Relationship of HER2 Alteration and Microsatellite Instability Status in Colorectal Adenocarcinoma

Prognostic and predictive molecular biomarkers in colorectal cancer

Precision medicine has brought revolutionary changes to the diagnosis and treatment of cancer patients, and is currently a hot and challenging research topic. Currently, the treatment regimens for most colorectal cancer (CRC) patients are mainly determined by several biomakers, including Microsatellite Instability (MSI), RAS, and BRAF. However, the roles of promising biomarkers such as HER-2, consensus molecular subtypes (CMS), and circulating tumor DNA (ctDNA) in CRC are not yet fully clear. Therefore, it is urgent to explore the potential of these emerging biomarkers in the diagnosis and treatment of CRC patients. In this paper, we discuss recent advances in CRC biomarkers, especially clinical data, and focus on the roles of biomarkers in prognosis, prediction, treatment strategies, and the intrinsic connections with clinical pathological features, hoping to promote better precision medicine for colorectal cancer.

Molecular characterization of mixed-histology endometrial carcinoma provides prognostic and therapeutic value over morphologic findings

We performed molecular analysis of a single-institution cohort of clinically diagnosed mixed-histology endometrial carcinoma (MEC). A gynecologic pathologist confirmed that 72 cases met diagnostic criteria for MEC based on WHO 2020 guidelines, and these were molecularly classified using both a DNA-based and histologic approach. Tumors were classified as: POLE-mutated (13.9%), microsatellite instability (MSI)-high/mismatch repair deficient (MMRd) (26.4%), TP53/p53 abnormal (p53abnl) (48.6%), no specific molecular profile (NSMP) (11.1%). Recurrence risk significantly differed based upon molecular class, but not histology. 44% of MEC cases had a HER2 IHC score of 2-3+, and this was not limited to p53abnl tumors. Transcriptional analysis demonstrated 93 differentially expressed genes between p53abnl and NSMP tumors, including many associated with the innate immune response and DNA damage repair. While p53abnl and NSMP tumors have similarly poor outcomes, transcriptome analysis revealed biologic differences that could impact targeted therapeutics in this high-risk group.

Intrahepatic cholangiocarcinoma with FGFR alterations: A series of Chinese cases with an emphasis on their clinicopathologic and genetic features

Intrahepatic Cholangiocarcinoma (iCCA) with FGFR alterations is relatively rare, and its identification is important in the era of targeted therapy. We collected a large series of FGFR-altered cases in the Chinese population and characterized their clinicopathological and genetic features. Among the 18 FGFR-altered cases out of 260 iCCAs, 10 were males and 8 were females, ranging in age from 35 to 74 years (mean, 57.3 years; median, 58 years). Pathologically, they include 9 cases of large duct (LD, 50 %) and small duct (SD, 50 %) types each. All of them (100 %, 18/18) showed microsatellite stable (MSS) and low tumor mutation burden (TMB). Genetically, FGFR alterations involved FGFR1 (20 %), FGFR2 (70 %), and FGFR3 (10 %), with FGFR2 rearrangement accounting for the most (11/18). The most frequently altered genes/biological processes were development/proliferation-related pathways (44 %), chromatin organization (20 %), and tumor suppressors (32 %). Our study further revealed the clinicopathological and genetic features of FGFR-altered iCCA and demonstrated that its occurrence may show regional or ethnic variability and is less common in the Chinese population. A significant number of LD-type iCCA cases also have FGFR alterations rather than the SD type.

Genomic profiling of colorectal cancer in large-scale Chinese patients: amplification and somatic mutations in ERBB2

Objectives

Human epidermal growth factor receptor 2 (HER2)-targeted therapies have demonstrated potential benefits for metastatic colorectal cancer (mCRC) patients with HER2 amplification, but are not satisfactory in cases of HER2 mutant CRCs.

Methods

Consequently, further elucidation of amplifications and somatic mutations in erythroblastic oncogene B-2 (ERBB2) is imperative. Comprehensive genomic profiling was conducted on 2454 Chinese CRC cases to evaluate genomic alterations in 733 cancer-related genes, tumor mutational burden, microsatellite instability, and programmed death ligand 1 (PD-L1) expression.

Results

Among 2454 CRC patients, 85 cases (3.46%) exhibited ERBB2 amplification, and 55 cases (2.24%) carried ERBB2 mutation. p.R678Q (28%), p.V8421 (24%), and p.S310F/Y (12%) were the most prevalent of the 16 detected mutation sites. In comparison to the ERBB2 altered (alt) group, KRAS/BRAF mutations were more prevalent in ERBB2 wild-type (wt) samples (ERBB2wt vs. ERBB2alt, KRAS: 50.9% vs. 25.6%, p < 0.05; BRAF: 8.5% vs. 2.3%, p < 0.05). 32.7% (18/55) of CRCs with ERBB2 mutation exhibited microsatellite instability high (MSI-H), while no cases with HER2 amplification displayed MSI-H. Mutant genes varied between ERBB2 copy number variation (CNV) and ERBB2 single nucleotide variant (SNV); TP53 alterations tended to co-occur with ERBB2 amplification (92.3%) as opposed to ERBB2 mutation (58.3%). KRAS and PIK3CA alterations were more prevalent in ERBB2 SNV cases (KRAS/PIK3CA: 45.8%/31.2%) compared to ERBB2 amplification cases (KRAS/PIK3CA: 14.1%/7.7%).

Conclusion

Our study delineates the landscape of HER2 alterations in a large-scale cohort of CRC patients from China. These findings enhance our understanding of the molecular features of Chinese CRC patients and offer valuable implications for further investigation.

Preclinical efficacy of a HER2 synNotch/CEA-CAR combinatorial immunotherapy against colorectal cancer with HER2 amplification

HER2 amplification occurs in approximately 5% of colorectal cancer (CRC) cases and is associated only partially with clinical response to combined human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR)-targeted treatment. An alternative approach based on adoptive cell therapy using T cells engineered with anti-HER2 chimeric antigen receptor (CAR) proved to be toxic due to on-target/off-tumor activity. Here we describe a combinatorial strategy to safely target HER2 amplification and carcinoembryonic antigen (CEA) expression in CRC using a synNotch-CAR-based artificial regulatory network. The natural killer (NK) cell line NK-92 was engineered with an anti-HER2 synNotch receptor driving the expression of a CAR against CEA only when engaged. After being transduced and sorted for HER2-driven CAR expression, cells were cloned. The clone with optimal performances in terms of specificity and amplitude of CAR induction demonstrated significant activity in vitro and in vivo specifically against HER2-amplified (HER2amp)/CEA+ CRC models, with no effects on cells with physiological HER2 levels. The HER2-synNotch/CEA-CAR-NK system provides an innovative, scalable, and safe off-the-shelf cell therapy approach with potential against HER2amp CRC resistant or partially responsive to HER2/EGFR blockade.

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.

Systematic literature review and meta-analysis of HER2 amplification, overexpression, and positivity in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of cancer death globally. Recent clinical trials suggest an emerging role for HER2 as a potential clinically relevant biomarker in CRC. Testing for HER2 in CRC is not standard practice; consequently, the prevalence of HER2 positivity (HER2+) in patients with CRC remains uncertain.

METHODS

A systematic literature review and meta-analysis were conducted to generate estimates of proportions of patients with CRC with HER2 overexpression or HER2 amplification and HER2+ (either overexpression or amplification), overall and in patients with rat sarcoma virus (RAS) wild-type cancer. HER2+ was defined as 1) immunohistochemistry with a score of 3+, 2) immunohistochemistry with a score of 2+ and in situ hybridization+, or 3) next-generation sequencing positive.

RESULTS

Of 224 studies identified with information on HER2 in CRC, 52 studies used a US Food and Drug Administration-approved assay and were selected for further analysis. Estimated HER2+ rate was 4.1% (95% confidence interval [CI] = 3.4% to 5.0%) overall (n = 17 589). HER2+ rates were statistically higher in RAS wild-type (6.1%, 95% CI = 5.4% to 6.9%) vs RAS mutant CRC (1.1%, 95% CI = 0.3% to 4.4%; P < .0001). Despite limited clinical information, we confirmed enrichment of HER2+ CRC in patients with microsatellite stable and left-sided CRC.

CONCLUSION

This meta-analysis provides an estimate of HER2+ CRC and confirms enrichment of HER2 in microsatellite stable, left-sided, RAS wild-type CRC tumors. Our work is important given the recently described clinical efficacy of HER2-targeted therapies in HER2+ CRC and informs strategies for incorporation of HER2 testing into standard of care.

Microsatellite Instability: A Review of Molecular Epidemiology and Implications for Immune Checkpoint Inhibitor Therapy

Microsatellite instability (MSI) is one of the most important molecular characteristics of a tumor, which occurs among various tumor types. In this review article, we examine the molecular characteristics of MSI tumors, both sporadic and Lynch-associated. We also overview the risks of developing hereditary forms of cancer and potential mechanisms of tumor development in patients with Lynch syndrome. Additionally, we summarize the results of major clinical studies on the efficacy of immune checkpoint inhibitors for MSI tumors and discuss the predictive role of MSI in the context of chemotherapy and checkpoint inhibitors. Finally, we briefly discuss some of the underlying mechanisms causing therapy resistance in patients treated with immune checkpoint inhibitors.

HER2+ endometrioid endometrial cancer possesses distinct molecular and immunologic features associated with a more active immune microenvironment and worse prognosis

OBJECTIVE

HER2 status is not routinely evaluated in endometrioid endometrial cancer (E-EMCA), though it is frequently overexpressed or amplified in high grade E-EMCA and uterine serous carcinoma. Defining characteristics and survival outcomes of HER2+ E-EMCA could reveal subsets of patients who may benefit from targeted therapies.

METHODS

2927 E-EMCA tumors from the Caris Life Sciences database were analyzed by next-generation sequencing and whole exome sequencing, whole transcriptome sequencing, and immunohistochemistry for molecular and genomic features in a CLIA/CAP-certified laboratory (Caris Life Sciences, Phoenix, AZ). HER2 status was determined by transcriptomic cutoff extrapolated from uterine serous carcinoma. The relationship between HER2 status and patient outcomes was determined by Kaplan-Meier analysis.

RESULTS

HER2 positivity was detected in 5.47% of E-EMCA. Differences in molecular alterations based on HER2 status were most apparent in microsatellite stable (MSS) tumors, which displayed increased TP53 mutations and loss of heterozygosity (LOH) and decreased PTEN and CTNNB1 mutations. HER2+ tumors had increased immune checkpoint gene expression and immune cell infiltration, particularly among MSS tumors. All HER2+ tumors displayed increased MAPK pathway activation scores (MPAS) and patients with HER2+ tumors experienced worse overall survival.

CONCLUSIONS

HER2 positivity in E-EMCA corresponds with a unique molecular landscape, particularly in MSS tumors. HER2+ tumors are also associated with increased MAPK pathway activation and exhibit features of a more active immune microenvironment. These findings suggest a potential benefit of HER2 and MAPK targeted therapies as well as immunotherapies in this patient population.

HER2 in Metastatic Colorectal Cancer: Pathology, Somatic Alterations, and Perspectives for Novel Therapeutic Schemes

HER2 is an emerging biomarker in colorectal cancer (CRC). This oncogene plays an essential role in regulating cell proliferation, differentiation, migration, and, more in general, tumorigenesis and tumor progression. The most frequent types of HER2 alterations in CRC include gene amplification and missense mutations in 7-8% of CRC, often being mirrored by HER2 protein overexpression, representing founder events in solid tumors, including CRC. There are currently no approved HER2-targeted therapy guidelines for CRC; however, several studies have shown that HER2 can be effectively targeted in meta-static CRC settings. In this review, we discuss the current knowledge of HER2 testing in CRC and the immediate future perspectives for HER2 targeting in the metastatic setting.

HER2 in Colorectal Cancer: The Long and Winding Road From Negative Predictive Factor to Positive Actionable Target

Human epidermal growth factor receptor 2 (HER2) is a well-known oncogenic driver in different tumors and an approved therapeutic target in breast and gastroesophageal cancer. In metastatic colorectal cancer, only 3% to 5% of patients present with HER2 alterations: somatic mutations and amplifications. HER2 was first assessed as a biomarker of resistance to anti-EGFR therapy; however, in more recent years, its role as a potential actionable target has emerged. In this article, we discuss the predictive and prognostic value of HER2 in metastatic colorectal cancer, its emerging role as an actionable therapeutic target, and its possible future developments.

Beyond RAS and BRAF: HER2, a New Actionable Oncotarget in Advanced Colorectal Cancer

The human epidermal growth factor receptor 2 (HER2) is a well-established oncogenic driver and a successful therapeutic target in several malignancies, such as breast and gastric cancers. HER2 alterations, including amplification and somatic mutations, have also been detected in a small but not negligible subset of patients affected by advanced colorectal cancer (aCRC). However, to date, there are no available oncotargets in this malignancy beyond RAS and BRAF that are available. Here we present an overview on the present predictive and prognostic role of HER2 expression in aCRC, as well as on its consequent potential therapeutic implications from preclinical investigations towards ongoing trials testing anti-HER2 agents in aCRC. While HER2's role as a molecular predictive biomarker for anti-EGFR therapies in CRC is recognized, HER2 prognostic value remains controversial. Moreover, thanks to the impressive and growing body of clinical evidence, HER2 is strongly emerging as a new potential actionable oncotarget in aCRC. In conclusion, in the foreseeable future, HER2-targeted therapeutic strategies may integrate the algorithm of aCRC treatment towards an increasingly tailored therapeutic approach to this disease.