HER2 as a potential biomarker guiding adjuvant chemotherapy in stage II colorectal cancer

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

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

Protein prognostic biomarkers in stage II colorectal cancer: implications for post-operative management

Colorectal cancer (CRC) poses a significant threat to many human lives worldwide and survival following resection is predominantly stage dependent. For early-stage cancer, patients are not routinely advised to undergo additional post-operative adjuvant chemotherapy. Acceptable clinical management guidelines are well established for patients in pTNM stages I, III and IV. However, recommendations for managing CRC stage II patients remain controversial and many studies have been conducted to segregate stage II patients into low- and high-risk of recurrence using genomic, transcriptomic and proteomic molecular markers. As proteins provide valuable insights into cellular functions and disease state and have a relatively easy translation to the clinic, this review aims to discuss potential prognostic protein biomarkers proposed for predicting tumour relapse in early-stage II CRC. It is suggested that a panel of markers may be more effective than a single marker and further evaluation is required to translate these into clinical practice.

Biomarkers in the development of individualized treatment regimens for colorectal cancer

Introduction

Colorectal cancer (CRC) is the third most common and second most deadly malignancy in the world with an estimated 1. 9 million cases and 0.9 million deaths in 2020. The 5-year overall survival for stage I disease is 92% compared to a dismal 11% in stage IV disease. At initial presentation, up to 35% of patients have metastatic colorectal cancer (mCRC), and 20–50% of stage II and III patients eventually progress to mCRC. These statistics imply both that there is a proportion of early stage patients who are not receiving adequate treatment and that we are not adequately treating mCRC patients.

Body

Targeted therapies directed at CRC biomarkers are now commonly used in select mCRC patients. In addition to acting as direct targets, these biomarkers also could help stratify which patients receive adjuvant therapies and what types. This review discusses the role of RAS, microsatellite instability, HER2, consensus molecular subtypes and ctDNA/CTC in targeted therapy and adjuvant chemotherapy.

Discussion

Given the relatively high recurrence rate in early stage CRC patients as well as the continued poor survival in mCRC patients, additional work needs to be done beyond surgical management to limit recurrence and improve survival. Biomarkers offer both a potential target and a predictive method of stratifying patients to determine those who could benefit from adjuvant treatment.

Heterogeneous clinical and pathological landscapes of HER2 positive colorectal cancer

Introduction: Metastatic (m) colorectal cancer (CRC) can be divided into specific subgroups under the 'one gene, one drug' paradigm of precision medicine. Progress of targeted therapy in mCRC patients significantly improved the overall survival rate, notably by therapy targeting of EGFR signaling in RAS wild-type mCRC patients. Activation of the HER2 pathway is an important mechanism of resistance for anti-EGFR therapy.Area covered: Inhibition of HER2 with monoclonal antibodies and/or tyrosine kinase inhibitors induces tumor responses in partial HER2-positive CRC refractory to standard systemic therapy. This manuscript aimed to provide an overall insight of the HER2 expression pattern and highlighted specific clinicopathological and molecular features involved in mCRC. In addition, we summarize preclinical and clinical trials in HER2-positive mCRC.Expert opinion: The status and progression of HER2-positive gastric cancer and breast cancer and anti-HER2 therapy have been reported widely. However, the understanding of HER2-positive CRC models which may guide future therapeutic decision-making is poor. Therefore, it is essential to summarize the existing research to extract similarity and difference among various studies.

Immunohistochemistry-Based Consensus Molecular Subtypes as a Prognostic and Predictive Biomarker for Adjuvant Chemotherapy in Patients with Stage II Colorectal Cancer

Background

For stage II colorectal cancer (CRC), the efficacy of adjuvant chemotherapy remains controversial. Consensus molecular subtype (CMS) has been validated to be a prognostic tool for CRCs. In this study, CMS status was investigated as a prognostic biomarker for the efficacy of adjuvant chemotherapy for stage II colorectal cancer.

Materials and Methods

The tissue microarray was retrospectively constructed of 165 nonconsecutive, primary, and sporadic stage II CRCs. CMS status was determined by immunohistochemistry staining of CDX2, HTR2B, FRMD6, and ZEB1, combining with microsatellite instability testing. The prognostic for adjuvant chemotherapy efficacy of CMS status was calculated by Kaplan‐Meier curves and Cox regression analysis. Subgroup analyses were conducted according to tumor location.

Results

Kaplan‐Meier curves indicated that CMS was associated with overall survival (OS) and disease‐free survival for stage II CRCs. Cox regression analysis showed that CMS was an independent risk factor for OS. Among high‐risk clinicopathological factors, patients with CMS2/3 (hazard ratio [HR]: 0.445, 95% confidence interval [CI]: 0.227–0.875), left‐sided tumors (HR: 0.488, 95% CI: 0.247–0.968), or fewer than 12 lymph nodes examined (HR: 0.307, 95% CI: 0.097–0.974) had survival benefit from adjuvant chemotherapy. Subgroup analysis showed that adjuvant chemotherapy only improved OS for patients with left‐sided tumors of CMS2/3 subtype. Regardless of CMS, right‐sided tumors had no benefit from adjuvant chemotherapy.

Conclusion

CMS is a better prognostic factor for adjuvant chemotherapy for stage II CRCs. Together with tumor location, CMS classification will aid in personalized treatment for stage II CRCs.

Implications for Practice

For stage II colorectal cancer (CRC), the efficacy of adjuvant chemotherapy remains controversial, in that its minimal benefit (no more than 5% on average) is considered not worth the toxic effects of the drugs. There are still no effective prognostic and predictive biomarkers. This study showed that consensus molecular subtype (CMS) status is a predictive marker for adjuvant chemotherapy efficacy. Patients with left‐sided tumors of CMS2/3 subtype have survival benefit by receiving adjuvant chemotherapy, which will aid in personalized treatment for stage II CRCs. Moreover, this test of CMS based on immunohistochemistry is cheap, not time consuming, and easily conducted in the laboratories of most hospitals.

Currently, no clinical evidence exists for the ability of consensus molecular subtype status to predict the efficacy of adjuvant chemotherapy for stage II colorectal cancer. This article reports results of a study that adopted an immunohistochemical‐based classifier to validate the feasibility of this approach, assessing the prognostic and predictive accuracy of consensus molecular subtype status as a biomarker for adjuvant chemotherapy compared with traditional clinicopathological high‐risk factors.

Genomic Profiling of Stage II Colorectal Cancer Identifies Candidate Genes Associated with Recurrence-Free Survival, Tumor Location, and Differentiation Grade

BACKGROUND

Identification of high-risk stage II colorectal cancer (CRC) patients, potential candidates for adjuvant chemotherapy, is challenging. Current clinical guidelines rely mainly on histopathological markers with relatively weak prognostic value. This motivates further search for prognostic markers.

METHODS

This explorative study aimed to identify potential candidate gene mutations to facilitate differentiation between subgroups of patients with CRC stage II. Panel-based massive parallel sequencing was used to genetically characterize tumor tissues from 85 patients radically operated for CRC stage II, of which 12 developed recurrent cancer during follow-up. Genetic data was compared between patients with or without cancer recurrence, between tumors located in colon and in rectum, and for association with tumor differentiation grade.

RESULTS

Genetic variation in ATM, C11ORF65 was associated with recurrence-free survival. Previous reports regarding the association between BRAF mutation and a higher age at diagnosis, and tumor location in colon were confirmed. APC, BRAF, or KRAS mutation was associated with tumor differentiation grade. Multiple correspondence analyses revealed no obvious clustering of patients with the studied clinical characteristics, indicating that the genetic signatures observed here were unique for each individual.

CONCLUSIONS

Taken together, we have demonstrated the utility of panel-based massive parallel sequencing to explore the pathogenesis of CRC stage II. We have identified promising candidate gene mutations associated with cancer recurrence, tumor location, and differentiation grade in patients with CRC stage II, which merit further investigation.

The Role of Formyl Peptide Receptor 1 Gene Polymorphisms in Human Colorectal Cancer

Formyl peptide receptor 1 (FPR1) belongs to G protein-coupled receptors expressed mainly in phagocytic leukocytes. The gene encoding FPR1 is highly polymorphic and related to inflammation. In this study, we investigated the single nucleotide polymorphisms (SNPs) of Fpr1 in human colorectal cancer (CRC), and analyzed the association of Fpr1 SNPs with clinicopathological parameters and some specific diagnostic markers of CRC. Although the allele and genotype frequencies of Fpr1 SNPs in CRC tissues were not significantly different from that in whole blood cells derived from healthy Chinese subjects. Significant associations were observed between genotypes of c.289C>A and distant metastasis (P=0.001), and between genotypes of c.306T>C and tumor size (P=0.016). Genotypes of c.546C>A was closer to tumor size and lymphatic invasion (P=0.012 and P=0.043, respectively). Meanwhile, genotypes of c.1037C>A was related with tumor location and differentiation (P=0.000 and P=0.005, respectively). Besides, genotypes of c.576T>C>G was related with pathological type (P=0.000). Furthermore, several Fpr1 SNP positions including c.289 (C>A) and c.576 (G>C>T) were related to the expression of P53 (P=0.004 and P=0.008, respectively), and similar results were observed between other Fpr1 SNP positions and CEA, HER2 and Ki-67 (P<0.05). Our data demonstrate that Fpr1 SNPs may play the important role in the progression and metastasis of CRC.

The Importance of Human Tissue Bioresources in Advancing Biomedical Research

Medical research advances enabling the realization of precision medicine have relied heavily on the biospecimens provided by bioresources to identify the targets and biomarkers that are the focus of the new generation of more effective molecular-based therapies for specific subtypes of diseases. Through the biospecimens they have distributed, bioresources have permitted subtypes of cancers to be identified and molecular features of these subtypes to be effectively targeted. A prototype example is the human epidermal growth factor receptor type 2 (HER2), which currently is targeted in breast and gastric cancers. In the future, the use of biospecimens from bioresources will continue to increase the understanding of the molecular actions of drugs and how drugs may be more or less active in subpopulations of patients. Although the biospecimen inventories of the initial forms of bioresources may not have always been optimally planned and, therefore, utilized in supporting biomedical research, bioresources are evolving and overall, bioresource inventories and increasingly their prospective collection capabilities will continue to be a critical component of the research infrastructure.