Mutation spectra of RAS gene family in colorectal cancer. Am J Surg. 2016;212:537-544.e3. [PMID: 27394063 DOI: 10.1016/j.amjsurg.2016.02.013]

KRAS/NRAS/BRAF mutational profile and association with clinicopathological characteristics in patients with metastatic colorectal cancer

Colorectal cancer (CRC) is increasingly prevalent in Jordan and poses a significant public health challenge. The presence of Kirsten rat sarcoma viral oncogene homolog (KRAS), neuroblastoma RAS viral oncogene homolog (NRAS) and v-Raf Murine Sarcoma Viral Oncogene Homolog B (BRAF) mutations is key in CRC diagnostics, as these mutations are associated with resistance to monoclonal antibodies targeting the epidermal growth factor receptor. The present study aimed to identify these mutations in patients with CRC and assess their associations with clinicopathological characteristics. A retrospective analysis was conducted using data from 262 patients with metastatic CRC (mCRC) at the Jordanian Military Cancer Center-Royal Medical Services (Amman, Jordan). Variables such as age, sex, tumor differentiation and the mutational status of KRAS, NRAS and BRAF, along with tumor location, were analyzed statistically to explore associations between mutations and tumor characteristics. Among the included patients, 48.5% had KRAS mutations, 3.8% had NRAS mutations and 0.8% had BRAF mutations. The majority of KRAS mutations were in exon 2 at codons 12 and 13, with the highest mutational rate at 45.8%. In the univariate model, NRAS mutations were significantly associated with moderately differentiated tumors and the multivariate hierarchical regression analysis established that KRAS mutations were significantly associated with histological subtypes [mucinous adenocarcinoma, tubular adenocarcinoma, signet adenocarcinoma and adenocarcinoma (not specified)]. These results highlighted the molecular profiles and clinicopathological characteristics of patients with mCRC, which demonstrated the associations between mutational status and the varying clinicopathological aspects based on the type of RAS mutation. Thus, these specific traits (patient's age, sex, CRC site, histological subtypes and tumor grade) may be taken into account when evaluating the predictive significance of RAS and BRAF status in CRC and tailored treatment strategies.

Somatic pharmacogenomics in the treatment prognosis of locally advanced rectal cancer patients: a narrative review of the literature

INTRODUCTION

Standard treatment for patients with locally advanced rectal cancer (LARC) includes neoadjuvant chemoradiotherapy (nCRT) with fluoropyrimidines, followed by surgical excision. The newly introduced therapeutic strategies propose intensified regimens or more conservative approaches based on risk stratification algorithms that currently include clinicoradiological criteria but not molecular variables. How to better stratify patients is a burning clinical question, and pharmacogenomics may prove useful in identifying new genetic markers that could be incorporated into clinical algorithms to personalize nCRT. An emerging area could be the evaluation of somatic mutations as potential genetic markers that correlate with patient prognosis. Tumor mutations in the RAS/BRAF genes, as well as microsatellite instability (MSI) status, are currently used in treatment selection for colorectal cancer (CRC); however, their clinical value in LARC is still unclear.

AREA COVERED

This literature review discusses the relevant findings on the prognostic role of mutations in the key oncogenes RAS, KRAS, BRAF, PIK3CA, SMAD4 and TP53, including MSI status in LARC patients treated with nCRT.

EXPERT OPINION

KRAS proved to be the most promising marker, consistently associated with poorer disease-free survival and overall survival. Therefore, KRAS could be a good candidate for integration into the risk stratification algorithm to develop a personalized treatment.

Impact of Systemic Treatments on Outcomes and Quality of Life in Patients with RAS-Positive Stage IV Colorectal Cancer: A Systematic Review

This systematic review critically evaluates the impact of systemic treatments on outcomes and quality of life (QoL) in patients with RAS-positive stage IV colorectal cancer, with studies published up to December 2023 across PubMed, Scopus, and Web of Science. From an initial pool of 1345 articles, 11 relevant studies were selected for inclusion, encompassing a diverse range of systemic treatments, including panitumumab combined with FOLFOX4 and FOLFIRI, irinotecan paired with panitumumab, regorafenib followed by cetuximab ± irinotecan and vice versa, and panitumumab as a maintenance therapy post-induction. Patient demographics predominantly included middle-aged to elderly individuals, with a slight male predominance. Racial composition, where reported, showed a majority of Caucasian participants, highlighting the need for broader demographic inclusivity in future research. Key findings revealed that the addition of panitumumab to chemotherapy (FOLFOX4 or FOLFIRI) did not significantly compromise QoL while notably improving disease-free survival, with baseline EQ-5D HSI mean scores ranging from 0.76 to 0.78 and VAS mean scores from 70.1 to 74.1. Improvements in FACT-C scores and EQ-5D Index scores particularly favored panitumumab plus best supportive care in KRAS wild-type mCRC, with early dropout rates of 38-42% for panitumumab + BSC. Notably, cetuximab + FOLFIRI was associated with a median survival of 25.7 months versus 16.4 months for FOLFIRI alone, emphasizing the potential benefits of integrating targeted therapies with chemotherapy. In conclusion, the review underscores the significant impact of systemic treatments, particularly targeted therapies and their combinations with chemotherapy, on survival outcomes and QoL in patients with RAS-positive stage IV colorectal cancer, and the need for personalized treatment.

Correlation between NGS panel-based mutation results and clinical information in colorectal cancer patients

Early mutation identification guides patients with colorectal cancer (CRC) toward targeted therapies. In the present study, 414 patients with CRC were enrolled, and amplicon-based targeted next-generation sequencing (NGS) was then performed to detect genomic alterations within the 73 cancer-related genes in the OncoAim panel. The overall mutation rate was 91.5 % (379/414). Gene mutations were detected in 38/73 genes tested. The most frequently mutated genes were TP53 (60.9 %), KRAS (46.6 %), APC (30.4 %), PIK3CA (15.9 %), FBXW7 (8.2 %), SMAD4 (6.8 %), BRAF (6.5 %), and NRAS (3.9 %). Compared with the wild type, TP53 mutations were associated with low microsatellite instability/microsatellite stability (MSI-L/MSS) (P = 0.007), tumor location (P = 0.043), and histological grade (P = 0.0009); KRAS mutations were associated with female gender (P = 0.026), distant metastasis (P = 0.023), TNM stage (P = 0.013), and histological grade (P = 0.004); APC mutations were associated with patients <64 years of age at diagnosis (P = 0.04); PIK3CA mutations were associated with tumor location (P = 4.97e-06) and female gender (P = 0.018); SMAD4 mutations were associated with tumor location (P = 0.033); BRAF mutations were associated with high MSI (MSI-H; P = 6.968e-07), tumor location (P = 1.58e-06), and histological grade (P = 0.04). Mutations in 164 individuals were found to be pathogenic or likely pathogenic. A total of 26 patients harbored MSI-H tumors and they all had at least one detected gene mutation. Mutated genes were enriched in signaling pathways associated with CRC. The present findings have important implications for improving the personalized treatment of patients with CRC in China.

Association of KRAS, NRAS, BRAF and PIK3CA gene mutations with clinicopathological features, prognosis and ring finger protein 215 expression in patients with colorectal cancer

The relationships of KRAS, NRAS, BRAF and PIK3CA gene mutations with the clinicopathological features and prognosis of colorectal cancer (CRC) in patient are lacking. Furthermore, the role of ring finger protein 215 (RNF215) in CRC patients with KRAS, NRAS, BRAF and PIK3CA mutations remains unclear. In the present study, 182 surgical resection specimens from patients with primary CRC for retrospective analysis, were collected. KRAS/NRAS/BRAF/PIK3CA gene mutations were confirmed by an amplification-refractory mutation system. Immunohistochemistry (IHC) was conducted to confirm KRAS, NRAS, BRAF and PIK3CA protein expression. RNF215 expression in patients with CRC was evaluated using TIMER 2.0 database and IHC. The individual mutation rates of KRAS, NRAS, BRAF and PIK3CA were 40.7% (74/182), 4.4% (8/182), 4.4% (8/182) and 3.3% (6/182), respectively. The KRAS exon 2 mutation rate was the highest (61.5%, 64/104), and these mutations mainly occurred at codons 12 and 13. KRAS/NRAS/BRAF/PIK3CA wild-type CRC patients had significantly longer overall survival and disease-free survival than mutated KRAS/NRAS/BRAF/PIK3CA CRC patients (P<0.05). Overall, 45.4% (5/11) of patients with PIK3CA mutations had concomitant KRAS mutations. The KRAS/NRAS/BRAF/PIK3CA gene mutation rate in patients with lymph node metastasis (76.1%, 35/46) was significantly higher than that in patients without lymph node metastasis (50.8%, 69/136) (P=0.0027). There were no significant differences in IHC expression between patients with and without KRAS, NRAS, BRAF and PIK3CA mutations (P>0.05). The TIMER 2.0 analysis showed that RNF215 expression was significantly higher in the mutated BRAF group than in the wild-type BRAF group in CRC (P<0.05). In conclusion, KRAS is the most commonly mutated gene, and KRAS mutations may be a poor prognostic factor for patients with CRC. KRAS wild-type patient resistance may be related to PIK3CA gene mutations, although this needs further verification in larger cohorts. BRAF mutations may be associated with RNF215 expression in patients with CRC.

Neuropsychiatric adverse drug reactions with oral tyrosine kinase inhibitors in metastatic colorectal cancer: an analysis from the FDA Adverse Event Reporting System

Introduction

New oral tyrosine kinase inhibitors (TKIs) are approved for metastatic colorectal cancer (mCRC). The aim of this study was to assess the neuropsychiatric adverse drug reactions (ADRs) of these drugs reported in the FDA Adverse Event Reporting System (FAERS) database.

Methods

All reports with regorafenib (REG) and encorafenib (ENC) as the primary suspect, and reported in the FAERS between 2012 and 2022, were collected. A descriptive and disproportionality analyses were conducted.

Results

Out of 4,984 cases, 1,357 (30.2%) reported at least one neuropsychiatric ADR. New potential signals for REG included neuropathy peripheral (n = 265; reporting odds ratio, ROR = 19.48, 95% confidence interval, CI 95% = 17.52-22.47; information component, IC = 2.89, IC025-IC075 = 2.77-3.02), hyperesthesia (n = 18; ROR = 12.56, CI 95% = 7.90-19.96; IC = 2.25, IC025-IC075 = 1.79-2.72), taste disorder (n = 41; ROR = 9.91, CI 95% = 7.29-13.49; IC = 2.18, IC025-IC075 = 1.88-2.49), poor quality sleep (n = 18; ROR = 6.56, CI 95% = 4.13-10.42; IC = 1.74, IC025-IC075 = 1.27-2.20), altered state of consciousness (n = 15; ROR = 5.50, CI 95% = 3.31-9.14; IC = 1.57, IC025-IC075 = 1.06-2.07), depressed mood (n = 13; ROR = 1.85, CI 95% = 1.07-3.19; IC = 0.58, IC025-IC075 = 0.04-1.13) and insomnia (n = 63; ROR = 1.48, CI 95% = 1.15-1.89; IC = 0.38, IC025-IC075 = 0.13-0.63). For ENC comprised depressed mood (n = 4; ROR = 5.75, CI 95% = 2.15-15.39; IC = 1.74, IC025-IC075 = 0.76-2.73) and cognitive disorders (n = 3; ROR = 4.71, CI 95% = 1.51-14.66; IC = 1.54, IC025-IC075 = 0.41-2.68).

Discussion

This study identified new unknown potential neuropsychiatric ADRs. Further investigations are required to better define the neurotoxicity of TKIs in mCRC patients.

Renal Disorders with Oral Tyrosine Kinase Inhibitors in Metastatic Colorectal Cancer: An Analysis from the FDA Adverse Event Reporting System Database

BACKGROUND

this study assessed the nephrotoxicity of regorafenib (REG) and encorafenib (ENC) in metastatic colorectal cancer (mCRC) through an analysis of reports from the US Food and Drug Administration's Adverse Event Reporting System (FAERS) database.

METHODS

descriptive and disproportional analyses were performed for all reports using ENC and REG as the primary suspect.

RESULTS

A total of 379 reports had at least one renal adverse drug reaction (ADR), and these ADRs were mainly related to REG (93.1%). Potential safety signals for REG included chromaturia (n = 44; ROR = 12.00, CI 95% = 8.92-16.16; IC = 2.36, IC025-IC075 = 2.06-2.66), hydronephrosis (10; 8.70, 4.67-16.19; 1.85, 1.23-2.47), nephrotic syndrome (7; 5.73, 2.73-12.03; 1.47, 0.73-2.21), renal impairment (53; 4.16, 3.17-5.45; 1.39, 1.12-1.66), dysuria (19; 3.06, 1.95-4.81; 1.06, 0.61-1.52), renal failure (38; 1.66, 1.20-2.28; 0.49, 0.17-0.81), and acute kidney injury (AKI) (43; 1.46, 1.08-1.97; 0.37, 0.07-0.67). For ENC, consistent disproportionalities were observed for AKI (n = 11; ROR = 3.79, CI 95% = 2.09-6.90; IC = 1.32, IC025-IC075 = 0.72-1.91) and dysuria (4; 6.50, 2.43-17.39; 1.86, 0.88-2.85).

CONCLUSIONS

these findings highlight some not extensively reported renal ADRs that require further investigations to better characterize the safety profiles of REG and ENC in patients with mCRC.

Drosophila melanogaster: A platform for anticancer drug discovery and personalized therapies

Cancer is a complex disease whereby multiple genetic aberrations, epigenetic modifications, metabolic reprogramming, and the microenvironment contribute to the development of a tumor. In the traditional anticancer drug discovery pipeline, drug candidates are usually screened in vitro using two-dimensional or three-dimensional cell culture. However, these methods fail to accurately mimic the human disease state. This has led to the poor success rate of anticancer drugs in the preclinical stages since many drugs are abandoned due to inefficacy or toxicity when transitioned to whole-organism models. The common fruit fly, Drosophila melanogaster, has emerged as a beneficial system for modeling human cancers. Decades of fundamental research have shown the evolutionary conservation of key genes and signaling pathways between flies and humans. Moreover, Drosophila has a lower genetic redundancy in comparison to mammals. These factors, in addition to the advancement of genetic toolkits for manipulating gene expression, allow for the generation of complex Drosophila genotypes and phenotypes. Numerous studies have successfully created Drosophila models for colorectal, lung, thyroid, and brain cancers. These models were utilized in the high-throughput screening of FDA-approved drugs which led to the identification of several compounds capable of reducing proliferation and rescuing phenotypes. More noteworthy, Drosophila has also unlocked the potential for personalized therapies. Drosophila ‘avatars’ presenting the same mutations as a patient are used to screen multiple therapeutic agents targeting multiple pathways to find the most appropriate combination of drugs. The outcomes of these studies have translated to significant responses in patients with adenoid cystic carcinoma and metastatic colorectal cancers. Despite not being widely utilized, the concept of in vivo screening of drugs in Drosophila is making significant contributions to the current drug discovery pipeline. In this review, we discuss the application of Drosophila as a platform in anticancer drug discovery; with special focus on the cancer models that have been generated, drug libraries that have been screened and the status of personalized therapies. In addition, we elaborate on the biological and technical limitations of this system.

Tumor profiling of KRAS, BRAF, and NRAS gene mutations in patients with colorectal cancer: A Lebanese major center cohort study

BACKGROUND

In the era of precision medicine, treatment schemes for advanced Colorectal (CRC) disease include monoclonal antibodies which block the epidermal growth factor receptor (EGFR) implicated in tumor proliferation, invasion, migration and neovascularization. Resistance to these agents has been correlated with activating downstream mutations in KRAS, BRAF and NRAS genes, among others, leading to constitutive activation of the EGFR axis bypassing EGFR blockade. The assessment of tumor RASandBRAFmutational status has thus become standard clinical practice. While multiple investigations reported roughly mutations rates of 40% in KRAS, 7% in NRAS and 5-15 % in BRAF, numbers vary across different populations with limited data specifically from the Middle East.

METHODS

This is a retrospective observational Laboratory information system (LIS) chart review of all the patients with pathologically confirmed colorectal carcinoma (CRC) or metastatic CRC who underwent KRAS, NRAS and/or BRAF mutational analysis testing at the Molecular Diagnostics Laboratory of the American University of Beirut Medical Center (AUBMC) from January 2012 to December 2018, inclusive. Data retrieved included the results of mutation testing performed for KRAS, NRAS and BRAF genes, the age, gender, and tumor location for each patient. Analysis of the mutations was performed using polymerase chain reaction (PCR) hybridization StripAssay® (ViennaLab, Vienna, Austria).

RESULTS

130 (47.6%) out of 273 histologically confirmed CRC cases, had positive KRAS mutations, namely in codons 12 (82%), 13 (17%), 146 (1.5%), 117 (0.75%), or 61 (0.75%). Two patients had two concomitant mutations: 12 + 12 (different mutations) and 12 + 146. Of 203 CRC cases tested for NRAS mutations, 16 (7.8%) were found to be positive for a mutation in codon 12 (37.5%), 61 (37.5%), or 13 (12.5%). Two patients had two concomitant mutations: 12 + 13 and 59 + 61. Of 172 CRC cases tested for BRAF mutations, 2 (1.2 %) were positive for the V600E -.

CONCLUSION

This retrospective study is the first to report the frequencies of KRAS, NRAS and BRAF gene mutations in a Lebanese CRC cohort diagnosed and managed at a tertiary care center. The frequencies of the studied somatic gene mutations were similar to previously reported cohorts in other populations however the rate of BRAF mutation was lower in this cohort than expected.

Mutant RAS and the tumor microenvironment as dual therapeutic targets for advanced colorectal cancer

RAS genes are the most frequently mutated oncogenes in cancer. These mutations occur in roughly half of the patients with colorectal cancer (CRC). RAS mutant tumors are resistant to therapy with anti-EGFR monoclonal antibodies. Therefore, patients with RAS mutant CRC currently have few effective therapy options. RAS mutations lead to constitutively active RAS GTPases, involved in multiple downstream signaling pathways. These alterations are associated with a tumor microenvironment (TME) that drives immune evasion and disease progression by mechanisms that remain incompletely understood. In this review, we focus on the available evidence in the literature explaining the potential effects of RAS mutations on the CRC microenvironment. Ongoing efforts to influence the TME by targeting mutant RAS and thereby sensitizing these tumors to immunotherapy will be discussed as well.

Oncogenic KRAS drives radioresistance through upregulation of NRF2-53BP1-mediated non-homologous end-joining repair

KRAS-activating mutations are oncogenic drivers and are correlated with radioresistance of multiple cancers, including colorectal cancer, but the underlying precise molecular mechanisms remain elusive. Herein we model the radiosensitivity of isogenic HCT116 and SW48 colorectal cancer cell lines bearing wild-type or various mutant KRAS isoforms. We demonstrate that KRAS mutations indeed lead to radioresistance accompanied by reduced radiotherapy-induced mitotic catastrophe and an accelerated release from G2/M arrest. Moreover, KRAS mutations result in increased DNA damage response and upregulation of 53BP1 with associated increased non-homologous end-joining (NHEJ) repair. Remarkably, KRAS mutations lead to activation of NRF2 antioxidant signaling to increase 53BP1 gene transcription. Furthermore, genetic silencing or pharmacological inhibition of KRAS, NRF2 or 53BP1 attenuates KRAS mutation-induced radioresistance, especially in G1 phase cells. These findings reveal an important role for a KRAS-induced NRF2-53BP1 axis in the DNA repair and survival of KRAS-mutant tumor cells after radiotherapy, and indicate that targeting NRF2, 53BP1 or NHEJ may represent novel strategies to selectively abrogate KRAS mutation-mediated radioresistance.

Implications for the colorectal surgeon following the 100 000 Genomes Project

AIM

The 100 000 Genomes Project was completed in 2019 with the objective of integrating genomic medicine into routine National Health Service (NHS) clinical pathways. This project and genomic research will revolutionize the way we practice colorectal surgery in the 21st century. This paper aims to provide an overview of genomic medicine and its implications for the colorectal surgeon.

RESULTS

Within NHS England, consolidation has created seven regional Genomic Laboratory Hubs. DNA from solid tumours, including colorectal cancers, will be assessed using 500-gene panels, results will be fed back to Genome Tumour Advisory Boards. Identifying variants from biopsies earlier in the clinical pathway may alter surgical and other treatment options for patients. However, there is an important distinction between somatic variants within a tumour biopsy and germline variants that may suggest a heritable condition such as Lynch syndrome. Novel drugs, for example immunotherapy, will increase treatment options including downstaging cancers and changing the surgical approach. The use of circulating tumour DNA (liquid biopsies) will have applications in diagnosis, treatment and surveillance of cancer. There are many exciting potential future applications of this technology for offering personalized medicine that will require multidisciplinary working and the colorectal community.

CONCLUSION

There are many challenges but also exciting opportunities to embed new 'omic' technologies and innovation into 21st century colorectal surgery. The next phase for the colorectal community is how we engage with this change, with questions around training, identification of genomic multidisciplinary team (MDT) champions and how we collaborate with the core members of the MDT, clinical geneticists and national genomic testing.

Enhancing the landscape of colorectal cancer using targeted deep sequencing

Targeted next-generation sequencing (NGS) technology detects specific mutations that can provide treatment opportunities for colorectal cancer (CRC) patients. We included 145 CRC patients who underwent surgery. We analyzed the mutation frequencies of common actionable genes and their association with clinicopathological characteristics and oncologic outcomes using targeted NGS. Approximately 97.9% (142) of patients showed somatic mutations. Frequent mutations were observed in TP53 (70%), APC (60%), and KRAS (49%). TP53 mutations were significantly linked to higher overall stage (p = 0.038) and lower disease-free survival (DFS) (p = 0.039). ATM mutation was significantly associated with higher tumor stage (p = 0.012) and shorter overall survival (OS) (p = 0.041). Stage 3 and 4 patients with ATM mutations (p = 0.023) had shorter OS, and FBXW7 mutation was significantly associated with shorter DFS (p = 0.002). However, the OS of patients with or without TP53, RAS, APC, PIK3CA, and SMAD4 mutations did not differ significantly (p = 0.59, 0.72, 0.059, 0.25, and 0.12, respectively). Similarly, the DFS between patients with RAS, APC, PIK3CA, and SMAD4 mutations and those with wild-type were not statistically different (p = 0.3, 0.79, 0.13, and 0.59, respectively). In multivariate Cox regression analysis, ATM mutation was an independent biomarker for poor prognosis of OS (p = 0.043). A comprehensive analysis of the molecular markers for CRC can provide insights into the mechanisms underlying disease progression and help optimize a personalized therapy.

Clinicopathological characteristics and mutational profile of KRAS and NRAS in Tunisian patients with sporadic colorectal cancer

Background/aim

Colorectal cancer (CRC) is a major public health problem worldwide and in Tunisia due to its increasing rate of incidence. KRAS and NRAS mutations have become a pivotal part of CRC diagnosis, given their association to treatment resistance with antiepidermal growth factor receptor (EGFR) monoclonal antibodies. In this study, we aimed to screen for mutations in KRAS and NRAS genes in Tunisian patients with CRC and explore their correlations with clinicopathological features.

Materials and methods

AmoyDx KRAS and NRAS mutation real-time PCR kits were used to screen for mutations in KRAS (exon 2) and NRAS (exons 2, 3, and 4) in 96 CRC tumors.

Results

KRAS exon 2 mutations were found in 41.7% (40/96) of the patients. Codon 12’s most abundant mutations were G12D and G12V, followed by G12A, while G13D is the predominant mutation in codon 13. KRAS exon 2 mutations were associated with older patients (P = 0.029), left-sided tumors (P = 0.037), and greater differentiation (P = 0.044). The prevalence rate of NRAS mutations was 7.3%, mostly in exon 2. These mutations were associated with early stages of the disease (P = 0.039) and the absence of lymph node metastasis (P = 0.045).

Conclusion

It can be inferred from this study that Tunisian CRC patients have a similar frequency of KRAS and NRAS mutations compared to those observed in other populations. Consequently, screening for KRAS and NRAS mutations is crucial for the orientation of therapies and the selection of appropriate candidates, while also helping to avoid unnecessary toxicity and increased costs for patients.

Prediction of clinically actionable genetic alterations from colorectal cancer histopathology images using deep learning

BACKGROUND

Identifying genetic mutations in cancer patients have been increasingly important because distinctive mutational patterns can be very informative to determine the optimal therapeutic strategy. Recent studies have shown that deep learning-based molecular cancer subtyping can be performed directly from the standard hematoxylin and eosin (H&E) sections in diverse tumors including colorectal cancers (CRCs). Since H&E-stained tissue slides are ubiquitously available, mutation prediction with the pathology images from cancers can be a time- and cost-effective complementary method for personalized treatment.

AIM

To predict the frequently occurring actionable mutations from the H&E-stained CRC whole-slide images (WSIs) with deep learning-based classifiers.

METHODS

A total of 629 CRC patients from The Cancer Genome Atlas (TCGA-COAD and TCGA-READ) and 142 CRC patients from Seoul St. Mary Hospital (SMH) were included. Based on the mutation frequency in TCGA and SMH datasets, we chose APC, KRAS, PIK3CA, SMAD4, and TP53 genes for the study. The classifiers were trained with 360 × 360 pixel patches of tissue images. The receiver operating characteristic (ROC) curves and area under the curves (AUCs) for all the classifiers were presented.

RESULTS

The AUCs for ROC curves ranged from 0.693 to 0.809 for the TCGA frozen WSIs and from 0.645 to 0.783 for the TCGA formalin-fixed paraffin-embedded WSIs. The prediction performance can be enhanced with the expansion of datasets. When the classifiers were trained with both TCGA and SMH data, the prediction performance was improved.

CONCLUSION

APC, KRAS, PIK3CA, SMAD4, and TP53 mutations can be predicted from H&E pathology images using deep learning-based classifiers, demonstrating the potential for deep learning-based mutation prediction in the CRC tissue slides.

Probiotic Lactobacillus salivarius Ren prevent dimethylhydrazine-induced colorectal cancer through protein kinase B inhibition

Probiotics are known to be a potential agent for colorectal cancer (CRC) inhibition, but the precise mechanisms by which probiotic exert anti-tumorigenic effects remain to be explored. Lactobacillus salivarius (LS) Ren was isolated from centenarians living in Bama of China, which showed an anticancer potent in animal model of oral cancer. Here, we investigated the effect of LS on colorectal carcinogenesis and its putative mechanism. Oral administration of LS effectively suppressed the formation of dimethylhydrazine (DMH)-induced CRC in both initial and post-initial stages. Significant antiproliferation and proapoptotic effects were observed with inhibition of tumor formation by dietary intake of LS. Besides, LS metabolites inhibited growth, arrested cell cycle, and induced apoptosis of HT-29 cells. Furthermore, upon the treatment of LS, protein kinase B (AKT) phosphorylation and the downstream proteins of cyclinD1 and cyclooxygenase-2 (COX-2) were significantly downregulated in both in vivo and in vitro tests. These results showed that LS inhibited the colorectal carcinogenesis through suppressing AKT signaling pathway, resulting in suppressing cell proliferation and inducing cell apoptosis. Our findings suggest that this probiotic may act as a prophylactic agent for CRC prevention. Key points • LS effectively prevented rat colorectal carcinogenesis induced by DMH. • LS modulated the proliferation and apoptosis in both in vivo and in vitro. • LS inhibited AKT phosphorylation and expressions of downstream cyclinD1 and COX-2.

Effect of Tumor Location on Clinicopathological and Molecular Markers in Colorectal Cancer in Eastern China Patients: An Analysis of 2,356 Cases

Colorectal cancer (CRC) has become a major health concern in China due to its increasing incidence and mortality. This study aimed to clarify the relationship between tumor locations and the clinicopathological molecular marker features in eastern China CRC patients. We continuously collected data on 2,356 CRC patients who underwent surgical resection from January 2017 to April 2019. Right-sided colorectal cancer (RCC), was located from the cecum to the transverse colon and left-side colorectal cancer (LCRC) was located from the splenic flexure to the rectum. The clinicopathological indices (including age, sex, pTNM stage, mucinous production, and distant metastasis) and frequency of molecular markers such as KRAS, NRAS, BRAF, and microsatellite instability (MSI) were statistically analyzed between the RCC and LCRC groups. The associations between clinicopathological characters and molecular markers were also investigated. LCRC and RCC proportions in eastern China CRC patients were 81.75% and 18.25%, respectively. RCC (vs. LCRC) was more frequently observed with higher frequencies of MSI-high (MSI-H) and BRAF mutations in female and younger patients, and was closely associated with metastasis, poor differentiation, and mucinous tumors. Tumor location also showed significant differences in bowel wall infiltration degree and pTNM stage. Mutation rates of KRAS, NRAS, MSI, and BRAF were 40.15%, 3.85%, 6.31%, and 2.30%, respectively. Patients with a KRAS mutation tended to be female, had mucinous, perineural invasive, and polypoid tumor. Those with NRAS mutation tended to develop well-differentiated ulcerative tumors. The BRAF mutation was more relevant with lymph node involvement, deeper infiltration of the bowel wall, mucinous, poorly-differentiated tumor with thrombus, and perineural invasion. Furthermore, MSI-H was more commonly found in younger patients with deeper bowel wall infiltration and a poorly-differentiated polypoid tumor, whereas MSS patients tended to develop lymph node involvement, and a mucinous and perineural invasive tumor. In our study, we found that LCRC and RCC showed different features on the clinicopathological and molecular markers in eastern China CRC patients. Since our data differ from those of Western countries and other regions in China, further studies are required to clarify the regional differences of the clinicopathological and molecular markers in CRC patients.

Anti-tumor effects of an antagonistic mAb against the ASCT2 amino acid transporter on KRAS-mutated human colorectal cancer cells

KRAS mutations are detected in numerous human cancers, but there are few effective drugs for KRAS-mutated cancers. Transporters for amino acids and glucose are highly expressed on cancer cells, possibly to maintain rapid cell growth and metabolism. Alanine-serine-cysteine transporter 2 (ASCT2) is a primary transporter for glutamine in cancer cells. In this study, we developed a novel monoclonal antibody (mAb) recognizing the extracellular domain of human ASCT2, and investigated whether ASCT2 can be a therapeutic target for KRAS-mutated cancers. Rats were immunized with RH7777 rat hepatoma cells expressing human ASCT2 fused to green fluorescent protein (GFP). Splenocytes from the immunized rats were fused with P3X63Ag8.653 mouse myeloma cells, and selected and cloned hybridoma cells secreting Ab3-8 mAb were established. This mAb reacted with RH7777 transfectants expressing ASCT2-GFP proteins in a GFP intensity-dependent manner. Ab3-8 reacted with various human cancer cells, but not with non-cancer breast epithelial cells or ASCT2-knocked out HEK293 and SW1116 cells. In SW1116 and HCT116 human colon cancer cells with KRAS mutations, treatment with Ab3-8 reduced intracellular glutamine transport, phosphorylation of AKT and ERK, and inhibited in vivo tumor growth of these cells in athymic mice. Inhibition of in vivo tumor growth by Ab3-8 was not observed in HT29 colon and HeLa uterus cancer cells with wild-type KRAS. These results suggest that ASCT2 is an excellent therapeutic target for KRAS-mutated cancers.

RAS and BRAF in the foreground for non-small cell lung cancer and colorectal cancer: Similarities and main differences for prognosis and therapies

Lung and colorectal cancer are included in the most tremendously threatening diseases in terms of incidence and death. Although they are located in completely different organs and differ in various characteristics they do share some common features, especially regarding their molecular mutational profile. Among several commonly mutated genes KRAS and BRAF are spotted to be highly associated with patient's poor disease outcome and resistance to targeted therapies mostly in liaison with other mutant activated genes. Many studies have shed light in these mechanisms for disease progression and numerous preclinical models, clinical trials and meta-analysis reports investigate the impact of specific treatments or combination of therapies. The present review is an effort to compare the mutational imprint of these genes between the two diseases and their impact in prognosis, current therapy, mechanisms of therapy resistance and future therapeutic plans and provide a spherical perspective regarding the systemic molecular profile of cancer.

Exploring the Pharmacological Mechanism of the Herb Pair "HuangLian-GanJiang" against Colorectal Cancer Based on Network Pharmacology

Since the herb pair Huang Lian-Gan Jiang (HL-GJ) was put forward as conventional compatibility for cold-heat regulation in the middle energizer in the theory of Traditional Chinese Medicine (TCM), their therapeutic effects were observed on the prevention and treatment of intestinal inflammation and tumors including colorectal cancer (CRC). However, the active compounds, crucial targets, and related pathways of HL-GJ against CRC remained unclear. The purpose of this research was to establish a comprehensive and systemic approach that could identify the active compounds, excavate crucial targets, and reveal anti-CRC mechanisms of HL-GJ against CRC based on network pharmacology. We used methods including chemical compound screening based on absorption, distribution, metabolism, and excretion (ADME), compound target prediction, CRC target collection, network construction and analysis, Gene Ontology (GO), and pathway analysis. In this study, eight main active compounds of HL-GJ were identified, including Gingerenone C, Isogingerenone B, 5,8-dihydroxy-2-(2-phenylethyl) Chromone, 2,3,4-trihydroxy-benzenepropanoic acid, 3,4-dihydroxyphenylethyl Alcohol Glucoside, 3-carboxy-4-hydroxy-phenoxy Glucoside, Moupinamide, and Obaculactone. HRAS, KRAS, PIK3CA, PDE5A, PPARG, TGFBR1, and TGFBR2 were identified as crucial targets of HL-GJ against CRC. There were mainly 500 biological processes and 70 molecular functions regulated during HL-GJ against CRC (P < 0.001). There were mainly 162 signaling pathways contributing to therapeutic effects (P < 0.001), the top 10 of which included DAP12 signaling, signaling by PDGF, signaling by EGFR, NGF signaling via TRKA from the plasma membrane, signaling by NGF, downstream signal transduction, DAP12 interactions, signaling by VEGF, signaling by FGFR3, and signaling by FGFR4. The study established a comprehensive and systematic paradigm to understand the pharmacological mechanisms of multiherb compatibility such as an herb pair, which might accelerate the development and modernization of TCM.

Prognosticators of Long-Term Outcomes of TNM Stage II Colorectal Cancer: Molecular Patterns or Clinicopathological Features

BACKGROUND

Patients with stage II colorectal cancer (CRC) have a higher risk of recurrence when they have certain risk factors, including clinical and pathological patterns. However, as the prognostic role of molecular patterns for stage II disease is still unclear, this study aimed to investigate it.

METHODS

A total of 509 patients with stage II CRC were enrolled, and all clinical, pathological, and molecular data were collected. Molecular patterns included microsatellite instability (MSI); elevated microsatellite alterations at selected tetranucleotides (EMAST) status; and expression of RAS/RAF genes, genes of the APC pathway, and other gene mutations. The endpoints were oncological outcomes, including overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS), local recurrence (LR), and distant recurrence (DR). Cox regression analysis was used.

RESULTS

Numerous molecular patterns influenced the oncological outcomes on univariate analysis, but no variable reached significance in LR. On multivariate analysis, a mucinous component (MC) > 50% (P < 0.01) was significant for OS and CSS. Lymphovascular invasion (LVI; P< 0.01), MC > 50% (P < 0.01), and EMAST-H (P = 0.02) significantly influenced DFS, whereas LVI (P < 0.01), MC > 50% (P < 0.01), and TP53 mutation (P = 0.02) were significant for DR.

CONCLUSIONS

In this study, MSI, EMAST, and RAS/RAF alterations did not influence the oncological outcomes. Overall, LVI and MC were two significant prognostic factors for DFS and DR. Thus, the histopathology, rather than the genes, plays a major role in the prognosis of patients with stage II CRC.

A personalized platform identifies trametinib plus zoledronate for a patient with KRAS-mutant metastatic colorectal cancer

Colorectal cancer remains a leading source of cancer mortality worldwide. Initial response is often followed by emergent resistance that is poorly responsive to targeted therapies, reflecting currently undruggable cancer drivers such as KRAS and overall genomic complexity. Here, we report a novel approach to developing a personalized therapy for a patient with treatment-resistant metastatic KRAS-mutant colorectal cancer. An extensive genomic analysis of the tumor's genomic landscape identified nine key drivers. A transgenic model that altered orthologs of these nine genes in the Drosophila hindgut was developed; a robotics-based screen using this platform identified trametinib plus zoledronate as a candidate treatment combination. Treating the patient led to a significant response: Target and nontarget lesions displayed a strong partial response and remained stable for 11 months. By addressing a disease's genomic complexity, this personalized approach may provide an alternative treatment option for recalcitrant disease such as KRAS-mutant colorectal cancer.

Targeting EGFR and RAS/RAF Signaling in the Treatment of Metastatic Colorectal Cancer: From Current Treatment Strategies to Future Perspectives

The epidermal growth factor receptor (EGFR) and RAS/RAF signaling pathway plays pivotal roles in tumor progression via proliferation, survival, invasion, and immune evasion. Two anti-EGFR monoclonal antibodies, cetuximab and panitumumab, have become essential components in the treatment of patients with metastatic colorectal cancer (mCRC). Treatment with these anti-EGFR antibodies has shown definite benefits when administered in all treatment lines and is strongly recommended as the preferred regimen to prolong survival, especially when administered in the first- and third-lines. Recent efforts have revealed not only mechanisms responsible for resistance to anti-EGFR antibodies, including expanded RAS mutations as a negative predictive biomarker, but also the possibility of continuing anti-EGFR antibody treatment in combination with chemotherapy. Furthermore, the challenges associated with the pharmaceutical development of treatments for patients with mutant-type BRAF mCRC are ongoing. In this review, we provide an overview of the EGFR and RAS/RAF signaling pathway and antitumor activity, focusing on practical aspects such as established treatments including patient selection, treatment strategies, and future perspectives for drug development targeting the EGFR and RAS/RAF signaling pathway.

Mutations of key driver genes in colorectal cancer progression and metastasis

The association between mutations of key driver genes and colorectal cancer (CRC) metastasis has been investigated by many studies. However, the results of these studies have been contradictory. Here, we perform a comprehensive analysis to screen key driver genes from the TCGA database and validate the roles of these mutations in CRC metastasis. Using bioinformatics analysis, we identified six key driver genes, namely APC, KRAS, BRAF, PIK3CA, SMAD4 and p53. Through a systematic search, 120 articles published by November 30, 2017, were included, which all showed roles for these gene mutations in CRC metastasis. A meta-analysis showed that KRAS mutations (combined OR 1.18, 95% CI 1.05-1.33) and p53 mutations (combined OR 1.49, 95% CI 1.23-1.80) were associated with CRC metastasis, including lymphatic and distant metastases. Moreover, CRC patients with a KRAS mutation (combined OR 1.29, 95% CI 1.13-1.47), p53 mutation (combined OR 1.35, 95% CI 1.06-1.72) or SMAD4 mutation (combined OR 2.04, 95% CI 1.41-2.95) were at a higher risk of distant metastasis. Subgroup analysis stratified by ethnic populations indicated that the BRAF mutation was related to CRC metastasis (combined OR 1.42, 95% CI 1.18-1.71) and distant metastasis (combined OR 1.51, 95% CI 1.20-1.91) in an Asian population. No significant association was found between mutations of APC or PIK3CA and CRC metastasis. In conclusion, mutations of KRAS, p53, SMAD4 and BRAF play significant roles in CRC metastasis and may be both potential biomarkers of CRC metastasis as well as therapeutic targets.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Developing Story of Predictive Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the third most common malignancy worldwide. Surgery remains the most important treatment for non-metastatic CRC, and the administration of adjuvant chemotherapy depends mainly on the disease stage, which is still the strongest prognostic factor. A refined understanding of the genomics of CRC has recently been achieved thanks to the widespread use of next generation sequencing with potential future therapeutic implications. Microsatellite instability (MSI) has been suggested as a predictive marker for response to anti-programmed-cell-death protein 1 (PD-1) therapy in solid tumors, including CRC. It should be noted that not all cancers with MSI phenotype respond to anti-PD-1 immunotherapy, highlighting the urgent need for even better predictive biomarkers. Mitogen-Activated Protein Kinase (MAPK) pathway genes KRAS, NRAS, and BRAF represent important molecular targets and could serve as independent prognostic biomarkers in CRC, and identify those who potentially benefit from anti-epidermal growth factor receptor (EGFR) treatment. Emerging evidence has attributed a significant role to inflammatory markers including blood cell ratios in the prognosis and survival of CRC patients; these biomarkers can be easily assessed in routine blood exams and be used to identify high-risk patients or those more likely to benefit from chemotherapy, targeted therapies and potentially immunotherapy. Analysis of cell-free DNA (cfDNA), circulating tumor cells (CTC) and/or micro RNAs (miRNAs) could provide useful information for the early diagnosis of CRC, the identification of minimal residual disease and, the evaluation of the risk of recurrence in early CRC patients. Even the selection of patients suitable for the new targeted therapy is becoming possible with the use of predictive miRNA biomarkers. Finally, the development of treatment resistance with the emergence of chemo-resistance clones after treatment remains the most important challenge in the clinical practice. In this context it is crucial to identify potential biomarkers and therapeutic targets which could lead to development of new and more effective treatments.

RAS-mediated oncogenic signaling pathways in human malignancies

Abnormally activated RAS proteins are the main oncogenic driver that governs the functioning of major signaling pathways involved in the initiation and development of human malignancies. Mutations in RAS genes and or its regulators, most frequent in human cancers, are the main force for incessant RAS activation and associated pathological conditions including cancer. In general, RAS is the main upstream regulator of the highly conserved signaling mechanisms associated with a plethora of important cellular activities vital for normal homeostasis. Mutated or the oncogenic RAS aberrantly activates a web of interconnected signaling pathways including RAF-MEK (mitogen-activated protein kinase kinase)-ERK (extracellular signal-regulated kinase), phosphoinositide-3 kinase (PI3K)/AKT (protein kinase B), protein kinase C (PKC) and ral guanine nucleotide dissociation stimulator (RALGDS), etc., leading to uncontrolled transcriptional expression and reprogramming in the functioning of a range of nuclear and cytosolic effectors critically associated with the hallmarks of carcinogenesis. This review highlights the recent literature on how oncogenic RAS negatively use its signaling web in deregulating the expression and functioning of various effector molecules in the pathogenesis of human malignancies.

Long-term survival of an elderly female with metastatic colon cancer after treated with capecitabine monotherapy: A case report

RATIONALE

Colorectal cancer (CRC) is one of the most common cancers all over the world, and approximately 70% of the newly diagnosed patients are over 65 years old. Due to the aging of society, there will be more and more elderly patients of CRC in the future. Treatment of CRC in elderly patients is much more challenging thanks to multiple factors including disabling comorbidities as well as declines in organs function, especially in advanced or metastatic settings.

PATIENT CONCERNS

An 82-year-old female without history of disease was admitted to the emergency room because of abdominal pain in December 2009. A computed tomography (CT) scan of the abdomen was performed immediately, which revealed bowel obstruction.

DIAGNOSES

The histopathological examination of the resected specimen confirmed well-to-moderately differentiated colonic adenocarcinoma with a stage of IIIB (T3N1M0) based on the NCCN tumor-node-metastasis (TNM) classification system.

INTERVENTIONS

The patient underwent emergency surgery and rejected adjuvant chemotherapy, but was diagnosed with multiple liver metastases 3 months later. Then she received capecitabine monotherapy as first-line treatment.

OUTCOMES

The efficacy achieved complete response (CR) when 8 cycles were completed and the agent was continued as maintenance treatment until totally 16 cycles were completed. Up to the latest follow-up, the disease remained CR and the progression-free survival (PFS) has achieved approximately 87 months. She is still alive and has good quality of life.

LESSONS

Capecitabine monotherapy may be an effective treatment in advanced or metastatic colorectal cancer (mCRC) for elderly patients.

Prognostic Value of NRAS Gene for Survival of Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

Introduction: NRAS gene is associated with malignant proliferation and metastasis of colorectal cancer (CRC). But its prognostic value on CRC is still unknown. The objective of this study is to perform a meta-analysis to obtain its prognostic value on survival of CRC patients. Methods: The systematic review and meta-analysis was designed, undertaken and reported using items from the PRISMA statement. Relevant articles were identified through PubMed (containing Medline), Embase, Web of Science databases and Google scholar search engines from their inception up to October 3, 2016. The articles about NRAS on prognosis of CRC patients were enrolled. The association between NRAS and CRC survival time (including overall survival [OS], progression-free survival [PFS], and disease-free survival [DFS]) was evaluated using hazard ratio (HR) with its corresponding 95% confidence interval (CI). Results: A total of fifteen articles were included. High-expression of NRAS was significantly associated with poor OS (HR: 1.36, 95% CI: 1.15–1.61), and poor PFS (HR: 1.75, 95% CI: 1.04–2.94). The combined HR of NRAS on DFS was 0.87 (95% CI: 0.37–2.03). Subgroup analysis showed that NRAS was significantly associated with poor OS for patients from Western countries (HR: 1.38, 95% CI: 1.09–1.73), but not for those from Asian countries. Conclusions: This meta-analysis demonstrate that NRAS gene could predict the poor prognosis for the CRC patients. More large-sample cohort studies are needed to further confirm this conclusion.

Small molecule inhibitors targeting the EGFR/ErbB family of protein-tyrosine kinases in human cancers

The EGFR family is among the most investigated receptor protein-tyrosine kinase groups owing to its general role in signal transduction and in oncogenesis. This family consists of four members that belong to the ErbB lineage of proteins (ErbB1-4). The ErbB proteins function as homo and heterodimers. These receptors contain an extracellular domain that consists of four parts: domains I and III are leucine-rich segments that participate in growth factor binding (except for ErbB2) and domains II and IV contain multiple disulfide bonds. Moreover, domain II participates in both homo and heterodimer formation within the ErbB/HER family of proteins. Seven ligands bind to EGFR including epidermal growth factor and transforming growth factor-α, none bind to ErbB2, two bind to ErbB3, and seven ligands bind to ErbB4. The extracellular domain is followed by a single transmembrane segment of about 25 amino acid residues and an intracellular portion of about 550 amino acid residues that contains (i) a short juxtamembrane segment, (ii) a protein kinase domain, and (iii) a carboxyterminal tail. ErbB2 lacks a known activating ligand and ErbB3 is kinase impaired. Surprisingly, the ErbB2-ErbB3 heterodimer complex is the most active dimer in the family. These receptors are implicated in the pathogenesis of a large proportion of lung and breast cancers, which rank first and second, respectively, in the incidence of all types of cancers (excluding skin) worldwide. On the order of 20% of non-small cell lung cancers bear activating mutations in EGFR. More than 90% of these patients have exon-19 deletions (⁷⁴⁶ELREA⁷⁵⁰) or the exon-21 L858R substitution. Gefitinib and erlotinib are orally effective type I reversible EGFR mutant inhibitors; type I inhibitors bind to an active enzyme conformation. Unfortunately, secondary resistance to these drugs occurs within about one year owing to a T790M gatekeeper mutation. Osimertinib is an irreversible type VI inhibitor that forms a covalent bond with C797 of EGFR and is FDA-approved for the treatment of patients with this mutation; type VI inhibitors generally form a covalent adduct with their target protein. Resistance also develops to this and related type VI inhibitory drugs owing to a C797S mutation; the serine residue is unable to react with the drugs to form a covalent bond. Approximately 20% of breast cancer patients exhibit ErbB2/HER2 gene amplification on chromosome 17q. One of the earliest targeted treatments in cancer involved the development of trastuzumab, a monoclonal antibody that interacts with the extracellular domain ErbB2/HER2 causing its down regulation. Surgery, radiation therapy, chemotherapy with cytotoxic drugs, and hormonal modulation are the mainstays in the treatment of breast cancer. Moreover, lapatinib and neratinib are FDA-approved small molecule ErbB2/HER2 antagonists used in the treatment of selected breast cancer patients. Of the approximate three dozen FDA-approved small molecule protein kinase inhibitors, five are type VI irreversible inhibitors and four of them including afatinib, osimertinib, dacomitinib, and neratinib are directed against the ErbB family of receptors (ibrutinib is the fifth and it targets Bruton tyrosine kinase). Avitinib, olmutinib, and pelitinib are additional type VI inhibitors in clinical trials for non-small cell lung cancer that target EGFR. Secondary resistance to both targeted and cytotoxic drugs is the norm, and devising and implementing strategies for minimizing or overcoming resistance is an important goal in cancer therapeutics.

Enhanced SLP-2 promotes invasion and metastasis by regulating Wnt/β-catenin signal pathway in colorectal cancer and predicts poor prognosis

Stomatin-like protein-2 (SLP-2) gene belongs to the stomatin supergene family, and previous studies have revealed up-regulated SLP-2 expression in gallbladder cancer, lung cancer, and esophageal cancer, while the role of SLP-2 in colorectal cancer (CRC) remains unclear and needs further investigation. Therefore, the expression levels of SLP-2 in CRC tissue and cell lines were tested in this study. Besides, we further explored the role of SLP-2 in CRC invasion and metastasis at molecular level via gene intervention technique. Our results demonstrated that the positive rate of SLP-2 expression in CRC tissues was higher than that in the adjacent non-cancerous tissues (P < 0.05); positive SLP-2 expression predicted poorer prognosis of CRC patients as an independent risk factor (P < 0.05). Cell activities and the capacity of migration and invasion significantly decreased after the suppression of SLP-2 in SW620 cells (P < 0.05). Furthermore, the suppression of SLP-2 in SW620 cells resulted in varieties of invasion and metastasis-related genes and Wnt/β-catenin signal pathway (P < 0.05). The present study identified that SLP-2 may predict a poor prognosis in CRC patients as a novel marker, and SLP-2 may facilitate the migration and invasion of CRC via regulating Wnt/β-catenin pathway activities.

Deficient mismatch repair and RAS mutation in colorectal carcinoma patients: a retrospective study in Eastern China

Objectives

To investigate the frequency and prognostic role of deficient mismatch repair (dMMR) and RAS mutation in Chinese patients with colorectal carcinoma.

Methods

Clinical and pathological information from 813 patients were reviewed and recorded. Expression of mismatch repair proteins was tested by immunohistochemistry. Mutation analyses for RAS gene were performed by real-time polymerase chain reaction. Correlations of mismatch repair status and RAS mutation status with clinicopathological characteristics and disease survival were determined.

Results

The overall percentage of dMMR was 15.18% (121/797). The proportion of dMMR was higher in patients <50 years old (p < 0.001) and in the right side of the colon (p < 0.001). Deficient mismatch repair was also associated with mucinous production (p < 0.001), poor differentiation (p < 0.001), early tumor stage (p < 0.05) and bowel wall invasion (p < 0.05). The overall RAS mutation rate was 45.88%, including 42.56% (346/813) KRAS mutation and 3.69% (30/813) NRAS mutation (including three patients with mutations in both). KRAS mutation was significantly associated with mucinous production (p < 0.05), tumor stage (p < 0.05) and was higher in non-smokers (p < 0.05) and patients with a family history of colorectal carcinoma (p < 0.05). Overall, 44.63% (54/121) dMMR tumors harbored KRAS mutation, however, dMMR tumors were less likely to have NRAS mutation. Moreover, dMMR, KRAS and NRAS mutation were not prognostic factors for stage I–III colorectal carcinoma.

Conclusions

This study confirms that the status of molecular markers involving mismatch repair status and RAS mutation reflects the specific clinicopathological characteristics of colorectal carcinoma.

Frequency of NRAS Gene Mutation in Wild Type KRAS and BRAF Colorectal Cancers; a Single Center Study

BACKGROUND Incidence of colorectal cancer is increasing in countries such as Iran. Molecular biomarkers play very important role in the diagnosis, treatment, and prognosis of this cancer. Mutation in the RAS family (including KRAS and NRAS) is one of these important molecular biomarkers, which should be tested before starting treatment with anti-EGRF (Epidermal growth factor) drugs. Objectives: There has been very few reports about the frequency of NRAS mutation from Iran and no study from south of the country. In this article we will describe our experience about the frequency of NRAS mutation in colorectal cancers from the largest referral center in the south of Iran. METHODS During 5 years (2011-2015), we had 52 cases of colorectal cancers with wild type KRAS and BRAF in the hospitals affiliated to Shiraz University of Medical Sciences with enough tissue for molecular studies. NRAS mutation analysis was performed on paraffin embedded formalin fixed tissue of these cases by polymerase chain reaction (PCR)-sequencing method. RESULTS Among these 52 cases of colorectal cancer with wild type KRAS and BRAF, there has been 3 (5.7%) cases with mutant NRAS. One of the mutations has been in codon 12 and two in codon 61. No mutation in codon 13 was found. All the three cases were women with stage IV and well differentiated histomorphology. CONCLUSION Our results showed that frequency of NRAS mutation in colorectal cancer is rare, which is very close to other studies from different geographic areas of the world.

Current and future biomarkers in colorectal cancer

Colorectal cancer (CRC), one of the leading causes of death among cancer patients, is a heterogeneous disease and is characterized by diversions in multiple molecular pathways throughout its evolutionary process. To date, specific mutations in RAS and RAF genes are tested in everyday clinical practice along with mismatch repair gene deficiency, serving either as prognostic or predictive biomarkers, providing information for patient risk stratification and the choice of appropriate therapy. However, ongoing studies are focusing on the potential role of recently discovered genetic and epigenetic alterations in the management of CRC patients and their potential prognostic or predictive value. To overcome the problem of tumor heterogeneity as well as the practical obstacles of access to tumor tissue, and to achieve real-time monitoring of disease and therapy efficacy, liquid biopsies constitute a novel technology worth exploring. CRC screening and management is entering a new era where molecular testing will be applied to genomic material extracted from easily accessible bodily fluids.

SensiScreen®KRAS exon 2-sensitive simplex and multiplex real-time PCR-based assays for detection of KRAS exon 2 mutations

Activating mutations in codon 12 and codon 13 of the KRAS (Kirsten rat sarcoma viral oncogene homolog) gene are implicated in the development of several human cancer types and influence their clinical evaluation, treatment and prognosis. Numerous different methods for KRAS genotyping are currently available displaying a wide range of sensitivities, time to answer and requirements for laboratory equipment and user skills. Here we present SensiScreen® KRAS exon 2 simplex and multiplex CE IVD assays, that use a novel real-time PCR-based method for KRAS mutation detection based on PentaBase's proprietary DNA analogue technology and designed to work on standard real-time PCR instruments. By means of the included BaseBlocker™ technology, we show that SensiScreen® specifically amplifies the mutated alleles of interest with no or highly subdued amplification of the wild type allele. Furthermore, serial dilutions of mutant DNA in a wild type background demonstrate that all SensiScreen® assays display a limit of detection that falls within the range of 0.25-1%. Finally, in three different colorectal cancer patient populations, SensiScreen® assays confirmed the KRAS genotype previously determined by commonly used methods for KRAS mutation testing, and notably, in two of the populations, SensiScreen® identified additional mutant positive cases not detected by common methods.

Regulation of intestinal myofibroblasts by KRas-mutated colorectal cancer cells through heparin-binding epidermal growth factor-like growth factor

In colorectal cancer, gain-of-function mutations in KRas play a critical role in malignant transformation. Tumor growth in colorectal cancer is known to be promoted by the intestinal myofibroblasts (IMFs) that localize adjacent to the cancer cells, but the mechanisms of interaction between KRas-mutated cancer cells and the myofibroblasts remain unclear. Here, we investigated the effects of KRas-mutated cells on the behavior of myofibroblasts by using mouse primary IMFs and cells of an IMF cell line (LmcMF) and a mouse colon epithelial cell line (aMoC1). Conditioned medium (CM) was collected from aMoC1 cells overexpressing a control vector or KRasV12 vector (KRasV12-CM), and the effects of KRasV12-CM on IMFs were analyzed by performing proliferation assays, wound-healing assays, Boyden chamber assays, and western blotting. Whereas KRasV12-CM exerted little effect on the differentiation and proliferation of primary IMFs, the CM promoted migration of both primary IMFs and LmcMF cells. In KRasV12-overexpressing aMoC1 cells, mRNA expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF) was higher than in mock-transfected aMoC1 cells, and HB-EGF promoted the migration of primary IMFs and LmcMF cells. Moreover, KRasV12-CM-induced IMF migration was suppressed by dacomitinib, an inhibitor of HB-EGF receptors. Notably, in LmcMF cells, both KRasV12-CM and HB-EGF activated extracellular signal-regulated kinase (ERK) and c-jun N-terminal kinase (JNK), whereas KRasV12-CM-induced migration of IMFs was suppressed following treatment with either an ERK inhibitor (FR180204) or a JNK inhibitor (SP600125). These results suggest that HB-EGF secreted from KRas-mutated colorectal cancer cells promotes IMF migration through ERK and JNK activation, which, in turn, could support cancer progression.