Recent Advances in Our Knowledge of mCRC Tumor Biology and Genetics: A Focus on Targeted Therapy Development

Recent Advances in Therapeutic Strategies to Improve Colorectal Cancer Treatment

Colorectal cancer (CRC) is the second-leading cause of cancer-related mortality worldwide. CRC mortality results almost exclusively from metastatic disease (mCRC) for which systemic chemotherapy is often a preferred therapeutic option. Biomarker-based stratification of mCRC enables the use of precision therapy based on individual tumor mutational profiles. Activating mutations in the RAS/RAF/MAPK pathway downstream of EGFR signaling have, until recently, limited the use of EGFR-targeted therapies for mCRC; however, the development of anti-RAS and anti-RAF therapies together with improved strategies to limit compensatory signaling pathways is resulting in improved survival rates in several highly lethal mCRC sub-types (e.g., BRAF-mutant). The use of fluoropyrimidine (FP)-based chemotherapy regimens to treat mCRC continues to evolve contributing to improved long-term survival. Future advances in chemotherapy for mCRC will need to position development relative to the advances made in precision oncology.

Survival benefit of metastasectomy in first-line cetuximab therapy in patients with RAS wild-type metastatic colorectal cancer: a nationwide registry

This multicenter study aimed to explore the survival benefit of metastasectomy by first-line cetuximab-based chemotherapy in real-world patients with RAS wild-type metastatic colorectal cancer (mCRC). The primary endpoints were overall survival (OS) and progression-free survival (PFS). The secondary endpoints included objective response rate (ORR), disease control rate (DCR), and metastasectomy rate. The exploratory endpoint was the optimal treatment cycle for better OS and PFS. Receiver operating characteristic curve with the area under curve (AUC) was used to identify the optimal cut-off cycle for survival outcomes. A total of 758 mCRC patients were enrolled in this study, with a median OS of 35.1 months, median PFS of 14.6 months, and metastasectomy rate of 21.4%. Left-sided mCRC had a significantly higher DCR (88.9% vs. 73.1%, P<0.001) and better OS (36.4 vs. 19.6 months, P<0.001). There were no significant differences in PFS and metastasectomy rate between left-sided and right-sided mCRC. However, mCRC patients who underwent metastasectomy over the course of treatment had better OS (54.9 vs. 28.6 months, P<0.001) and PFS (21.0 vs. 13.1 months, P<0.001) than those who did not. Notably, right-sided mCRC who benefited from first-line cetuximab-based chemotherapy to underwent metastasectomy also had favorable outcomes, on a par with left-sided mCRC. The optimal treatment cycle was 14 cycles (AUC: 0.779, P<0.001). Patients who received ≥14 cycles had higher metastasectomy rates (27.5% vs. 13.5%, P<0.001), favorable OS (42.6 vs. 23.4 months, P<0.001) and PFS (18.1 vs. 8.6 months, P<0.001), and, importantly, had comparable adverse events compared with patients who received <14 cycles of treatment. Patients who underwent metastasectomy after or during first-line cetuximab therapy have an improved OS in both left-sided and right-sided mCRC. Furthermore, patients receive ≥14 cycles of treatment whenever possible to achieve a higher likelihood of metastasectomy was associated with favorable survival outcomes.

Review of 5-FU resistance mechanisms in colorectal cancer: clinical significance of attenuated on-target effects

The emergence of chemoresistant disease during chemotherapy with 5-Fluorouracil-based (5-FU-based) regimens is an important factor in the mortality of metastatic CRC (mCRC). The causes of 5-FU resistance are multi-factorial, and besides DNA mismatch repair deficiency (MMR-D), there are no widely accepted criteria for determining which CRC patients are not likely to be responsive to 5-FU-based therapy. Thus, there is a need to systematically understand the mechanistic basis for 5-FU treatment failure and an urgent need to develop new approaches for circumventing the major causes of 5-FU resistance. In this manuscript, we review mechanisms of 5-FU resistance with an emphasis on: (1) altered anabolic metabolism limiting the formation of the primary active metabolite Fluorodeoxyuridylate (5-Fluoro-2'-deoxyuridine-5'-O-monophosphate; FdUMP); (2) elevated expression or activity of the primary enzymatic target thymidylate synthase (TS); and (3) dysregulated programmed cell death as important causes of 5-FU resistance. Importantly, these causes of 5-FU resistance can potentially be overcome through the use of next-generation fluoropyrimidine (FP) polymers (e.g., CF10) that display reduced dependence on anabolic metabolism and more potent TS inhibitory activity.

Rise of the natural red pigment 'prodigiosin' as an immunomodulator in cancer

Cancer is a heterogeneous disease with multifaceted drug resistance mechanisms (e.g., tumour microenvironment [TME], tumour heterogeneity, and immune evasion). Natural products are interesting repository of bioactive molecules, especially those with anticancer activities. Prodigiosin, a red pigment produced by Serratia marcescens, possesses inherent anticancer characteristics, showing interesting antitumour activities in different cancers (e.g., breast, gastric) with low or without harmful effects on normal cells. The present review discusses the potential role of prodigiosin in modulating and reprogramming the metabolism of the various immune cells in the TME, such as T and B lymphocytes, tumour-associated macrophages (TAMs), natural killer (NK) cells, and tumour-associated dendritic cells (TADCs), and myeloid-derived suppressor cells (MDSCs) which in turn might introduce as an immunomodulator in cancer therapy.

Utility and specificity of plasma heat shock protein 90 alpha, CEA, and CA199 as the diagnostic test in colorectal cancer liver metastasis

BACKGROUND

Plasma heat shock protein 90 alpha (Hsp90α) has been suggested as a novel biomarker for the diagnosis and prognosis of cancer. Carcinoembryonic antigen (CEA) and carbohydrate antigen199 (CA199) are traditional tumor biomarkers for colorectal cancer (CRC). Previous studies have shown that Hsp90α and the combination of Hsp90α and CEA are optimal biomarkers for CRC at an early stage. However, research on the use of Hsp90α alone or in combination with CEA and/or CA199 in diagnosing CRC development, particularly liver metastasis, is limited. This study sought to investigate the value of Hsp90α alone or in combination with CEA/CA199 in diagnosing CRC liver metastasis.

METHODS

The clinical data of 472 CRC patients were retrospectively analyzed, which were confirmed by clinical manifestations and a histopathological examination associated with an imaging diagnosis. The levels of Hsp90α, and CEA, and CA199 were assessed by enzyme-linked immunoassays and electrochemiluminescence immunoassays. Liver metastasis was diagnosed by imaging or pathology of the liver. Logistic regression models were used to analyze associations between Hsp90α, CEA, and CA199, and liver metastasis in CRC. The areas under the curves (AUCs) were used to compare the utility of Hsp90α, CEA, and CA199 in the diagnosis of CRC liver metastasis (CRLM). Additionally, we compared the diagnostic utility of the models, including the Hsp90α plus 1 of the other serum markers, and a combination of the 3 serum makers.

RESULTS

The plasma levels of Hsp90α, CEA, and CA199 were positively associated with a higher risk of CRLM [odds ratios (OR) ranging from 1.36-2.72]. The AUCs of CEA, CA199, and Hsp90α for CRLM were 0.80, 0.69, and 0.55, respectively. The AUCs for the combination of Hsp90α and CEA, combination of Hsp90α and CA199, combinations of Hsp90α, CEA, and CA199 were 0.75, 0.66, 0.76, respectively. The combination of Hsp90α, CEA, and CA199 did not improve the diagnostic utility for liver metastasis in CRC.

CONCLUSIONS

The level of Hsp90α was elevated in CRC and was associated with CRLM. Thus, the Hsp90α is a potential biomarker for CRLM. CEA has the largest diagnostic utility for CRLM. Adding Hsp90α to CEA/CA199 did not improve their diagnostic utility for CRLM.

Cyclin-dependent kinases as potential targets for colorectal cancer: past, present and future

Colorectal cancer (CRC) is a common cancer in the world and its prevalence is increasing in developing countries. Deregulated cell cycle traverse is a hallmark of malignant transformation and is often observed in CRC as a result of imprecise activity of cell cycle regulatory components, viz. cyclins and cyclin-dependent kinases (CDKs). Apart from cell cycle regulation, some CDKs also regulate processes such as transcription and have also been shown to be involved in colorectal carcinogenesis. This article aims to review cyclin-dependent kinases as potential targets for CRC. Furthermore, therapeutic candidates to target CDKs are also discussed.

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

Globally, colorectal carcinoma (CRC) is the third most common cancer and the third major cause of cancer-related death in both sexes. KRAS and BRAF mutations are almost mutually exclusively involved in the pathogenesis of CRC. Both are major culprits in treatment failure and poor prognosis for CRC. Method. A systematic review and meta-analysis of various research was done following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. This trial is registered with PROSPERO CRD42021256452. The initial search included 646 articles; after the removal of noneligible studies, a total of 88 studies was finally selected. Data analysis was carried out using OpenMeta Analyst and Comprehensive Meta-Analysis 3.0 (CMA 3.0) software to investigate the prevalence of KRAS and BRAF mutations among patients with CRC in Asia. Results. The meta-analysis comprises of 25,525 sample sizes from Asia with most being male 15,743/25525 (61.7%). Overall prevalence of KRAS mutations was (59/88) 36.3% (95% CI: 34.5-38.2) with I² = 85.54% (P value < 0.001). In 43/59 studies, frequency of KRAS mutations was majorly in codon 12 (76.6% (95% CI: 74.2–78.0)) and less in codon 13 (21.0% (95% CI: 19.1-23.0)). Overall prevalence of BRAF mutations was 5.6% (95% CI: 3.9-8.0) with I² = 94.00% (P value < 0.001). When stratified according to location, a higher prevalence was observed in Indonesia (71.8%) while Pakistan has the lowest (13.5%). Conclusion. Total prevalence of KRAS and BRAF mutations in CRC was 36.6% and 5.6%, respectively, and the results conformed with several published studies on KRAS and BRAF mutations.

Treatment pathways and associated costs of metastatic colorectal cancer in Greece

Objectives

Colorectal cancer (CRC) is the second leading cause of cancer in Europe, with 1.931.590 people newly diagnosed in 2020. The purpose of this study is the investigation of treatment options and healthcare resource metastatic CRC (mCRC) in Greece.

Methods

This study is based on the information collected in November 2020 by an expert panel comprising of 6 medical oncologists from major public and private centers around Greece. A 3-round survey was undertaken, according to Delphi method. The treatment phases studied were: pre-progression; disease progression and terminal care. Pharmaceutical costs and resource utilization data were considered from the perspective of the Greek National Services Organization (EOPYY). RESULTS: Experts agreed that the anticipated prevalence of RAS mutation in mCRC is 47% (30% RAS/BRAF WT Left, 17% RAS/BRAF WT Right); 8% BRAF while, MSI-H/dMMR are found in 5% of mCRC tumors. Based on mutational status, 74.8% of patients receive biological targeted therapies in combination with fluoropyrimidine/based combination chemotherapy, as 1st line treatment, and 25.2% combination chemotherapy alone. At 2nd line, 58.6% of patients receive biological targeted therapies in combination with chemotherapy, 25.4% immunotherapy, 11% combination chemotherapy and 5% biological targeted therapies. At 3rd line 56% of patients receive combination chemotherapy, 28% biological targeted therapies, 10% biological targeted therapies in combination with chemotherapy and 6% immunotherapy. The weighted annual cost (pharmaceuticals and resource use cost) in 1st line per mCRC patient was calculated at €28,407, in 2nd line €33,568, in 3rd line €25,550. The annual cost beyond 3rd line per patient regardless mutation was €19,501 per mCRC patient.

Conclusions

mCRC is a societal challenge for healthcare systems as the treatment is more prolonged but expand patients’ survival. Thus, reimbursement decisions should be based not just on the cost of the treatment, but on the magnitude of the benefit of its treatment on patients’ survival and quality of life.

A narrative review of genetic factors affecting fluoropyrimidine toxicity

OBJECTIVE

Our objective is to document progress in developing personalized therapy with fluoropyrimidine drugs (FPs) to improve outcomes for cancer patients and to identify areas requiring further investigation.

BACKGROUND

FPs including 5-fluorouracil (5-FU), are among the most widely used drugs for treating colorectal cancer (CRC) and other gastrointestinal (GI) malignancies. While FPs confer a survival benefit for CRC patients, serious systemic toxicities, including neutropenia, occur in ~30% of patients with lethality in 0.5-1% of patients. While serious systemic toxicities may occur in any patient, patients with polymorphisms in DPYD, which encodes the rate-limiting enzyme for pyrimidine degradation are at very high risk. Other genetic factors affecting risk for 5-FU toxicity, including miR-27a, are under investigation.

METHODS

Literature used to inform the text of this article was selected from PubMed.gov from the National Library of Medicine while regulatory documents were identified via Google search.

CONCLUSIONS

Clinical studies to date have validated four DPYD polymorphisms (DPYD*2A, DPYD*13, c.2846A>T, HapB3) associated with serious toxicities in patients treated with 5-FU. Genetic screening for these is being implemented in the Netherlands and the UK and has been shown to be a cost-effective way to improve outcomes. Factors other than DPYD polymorphisms (e.g., miR-27a, TYMS, ENOSF1, p53) also affect 5-FU toxicity. Functional testing for deficient pyrimidine catabolism {defined as [U] >16 ng/mL or [UH2]:[U] <10} is being implemented in France and has demonstrated utility in identifying patients with elevated risk for 5-FU toxicity. Therapeutic drug monitoring (TDM) from plasma levels of 5-FU during first cycle treatment also is being used to improve outcomes and pharmacokinetic-based dosing is being used to increase the percent of patients within optimal area under the curve (AUC) (18-28 mg*h/L) values. Patients maintained in the optimal AUC range experienced significantly reduced systemic toxicities. As understanding the genetic basis for increased risk of 5-FU toxicity becomes more refined, the development of functional-based methods to optimize treatment is likely to become more widespread.

Resectable Colorectal Cancer: Current Perceptions on the Correlation of Recurrence Risk, Microbiota and Detection of Genetic Mutations in Liquid Biopsies

Metastatic colorectal cancer (mCRC) remains a highly lethal malignancy, although considerable progress has resulted from molecular alterations in guiding optimal use of available treatments. CRC recurrence remains a great barrier in the disease management. Hence, the spotlight turns to newly mapped fields concerning recurrence risk factors in patients with resectable CRC with a focus on genetic mutations, microbiota remodeling and liquid biopsies. There is an urgent need for novel biomarkers to address disease recurrence since specific genetic signatures can identify a higher or lower recurrence risk (RR) and, thus, be used both as biomarkers and treatment targets. To a large extent, CRC is mediated by the immune and inflammatory interplay of microbiota, through intestinal dysbiosis. Clarification of these mechanisms will yield new opportunities, leading not only to the appropriate stratification policies, but also to more precise, personalized monitoring and treatment navigation. Under this perspective, early detection of post-operative CRC recurrence is of utmost importance. Ongoing trials, focusing on circulating tumor cells (CTCs) and, even more, circulating tumor DNA (ctDNA), seem to pave the way to a promising, minimally invasive but accurate and life-saving monitoring, not only supporting personalized treatment but favoring patients' quality of life, as well.