RAS and BRAF in metastatic colorectal cancer management

Molecular Pattern and Clinical Implications of KRAS/NRAS and BRAF Mutations in Colorectal Cancer

The aim of our study was to evaluate the incidence of KRAS/NRAS and BRAF mutations, analyze molecular patterns, and investigate associations with clinical parameters of these mutations in CRC KRAS/NRAS and BRAF mutations analyzed by next-generation sequencing. The detection rates of these mutations and patients' demographics were recorded and the relationship between them was evaluated using the chi-square test. KRAS mutation was detected in 332 of 694 patients, while the mutation rates in KRAS exons 2/3 and 4 were 39.6%/3.2% and 5%, respectively. The most common mutation pattern was KRAS G12D. Five atypical variants were detected: V14I in KRAS exon 2, A18D, Q22K and T50I in exon 3, and T148P in exon 4. NRAS mutation was detected in 29 (4.5%) patients. One atypical variant L80W was detected in NRAS exon 3. BRAF mutation was seen in 37 (5.3%) patients, with BRAFV600E (83.8%) being the most common mutation pattern. NRAS mutation was significantly more frequent in patients > 64 years of age, BRAF mutation in women, and NRAS/BRAF mutations in right colon tumors. Grouping BRAF mutations into BRAFV600E and BRAFnon-V600E and their analysis according to specific tumor localizations showed that all four BRAFnon-V600E mutations originated in the rectum. In our study, KRAS exon 2 and other RAS mutation rates were higher than in the literature, while the BRAF v.600E mutation rate was similar. NRAS and BRAF mutations were significantly more frequent in the right colon. BRAF mutation was more common in women and in the right colon.

Can immunotherapy reinforce chemotherapy efficacy? a new perspective on colorectal cancer treatment

As one of the main threats to human life (the fourth most dangerous and prevalent cancer), colorectal cancer affects many people yearly, decreases patients' quality of life, and causes irreparable financial and social damages. In addition, this type of cancer can metastasize and involve the liver in advanced stages. However, current treatments can't completely eradicate this disease. Chemotherapy and subsequent surgery can be mentioned among the current main treatments for this disease. Chemotherapy has many side effects, and regarding the treatment of this type of tumor, chemotherapy can lead to liver damage, such as steatohepatitis, steatosis, and sinus damage. These damages can eventually lead to liver failure and loss of its functions. Therefore, it seems that other treatments can be used in addition to chemotherapy to increase its efficiency and reduce its side effects. Biological therapies and immunotherapy are one of the leading suggestions for combined treatment. Antibodies (immune checkpoint blockers) and cell therapy (DC and CAR-T cells) are among the immune system-based treatments used to treat tumors. Immunotherapy targets various aspects of the tumor that may lead to 1) the recruitment of immune cells, 2) increasing the immunogenicity of tumor cells, and 3) leading to the elimination of inhibitory mechanisms established by the tumor. Therefore, immunotherapy can be used as a complementary treatment along with chemotherapy. This review will discuss different chemotherapy and immunotherapy methods for colorectal cancer. Then we will talk about the studies that have dealt with combined treatment.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The role of heavy metals in the development of colorectal cancer

OBJECTIVE

To investigate the relationship among 18 heavy metals, microsatellite instability (MSI) status, ERCC1, XRCC1 (rs25487), BRAF V600E and 5 tumor markers and their role in the development of colorectal cancer (CRC).

METHODS

A total of 101 CRC patients and 60 healthy controls were recruited in the present study. The levels of 18 heavy metals were measured by ICP-MS. MSI status and the genetic polymorphism were determined by PCR (FP205-02, Tiangen Biochemical Technology Co., Ltd., Beijing, China) and Sanger sequencing. Spearman's rank correlation was used to analyze the relationship among various factors.

RESULTS

The level of selenium (Se) was lower in the CRC group compared with the control group (p < 0.01), while vanadium (V), arsenic (As), tin (Sn), barium (Ba) and lead (Pb) were higher (p < 0.05), chromium (Cr) and copper (Cu) were significantly higher (p < 0.0001) in the CRC group than those in the control group. Multivariate logistic regression analysis indicated that Cr, Cu, As and Ba were the risk factors for CRC. In addition, CRC was positively correlated with V, Cr, Cu, As, Sn, Ba and Pb, but negatively correlated with Se. MSI was positively correlated with BRAF V600E, but negatively correlated with ERCC1. BRAF V600E was positively correlated with antimony (Sb), thallium (Tl), CA19-9, NSE, AFP and CK19. XRCC1 (rs25487) was found to be positively correlated with Se but negatively correlated with Co. The levels of Sb and Tl were significantly higher in the BRAF V600E positive group compared to the negative group. The mRNA expression level of ERCC1 was significantly higher (P = 0.035) in MSS compared to MSI. And there was a significant correlation between XRCC1 (rs25487) polymorphism and MSI status (P<0.05).

CONCLUSION

The results showed that low level of Se and high levels of V, As, Sn, Ba, Pb, Cr, and Cu increased the risk of CRC. Sb and Tl may cause BRAF V600E mutations, leading to MSI. XRCC1 (rs25487) was positively correlated with Se but negatively correlated with Co. The expression of ERCC1 may be related to MSS, while the XRCC1 (rs25487) polymorphism is related to MSI.

An Unconventional Regimen of Carboplatin and Paclitaxel in Metastatic Colorectal Carcinosarcoma: A Case Report and Review of Literature

Colorectal carcinosarcoma is an exceedingly rare subtype of colorectal cancer that displays the histological and molecular features of both mesenchymal and epithelial tumors. Due to its rarity, there are no guidelines regarding the systemic treatment of this disease. This report describes a case of a 76-year-old woman with colorectal carcinosarcoma with extensive metastatic burden treated with carboplatin and paclitaxel. After four cycles of chemotherapy, the patient had an excellent clinical and radiographical response to treatment. To the best of our knowledge, this is the first report addressing the use of carboplatin and paclitaxel in this disease. We reviewed seven published case reports of metastatic colorectal carcinosarcoma where various systemic treatments were offered. Remarkably, there are no previously published reports where even a partial response was noted, which underscores the aggressiveness of this disease. While further studies are required to validate our experience and assess long-term outcomes, this case suggests an alternative treatment regimen for metastatic colorectal carcinosarcoma.

POLE-Mutant Colon Cancer Treated with PD-1 Blockade Showing Clearance of Circulating Tumor DNA and Prolonged Disease-Free Interval

Colon cancer with high microsatellite instability is characterized by a high tumor mutational burden and responds well to immunotherapy. Mutations in polymerase ɛ, a DNA polymerase involved in DNA replication and repair, are also associated with an ultra-mutated phenotype. We describe a case where a patient with POLE-mutated and hypermutated recurrent colon cancer was treated with pembrolizumab. Treatment with immunotherapy in this patient also led to the clearance of circulating tumor DNA (ctDNA). ctDNA is beginning to emerge as a marker for minimal residual disease in many solid malignancies, including colon cancer. Its clearance with treatment suggests that the selection of pembrolizumab on the basis of identifying a POLE mutation on next-generation sequencing may increase disease-free survival in this patient.

The five-year KRAS, NRAS and BRAF analysis results and treatment patterns in daily clinical practice in Slovenia in 1st line treatment of metastatic colorectal (mCRC) patients with RAS wild-type tumour (wtRAS) - a real- life data report 2013-2018

BACKGROUND

We preformed a Phase IV non-interventional study to assess KRAS, NRAS and BRAF status in metastatic colorectal cancer (mCRC) patients suitable for 1^st line treatment and to evaluate the decisions for 1^st line treatment considering the treatment goals in the RAS wild type (wt) patients. The aim of our study was also to evaluate the influence of a waiting period for biomarkers analysis on the start of first-line treatment.

PATIENTS AND METHODS

Patients with histologically confirmed mCRC adenocarcinoma suitable for first-line treatment fulfilling all inclusion criteria were included in the study. The KRAS, NRAS and BRAF analysis was performed from tissue samples of primary tumor site or metastatic site. All included patients have given consent to participate in the study by signing the informed consent form.

RESULTS

From April 2013 to March 2018 at the Institute of Oncology Ljubljana 650 patients were included, 637 of them were treated with first- line systemic treatment according to RAS and BRAF status. Remaining 13 patients with mCRC did not receive systemic first-line treatment. The distribution of patients with KRAS mutated and wild-type tumors, was almost equal, 48.8% and 47.9% respectively, 89 % of the patients had wt NRAS tumours and 86.1% had wt BRAF tumours. The most frequently prescribed treatment was bevacizumab-based therapy (53.1%), either in combination with doublet chemotherapy or with mono-chemotherapy. EGFR inhibitors cetuximab and panitumumab were prescribed in wt RAS mCRC patients (30.9%). The waiting period for biomarkers analysis was two weeks.

CONCLUSIONS

Our real-world data, single centre 5-year analysis showed that the distribution between wild type and mutated type tumors of the patients with mCRC was approximately the same, as worldwide, so the Slovenian population with mCRC has the same ratio distribution of KRAS, NRAS and BRAF wild and mutated genes. We concluded that a two-week waiting period for biomarkers analysis did not influence the first line treatment decision, so it was in the accordance with the worldwide treatment guidelines based on evidence-based medicine.

Starring Role of Biomarkers and Anticancer Agents as a Major Driver in Precision Medicine of Cancer Therapy

Precision medicine is the most modern contemporary medicine approach today, based on great amount of data on people's health, individual characteristics, and life circumstances, and employs the most effective ways to prevent and cure diseases. Precision medicine in cancer is the most precise and viable treatment for every cancer patient based on the disease's genetic profile. Precision medicine changes the standard one size fits all medication model, which focuses on average responses to care. Consolidating modern methodologies for streamlining and checking anticancer drugs can have long-term effects on understanding the results. Precision medicine can help explicit anticancer treatments using various drugs and even in discovery, thus becoming the paradigm of future cancer medicine. Cancer biomarkers are significant in precision medicine, and findings of different biomarkers make this field more promising and challenging. Naturally, genetic instability and the collection of extra changes in malignant growth cells are ways cancer cells adapt and survive in a hostile environment, for example, one made by these treatment modalities. Precision medicine centers on recognizing the best treatment for individual patients, dependent on their malignant growth and genetic characterization. This new era of genomics progressively referred to as precision medicine, has ignited a new episode in the relationship between genomics and anticancer drug development.

Targeting of colorectal cancer organoids with zoledronic acid conjugated to the anti-EGFR antibody cetuximab

BACKGROUND

Antibody-drug conjugates (ADC) are essential therapeutic options to treat solid and hematological cancers. The anti-epidermal growth factor-receptor (EGFR) antibody cetuximab (Cet) is used for the therapy of colorectal carcinoma (CRC). Anti-CRC Vδ2 cytolytic T lymphocytes can be elicited by the priming of tumor cells with the aminobisphosphonate zoledronic acid (ZA) and consequent presentation of isopentenyl pyrophosphates through butyrophilin (BTN) family members such as BTN3A1 and BTN2A1. A major drawback that impairs the targeting of ZA to CRC is the bone tropism of aminobisphosphonates.

METHODS

The phosphoric group of ZA was linked to free amino groups of Cet in the presence of imidazole following the labeling of phosphoric groups of DNA to amino groups of proteins. The generation of Cet-ZA ADC was confirmed by matrix assisted laser desorption ionization mass spectrometry and inductively coupled plasma-mass spectrometry analysis. Thirteen CRC organoids were obtained with a chemically defined serum-free medium in Geltrex domes. Proliferation and activation of cytolytic activity against CRC organoids by Vδ2 T cells was detected with flow cytometry, crystal violet and cytotoxic probe assays and image analysis. Immunohistochemistry and quantification of BTN3A1 or BTN2A1 expression and the number of tumor infiltrating Vδ2 T cells in CRC were performed by automatic immunostaining, whole slide scanning and computerized analysis of digital pathology imaging.

RESULTS

The novel ADC Cet-ZA was generated with a drug antibody ratio of 4.3 and displayed a reactivity similar to the unconjugated antibody. More importantly, patient-derived CRC organoids, or CRC tumor cell suspensions, could trigger the expansion of Vδ2 T cells from peripheral blood and tumor infiltrating lymphocytes when primed with Cet-ZA. Furthermore, Cet-ZA triggered Vδ2 T cell-mediated killing of CRC organoids. The expression of BTN3A1 and BTN2A1 was detected not only in CRC organoids but also in CRC specimens, together with a considerable amount of tumor infiltrating Vδ2 T cells.

CONCLUSIONS

These findings are proof of concept that the Cet-ZA ADC can be used to target specifically CRC organoids and may suggest a new experimental approach to deliver aminobisphosphonates to EGFR⁺ solid tumors.

miR-106b as an emerging therapeutic target in cancer

MicroRNAs (miRNAs) comprise short non-coding RNAs that function in regulating the expression of tumor suppressors or oncogenes and modulate oncogenic signaling pathways in cancer. miRNAs expression alters significantly in several tumor tissues and cancer cell lines. For example, miR-106b functions as an oncogene and increases in multiple cancers. The miR-106b directly targets genes involved in tumorigenesis, proliferation, invasion, migration, and metastases. This review has focused on the miR-106b function and its downstream target in different cancers and provide perspective into how miR-106 regulates cancer cell proliferation, migration, invasion, and metastases by regulating the tumor suppressor genes. Since miRNAs-based therapies are currently being developed to enhance cancer therapy outcomes, miR-106b could be an attractive and prospective candidate in different cancer types for detection, diagnosis, and prognosis assessment in the tumor.

Diagnostic and therapeutic biomarkers in colorectal cancer: a review

Colorectal cancer (CRC) is a public health concern and the second most common type of cancer among men and women causing a significant mortality. Biomarkers closely linked to the disease morbidity could holds potential as diagnostic and/or prognostic biomarker for the disease. This review provides an overview of recent advances in the search for colorectal cancer biomarkers through genomics and proteomics according to clinical function and application. Specifically, a number of biomarkers were identified and discussed. Emphasis was placed on their clinical applications relative to the diagnosis and prognosis of CRC. The discovery of more sensitive and specific markers for CRC is an urgent need, and the study of molecular targets is extremely important in this process, as they will allow for a better understanding of colorectal carcinogenesis, identification and validation of potential genetic signatures.

Unlocking Access to Broad Molecular Profiling: Benefits, Barriers, and Policy Solutions

OBJECTIVES

"Personalized healthcare" is generating new approaches to disease management by considering inter-individual variability in genes, environment, and lifestyle. Technologies such as comprehensive genomic profiling (CGP) are drivers of this shift. Here, we address the significant hurdles to the equitable implementation of CGP into routine clinical practice.

METHODS

This article draws on published evidence on the value of genomic profiling, as well as interviews with nine academic and clinical experts from six different countries to validate findings and test policy proposals for reforms.

RESULTS

The potential benefits of CGP extend beyond direct patient outcomes, to healthcare systems with societal and economic impacts. Among key barriers impeding integration into routine clinical practice are the lack of infrastructure to ensure reliable clinical testing and the limited understanding of genomics among healthcare personnel. In addition, the absence of health economic evidence supporting broader use of CGP is creating concerns for payers regarding the systemic benefits and affordability of this technology.

CONCLUSION

Policy proposals that aim to improve equitable patient access to CGP will need to consider new funding models, health technology assessment processes that capture both patient and systemic benefits, and appropriate regulatory standards to determine the quality of genomic profiling tests.

The Therapeutic Potential of MAPK/ERK Inhibitors in the Treatment of Colorectal Cancer

The MAPK/ERK signaling pathway regulates cancer cell proliferation, apoptosis, inflammation, angiogenesis, metastasis and drug resistance. Mutations and up-regulation of components of the MAPK/ERK signaling pathway, as well as over-activation of this critical signaling pathway, are frequently observed in colorectal carcinomas. Targeting the MAPK/ERK signaling pathway, using specific pharmacological inhibitors, elicits potent anti-tumor effects, supporting the therapeutic potential of these inhibitors in the treatment of CRC. Several drugs have recently been developed for the inhibition of the MEK/ERK pathway in preclinical and clinical settings, such as MEK162 and MK-2206. MEK1/2 inhibitors demonstrate promising efficacy and anticancer activity for the treatment of this malignancy. This review summarizes the current knowledge on the role of the MAPK/ERK signaling pathway in the pathogenesis of CRC and the potential clinical value of synthetic inhibitors of this pathway in preventing CRC progression for a better understanding, and hence, better management of colorectal cancer.

Surgical resection and survival outcomes in metastatic young adult colorectal cancer patients

Background

The incidence of colorectal cancer in adults younger than age 50 has increased with rates expected to continue to increase over the next decade. The objective of this study is to examine the survival benefit of surgical resection (primary and/or metastatic) versus palliative therapy in this patient population.

Methods

We identified 6708 young adults aged 18–45 years diagnosed with metastatic colorectal cancer (mCRC) from 2004 to 2015 from the SEER database. Overall survival (OS) was analyzed using Kaplan–Meier estimation, log rank test, and multivariate Cox proportional hazards model.

Results

Sixty‐three percent of patients in our study underwent primary tumor resection (PTR), with 40% undergoing PTR alone and 23% undergoing both resection of primary disease and metastasectomy. The median OS for patients who underwent both PTR and metastasectomy was 36 months, compared to 13 months for those who did not receive any surgical intervention. The multivariate analysis showed significant OS benefit of receiving both PTR and metastasectomy (HR 0.34, 95% CI: 0.31–0.37, p < 0.001) compared to palliative therapy. Undergoing PTR only and metastasectomy only were also associated with improved OS (HR 0.46, 95% CI: 0.43–0.49, p < 0.001 and HR 0.64, 95% CI: 0.55–0.76, p < 0.001, respectively).

Conclusion

This is the largest observational study to evaluate survival outcomes in young‐onset mCRC patients and the role of surgical intervention of the primary and/or metastatic site. Our study provides evidence of statistically significant increase in OS for young mCRC patients who undergo surgical intervention of the primary and/or metastatic site.

RAC1B modulates intestinal tumourigenesis via modulation of WNT and EGFR signalling pathways

Current therapeutic options for treating colorectal cancer have little clinical efficacy and acquired resistance during treatment is common, even following patient stratification. Understanding the mechanisms that promote therapy resistance may lead to the development of novel therapeutic options that complement existing treatments and improve patient outcome. Here, we identify RAC1B as an important mediator of colorectal tumourigenesis and a potential target for enhancing the efficacy of EGFR inhibitor treatment. We find that high RAC1B expression in human colorectal cancer is associated with aggressive disease and poor prognosis and deletion of Rac1b in a mouse colorectal cancer model reduces tumourigenesis. We demonstrate that RAC1B interacts with, and is required for efficient activation of the EGFR signalling pathway. Moreover, RAC1B inhibition sensitises cetuximab resistant human tumour organoids to the effects of EGFR inhibition, outlining a potential therapeutic target for improving the clinical efficacy of EGFR inhibitors in colorectal cancer.

Complete Response to Pembrolizumab in Advanced Colon Cancer Harboring Somatic POLE F367S Mutation with Microsatellite Stability Status: A Case Study

Background

Polymerase epsilon (POLE) mutations are considered as one of the most potential and promising biomarkers for immune checkpoint inhibitors (ICIs) in patients with colorectal cancer. However, the treatment of ICIs sometimes also resulted in unsatisfactory results in patients with POLE mutations, which revealed that not all mutations on POLE contribute to tumor regression in colorectal cancer.

Case Presentation

We herein reported a case in which the patient with advanced colon cancer harboring somatic POLE F367S mutation, along with microsatellite stability status, has achieved efficacy of complete response to the programmed cell death 1 (PD-1) receptor inhibitor pembrolizumab, as well as a progression-free survival more than 49 months, and still in extension.

Conclusion

Somatic POLE F367S mutation might be presented as a sensitive predictor to pembrolizumab in patients with colon cancer.

Overcoming Obstacles to Targeting Muscarinic Receptor Signaling in Colorectal Cancer

Despite great advances in our understanding of the pathobiology of colorectal cancer and the genetic and environmental factors that mitigate its onset and progression, a paucity of effective treatments persists. The five-year survival for advanced, stage IV disease remains substantially less than 20%. This review examines a relatively untapped reservoir of potential therapies to target muscarinic receptor expression, activation, and signaling in colorectal cancer. Most colorectal cancers overexpress M₃ muscarinic receptors (M₃R), and both in vitro and in vivo studies have shown that activating these receptors stimulates cellular programs that result in colon cancer growth, survival, and spread. In vivo studies using mouse models of intestinal neoplasia have shown that using either genetic or pharmacological approaches to block M₃R expression and activation, respectively, attenuates the development and progression of colon cancer. Moreover, both in vitro and in vivo studies have shown that blocking the activity of matrix metalloproteinases (MMPs) that are induced selectively by M₃R activation, i.e., MMP1 and MMP7, also impedes colon cancer growth and progression. Nonetheless, the widespread expression of muscarinic receptors and MMPs and their importance for many cellular functions raises important concerns about off-target effects and the safety of employing similar strategies in humans. As we highlight in this review, highly selective approaches can overcome these obstacles and permit clinicians to exploit the reliance of colon cancer cells on muscarinic receptors and their downstream signal transduction pathways for therapeutic purposes.

Hexameric procyanidins inhibit colorectal cancer cell growth through both redox and non-redox regulation of the epidermal growth factor signaling pathway

Dietary proanthocyanidins (PAC) consumption is associated with a decreased risk for colorectal cancer (CRC). Dysregulation of the epidermal growth factor (EGF) receptor (EGFR) signaling pathway is frequent in human cancers, including CRC. We previously showed that hexameric PAC (Hex) exert anti-proliferative and pro-apoptotic actions in human CRC cells. This work investigated if Hex could exert anti-CRC effects through its capacity to regulate the EGFR pathway. In proliferating Caco-2 cells, Hex acted attenuating EGF-induced EGFR dimerization and NADPH oxidase-dependent phosphorylation at Tyr 1068, decreasing EGFR location at lipid rafts, and inhibiting the downstream activation of pro-proliferative and anti-apoptotic pathways, i.e. Raf/MEK/ERK1/2 and PI3K/Akt. Hex also promoted EGFR internalization both in the absence and presence of EGF. While Hex decreased EGFR phosphorylation at Tyr 1068, it increased EGFR Tyr 1045 phosphorylation. The latter provides a docking site for the ubiquitin ligase c-Cbl and promotes EGFR degradation by lysosomes. Importantly, Hex acted synergistically with the EGFR-targeted chemotherapeutic drug Erlotinib, both in their capacity to decrease EGFR phosphorylation and inhibit cell growth. Thus, dietary PAC could exert anti-CRC actions by modulating, through both redox- and non-redox-regulated mechanisms, the EGFR pro-oncogenic signaling pathway. Additionally, Hex could also potentiate the actions of EGFR-targeted drugs.

Role of NEU3 Overexpression in the Prediction of Efficacy of EGFR-Targeted Therapies in Colon Cancer Cell Lines

The epidermal growth factor receptor (EGFR), through the MAP kinase and PI3K-Akt-mTOR axis, plays a pivotal role in colorectal cancer (CRC) pathogenesis. The membrane-associated NEU3 sialidase interacts with and desialylates EGFR by promoting its dimerization and downstream effectors’ activation. Among the targeted therapies against EGFR, the monoclonal antibody cetuximab is active only in a subgroup of patients not carrying mutations in the MAP kinase pathway. In order to better understand the EGFR-NEU3 interplay and the mechanisms of pharmacological resistance, we investigated the role of NEU3 deregulation in cetuximab-treated CRC cell lines transiently transfected with NEU3 using Western blot analysis. Our results indicate that NEU3 overexpression can enhance EGFR activation only if EGFR is overexpressed, indicating the existence of a threshold for NEU3-mediated EGFR activation. This enhancement mainly leads to the constitutive activation of the MAP kinase pathway. Consequently, we suggest that the evaluation of NEU3 expression cannot entirely substitute the evaluation of EGFR because EGFR-negative cases cannot be stimulated by NEU3. Furthermore, NEU3-mediated hyperactivation of EGFR is counterbalanced by the administration of cetuximab, hypothesizing that a combined treatment of NEU3- and EGFR-targeted therapies may represent a valid option for CRC patients, which must be investigated in the future.

Prognostic Value of BRAF and KRAS Mutation in Relation to Colorectal Cancer Survival in Iranian Patients: Correlated to Microsatellite Instability

PURPOSE

To evaluate the prognostic role of BRAF and KRAS mutations after adjustment for microsatellite instability (MSI) in Iranian colorectal cancer (CRC) patients.

METHODS

BRAF and KRAS mutations and MSI status were assessed in 258 Iranian subjects with CRC. Two hundred fifty-eight consecutive stages I-IV CRC patients, who underwent surgical resection of adenocarcinoma from 2012 to 2016, were enrolled in the research. Pyrosequencing and Cast-PCR methods were used to the detection of KRAS and BRAF mutations. Kaplan-Meier and Cox regression were employed to estimate hazard ratios (HR) for the association between BRAF and KRAS mutation and overall survival (OS).

RESULTS

KRAS and BRAF mutations were detected in 36 (14%) and 15 (5.8%) cases of 258 patients with CRC, respectively. BRAF mutations that all comprised V600E and KRAS mutations was found in codon 12 and 13 (80.6% and 19.4%), respectively. KRAS mutations were detected in 19 (15.4%) patients of 123 microsatellite stable (MSS) CRC and it is significantly associated with tumor location and metastasis. BRAF and KRAS mutant vs. wild type of BRAF and KRAS, 5-year OS was 73.3% vs. 82.3% and 83.3% vs. 81.5% (long-rank P > 0.05), respectively. KRAS mutant vs. KRAS-wild-type tumors in MSS/MSI-L status CRC patients, 5-year OS was 78.9% vs. 90.4% (long-rank p = 0.046).

CONCLUSION

The present study revealed that BRAF and KRAS mutations were not related to the worse overall survival, while KRAS mutation can be a prognostic factor for overall survival in sporadic microsatellite-stable (MSS) status in Iranian CRC patients.

High TKTL1 expression as a sign of poor prognosis in colorectal cancer with synchronous rather than metachronous liver metastases

Colorectal cancer (CRC) is the third most common cancer in the world. More than half of all affected patients develop liver metastases during the course of the disease, and over half experience recurrence despite radical primary surgery. Transketolase-like protein 1 (TKTL1) is a key enzyme in the glucose metabolism of cancer cells, and its expression in tumor tissue was previously shown to indicate a poor prognosis in colorectal cancer. In this study, we investigated the prognostic significance of TKTL1 in 111 patients with surgically resected colorectal liver metastases, with a minimum follow-up time of 10.3 years. TKTL1 expression was examined in tissue samples of both primary tumors and liver metastases, and compared to clinicopathological parameters, disease-free survival, and overall survival. We show that a high expression of TKTL1 in primary tumor tissue associated with poor disease-free survival in patients with synchronous liver metastases (P = .026, Kaplan-Meier log-rank test), but with better disease-free survival in patients with metachronous metastases, although not statistically significantly (P = .073). We found similar tendencies for TKTL1 expression in liver metastases. Thus, TKTL1 could serve as a candidate marker to identify patients who benefit from liver resection or who need more aggressive perioperative chemotherapy.

Integrating Academic and Community Practices in the Management of Colorectal Cancer: The City of Hope Model

Colorectal cancer (CRC) management continues to evolve. In metastatic CRC, several clinical and molecular biomarkers are now recommended to guide treatment decisions. Primary tumor location (right versus left) has been shown to predict benefit from anti-epidermal growth factor receptors (EGFRs) in rat sarcoma viral oncogene homologue (RAS) and v-raf murine sarcoma viral oncogene homolog B1 (BRAF) wild-type patients. Anti-EGFR therapy has not resulted in any benefit in RAS-mutated tumors, irrespective of the primary tumor location. BRAF-V600E mutations have been associated with poor prognosis and treatment resistance but may benefit from a combination of anti-EGFR therapy and BRAF inhibitors. Human epidermal growth factor receptor 2 (HER-2) amplification was recently shown to predict relative resistance to anti-EGFR therapy but a response to dual HER-2 targeting within the RAS wild-type population. Finally, the mismatch repair (MMR)-deficient subgroup benefits significantly from immunotherapeutic strategies. In addition to the increasingly complex biomarker landscape in CRC, metastatic CRC remains one of the few malignancies that benefits from metastasectomies, ablative therapies, and regional hepatic treatments. This treatment complexity requires a multi-disciplinary approach to treatment and close collaborations between various stakeholders in large cancer center networks. Here, we describe the City of Hope experience and strategy to enhance colorectal cancer care across its network.

Recent Advances in Targeted Therapies for Advanced Gastrointestinal Malignancies

The treatment of advanced gastrointestinal (GI) cancers has become increasingly molecularly driven. Molecular profiling for HER2 and PD-L1 status is standard for metastatic gastroesophageal (GEJ) cancers to predict benefits from trastuzumab (HER2-targeted therapy) and pembrolizumab (anti-PD-1 therapy), while extended RAS and BRAF testing is standard in metastatic colorectal cancer to predict benefits from epidermal growth factor receptor (EGFR)-targeted therapies. Mismatch repair (MMR) or microsatellite instability (MSI) testing is standard for all advanced GI cancers to predict benefits from pembrolizumab and in metastatic colorectal cancer, nivolumab with or without ipilimumab. Here we review recent seminal trials that have further advanced targeted therapies in these cancers including Poly (adenosine diphosphate-ribose) polymerases (PARP) inhibition in pancreas cancer, BRAF inhibition in colon cancer, and isocitrate dehydrogenase (IDH) and fibroblast growth factor receptor (FGFR) inhibition in biliary tract cancer. Targeted therapies in GI malignancies constitute an integral component of the treatment paradigm in these advanced cancers and have widely established the need for standard molecular profiling to identify candidates.

Prevalence of the BRAF p.v600e variant in patients with colorectal cancer from Mexico and its estimated frequency in Latin American and Caribbean populations

This study aimed to investigate the frequency of the somatic BRAF p.V600E in patients with colorectal cancer (CRC) in Mexico and compare it with those estimated for Latin American and Caribbean populations. One hundred and one patients with CRC with AJCC stages ranging I–IV from Western Mexico were included, out of which 55% were male and 61% had AJCC stage III–IV, with a mean age of 60 years. PCR-Sanger sequencing was used to identify the BRAF p.V600E variant. In addition, a systematic literature search in PubMed/Medline database and Google of the 42 countries in Latin America and the Caribbean led to the collection of information on the BRAF p.V600E variant frequency of 17 population reports. To compare the BRAF variant prevalence among populations, a statistical analysis was performed using GraphPad Prism V.6.0. We found that 4% of patients with CRC were heterozygous for the p.V600E variant. The χ² test showed no significant difference (p>0.05) in p.V600E detection when comparing with other Latin American and Caribbean CRC populations, except for Chilean patients (p=0.02). Our observational study provides the first evidence on the frequency of BRAF p.V600E in patients with CRC from Western Mexico, which is 4%, but increases to 7.8% for all of Latin America and the Caribbean. The patient mean age and genetic descent on the observed frequencies of the variant in populations could influence the frequency differences.

Treatment patterns for metastatic colorectal cancer in Spain

Purpose

The primary aim of this retrospective study was to describe the treatment patterns according to the type of treatment received by patients with metastatic colorectal cancer (mCRC) in Spain.

Methods

This was a retrospective, observational, multicenter study performed by 33 sites throughout Spain that included consecutive patients aged 18 years or older who had received or were receiving treatment for mCRC.

Results

At the time of inclusion, of the 873 evaluable patients, 507 (58%) had received two lines, 235 (27%) had received three lines, 106 (12%) had received four lines, and the remaining patients had received up to ten lines. The most frequent chemotherapy schemes were the FOLFOX or CAPOX regimens (66%) for first-line treatment, FOLFOX, CAPOX or FOLFIRI (70%) for second-line treatment, and FOLFOX, FOLFIRI or other fluoropyrimidine-based regimens for third- and fourth-line (over 60%) treatment. Sixty percent of patients received targeted therapy as part of their first-line treatment, and this proportion increased up to approximately 70% of patients as part of the second-line of treatment. A relevant proportion of patients were treated with unknown KRAS, and especially the BRAF, mutation statuses.

Conclusions

This study reveals inconsistencies regarding adherence to the recommendations of the ESMO guidelines for the management of mCRC in Spain. Improved adherence to the standard practice described in such guidelines for the determination of RAS and BRAF mutation statuses and the use of targeted therapies in first-line treatment should be considered to guarantee that patients can benefit from the best therapeutic approaches available.

Adjunctive Strategies for Benign Maxillofacial Pathology

Benign cysts and neoplasms of the maxillofacial region can vary in behavior, with some growing rapidly and resulting in destruction of surrounding structures. Despite their benign histology, many require often-morbid treatment to prevent recurrence of these lesions. Several less invasive and adjunctive medical treatments have been developed to lessen the morbidity of surgical treatment. As the molecular and genomic pathogenesis of these lesions is better understood, more directed treatments may lessen the burden for patients.

Molecular characterization of colorectal cancer using whole-exome sequencing in a Taiwanese population

Next‐generation sequencing (NGS) technology is currently used to establish mutational profiles in many heterogeneous diseases. The aim of this study was to evaluate the mutational spectrum in Taiwanese patients with colorectal cancer (CRC) to help clinicians identify the best treatment method. Whole‐exome sequencing was conducted in 32 surgical tumor tissues from patients with CRC. DNA libraries were generated using the Illumina TruSeq DNA Exome, and sequencing was performed on the Illumina NextSeq 500 system. Variants were annotated and compared to those obtained from publicly available databases. The analysis revealed frequent mutations in APC (59.38%), TP53 (50%), RAS (28.13%), FBXW7 (18.75%), RAF (9.38%), PIK3CA (9.38%), SMAD4 (9.38%), and SOX9 (9.38%). A mutation in TCF7L2 was also detected, but at lower frequencies. Two or more mutations were found in 22 (68.75%) samples.

The mutation rates for the WNT, P53, RTK‐RAS, TGF‐β, and PI3K pathways were 78.13%, 56.25%, 40.63%, 18.75%, and 15.63%, respectively. RTK‐RAS pathway mutations were correlated with tumor size (P = 0.028). We also discovered 23 novel mutations in NRAS, PIK3CA, SOX9, APC, SMAD4, MSH3, MSH4, PMS1 PMS2, AXIN2, ERBB2, PIK3R1, TGFBR2, and ATM that were not reported in the COSMIC, The Cancer Genome Atlas, and dbSNP databases. In summary, we report the mutational landscape of CRC in a Taiwanese population. NGS is a cost‐effective and time‐saving method, and we believe that NGS will help clinicians to treat CRC patients in the near future.

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.

Class 1, 2, and 3 BRAF-Mutated Metastatic Colorectal Cancer: A Detailed Clinical, Pathologic, and Molecular Characterization

PURPOSE

BRAF mutations are grouped in activating RAS-independent signaling as monomers (class 1-V600E) or as dimers (class 2-codons 597/601), and RAS-dependent with impaired kinase activity (class 3-codons 594/596). Although clinical, pathologic, and molecular features of ^V600EBRAF-mutated metastatic colorectal cancer (mCRC) are well known, limited data are available from the two other classes.

EXPERIMENTAL DESIGN

Data from 117 patients with BRAF (92 class 1, 12 class 2, and 13 class 3)-mutated mCRC were collected. A total of 540 BRAF wt mCRCs were included as control. IHC profiling was performed to determine the consensus molecular subtypes (CMS), cytokeratin 7/20 profiles, tumor-infiltrating lymphocyte infiltration, and BM1/BM2 categorization. Overall survival (OS) and progression-free survival were evaluated by Kaplan-Meier and log-rank test.

RESULTS

Class 3 BRAF-mutated mCRC was more frequently left sided (P = 0.0028), pN0 (P = 0.0159), and without peritoneal metastases (P = 0.0176) compared with class 1, whereas class 2 cases were similar to class 1. Hazard ratio for OS, as compared with BRAF wt, was 2.38 [95% confidence interval (CI), 1.61-3.54] for class 1, 1.90 (95% CI, 0.85-4.26) for class 2, and 0.93 (95% CI, 0.51-1.69) for class 3 (P < 0.0001). Class 2 and 3 tumors were all assigned to CMS2-3. A higher median CD3/CD8-positive lymphocyte infiltration was observed in BRAF-mutated class 2 (P = 0.033) compared with class 3 cases.

CONCLUSIONS

For the first time, different clinical and pathologic features and outcome data were reported according to the three BRAF mutation classes in mCRC. Specific targeted treatment strategies should be identified in the near future for such patients.

Precision oncology in Latin America: current situation, challenges and perspectives

BACKGROUND

Anti-cancer cytotoxic treatments like platinum-derived compounds often show low therapeutic efficacy, high-risk side effects and resistance. Hence, targeted treatments designed to attack only tumour cells avoiding these harmful side effects are highly needed in clinical practice. Due to this, precision oncology has arisen as an approach to specifically target alterations present only in cancer cells, minimising side effects for patients. It involves the use of molecular biomarkers present in each kind of tumour for diagnosis, prognosis and treatment. Since these biomarkers are specific for each cancer type, physicians use them to stratify, diagnose or take the best therapeutic options for each patient depending on the features of the specific tumour.

AIM

This review aims to describe the current situation, limitations, advantages and perspectives about precision oncology in Latin America.

MAIN BODY

For many years, many biomarkers have been used in a clinical setting in developed countries. However, in Latin American countries, their broad application has not been affordable partially due to financial and technical limitations associated with precarious health systems and poor access of low-income populations to quality health care. Furthermore, the genetic mixture in Latin American populations could generate differences in treatment responses from one population to another (pharmacoethnicity) and this should be evaluated before establishing precision therapy in particular populations. Some research groups in the region have done a lot of work in this field and these data should be taken as a starting point to establish networks oriented to finding clinically useful cancer biomarkers in Latin American populations.

CONCLUSION

Latin America must create policies allowing excluded populations to gain access to health systems and next generation anti-cancer drugs, i.e. high-cost targeted therapies to improve survival. Also, cancer clinical research must be oriented to establish cancer biomarkers adapted to specific populations with different ethnicity, allowing the improvement of patient outcomes.

Systemic treatment for metastatic colorectal cancer in the era of precision medicine

The treatment of metastatic colorectal cancer has evolved over the last two decades with the FDA approval of several cytotoxic, biological, and targeted agents. In this paper, we review the impact of sidedness, RAS, BRAF, HER-2, and other immune biomarkers on metastatic colorectal cancer treatment selection and sequencing in both the palliative and curative intent settings.

Report from the 19th annual Western Canadian Gastrointestinal Cancer Consensus Conference; Winnipeg, Manitoba; 29-30 September 2017

The 19th annual Western Canadian Gastrointestinal Cancer Consensus Conference (wcgccc) was held in Winnipeg, Manitoba, 29-30 September 2017. The wcgccc is an interactive multidisciplinary conference attended by health care professionals from across Western Canada (British Columbia, Alberta, Saskatchewan, and Manitoba) who are involved in the care of patients with gastrointestinal cancer. Surgical, medical, and radiation oncologists; pathologists; radiologists; and allied health care professionals participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of colorectal cancer.

Significant Improvement in Detecting BRAF, KRAS, and EGFR Mutations Using Next-Generation Sequencing as Compared with FDA-Cleared Kits

Introduction

We compared mutations detected in EGFR, KRAS, and BRAF genes using next-generation sequencing (NGS) and confirmed by Sanger sequencing with mutations that could be detected by FDA-cleared testing kits.

Methods

Paraffin-embedded tissue from 822 patients was tested for mutations in EGFR, KRAS, and BRAF by NGS. Sanger sequencing of hot spots was used with locked nucleic acid to increase sensitivity for specific hot-spot mutations. This included 442 (54%) lung cancers, 168 (20%) colorectal cancers, 29 (4%) brain tumors, 33 (4%) melanomas, 14 (2%) thyroid cancers, and 16% others (pancreas, head and neck, and cancer of unknown origin). Results were compared with the approved list of detectable mutations in FDA kits for EGFR, KRAS, and BRAF.

Results

Of the 101 patients with EGFR abnormalities as detected by NGS, only 58 (57%) were detectable by cobas v2 and only 35 (35%) by therascreen. Therefore, 42 and 65%, respectively, more mutations were detected by NGS, including two patients with EGFR amplification. Of the 117 patients with BRAF mutation detected by NGS, 62 (53%) mutations were within codon 600, detectable by commercial kits, but 55 (47%) of the mutations were outside codon V600, detected by NGS only. Of the 321 patients with mutations in KRAS detected by NGS, 284 (88.5%) had mutations detectable by therascreen and 300 (93.5%) had mutations detectable by cobas. Therefore, 11.5 and 6.5% additional KRAS mutations were detected by NGS, respectively.

Conclusion

NGS provides significantly more comprehensive testing for mutations as compared with FDA-cleared kits currently available commercially.

Combination of BEZ235 and Metformin Has Synergistic Effect on Cell Viability in Colorectal Cancer Cells

Patients with type II diabetes mellitus are more susceptible to colorectal cancer (CRC) incidence than non-diabetics. The anti-diabetic drug metformin is most commonly prescribed for the treatment of this disease and has recently shown antitumor effect in preclinical studies. The aberrant mutational activation in the components of RAS/RAF/MEK/ERK and PI3K/AKT/mTOR signaling pathway is very frequently observed in CRC. We previously reported that metformin inhibits the phosphorylation of ERK and BEZ235, a dual inhibitor of PI3K and mTOR, has anti-tumor activity against HCT15 CRC cells harboring mutations of KRAS and PIK3CA. Therefore, we hypothesized that simultaneous inhibition of two pathways by combining metformin with BEZ235 could be more effective in the suppression of proliferation than single agent treatment in HCT15 CRC cells. Here, we investigated the combinatory effect of metformin and BEZ235 on the cell survival in HCT15 CRC cells. Our study shows that both of the two signaling pathways can be blocked by this combinational strategy: metformin suppressed both pathways by inhibiting the phosphorylation of ERK, 4E-BP1 and S6, and BEZ235 suppressed PI3K/AKT/ mTOR pathway by reducing the phosphorylation of 4E-BP1 and S6. This combination treatment synergistically reduced cell viability. The combination index (CI) values ranged from 0.44 to 0.88, indicating synergism for the combination. These results offer a preclinical rationale for the potential therapeutic option for the treatment of CRC.

BRAF Inhibitors for BRAF V600E Mutant Colorectal Cancers: Literature Survey and Case Report

The main method of fighting against colon cancer is targeted treatment. BRAF inhibitors, which are accepted as standard treatment for V600E mutant malign melanomas, are the newest approach for targeted treatment of V600E mutant colorectal cancers. In this case report, we share our experience about the use of BRAF inhibitor vemurafenib on a V600E mutant metastatic right colon adenocarcinoma patient. A 59-year-old male with only lung multiple metastatic V600E mutant right colon cancer presented to our clinic. The patient was evaluated and FOLFOX + bevacizumab treatment was initiated, which was then continued with vemurafenib. A remarkable response was achieved with vemurafenib treatment in which the drug resistance occurred approximately in the sixth month. Even though the patient benefited majorly from vemurafenib, he died on the 20th month of the diagnosis. The expected overall survival for metastatic V600E mutant colon adenocarcinoma patients is 4.7 months. BRAF inhibitors provide new treatment alternatives for V600E mutant colorectal cancers, with prolonged overall survival. BRAF inhibitors in combination with MEK inhibitors are reported as feasible treatment to overcome BRAF inhibitor drug resistance on which phase studies are still in progress. To conclude, BRAF inhibitors alone or in combination with other drugs provide a chance for curing BRAF V600E mutant colorectal cancer patients.

A Network Pharmacology Approach to Uncover the Multiple Mechanisms of Hedyotis diffusa Willd. on Colorectal Cancer

Background

As one of the most frequently diagnosed cancer diseases globally, colorectal cancer (CRC) remains an important cause of cancer-related death. Although the traditional Chinese herb Hedyotis diffusa Willd. (HDW) has been proven to be effective for treating CRC in clinical practice, its definite mechanisms have not been completely deciphered.

Objective

The aim of our research is to systematically explore the multiple mechanisms of HDW on CRC.

Methods

This study adopted the network pharmacology approach, which was mainly composed of active component gathering, target prediction, CRC gene collection, network analysis, and gene enrichment analysis.

Results

The network analysis showed that 10 targets might be the therapeutic targets of HDW on CRC, namely, HRAS, PIK3CA, KRAS, TP53, APC, BRAF, GSK3B, CDK2, AKT1, and RAF1. The gene enrichment analysis implied that HDW probably benefits patients with CRC by modulating pathways related to cancers, infectious diseases, endocrine system, immune system, nervous system, signal transduction, cellular community, and cell motility.

Conclusions

This study partially verified and predicted the pharmacological and molecular mechanism of HDW against CRC from a holistic perspective, which will also lay a foundation for the further experimental research and clinical rational application of HDW.

MicroRNAs in the etiology of colorectal cancer: pathways and clinical implications

MicroRNAs (miRNAs) are small single-stranded RNAs that repress mRNA translation and trigger mRNA degradation. Of the ∼1900 miRNA-encoding genes present in the human genome, ∼250 miRNAs are reported to have changes in abundance or altered functions in colorectal cancer. Thousands of studies have documented aberrant miRNA levels in colorectal cancer, with some miRNAs reported to actively regulate tumorigenesis. A recurrent phenomenon with miRNAs is their frequent participation in feedback loops, which probably serve to reinforce or magnify biological outcomes to manifest a particular cellular phenotype. Here, we review the roles of oncogenic miRNAs (oncomiRs), tumor suppressive miRNAs (anti-oncomiRs) and miRNA regulators in colorectal cancer. Given their stability in patient-derived samples and ease of detection with standard and novel techniques, we also discuss the potential use of miRNAs as biomarkers in the diagnosis of colorectal cancer and as prognostic indicators of this disease. MiRNAs also represent attractive candidates for targeted therapies because their function can be manipulated through the use of synthetic antagonists and miRNA mimics.

Summary: This Review provides an overview of some important microRNAs and their roles in colorectal cancer.

Moving Beyond Conventional Clinical Trial End Points in Treatment-refractory Metastatic Colorectal Cancer: A Composite Quality-of-life and Symptom Control End Point

PURPOSE

This review highlights the evidence supporting symptom control and quality-of-life (QOL) measures as predictors of survival in treatment-refractory metastatic colorectal cancer (mCRC) and describes a composite symptom control and QOL end point recently reported in a Phase III trial that may serve as a more reasonable end point of efficacy in this population.

METHODS

A literature search was conducted using MEDLINE to identify clinical studies (including case series and observational, retrospective, and prospective studies) that reported the predictive value of QOL measures for survival in mCRC. The search was limited by the following key words: quality of life, survival, and colorectal cancer. We then performed a second search limited to studies of randomized and Phase III design in mCRC to identify studies that used QOL assessments as their primary end points. A manual search was also performed to include additional studies of potential relevance.

FINDINGS

There is increasing evidence to support that symptom control and QOL measures are predictors of survival in treatment-refractory mCRC and can serve as an alternative but equally as important end point to survival in this population. A recent large, randomized Phase III trial using a composite primary end point of lean body mass, pain, anorexia, and fatigue reported the feasibility in evaluating benefit in mCRC beyond conventional clinical trial end points.

IMPLICATIONS

Future studies in treatment-refractory mCRC may be better served by evaluating improvement in symptom control and QOL, which may otherwise serve as the best predictor of survival in last-line treatment settings.

Molecular targeted treatment of metastatic colorectal cancer: the cardiovascular adverse effects of Bevacizumab and Cetuximab

Novel emerging therapies have changed paradigms in metastatic colorectal cancer. The advantages of molecular targeted treatments, either the anti-angiogenic or the anti-epidermal growth factor receptor drugs, reside in the fact that while their specificity for the cancer cell is higher, their toxicity on normal tissues is significantly lower when compared to chemotherapy. But when it comes to their safety, especially from a cardiovascular point of view, they still need to pass the test of time and further prospective studies are needed. Clinical trial patients are very well selected with regards to comorbidities and therefore, they often differ from real-life patients. In order to maximize the benefits from these drugs, we need to better identify the population at risk, understand and early diagnose their on- and off-target adverse effects and to adequately choose the diagnostic tools; with a better prevention and early treatment, the quality and quantity of our patients' lives can be significantly improved.

MEK162 Enhances Antitumor Activity of 5-Fluorouracil and Trifluridine in KRAS-mutated Human Colorectal Cancer Cell Lines

BACKGROUND

Preclinical evidence demonstrates that mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway inhibition increases sensitivity to 5-fluorouracil (5-FU) in colorectal cancer (CRC) cell lines and xenografts. Here, we aimed to investigate how CRC cell sensitivity to this combination is correlated to Kirsten rat sarcoma (KRAS) and proto-oncogene B-rapidly accelerated fibrosarcoma (BRAF) mutation, that are common in CRC and often lead to resistance to chemotherapy.

MATERIALS AND METHODS

Wild-type and mutant KRAS/BRAF human CRC cell lines were treated with escalating doses of 5-FU or trifluridine with MEK162 (MEK1/2 inhibitor) for 72 h. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and synergism expressed by the combination index was calculated using CalcuSyn.

RESULTS

Evidence of synergistic antitumor activity was observed for the majority of human CRC cell lines treated with MEK162 plus 5-FU (4/6) or trifluridine (7/9). Synergism was greater in KRAS- or BRAF-mutant cell lines compared to wild-type KRAS/BRAF CRC cell lines.

CONCLUSION

The combination of MEK inhibition and trifluridine is worthwhile advancing in clinical development, particularly for treatment-refractory KRAS- or BRAF-mutated metastatic CRC.

A single institute retrospective trial of concurrent chemotherapy with SIR-Spheres® versus SIR-Spheres® alone in chemotherapy-resistant colorectal cancer liver metastases

BACKGROUND

The use of selective internal radiation therapy with yttrium 90 resin microspheres (SIR-Spheres^®) in chemotherapy-resistant colorectal cancer liver metastases has been associated with favorable progression-free survival (PFS) and overall survival when given alone or concurrently with chemotherapy. We conducted a single institute retrospective trial to explore the potential impact of SIR-Spheres^® with concurrent chemotherapy vs. SIR-Spheres^® alone on liver PFS in patients with colorectal liver metastases (CRLM).

METHODS

Patients with 5-fluorouracil-refractory CRLM treated with SIR-Spheres^® between 2009 and 2014 were identified. Patients were excluded if they received any chemotherapy/targeted regimen following radioembolization on which they did not previously progress. This strategy was adopted to minimize the impact of post-SIR-Spheres^® systemic therapy bias on PFS.

RESULTS

Twenty-seven patients satisfied inclusion criteria and were included in this analysis. Patients' demographics were similar between the two treatment arms, except for the median number of prior therapies. No associated ≥ grade 3 toxicities were noted. Liver disease control rates were 84% and 14% on the SIR-Spheres^® plus chemotherapy arms and SIR-Spheres^® alone arms, respectively (P=0.001). Median PFS in the liver was 176 days in the SIR-Spheres^® plus chemotherapy group vs. 91 days in the SIR-Sphere^® alone group (P=0.0009). Median overall survival was 212 days in the SIR-Spheres^® plus chemotherapy group vs. 154 days in the SIR-Spheres^® alone group (P=0.1023).

CONCLUSIONS

In patients with 5-fluorouracil-refractory disease, SIR-Spheres^® plus chemotherapy is associated with an increased liver disease control rate and a prolonged liver PFS in comparison with SIR-Spheres^® alone.

Next-Generation Sequencing to Guide Treatment of Advanced Melanoma

Next-generation sequencing (NGS) has provided significant insights into the pathogenesis of human malignancies. In advanced melanoma, two therapeutic avenues have appeared and have immediately become the standard of care, i.e. targeted therapy with small molecule inhibitors, and immune checkpoint blockade. Sequencing has always been essential for determining which patients may benefit from targeted therapies (e.g. the presence of BRAF mutations). While sequencing does not currently help recognize which patients might benefit from immune checkpoint blockade, recent data suggest that this may change. Multiple studies have identified tumor mutation profiles associated with patients benefiting from immune checkpoint blockade therapy. These findings suggest comprehensive tumor sequencing may become a critical step for predicting therapy responses to all systemic therapies. In this review, the current and potential future impact of NGS on treatment decisions in advanced melanoma will be summarized and discussed.

Co-targeting of EGFR and autophagy signaling is an emerging treatment strategy in metastatic colorectal cancer

The epidermal growth factor receptor (EGFR) and its associated pathway is a critical key regulator of CRC development and progression. The monoclonal antibodies (MoAbs) cetuximab and panitumumab, directed against EGFR, represent a major step forward in the treatment of metastatic colorectal cancer (mCRC), in terms of progression-free survival and overall survival in several clinical trials. However, the activity of anti-EGFR MoAbs appears to be limited to a subset of patients with mCRC. Studies have highlighted that acquired-resistance to anti-EGFR MoAbs biochemically converge into Ras/Raf/Mek/Erk and PI3K/Akt/mTOR pathways. Recent data also suggest that acquired-resistance to anti-EGFR MoAbs is accompanied by inhibition of EGFR internalization, ubiqutinization, degradation and prolonged downregulation. It is well established that autophagy, a self-cannibalization process, is considered to be associated with resistance to the anti-EGFR MoAbs therapy. Additionally, autophagy induced by anti-EGFR MoAbs acts as a protective response in cancer cells. Thus, inhibition of autophagy after treatment with EGFR MoAbs can result in autophagic cell death. A combination therapy comprising of anti-EGFR MoAbs and autophagy inhibitors would represent a multi-pronged approach that could be evolved into an active therapeutic strategy in mCRC patients.