the prevalence of specific KRAS mutations and their prognostic value in a homogeneous cohort of patients with isolated CRC PM treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

MATERIALS AND METHODS

Data were collected from 13 Italian centers, gathered in a collaborative group of the Italian Society of Surgical Oncology. KRAS mutation subtypes have been correlated with clinical and pathological characteristics and survival [overall survival (OS), local (peritoneal) disease-free survival (LDFS) and disease-free survival (DFS)].

RESULTS

KRAS mutations occurred in 172 patients (47.5%) out of the 362 analyzed. Two different prognostic groups of KRAS mutation subtypes were identified: KRASMUT1 (G12R, G13A, G13C, G13V, Q61H, K117N, A146V), median OS > 120 months and KRASMUT2 (G12A, G12C, G12D, G12S, G12V, G13D, A59E, A59V, A146T), OS: 31.2 months. KRASMUT2 mutations mainly occurred in the P-loop region (P < 0.001) with decreased guanosine triphosphate (GTP) hydrolysis activity (P < 0.001) and were more frequently related to size (P < 0.001) and polarity change (P < 0.001) of the substituted amino acid (AA). When KRASMUT1 and KRASMUT2 were combined with other known prognostic factors (peritoneal cancer index, completeness of cytoreduction score, grading, signet ring cell, N status) in multivariate analysis, KRASMUT1 showed a similar survival rate to KRASWT patients, whereas KRASMUT2 was independently associated with poorer prognosis (hazard ratios: OS 2.1, P < 0.001; DFS 1.9, P < 0.001; LDFS 2.5, P < 0.0001).

CONCLUSIONS

In patients with CRC PM, different KRAS mutation subgroups can be determined according to specific codon substitution, with some mutations (KRASMUT1) that could have a similar prognosis to wild-type patients. These findings should be further investigated in larger series.

Sex Difference of Colon Adenoma Pathway and Colorectal Carcinogenesis

Colorectal cancer (CRC) is one of the most common causes of cancer morbidity in both sexes but shows sex differences. First, sex-specific differences in tumor recurrence and survival rates have been reported. For example, the development of CRC is found about 1.5 times higher and 4-8 years earlier in males compared to females, suggesting the protective role of estrogen in the disease. Furthermore, female patients have a higher risk of developing right-sided (proximal) colon cancer than male patients, which is known to have more aggressive clinical character compared to left-sided (distal) colon cancer. That is, left and right CRCs show differences in carcinogenic mechanism, that the chromosomal instability pathway is more common in left colon cancer while the microsatellite instability and serrated pathways are more common in right colon cancer. It is thought that there are sex-based differences on the background of carcinogenesis of CRC. Sex differences of CRC have two aspects, sexual dimorphism (biological differences in hormones and genes) and gender differences (non-biological differences in societal attitudes and behavior). Recently, sex difference of colon adenoma pathway and sexual dimorphism in the biology of gene and protein expression, and in endocrine cellular signaling in the CRC carcinogenesis have been accumulated. In addition, behavioral patterns can lead to differences in exposure to risk factors such as drinking or smoking, diet and physical activity. Therefore, understanding sex/gender-related biological and sociocultural differences in CRC risk will help in providing strategies for screening, treatment and prevention protocols to reduce the mortality and improve the quality of life. In this review, sex/gender differences in colon adenoma pathway and various aspects such as clinicopathological, biological, molecular, and socio-cultural aspects of CRC were described.

Overall Survival, BRAF, RAS, and MSI Status in Patients Who Underwent Cetuximab After Refractory Chemotherapy for Metastatic Colorectal Cancer

PURPOSE

Evaluate overall survival (OS), RAS, BRAF, and MSI frequencies in patients with metastatic colorectal cancer (mCRC), refractory to chemotherapy, and finally treated with cetuximab.

METHODS

A retrospective cohort study to evaluate 211 mCRC patients with wild-type KRAS treated with cetuximab. BRAF V600E, KRAS, NRAS gene mutations, and MSI status were identified using PCR techniques in a population of pre-treated patients who were refractory to fluoropyrimidines, oxaliplatin, and irinotecan. In addition, we evaluated the mutation frequency of the BRAF and NRAS genes and the MSI status of this population. Uni- and multivariate analyses were performed for independent prognostic factors of OS.

RESULTS

The median OS was 10.4 months, 6.6 months for patients with right and 11.5 months for left colon cancers (p = 0.02). The frequencies of mutations were BRAF at 3.9% (median OS of 4.9 months), NRAS at 3.38% (median OS of 6.9 months), and MSI-High status at 3.3% (median OS of 4.6 months). The OS, NRAS, and MSI frequencies were similar to those found in other studies that evaluated cetuximab in poly-treated patients and were associated with lower survival rates in univariate analyses. The frequency of BRAF mutations was lower than that found in previous studies. The only variable that remained significant for OS in the multivariate model was tumour laterality, with patients with right colon cancer presenting a worse prognosis (HR = 2.81).

CONCLUSION

Although BRAF, NRAS mutations, and MSI-High status were associated with shorter OS in univariate analyses, only tumour laterality remained an independent prognostic factor in the multivariate analysis.

Serum copper status of patients with colorectal cancer: A systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide and a public health problem. Several clinical studies have shown that copper (Cu) is involved in carcinogenesis, possibly via cuproptosis, a new form of programmed cell death, but the conclusions from published reports are inconsistent. This study aimed at evaluating the potential of Cu dysregulation as a CRC susceptibility factor.

METHODS

In this systematic review and meta-analysis, we searched Cochrane Library, EBSCOhost, EMBASE, ProQuest, PubMed/MEDLINE, Scopus, and Web of Science for studies reporting serum Cu concentrations in CRC patients and controls from articles published till June 2023. The studies included reported measurements of serum/plasma/blood Cu levels. Meta-analyses were performed as well as study quality, heterogeneity, and small study effects were assessed. Based on a random effects model, summary standardized mean differences (SMDs) and the corresponding 95% confidence intervals (95% CIs) were applied to compare the levels of Cu between CRC patients and controls.

RESULTS

26 studies with a pooled total of9628 participants and 2578 CRC cases were included. The pooled SMD was equal to 0.85 (95% CIs -0.44; 2.14) showing that the CRC patients had higher mean Cu levels than the control subjects, but the difference was not significant (p = 0.185) and the heterogeneity was very high, I2 = 97.9% (95% CIs: 97.5-98.3%; p < 0.001).

CONCLUSION

The pooled results were inconclusive, likely due to discordant results and inaccuracy in reporting data of some studies; further research is needed to establish whether Cu dysregulation might contribute to the CRC risk and whether it might reflect different CRC grades.

A literature review of a meta-analysis of BRAF mutations in non-small cell lung cancer

BACKGROUND

The research on the relationship between the Braf Proto-oncogene (BRAF) mutation and lung cancer has generated conflicting findings. Nevertheless, there is an argument suggesting that assessing the BRAF status could offer benefits in terms of managing and prognosing individuals with non-small cell lung cancer (NSCLC). To present a comprehensive overview of this subject, we undertook an up-to-date meta-analysis of pertinent publications.

METHODS

We conducted an extensive literature search utilizing Medical Subject Headings keywords, namely "BRAF", "mutation", "lung", "tumor", "NSCLC", and "neoplasm", across multiple databases, including PubMed, EMBASE, ISI Science Citation Index, and CNKI. For each study, we calculated and evaluated the odds ratio and confidence interval, focusing on the consistency of the eligible research.

RESULTS

The meta-analysis unveiled a noteworthy correlation between BRAF mutation and lung cancer. No significant evidence was found regarding the connection between smoking and staging among individuals with BRAF mutations. Furthermore, a substantial disparity in the rate of BRAF mutations was observed between males and females.

CONCLUSION

Our meta-analysis revealed a significant correlation between BRAF mutations and NSCLC. Moreover, we observed a higher incidence of BRAF lung mutations in females compared to males. Additionally, the BRAFV600E mutation was found to be more prevalent among female patients and nonsmokers.

The effects of oxaliplatin-based adjuvant chemotherapy in high-risk stage II colon cancer with mismatch repair-deficient: a retrospective study

BACKGROUND

For high-risk stageIImismatch repair deficient (dMMR) colon cancers, the benefit of adjuvant chemotherapy remains debatable. The principal aim of this study was to evaluate the prognostic value of high-risk factors and the effect of oxaliplatin-based adjuvant chemotherapy among dMMR stageIIcolon cancers.

METHODS

Patients with stage II dMMR colon cancers diagnosed between June 2011 and May 2018 were enrolled in the study. Clinicopathological characteristics, treatment, and follow-up data were retrospectively collected. The high-risk group was defined as having one of the following factors: pT4 disease, fewer than twelve lymph nodes harvested (< 12 LNs), poorly differentiated histology, perineural invasion (PNI), lymphatic vascular invasion (LVI), or elevated preoperative carcinoembryonic antigen (CEA). The low-risk group did not have any risk factors above. Factors associated with disease-free survival (DFS) were included in univariate and multivariate Cox analyses.

RESULTS

We collected a total of 262 consecutive patients with stage II dMMR colon cancer. 179 patients (68.3%) have at least one high-risk factor. With a median follow-up of 50.1 months, the low-risk group was associated with a tended to have a better 3-year DFS than the high-risk group (96.4% vs 89.4%; P = 0.056). Both elevated preoperative CEA (HR 2.93; 95% CI 1.26-6.82; P = 0.013) and pT4 disease (HR 2.58; 95% CI 1.06-6.25; P = 0.037) were independent risk factors of recurrence. Then, the 3-year DFS was 92.6% for the surgery alone group and 88.1% for the adjuvant chemotherapy group (HR 1.64; 95% CI 0.67-4.02; P = 0.280). Furthermore, no survival benefit from oxaliplatin-based adjuvant chemotherapy was observed in the high-risk group and in the subgroups with pT4 disease or < 12 LNs.

CONCLUSIONS

These data suggests that not all high-risk factors have a similar impact on stage II dMMR colon cancers. Elevated preoperative CEA and pT4 tumor stage are associated with increased recurrence risk. However, oxaliplatin-based adjuvant chemotherapy shows no survival benefits in stage II dMMR colon cancers, either with or without high-risk factors.

Reclassification of RAS/BRAF allele mutations predicts the survival benefit of triplet chemotherapy in metastatic colorectal cancer

Background

Different RAS/BRAF allele mutations imply distinct biological properties in various solid tumors. Recently, several studies have focused on the predictive and prognostic roles of various RAS/BRAF allele mutations in colorectal cancer (CRC) but the results remain controversial.

Methods

Between March 2017 and September 2022, the patients diagnosed as stages I-IV CRC with detailed medical records including next-generation sequencing (NGS) data and clinicopathological follow-up information available at our center were enrolled. Survival data were estimated using the Kaplan-Meier method, and the difference was tested in a log-rank test. Multivariate tests were carried out using Cox models.

Results

A total of 1029 CRC patients were included, and the incidence of RAS/BRAF mutation was 58.4%. The hypermutated cohort was defined as patients with microsatellite instability-H or POLE/D mutation. In the non-hypermutational cohort, only KRAS G13D mutation was associated with a higher incidence and inferior disease-free survival in patients with stage I-III CRC. In the cohort of patients with non-hypermutated metastatic colorectal cancer (mCRC), we assessed the risk of various RAS/BRAF allele mutations and subsequently reclassified patients into four groups based on first-line median progression-free survival: wild type (group 1), low-risk RAS/BRAF mutation (group 2, RAS/BRAF mutations other than KRAS G13D/G12V/G12C or BRAF V600E), high-risk RAS mutation (group 3, KRAS G13D/G12V/G12C), and BRAF V600E mutation (group 4). mCRC patients with high-risk RAS mutation could significantly benefit from intensive triplet chemotherapy (hazard ratio, 2.54; 95% confidence interval, 1.36-5.12; p = 0.0091).

Conclusion

In the non-hypermutated CRC cohort, the prognostic risk of various RAS/BRAF allele mutations varied between local and metastatic CRC. KRAS G13D mutation tended to be the only prognostic marker for stages I-III CRC; however, KRAS G13D/G12V/G12C mutations collectively defined a high-risk subgroup of mCRC patients with poor prognosis, who would benefit from intensive triplet chemotherapy.

A cautionary tale: an evaluation of the performance of treatment switching adjustment methods in a real world case study

BACKGROUND

Treatment switching in randomised controlled trials (RCTs) is a problem for health technology assessment when substantial proportions of patients switch onto effective treatments that would not be available in standard clinical practice. Often statistical methods are used to adjust for switching: these can be applied in different ways, and performance has been assessed in simulation studies, but not in real-world case studies. We assessed the performance of adjustment methods described in National Institute for Health and Care Excellence Decision Support Unit Technical Support Document 16, applying them to an RCT comparing panitumumab to best supportive care (BSC) in colorectal cancer, in which 76% of patients randomised to BSC switched onto panitumumab. The RCT resulted in intention-to-treat hazard ratios (HR) for overall survival (OS) of 1.00 (95% confidence interval [CI] 0.82-1.22) for all patients, and 0.99 (95% CI 0.75-1.29) for patients with wild-type KRAS (Kirsten rat sarcoma virus).

METHODS

We tested several applications of inverse probability of censoring weights (IPCW), rank preserving structural failure time models (RPSFTM) and simple and complex two-stage estimation (TSE) to estimate treatment effects that would have been observed if BSC patients had not switched onto panitumumab. To assess the performance of these analyses we ascertained the true effectiveness of panitumumab based on: (i) subsequent RCTs of panitumumab that disallowed treatment switching; (ii) studies of cetuximab that disallowed treatment switching, (iii) analyses demonstrating that only patients with wild-type KRAS benefit from panitumumab. These sources suggest the true OS HR for panitumumab is 0.76-0.77 (95% CI 0.60-0.98) for all patients, and 0.55-0.73 (95% CI 0.41-0.93) for patients with wild-type KRAS.

RESULTS

Some applications of IPCW and TSE provided treatment effect estimates that closely matched the point-estimates and CIs of the expected truths. However, other applications produced estimates towards the boundaries of the expected truths, with some TSE applications producing estimates that lay outside the expected true confidence intervals. The RPSFTM performed relatively poorly, with all applications providing treatment effect estimates close to 1, often with extremely wide confidence intervals.

CONCLUSIONS

Adjustment analyses may provide unreliable results. How each method is applied must be scrutinised to assess reliability.

Gastrointestinal Malignancy: Genetic Implications to Clinical Applications

Advances in molecular genetics have revolutionized our understanding of the pathogenesis, progression, and therapeutic options for treating gastrointestinal (GI) cancers. This chapter provides a comprehensive overview of the molecular landscape of GI cancers, focusing on key genetic alterations implicated in tumorigenesis across various anatomical sites including GIST, colon and rectum, and pancreas. Emphasis is placed on critical oncogenic pathways, such as mutations in tumor suppressor genes, oncogenes, chromosomal instability, microsatellite instability, and epigenetic modifications. The role of molecular biomarkers in predicting prognosis, guiding treatment decisions, and monitoring therapeutic response is discussed, highlighting the integration of genomic profiling into clinical practice. Finally, we address the evolving landscape of precision oncology in GI cancers, considering targeted therapies and immunotherapies.

Conditional Overall Survival After Diagnosis of Non-Metastatic Colon Cancer: Impact of Laterality, MSI, and KRAS Status

BACKGROUND

The prognostic relevance of laterality, microsatellite instability (MSI), and KRAS status in colon cancer has been established. However, their effect on conditional overall survival (COS) remains unknown.

METHODS

COS is the probability of surviving additional years after a time from diagnosis. The National Cancer Database (2010-2017) was queried for adults with non-metastatic colon cancer and known mutation status undergoing curative resection. COS was investigated at 2 years.

RESULTS

Of 4838 patients, 3716 survived at least 2 years: 15% had stage I, 38% stage II, and 46% stage III disease. Fifty-nine percent had a right-sided tumor, 16% were MSI-high, and 37% were mutated KRAS (mKRAS). The proportion of patients alive at 2 years was higher for stage I compared with stage II and III (65 vs. 61 vs. 54%). The 5-year overall survival for stage I-III was 80, 76, and 67% for the initial cohort, and 90, 88, and 86% for those alive at 2 years. After adjustment, higher pathologic T and N stage, tumor deposits, and no chemotherapy were associated with worse COS (p < 0.01). While laterality and MSI status were not associated with COS, mKRAS was independently associated with decreased COS (HR 1.35, 95% CI 1.12-1.62).

CONCLUSION

Patients with mKRAS had worse COS, suggesting that these mutations confer an aggressive biologic behavior, with patients remaining at higher risk of death 2 years after diagnosis. Routine evaluation of KRAS status should be considered in patients with non-metastatic disease for prognostication and to identify those who might benefit from modified surveillance protocols.

Leveraging a KRAS-based signature to predict the prognosis and drug sensitivity of colon cancer and identifying SPINK4 as a new biomarker

KRAS is one of the leading mutations reported in colon cancer. However, there are few studies on the application of KRAS related signature in predicting prognosis and drug sensitivity of colon cancer patient. We identified KRAS related differentially expressed genes (DEGs) using The Cancer Genome Atlas (TCGA) database. A signature closely related to overall survival was recognized with Kaplan-Meier survival analysis and univariate cox regression analysis. Then we validated this signature with overall expression score (OE score) algorithm using both scRNA-seq and bulk RNA-seq data. Based on this signature, we performed LASSO cox regression to establish a prognostic model, and corresponding scores were calculated. Differences in genomic alteration, immune microenvironment, drug sensitivity between high- and low-KRD score groups were investigated. A KRAS related signature composed of 80 DEGs in colon cancer were recognized, among which 19 genes were selected to construct a prognostic model. This KRAS related signature was significantly correlated with worse prognosis. Furthermore, patients who scored lower in the prognostic model presented a higher likelihood of responding to chemotherapy, targeted therapy and immunotherapy. Furthermore, among the 19 selected genes in the model, SPINK4 was identified as an independent prognostic biomarker. Further validation in vitro indicated the knockdown of SPINK4 promoted the proliferation and migration of SW48 cells. In conclusion, a novel KRAS related signature was identified and validated based on clinical and genomic information from TCGA and GEO databases. The signature was proved to regulate genomic alteration, immune microenvironment and drug sensitivity in colon cancer, and thus might serve as a predictor for individual prognosis and treatment.

Prognostic Value of Tumor Size in Colon Cancer-Smaller is Better?

BACKGROUND

The prognostic value of tumor size in colon cancer remains controversial. This study aimed to reveal the correlation between tumor size and prognosis of colon cancer.

METHODS

A total of 491 patients with colon cancer were included in this study. The correlation of tumor size with prognosis, mismatch repair status, and other clinicopathological characteristics as well as tumor microenvironment was analyzed.

RESULTS

For stage IIA microsatellite stable (MSS) colon cancer, tumors sized <3.5 cm and ≥5 cm were associated with a poorer disease free survival (DFS) compared with tumors sized between 3.5 and 5 cm (P = .002). Small tumor size (HR = 5.098, P = .001) and large tumor size (HR = 2.749, P = .029) were found to be independent prognostic factors for stage IIA MSS colon cancer. Moreover, high expression of transgelin (TAGLN), a marker of cancer-associated fibroblasts (CAFs), was found to be an independent prognostic factor for poorer DFS (HR = 9.651, P = .009), which was also associated with smaller tumor size (P = .027).

CONCLUSION

Small (<3.5 cm) and large (≥5 cm) tumor sizes are associated with decreased DFS in stage IIA MSS colon cancer. Enrichment of TAGLN+ CAFs is associated with decreased DFS and small tumor size.

China special issue on gastrointestinal tumors-Regulatory-immunoscore-A novel indicator to guide precision adjuvant chemotherapy in colorectal cancer

Novel biomarkers are essential to improve the treatment efficacy and overall survival of stage II and III colorectal cancer (CRC), allowing for personalized treatment decisions. Here, the densities of CD8+ and FOXP3+ T cells in the tumor and invasive margin were processed by immunohistochemistry and digital pathology to form a scoring system named regulatory-Immunoscore (RIS). Cox proportional hazards regression models were used to determine the risk factors associated with time to recurrence. Harrell's concordance index and the time-dependent area under the curve were used to assess model performance. A total of 1213 stage I-III DNA mismatch repair-proficient colorectal cancer (pMMR CRC) patients were randomly assigned to a training set (n = 642) and a validation set (n = 571). From the Cox multivariable analysis, the association of RIS with survival was independent of patient age, sex and anatomy-based tumor risk parameters (P < .0001). For stage II patients, chemotherapy was significantly associated with better recurrence time in patients with low (95% confidence interval [CI]: 0.11-0.54, P = .001) and intermediate (95% CI = 0.25-0.57, P < .001) RIS values. In stage III patients treated with adjuvant chemotherapy, a treatment duration of 6 or more months was significantly associated with better recurrence time in patients with intermediate RIS values (95% CI = 0.38-0.90, P = .016) when compared with duration under 6 months. Therefore, these findings suggest that RIS is reliable for predicting recurrence risk and treatment responsiveness for patients with stage I-III pMMR CRC.

Prevalence of KRAS G12C Mutation and Co-mutations and Associated Clinical Outcomes in Patients With Colorectal Cancer: A Systematic Literature Review

PURPOSE

A systematic literature review was conducted to estimate the global prevalence of Kirsten rat sarcoma virus gene (KRAS) mutations, with an emphasis on the clinically significant KRAS G12C mutation, and to estimate the prognostic significance of these mutations in patients with colorectal cancer (CRC).

DESIGN

Relevant English-language publications in the Embase, MEDLINE, and the Cochrane Library databases (from 2009 to 2021) and congress presentations (from 2016 to 2021) were reviewed. Eligible studies were those that reported the prevalence and clinical outcomes of the KRAS G12C mutation in patients with CRC.

RESULTS

A total of 137 studies (interventional [n = 8], post hoc analyses of randomized clinical trials [n = 6], observational [n = 122], and longitudinal [n =1]) were reviewed. Sixty-eight studies reported the prevalence of KRAS mutations (KRASm) in 42 810 patients with CRC. The median global prevalence of KRASm was 38% (range, 13.3%-58.9%) and that of the KRAS G12C mutation (KRAS G12C) 3.1% (range, 0.7%-14%). Available evidence suggests that KRASm are possibly more common in tumors that develop on the right side of the colon. Limited evidence suggests a lower objective response rate and inferior disease-free/relapse-free survival in patients with KRAS G12C compared with patients with KRASwt or other KRASm.

CONCLUSION

Our analysis reveals that KRAS G12C is prevalent in 3% of patients with CRC. Available evidence suggests a poor prognosis for patients with KRAS G12C. Right-sided tumors were more likely to harbor KRASm; however, their role in determining clinical outcomes needs to be investigated further.

KRAS Sequence Variation as Prognostic Marker in Patients With Young- vs Late-Onset Colorectal Cancer

Importance

The understanding of the association between KRAS sequence variation status and clinical outcomes in colorectal cancer (CRC) has evolved over time.

Objective

To characterize the association of age at onset, tumor sidedness, and KRAS sequence variation with survival among patients diagnosed with CRC.

Design, Setting, and Participants

This cross-sectional study used data extracted from the Surveillance, Epidemiology, and End Results database. Patients diagnosed with adenocarcinoma of the colon or rectum from 2010 through 2015 were included and were classified as having young-onset (YO) cancer if diagnosed between ages 20 to 49 years and late-onset (LO) cancer if diagnosed at age 50 years or older. Data were analyzed from April 2021 through August 2023.

Main Outcomes and Measures

CRC cause-specific survival (CSS) was summarized using Fine and Gray cumulative incidence and Kaplan-Meier curves. Estimation of subdistribution hazard ratios (sHRs) for the association of KRAS status, age at onset, and tumor location with CRC CSS was conducted using the Fine and Gray competing risk model. Cox proportional hazards regression was used to estimate and compare HRs.

Results

Among 21 661 patients with KRAS sequence variation status (mean [SD] age at diagnosis, 62.50 [13.78] years; 9784 females [45.2%]), 3842 patients had YO CRC, including 1546 patients with KRAS variants, and 17 819 patients had LO CRC, including 7311 patients with KRAS variants. There was a significant difference in median CSS time between patients with variant vs wild-type KRAS (YO: 3.0 years [95% CI, 2.8-3.3 years] vs 3.5 years [95% CI, 3.3-3.9 years]; P = .02; LO: 2.5 years [95% CI, 2.4-2.7 years] vs 3.4 years [95% CI, 3.3-3.6 years]; P < .001). Tumors with variant compared with wild-type KRAS were associated with higher risk of CRC-related death (YO: sHR, 1.09 [95% CI, 1.01-1.18]; P = .03; LO: sHR, 1.06 [95% CI, 1.02-1.09]; P = .002). Among patients with YO cancer, mortality hazards increased by location, from right (sHR, 1.02 [95% CI, 0.88-1.17) to left (sHR, 1.15 [95% CI, 1.02-1.29) and rectum (sHR, 1.16 [95% CI, 0.99-1.36), but no trend by tumor location was seen for LO cancer.

Conclusions and Relevance

In this study of patients diagnosed with CRC, KRAS sequence variation was associated with increased mortality among patients with YO and LO tumors. In YO cancer, variant KRAS-associated mortality risk was higher in distal tumors than proximal tumors.

Impact of encorafenib on survival of patients with BRAFV600E-mutant metastatic colorectal cancer in a real-world setting

PURPOSE

Patients with BRAFV600E-mutant metastatic colorectal cancer (mCRC) have a dismal prognosis. The best strategies in these patients remain elusive. Against this background, we report the clinical course of patients with BRAFV600E-mutant mCRC to retrieve the best treatment strategy.

PATIENTS AND METHODS

Clinico-pathological data were extracted from the electronic health records. Kaplan-Meier method was used to estimate overall (OS) and progression-free survival (PFS). Objective response rate (ORR) was assessed according to RECIST 1.1.

RESULTS

In total, 51 patients were enrolled. FOLFOXIRI was administered to 12 patients; 29 patients received FOLFOX or FOLFIRI as first-line treatment. Median OS was 17.6 months. Median PFS with FOLFOXIRI (13.0 months) was significantly prolonged (HR 0.325) as compared to FOLFOX/FOLFIRI (4.3 months). However, this failed to translate into an OS benefit (p = 0.433). Interestingly, addition of a monoclonal antibody to chemotherapy associated with superior OS (HR 0.523). A total of 64.7% patients received further-line therapy, which included a BRAF inhibitor in 17 patients. Targeted therapy associated with very favourable OS (25.1 months).

CONCLUSION

Patients with BRAFV600E-mutated mCRC benefit from the addition of an antibody to first-line chemotherapy. Further-line treatment including a BRAF inhibitor has a dramatic impact on survival.

Histopathology and levels of proteins in plasma associate with survival after colorectal cancer diagnosis

BACKGROUND

The TNM system is used to assess prognosis after colorectal cancer (CRC) diagnosis. Other prognostic factors reported include histopathological assessments of the tumour, tumour mutations and proteins in the blood. As some of these factors are strongly correlated, it is important to evaluate the independent effects they may have on survival.

METHODS

Tumour samples from 2162 CRC patients were visually assessed for amount of tumour stroma, severity of lymphocytic infiltrate at the tumour margins and the presence of lymphoid follicles. Somatic mutations in the tumour were assessed for 2134 individuals. Pre-surgical levels of 4963 plasma proteins were measured in 128 individuals. The associations between these features and prognosis were inspected by a Cox Proportional Hazards Model (CPH).

RESULTS

Levels of stroma, lymphocytic infiltration and presence of lymphoid follicles all associate with prognosis, along with high tumour mutation burden, high microsatellite instability and TP53 and BRAF mutations. The somatic mutations are correlated with the histopathology and none of the somatic mutations associate with survival in a multivariate analysis. Amount of stroma and lymphocytic infiltration associate with local invasion of tumours. Elevated levels of two plasma proteins, CA-125 and PPP1R1A, associate with a worse prognosis.

CONCLUSIONS

Tumour stroma and lymphocytic infiltration variables are strongly associated with prognosis of CRC and capture the prognostic effects of tumour mutation status. CA-125 and PPP1R1A may be useful prognostic biomarkers in CRC.

Specific Mutations in APC, with Prognostic Implications in Metastatic Colorectal Cancer

PURPOSE

Loss-of-function mutations in the adenomatous polyposis coli (APC) gene are common in metastatic colorectal cancer (mCRC). However, the characteristic of APC specific mutations in mCRC is poorly understood. Here, we explored the clinical and molecular characteristics of N-terminal and C-terminal side APC mutations in Chinese patients with mCRC.

MATERIALS AND METHODS

Hybrid capture-based next-generation sequencing was performed on tumor tissues from 275 mCRC pati-ents to detect mutations in 639 tumor-associated genes. The prognostic value and gene-pathway difference between APC specific mutations in mCRC patients were analyzed.

RESULTS

APC mutations were highly clustered, accounting for 73% of all mCRC patients, and most of them were truncating mutations. The tumor mutation burden of the N-terminal side APC mutations group (n=76) was significantly lower than that of the C-terminal side group (n=123) (p < 0.001), further confirmed by the public database. Survival analysis showed that mCRC patients with N-terminus side APC mutations had longer overall survival than C-terminus side. Tumor gene pathway analysis showed that gene mutations in the RTK/RAS, Wnt and transforming growth factor β signaling pathways of the C-terminal group were significantly higher than those of the N-terminal group (p < 0.05). Additionally, KRAS, AMER1, TGFBR2, and ARID1A driver mutations were more common in patients with C-terminal side APC mutations.

CONCLUSION

APC specific mutations have potential function as mCRC prognostic biomarkers. There are obvious differences in the gene mutation patterns between the C-terminus and N-terminus APC mutations group, which may have certain guiding significance for the subsequent precise treatment of mCRC.

[Molecular pathology of colorectal cancer]

In recent years, the treatment of colorectal carcinoma has experienced increasing individualization. In addition to RAS and BRAF mutational status that is firmly established in routine diagnostics, new therapeutic options evolved based on MSI and HER2 status as well as primary tumour localization. Offering the best targeted options in therapy requires new evidence-based decision-making algorithms regarding timing and scope of molecular pathological diagnostics in order for patients to receive an optimized therapy according to current treatment guidelines. New targeted therapies, some of which are about to be approved and for which pathology has to provide new molecular pathological biomarkers, will also play an increasingly important role in the future.

Cell-free circulating RAS mutation concentrations significantly impact the survival of metastatic colorectal cancer patients

PURPOSE

RAS mutations are predictors of an adverse outcome in EGFR-targeted therapies and have been proposed as prognostic biomarkers of survival in metastatic colorectal cancer (mCRC). The analysis of circulating tumor DNA from plasma samples, known as liquid biopsies, has indicated that the RAS mutation status may change over time, potentially affecting patients' prognosis. To further evaluate the clinical validity of RAS mutation retesting using liquid biopsies, we prospectively investigated the impact of the circulating quantitative RAS mutation status on the course of mCRC.

METHODS

The present study included 81 consecutively recruited patients with mCRC. We used targeted next-generation sequencing of circulating cell-free DNA to determine and quantify plasma RAS mutation status.

RESULTS

Patients with a RAS mutation detected by liquid biopsy (37%; n = 30) were at increased risk of death during the follow-up period compared to RAS wild-type patients. Patients with evidence of a RAS mutation in the primary tumor but a putative RAS mutation loss in plasma (28%; n = 11) showed a prolonged survival compared to patients with a preserved RAS mutation status. Also, circulating RAS mutation concentrations significantly affected the outcome: The mortality risk of patients with a high RAS mutation concentration increased fivefold compared to subjects with a putative RAS mutation loss or low RAS mutation concentration.

CONCLUSION

Our results emphasize the clinical value of circulating RAS mutations in managing mCRC.

Prognostic Significance of Systemic Inflammation Indices by K-ras Status in Patients With Metastatic Colorectal Cancer

BACKGROUND

Systemic inflammation markers are useful prognostic indicators for metastatic colorectal cancer. However, the influence of K-ras genotypes on these markers in patients with metastatic colorectal cancer is unclear.

OBJECTIVE

This study aimed to evaluate the associations between systems of evaluating pretreatment systemic inflammation and outcomes according to K-ras genotypes in patients with metastatic colorectal cancer.

DESIGN

This was a retrospective study.

SETTINGS

This study was conducted at a university hospital.

PATIENTS

This study included a total of 272 patients ( K-ras wild type: K-ras mutant = 169:103) who received first-line systemic chemotherapy for metastatic colorectal cancer.

MAIN OUTCOME MEASURES

We retrospectively calculated 8 systemic inflammation indices: neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, lymphocyte/monocyte ratio, prognostic nutritional index, Glasgow prognostic score, Naples prognostic score, systemic inflammation score, and systemic immune-inflammation index. Patients were categorized into high or low groups for each index. The prognostic relevance of these indices for overall survival was evaluated according to the K-ras genotype.

RESULTS

Kaplan-Meier survival analyses showed that median overall survival significantly differed between the high and low groups for all indices in the K-ras wild-type group but not in the K-ras mutant group, except for Glasgow prognostic score and lymphocyte/monocyte ratio. Multivariate Cox regression analyses identified all indices as independent prognostic factors. In the K-ras wild-type group, all indices except platelet/lymphocyte ratio had strong prognostic effects, but not in the K-ras mutant group. Interaction tests indicated that K-ras genotype significantly influenced the prognostic impacts of the neutrophil/lymphocyte ratio ( p = 0.042), prognostic nutritional index ( p = 0.048), Naples prognostic score ( p < 0.001), and systemic immune-inflammation index ( p = 0.004).

LIMITATIONS

A major limitation of this study is the lack of external validation.

CONCLUSIONS

The prognostic significance of systemic inflammation indices is more useful in patients with K-ras wild-type metastatic colorectal cancer than those with K-ras mutant cancer. See Video Abstract at http://links.lww.com/DCR/B921 .

IMPORTANCIA PRONSTICA DE LOS NDICES DE INFLAMACIN SISTMICA POR ESTADO DE KRAS EN PACIENTES CON CNCER COLORRECTAL METASTSICO

ANTECEDENTES:Los marcadores de inflamación sistémica son indicadores de pronósticos útiles para el cáncer colorrectal metastásico. Sin embargo, la influencia de los genotipos KRAS en estos marcadores en pacientes con cáncer colorrectal metastásico no está clara.OBJETIVO:Evaluamos las asociaciones entre los sistemas de evaluación de la inflamación sistémica previa al tratamiento y los resultados según los genotipos K-ras en pacientes con cáncer colorrectal metastásico.AJUSTE:Este estudio se realizó en un hospital universitario.DISEÑO:Este fue un estudio retrospectivo.PACIENTES:Un total de 272 pacientes (K-ras wildtype [K-raswt]:mutant [K-rasMut] = 169:103) que recibieron quimioterapia sistémica de primera línea para el cáncer colorrectal metastásico.PRINCIPALES MEDIDAS DE RESULTADO:Calculamos retrospectivamente 8 índices de inflamación sistémica: proporción de neutrófilos/linfocitos, proporción de plaquetas/linfocitos, proporción de linfocitos/monocitos, índice nutricional pronóstico, puntuación de pronóstico de Glasgow, puntuación de pronóstico de Nápoles, puntuación de inflamación sistémica e índice de inmunoinflamación sistémica. Los pacientes se clasificaron en grupos altos o bajos para cada índice. La relevancia pronóstica de estos índices para la supervivencia global se evaluó según el genotipo K-ras.RESULTADOS:Los análisis de supervivencia de Kaplan-Meier mostraron que la mediana de la supervivencia general difería significativamente entre los grupos alto y bajo para todos los índices en el grupo K-raswt pero no en el grupo K-rasMut, excepto para la puntuación de pronóstico de Glasgow y la proporción de linfocitos/monocitos. Los análisis de regresión multivariable de Cox identificaron todos los índices como factores pronósticos independientes. En el grupo K-raswt, todos los índices, excepto el cociente plaquetas/linfocitos, tuvieron fuertes efectos pronósticos, pero no en el grupo K-rasMut. Las pruebas de interacción indicaron que el genotipo K-ras influyó significativamente en los impactos pronósticos de la proporción de neutrófilos/linfocitos (p = 0,042), el índice nutricional pronóstico (p = 0,048), la puntuación pronóstica de Nápoles (p < 0,001) y el índice de inflamación inmunológica sistémica (p = 0,004).LIMITACIÓN:Una limitación importante de este estudio es la falta de validación externa.CONCLUSIÓNES:La importancia pronóstica de los índices de inflamación sistémica es más útil en pacientes con cáncer colorrectal metastásico K-raswt. Consulte Video Resumen en http://links.lww.com/DCR/B921 . (Traducción-Dr. Yolanda Colorado ).

KRAS mutations and their associations with clinicopathological features and survival in Vietnamese non‑polyp colon cancer patients

The aim of the present study was to determine Kirsten Ras sarcoma virus (KRAS) mutations and the associations of KRAS mutations with clinicopathological features and treatment outcomes in Vietnamese non-polyp colon cancer (NPCC) patients. The data in the present study covered 194 patients with non-polyp colon cancers at stages II or III, according to the 8th edition of the American Joint Committee on Cancer staging system, in northern Vietnam from January 2016 to August 2020. All patients underwent radical surgery and adjuvant therapy with FOLFOX4 or XELOX. Subsequently, the recruited patients were followed-up with scheduled hospital exams for diagnosing recurrence. Genomic DNA samples were prepared from dissected tumors and specific sequences of the KRAS gene were amplified by polymerase chain reactions (PCR). The mutations at codons 12, 13, 59, 60, 61, 117 and 146 of the gene were determined. Possible associations of the KRAS mutations with clinicopathological properties and the survival of patients were analysed. The KRAS mutation rate was 47.9% in Vietnamese patients with NPCC, of those, mutations in exon 2 accounted for 91.4% of all detected mutations. The mutated-KRAS patients exhibited a significantly higher rate of anemia. Moreover, the KRAS mutation rate was higher in females (57.1%) than in males (39.8%). The KRAS mutation rate was also higher in patients with right colon cancers. Furthermore, KRAS mutations were an independent prognosis for poor disease-free survival (DFS) and overall survival (OS) in stage II patients. Among left-sided colon patients, mutated KRAS was a significant predictive factor for poor DFS but not for OS. The present study revealed a very high mutation rate of KRAS in Vietnamese patients with NPCC. The data of the present study indicated that the mutation status was associated with female patients and right-sided tumors. The KRAS mutations were a negative factor for the survival of patients with stage II NPCC and patients with left-sided colon cancer.

T Cells in Colorectal Cancer: Unravelling the Function of Different T Cell Subsets in the Tumor Microenvironment

Therapeutic options for metastatic colorectal cancer (mCRC) are very limited, and the prognosis using combination therapy with a chemotherapeutic drug and a targeted agent, e.g., epidermal growth factor receptor or tyrosine kinase, remains poor. Therefore, mCRC is associated with a poor median overall survival (mOS) of only 25-30 months. Current immunotherapies with checkpoint inhibitor blockade (ICB) have led to a substantial change in the treatment of several cancers, such as melanoma and non-small cell lung cancer. In CRC, ICB has only limited effects, except in patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) tumors, which comprise about 15% of sporadic CRC patients and about 4% of patients with metastatic CRC. The vast majority of sporadic CRCs are microsatellite-stable (MSS) tumors with low levels of infiltrating immune cells, in which immunotherapy has no clinical benefit so far. Immunotherapy with checkpoint inhibitors requires the presence of infiltrating T cells into the tumor microenvironment (TME). This makes T cells the most important effector cells in the TME, as evidenced by the establishment of the immunoscore-a method to estimate the prognosis of CRC patients. The microenvironment of a tumor contains several types of T cells that are anti-tumorigenic, such as CD8⁺ T cells or pro-tumorigenic, such as regulatory T cells (Tregs) or T helper 17 (Th17) cells. However, even CD8⁺ T cells show marked heterogeneity, e.g., they can become exhausted, enter a state of hyporesponsiveness or become dysfunctional and express high levels of checkpoint molecules, the targets for ICB. To kill cancer cells, CD8⁺ T cells need the recognition of the MHC class I, which is often downregulated on colorectal cancer cells. In this case, a population of unconventional T cells with a γδ T cell receptor can overcome the limitations of the conventional CD8⁺ T cells with an αβT cell receptor. γδ T cells recognize antigens in an MHC-independent manner, thus acting as a bridge between innate and adaptive immunity. Here, we discuss the effects of different T cell subsets in colorectal cancer with a special emphasis on γδ T cells and the possibility of using them in CAR-T cell therapy. We explain T cell exclusion in microsatellite-stable colorectal cancer and the possibilities to overcome this exclusion to enable immunotherapy even in these "cold" tumors.

Node-negative colon cancer: histological, molecular, and stromal features predicting disease recurrence

BACKGROUND

Within the group of node-negative colon cancer patients, presumed to have a good prognosis, a significant percentage of patients develops cancer-recurrence. Current high-risk features prove inadequate to select these particular high-risk patients. In the process of tailor-made care and shared decision-making the need to identify these patients grows. In this study we investigate the value of adding molecular markers and the tumour-stroma ratio (TSR) to conventional histological tumour staging methods to improve the selection of high risk patients.

METHODS

We retrospectively analysed 201 patients diagnosed with TNM-stage I-II colon cancer and treated by complete oncological resection between November 1st 2002 and December 31st 2012 at the Jeroen Bosch Hospital. Conventional histological tumour staging, BRAF mutations, KRAS mutations, MSI status and TSR were determined. Differences between groups based on TSR and mutation status, in disease free survival were analysed using Cox-Regression analyses.

RESULTS

Poorly differentiated histology (p = 0.002), high-TSR (p = 0.033), BRAF-mutation (p = 0.008) and MSI (p = 0.011) were identified as significant risk factors for cancer recurrence. The risk of recurrence increased in the presence of both a BRAF-mutation and high-TSR compared to the absence of both factors or presence of only one factor (HR = 3.66 BRAF-mt/TSR-low (p = 0.006), HR 2.82 BRAF-wt/TSR-high (p = 0.015), HR = 4.39 BRAF-mt/TSR-high (p = 0.023)). This was also seen in tumours with MSI and high-TSR (HR = 2.46 MSS/TSR-high (p = 0.041), HR = 3.31 MSI/TSR-high (p = 0.045).

CONCLUSION

Judging by the higher HR for the combination of the prognostic factors TSR and BRAF compared to the HRs of these prognostic factors individually, the prognostication for disease free survival can be improved by determining both TSR and BRAF instead of BRAF alone, as is done in current daily practise. In this study MSI also shows additional value to TSR in the prognostication of disease free survival. Adopting TSR into daily diagnostics will be of additional value next to currently used molecular markers in risk stratification of patients with node negative colon cancer and is therefore advised.

Clinical Characterization of Targetable Mutations (BRAF V600E and KRAS G12C) in Advanced Colorectal Cancer-A Nation-Wide Study

BRAF V600E and KRAS mutations that occur in colorectal cancer (CRC) define a subpopulation of patients with an inferior prognosis. Recently, the first BRAF V600E-targeting therapy has been approved and novel agents targeting KRAS G12C are being evaluated in CRC. A better understanding of the clinical characteristics of the populations defined by those mutations is needed. We created a retrospective database that collects clinical characteristics of patients with metastatic CRC evaluated for RAS and BRAF mutations in a single laboratory. A total of 7604 patients tested between October 2017 and December 2019 were included in the analysis. The prevalence of BRAF V600E was 6.77%. Female sex, primary in the right colon, high-grade, mucinous, signet cell, partially neuroendocrine histology, perineural and vascular invasion, and surgical tissue sample were factors associated with increased mutation rates. The prevalence of KRAS G12C was 3.11%. Cancer of primary origin in the left colon and in samples from brain metastases were associated with increased mutation rates. The high prevalence of the BRAF V600E mutation in cancers with a neuroendocrine component identifies a potential candidate population for BRAF inhibition. The association of KRAS G12C with the left part of the intestine and brain metastases of CRC are new findings and require further investigation.

Recent application of artificial intelligence on histopathologic image-based prediction of gene mutation in solid cancers

PURPOSE

Evaluation of genetic mutations in cancers is important because distinct mutational profiles help determine individualized drug therapy. However, molecular analyses are not routinely performed in all cancers because they are expensive, time-consuming and not universally available. Artificial intelligence (AI) has shown the potential to determine a wide range of genetic mutations on histologic image analysis. Here, we assessed the status of mutation prediction AI models on histologic images by a systematic review.

METHODS

A literature search using the MEDLINE, Embase and Cochrane databases was conducted in August 2021. The articles were shortlisted by titles and abstracts. After a full-text review, publication trends, study characteristic analysis and comparison of performance metrics were performed.

RESULTS

Twenty-four studies were found mostly from developed countries, and their number is increasing. The major targets were gastrointestinal, genitourinary, gynecological, lung and head and neck cancers. Most studies used the Cancer Genome Atlas, with a few using an in-house dataset. The area under the curve of some of the cancer driver gene mutations in particular organs was satisfactory, such as 0.92 of BRAF in thyroid cancers and 0.79 of EGFR in lung cancers, whereas the average of all gene mutations was 0.64, which is still suboptimal.

CONCLUSION

AI has the potential to predict gene mutations on histologic images with appropriate caution. Further validation with larger datasets is still required before AI models can be used in clinical practice to predict gene mutations.

Pathobionts in the tumour microbiota predict survival following resection for colorectal cancer

BACKGROUND AND AIMS

The gut microbiota is implicated in the pathogenesis of colorectal cancer (CRC). We aimed to map the CRC mucosal microbiota and metabolome and define the influence of the tumoral microbiota on oncological outcomes.

METHODS

A multicentre, prospective observational study was conducted of CRC patients undergoing primary surgical resection in the UK (n = 74) and Czech Republic (n = 61). Analysis was performed using metataxonomics, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), targeted bacterial qPCR and tumour exome sequencing. Hierarchical clustering accounting for clinical and oncological covariates was performed to identify clusters of bacteria and metabolites linked to CRC. Cox proportional hazards regression was used to ascertain clusters associated with disease-free survival over median follow-up of 50 months.

RESULTS

Thirteen mucosal microbiota clusters were identified, of which five were significantly different between tumour and paired normal mucosa. Cluster 7, containing the pathobionts Fusobacterium nucleatum and Granulicatella adiacens, was strongly associated with CRC (P_FDR = 0.0002). Additionally, tumoral dominance of cluster 7 independently predicted favourable disease-free survival (adjusted p = 0.031). Cluster 1, containing Faecalibacterium prausnitzii and Ruminococcus gnavus, was negatively associated with cancer (P_FDR = 0.0009), and abundance was independently predictive of worse disease-free survival (adjusted p = 0.0009). UPLC-MS analysis revealed two major metabolic (Met) clusters. Met 1, composed of medium chain (MCFA), long-chain (LCFA) and very long-chain (VLCFA) fatty acid species, ceramides and lysophospholipids, was negatively associated with CRC (P_FDR = 2.61 × 10^-11); Met 2, composed of phosphatidylcholine species, nucleosides and amino acids, was strongly associated with CRC (P_FDR = 1.30 × 10^-12), but metabolite clusters were not associated with disease-free survival (p = 0.358). An association was identified between Met 1 and DNA mismatch-repair deficiency (p = 0.005). FBXW7 mutations were only found in cancers predominant in microbiota cluster 7.

CONCLUSIONS

Networks of pathobionts in the tumour mucosal niche are associated with tumour mutation and metabolic subtypes and predict favourable outcome following CRC resection. Video Abstract.

Neuroglobin plays as tumor suppressor by disrupting the stability of GPR35 in colorectal cancer

BACKGROUND

The incidence of colorectal cancer (CRC) has increased in recent years. Identification of accurate tumor markers has become the focus of CRC research. Early and frequent DNA methylation tends to occur in cancer. Thus, identifying accurate methylation biomarkers would improve the efficacy of CRC treatment. Neuroglobin (NGB) is involved in neurological and oncological diseases. However, there are currently no reports on epigenetic regulation involvement of NGB in CRC.

RESULTS

NGB was downregulated or silenced in majority CRC tissues and cell lines. The hypermethylation of NGB was detected in tumor tissue, but no or a very low methylation frequency in normal tissues. Overexpression of NGB induced G2/M phase arrest and apoptosis, suppressed proliferation, migration, invasion in vitro, and inhibited CRC tumor growth and angiogenesis in vivo. Isobaric tag for relative and absolute quantitation (Itraq)-based proteomics identified approximately 40% proteins related to cell-cell adhesion, invasion, and tumor vessel formation in the tumor microenvironment, among which GPR35 was proved critical for NGB-regulated tumor angiogenesis suppression in CRC.

CONCLUSIONS

NGB, an epigenetically silenced factor, inhibits metastasis through the GPR35 in CRC. It is expected to grow into a potential cancer risk assessment factor and a valuable biomarker for early diagnosis and prognosis assessment of CRC.

Peritoneal metastases from primary appendiceal and colorectal carcinomas demonstrate distinct molecular identities on comprehensive tumor analysis

BACKGROUND AND OBJECTIVES

Published data comparing peritoneal metastases from appendiceal cancers (pAC) and colorectal cancers (pCRC) remain sparse. We compared pAC and pCRC using comprehensive tumor profiling (CTP).

METHODS

CTP was performed, including next-generation sequencing and analysis of copy number variation (CNV), microsatellite instability (MSI) and tumor mutational burden (TMB).

RESULTS

One hundred thirty-six pAC and 348 pCRC samples underwent CTP. The cohorts' age and gender were similar. pCRC demonstrated increased pathogenic variants (PATHs) in APC (48% vs. 3%, p < 0.01), ARID1A (12% vs. 2%, p < 0.01), BRAF (12% vs. 2%, p < 0.01), FBXW7 (7% vs. 2%, p < 0.01), KRAS (52% vs. 41%, p < 0.05), PIK3CA (15% vs. 2%, p < 0.01), and TP53 (53% vs. 23%, p < 0.01), and decreased PATHs in GNAS (8% vs. 31%, p < 0.01). There was no difference in CNV, fusion rate, or MSI. Median TMB was higher in pCRC (5.8 vs. 5.0 mutations per megabase, p = 0.0007). Rates of TMB-high tumors were similar (pAC 2.1% vs. pCRC 9.0%, p = 0.1957). pCRC had significantly more TMB-high tumors at lower thresholds.

CONCLUSIONS

Despite a reduced overall TMB, pAC demonstrated mutations distinct from those seen in pCRC. These may serve as discrete biomarkers for future study.

Impact of the 12-gene recurrence score in influencing adjuvant chemotherapy prescription in mismatch repair proficient stage II/III colonic carcinoma-a systematic review and meta-analysis

INTRODUCTION

The 12-gene recurrence score (RS) is a clinically validated assay which predicts recurrence risk in patients with stage II/III colon cancer. Decisions regarding adjuvant chemotherapy may be guided using this assay or based on the judgement of tumour board.

AIMS

To assess the concordance between the RS and MDT decisions regarding adjuvant chemotherapy in colon cancer.

METHODS

A systematic review was performed in accordance with PRISMA guidelines. Meta-analyses were performed using the Mantel-Haenszel method using the Review Manager version 5.4 software.

RESULTS

Four studies including 855 patients with a mean age of 68 years (range: 25-90 years) met inclusion criteria. Overall, 79.2% had stage II disease (677/855) and 20.8% had stage III disease (178/855). For the entire cohort, concordant results between the 12-gene assay and MDT were more likely than discordant (odds ratio (OR): 0.38, 95% confidence interval (CI): 0.25-0.56, P < 0.001). Patients were more likely to have chemotherapy omitted than escalated when using the RS (OR: 9.76, 95% CI: 6.72-14.18, P < 0.001). For those with stage II disease, concordant results between the 12-gene assay and MDT were more likely than discordant (OR: 0.30, 95% CI: 0.17-0.53, P < 0.001). In stage II disease, patients were more likely to have chemotherapy omitted than escalated when using the RS (OR: 7.39, 95% CI: 4.85-11.26, P < 0.001).

CONCLUSIONS

The use of the 12-gene signature refutes the decision of tumour board in 25% of cases, with 75% of discordant decisions resulting in omission of adjuvant chemotherapy. Therefore, it is possible that a proportion of such patients are being overtreated when relying on tumour board decisions alone.

Molecular mechanisms targeting drug-resistance and metastasis in colorectal cancer: Updates and beyond

Colorectal cancer (CRC) is the third most diagnosed malignancy and a major leading cause of cancer-related deaths worldwide. Despite advances in therapeutic regimens, the number of patients presenting with metastatic CRC (mCRC) is increasing due to resistance to therapy, conferred by a small population of cancer cells, known as cancer stem cells. Targeted therapies have been highly successful in prolonging the overall survival of patients with mCRC. Agents are being developed to target key molecules involved in drug-resistance and metastasis of CRC, and these include vascular endothelial growth factor, epidermal growth factor receptor, human epidermal growth factor receptor-2, mitogen-activated extracellular signal-regulated kinase, in addition to immune checkpoints. Currently, there are several ongoing clinical trials of newly developed targeted agents, which have shown considerable clinical efficacy and have improved the prognosis of patients who do not benefit from conventional chemotherapy. In this review, we highlight recent developments in the use of existing and novel targeted agents against drug-resistant CRC and mCRC. Furthermore, we discuss limitations and challenges associated with targeted therapy and strategies to combat intrinsic and acquired resistance to these therapies, in addition to the importance of implementing better preclinical models and the application of personalized therapy based on predictive biomarkers for treatment selection.

KRAS, NRAS, BRAF signatures, and MMR status in colorectal cancer patients in North China

We assessed the clinicopathological features and prognostic values of KRAS, NRAS, BRAF, and DNA mismatch repair status in colorectal cancer (CRC) to provide real-world data in developing countries. We enrolled 369 CRC patients and analyzed the correlation between RAS/BRAF mutation, mismatch repair status with clinicopathological features, and their prognostic roles. The mutation frequencies of KRAS, NRAS, and BRAF were 41.7%, 1.6%, and 3.8%, respectively. KRAS mutations and deficient mismatch repair (dMMR) status were associated with right-sided tumors, aggressive biological behaviors, and poor differentiation. BRAF (V600E) mutations are associated with well-differentiated and lymphovascular invasion. The dMMR status predominated in young and middle-aged patients and tumor node metastasis stage II patients. dMMR status predicted longer overall survival in all CRC patients. KRAS mutations indicated inferior overall survival in patients with CRC stage IV. Our study showed that KRAS mutations and dMMR status could be applied to CRC patients with different clinicopathological features.

EPIDEMIOLOGICAL AND MOLECULAR EVALUATION OF BRAF, KRAS, NRAS GENES, AND MSI IN THE DEVELOPMENT OF COLORECTAL CANCER

BACKGROUND AND OBJECTIVES

KRAS, NRAS, BRAF Mutations and microsatellite instability (MSI) can be associated with Colorectal Cancer (CRC) development.

MATERIAL AND METHODS

We evaluated 828 medical records of CRC patients from a school hospital from January/2016 to December/2020. Variables such as age, gender, ethnicity, literacy level, smoking, alcoholism, primary anatomical site, tumor staging, presence of BRAFV600E, KRAS, NRAS and MSI mutations, survival and metastasis were identified. The statistical analyses were performed (p<0.05 is significant.

RESULTS

There was a predominance of males (51.93%), whites (90.70%), low education (72.34%), smokers (73.79%), and non- alcoholics (79.10%). Rectum was the most affected site (42.14%), advanced tumor stage was most prevalent (62.07%), and metastasis occurred in (64.61%). Of the enrolled patients; 204 were investigated for BRAF mutation and detected in (2.94%); 216 for KRAS gene and detected in (26.08%); 210 for NRAS gene, and detected in (25.36%); 370 for MSI, and detected in (44.68%). A significant association of CRC with NRAS mutation and alcohol habit (p = 0.043) was observed. The presence of MSI was associated with primary site proximal colon (p<0.000), distal colon (p=0.001) and rectum (p=0.010).

CONCLUSION

Patients with CRC are male, over 64 years old, white, with low education, smokers and non-alcoholics. The most affected primary site is rectum in advanced stage with metastasis. CRC is associated with NRAS mutation and alcohol habit, there is increased risk for primary site of proximal colon and MSI; decreased risk for distal colon and rectum in the presence of MSI mutation.

Microsatellite instability is associated with worse overall survival in resectable colorectal liver metastases

BACKGROUND

Microsatellite instability (MSI) has been associated with improved overall survival (OS) in locoregional colorectal cancer; however, the effects on colorectal liver metastases (CRLM) have not been studied.

METHODS

The National Cancer Database (NCDB) was queried for patients with CRLM that underwent metastasectomy. Patients with microsatellite stable tumors (MSS) (n = 2,316, 84.4%) were compared those with MSI (n = 427, 15.6%).

RESULTS

Baseline characteristics, including sex, race, and underlying comorbidities, were similar between groups. MSS patients had lower rates of high-risk pathologic features and higher rates of receiving multi-agent chemotherapy. On Kaplan-Meier analysis, median OS in the MSS group was improved compared with the MSI group (41.1 mo vs. 33.2 mo, p < 0.01). On multivariate analysis MSI status remained associated with worse OS (HR: 1.21 95% CI: 1.01-1.46, p = 0.04).

CONCLUSIONS

This national analysis of CRLM validates MSI status as a biomarker to guide clinical decision-making due to the associated poor prognosis.

Integrated Decision-Making in the Treatment of Colon-Rectal Cancer: The Case of KRAS-Mutated Tumors

In recent years, precision medicine has taken an increasing place in various branches of medical oncology, including colorectal cancer. Among the potentially relevant mutations for this cancer is the KRAS mutation, initially defined as "untargetable"; today, we see the birth of new molecules that target one of the variants of the KRAS mutation, KRAS G12C, having a significant impact on the therapeutic options for other malignancies, such as metastatic lung cancer. This fundamental step forward has stimulated scientific research on other potential targets of KRAS, both indirect and direct, and combination treatments aiming to overcome the mechanisms of resistance to these drugs that decrease in efficacy in colorectal cancer. What was once a negative predictive marker of response to anti-EGFR drugs today has become a potential target for targeted treatments. In turn, the prognostic role of the mutation has become extremely interesting, making it a potentially useful element in therapeutic decision-making, not only regarding oncological treatments but also in a more complex and complete manner within a global vision of the patient, involving other figures on the multidisciplinary team, such as surgeons, radiotherapists, and interventional radiologists.

Relationship between prognostic impact of N3 lymph node metastasis at the root of the feeding artery and location of colon cancer

PURPOSE

To determine whether N3 nodal involvement predicts outcomes and whether its prognostic implications vary with tumor location in patients with Stage III colon cancer (CC).

METHODS

We defined N3 as lymph node metastases near the bases of the major feeding arteries. We retrospectively examined recurrence rates and patterns by tumor location and sites of lymph node metastases in 57 patients with N3 CC who had undergone curative resections between January 2000 and March 2019. Survival analysis was performed to compare the prognoses of patients with and without N3 lymph node metastasis.

RESULTS

Most N3 patients had large tumors (T ≥ 3); five had T2 disease. Recurrence occurred quickly in one patient with T2N3M0 disease. Multivariate survival analysis demonstrated that N3 lymph node metastasis is an independent predictor of poor prognosis in Stage III CC patients (P < 0.001). Categorizing N3 patients according to UICC-TNM staging system does not stratify risk of recurrence (P = 0.970). To investigate the impact of tumor location on recurrence risk, we classified N3 CC into two subtypes according to tumor location: metastasis at the base of the superior mesenteric artery in right-sided CC and inferior mesenteric artery in left-sided CC. The former was found to have a statistically significant poorer prognosis than the latter (P = 0.091).

CONCLUSION

N3 is a robust prognostic marker in CC patients. Recurrence risk varies by tumor location. N3 right-sided CCs with lymph node metastasis at the base of the superior mesenteric artery have poorer prognoses than do N3 left-sided CCs.