HER2 in gastric cancer: a new prognostic factor and a novel therapeutic target

KRT18 Modulates Alternative Splicing of Genes Involved in Proliferation and Apoptosis Processes in Both Gastric Cancer Cells and Clinical Samples

Keratin 18 (KRT18), one of the most abundant keratins in epithelial and endothelial cells, has been reported to be aberrantly expressed in many malignancies and extensively regarded as a biomarker and important regulator in multiple cancers, including gastric cancer (GC). But the molecular regulatory mechanisms of KRT18 in GC patients and cells are largely unknown. In the present study, we analyzed the expression level of KRT18 in 450 stomach adenocarcinoma tissue samples from TCGA database and found a significantly higher expression level in tumor tissues. We then explored the potential functions of KRT18 in AGS cells (human gastric adenocarcinoma cell line) by KRT18 knockdown using siRNA and whole transcriptome RNA-seq analysis. Notably, KRT18 selectively regulates expression of cell proliferation and apoptotic genes. Beyond this, KRT18 affects the alternative splicing of genes enriched in apoptosis, cell cycle, and other cancer-related pathways, which were then validated by reverse transcription-quantitative polymerase chain reaction approach. We validated KRT18-KD promoted apoptosis and inhibited proliferation in AGS cells. We then used RNA-seq data of GC samples to further demonstrate the modulation of KRT18 on alternative splicing regulation. These results together support the conclusion that KRT18 extensively modulates diverse alternative splicing events of genes enriched in proliferation and apoptosis processes. And the dysregulated splicing factors at transcriptional or posttranscriptional level by KRT18 may contribute to the alternative splicing change of many genes, which expands the functional importance of keratins in apoptotic and cell cycle pathways at the posttranscriptional level in GC.

Immune-Related Nine-MicroRNA Signature for Predicting the Prognosis of Gastric Cancer

Recent findings have demonstrated the superiority and utility of microRNAs (miRNAs) as new biomarkers for cancer diagnosis, therapy, and prognosis. In this study, to explore the prognostic value of immune-related miRNAs in gastric cancer (GC), we analyzed the miRNA-expression profiles of 389 patients with GC, using data deposited in The Cancer Genome Atlas database. Using a forward- and backward-variable selection and multivariate Cox regression analyses model, we identified a nine-miRNA signature (the “ImmiRSig,” consisting of miR-125b-5p, miR-99a-3p, miR-145-3p, miR-328-3p, miR-133a-5p, miR-1292-5p, miR-675-3p, miR-92b-5p, and miR-942-3p) in the training cohort that enabled the division of patients into high- and low-risk groups with significantly different survival rates. The ImmiRSig was successfully validated with an independent test cohort of 193 GC patients. Univariate and multivariate Cox regression analyses indicated that the ImmiRSig would serve as an independent prognostic factor after adjusting for other clinical covariates. Pending further prospective validation, the identified ImmiRSig appears to have significant clinical importance in terms of improving outcome predictions and guiding personalized treatment for patients with GC. Finally, significant associations between the ImmiRSig and the half-maximal inhibitory concentrations of chemotherapeutic agents were observed, suggesting that ImmiRSig may predict the clinical efficacy of chemotherapy.

Human epidermal growth factor receptor 2 (HER2) in advanced gastric cancer: where do we stand?

Gastric cancer is one of the most common malignancy worldwide. In unresectable or metastatic disease, the prognosis is poor and in generally less than a year. HER2 expression remains an important biomarker to lead the addition of trastuzumab to first-line systemic chemotherapy in unresectable or metastatic gastroesophageal adenocarcinoma. To date, a major issue is represented by resistance to trastuzumab developed during treatment, considering the not improved outcomes in this molecular subtype of gastroesophageal adenocarcinoma to other HER2 target strategies. In this review, we summarize the available data on the mechanisms underlying primary and secondary resistance to HER2-targeted therapy and current challenges in the treatment of HER2-positive advanced gastric cancer refractory to trastuzumab. Furthermore, we describe the prognostic value of new non-invasive screening methods, under development novel agents (e.g., HER2 antibody-drug conjugates and bispecific antibodies) and strategies with antitumor activity in early studies.

Precision medicine: Uses and challenges

Precision medicine has brought in many changes to the practise of medicine. The omics-based development of biomarkers and pharmaco-omics-based drug development programmes are evidences for the advancement. However, the field where it has proved to be most useful is in the development of various modalities of treatment in oncology. Various drugs targeting vascular endothelial growth factor, epidermal growth factor, tyrosine kinase receptor and rat sarcoma mutations have come to the forefront proving to be beneficial in many cancers. Some of the classic drugs developed using this concept include trastuzumab, bevacizumab, cetuximab and panitumumab among others. Precision medicine has been put to best use in the COVID-19 pandemic through use of various biomarkers such as IL-6 and c-reactive protein in assessing severity of disease, for development of various therapies and also to judge efficacy of vaccines. Precision medicine is also finding its place in management of infectious diseases, chronic diseases such as asthma, connective tissue diseases, cardiovascular diseases, diabetes and obesity. India has also made its presence felt in the field by launching various initiatives such as the Indian genome project and Indian cancer genome atlas. Numerous challenges still exist to the future of precision medicine such as cost involved, ethics, security of the Big data, merger of various platforms to integrate data and also availability of trained manpower to manage the data and algorithms. This new age medicine is a big step forward for mankind and hopefully it will bring more benefits for both patients and the caregivers in the near future.

Evaluation of Near-infrared Fluorescence-conjugated Peptides for Visualization of Human Epidermal Receptor 2-overexpressed Gastric Cancer

Purpose

A near-infrared (NIR) fluorescence imaging is a promising tool for cancer-specific image guided surgery. Human epidermal receptor 2 (HER2) is one of the candidate markers for gastric cancer. In this study, we aimed to synthesize HER2-specific NIR fluorescence probes and evaluate their applicability in cancer-specific image-guided surgeries using an animal model.

Materials and Methods

An NIR dye emitting light at 800 nm (IRDye800CW; Li-COR) was conjugated to trastuzumab and an HER2-specific affibody using a click mechanism. HER2 affinity was assessed using surface plasmon resonance. Gastric cancer cell lines (NCI-N87 and SNU-601) were subcutaneously implanted into female BALB/c nu (6–8 weeks old) mice. After intravenous injection of the probes, biodistribution and fluorescence signal intensity were measured using Lumina II (Perkin Elmer) and a laparoscopic NIR camera (InTheSmart).

Results

Trastuzumab-IRDye800CW exhibited high affinity for HER2 (K_D=2.093(3) pM). Fluorescence signals in the liver and spleen were the highest at 24 hours post injection, while the signal in HER2-positive tumor cells increased until 72 hours, as assessed using the Lumina II system. The signal corresponding to the tumor was visually identified and clearly differentiated from the liver after 72 hours using a laparoscopic NIR camera. Affibody-IRDye800CW also exhibited high affinity for HER2 (K_D=4.71 nM); however, the signal was not identified in the tumor, probably owing to rapid renal clearance.

Conclusions

Trastuzumab-IRDye800CW may be used as a potential NIR probe that can be injected 2–3 days before surgery to obtain high HER2-specific signal and contrast. Affibody-based NIR probes may require modifications to enhance mobilization to the tumor site.

UCP-2 inhibitor enhanced the efficacy of trastuzumab against HER2 positive breast cancer cells

Purpose

This study aimed to investigate the possibility of UCP-2 inhibitor in reducing acquired resistance of trastuzumab to improve the outcome of patients receiving trastuzumab therapy by exploring the relationship between UCP-2 expression and HER2 signaling pathway and examining whether UCP-2 expression was modulated by trastuzumab treatment.

Methods

32 women diagnosed with primary HER2-positive breast cancer were recruited in this study. Needle biopsy was obtained from patients before they received at least four cycles neoadjuvant therapy containing trastuzumab in combination with chemotherapy. Surgical tumor biopsy was obtained during surgical procedure after the neoadjuvant therapy. Levels of HER2 phosphorylation and UCP-2 expression were detected by immunohistochemistry (IHC) and compared between tumor needle biopsy tissue and surgical tumor samples of these patients, as well as in BT474 breast cancer cells before and after trastuzumab treatment. HER2-selective phosphorylation/kinase activity inhibitor ONT-380 was used to identify the correlation between HER2 phosphorylation level and UCP-2 expression. UCP-2 inhibitor Genipin was then used to evaluate the apoptosis index in BT474 cells treated with trastuzumab.

Results

UCP-2 expression was significantly elevated in surgical tumor samples from breast cancer patients receiving trastuzumab in a neoadjuvant setting. We further confirmed our findings in HER2-positive BT474 cell line and found that trastuzumab treatment induced phosphorylation of HER2 and the overexpression of UCP-2, and the latter can be reversed by HER2 selective kinase inhibitor ONT-380. Moreover, UCP-2 inhibitor Genipin significantly enhanced the proliferation suppression effects of trastuzumab and markedly promoted apoptosis.

Conclusion

Taken together, our study identified UCP-2 as a novel therapeutic target for HER2 positive breast cancer and UCP-2 inhibitor may have great potential to enhance the response rate and efficacy of trastuzumab therapy.

Increased expression levels of AURKA and KIFC1 are promising predictors of progression and poor survival associated with gastric cancer

Increased cell proliferation is a critical hallmark of cancer development and progression. The proliferation of tumor cells depends on mitotic deregulation. Here, we identified the differentially expressed genes (DEGs) in gastric cancer (GC) through RNA sequencing data and bioinformatics analysis. Subsequent functional and pathway enrichment analyses showed that the screened DEGs were enriched in the mitosis-associated pathway. Based on the analysis results, we selected two signatures (aurora kinase A [AURKA] and kinesin family member C1 [KIFC1]) to determine their clinicopathological significance. The results showed a significant positive correlation between AURKA and KIFC1 expression both at the mRNA and protein levels. AURKA expression was positively correlated with distant metastases (p = 0.032) and tumor-node-metastasis (TNM) stage (p = 0.001). Elevated KIFC1 expression was significantly associated with tumor size (p = 0.029), depth of invasion (p < 0.001), lymph node metastasis (p < 0.001), distant metastasis (p = 0.023), and TNM stage (p < 0.001). Higher AURKA (hazard ratio [HR] = 1.3, p < 0.001) and KIFC1 (HR = 1.41, p < 0.001) mRNA levels were also significantly correlated with poor overall survival. Thus, AURKA and KIFC1 could serve as potential prognostic markers and therapeutic targets for GC.

The Pyroptosis-Related Signature Predicts Prognosis and Indicates Immune Microenvironment Infiltration in Gastric Cancer

Gastric cancer (GC) is one of the leading causes of cancer-related deaths and shows high levels of heterogeneity. The development of a specific prognostic model is important if we are to improve treatment strategies. Pyroptosis can arise in response to H. pylori, a primary carcinogen, and also in response to chemotherapy drugs. However, the prognostic evaluation of GC to pyroptosis is insufficient. Consensus clustering by pyroptosis-related regulators was used to classify 618 patients with GC from four GEO cohorts. Following Cox regression with differentially expressed genes, our prognosis model (PS-score) was built by LASSO-Cox analysis. The TCGA-STAD cohort was used as the validation set. ESTIMATE, CIBERSORTx, and EPIC were used to investigate the tumor microenvironment (TME). Immunotherapy cohorts by blocking PD1/PD-L1 were used to investigate the treatment response. The subtyping of GC based on pyroptosis-related regulators was able to classify patients according to different clinical traits and TME. The difference between the two subtypes identified in this study was used to develop a prognosis model which we named “PS-score.” The PS-score could predict the prognosis of patients with GC and his/her overall survival time. A low PS-score implies greater inflammatory cell infiltration and better response of immunotherapy by PD1/PD-L1 blockers. Our findings provide a foundation for future research targeting pyroptosis and its immune microenvironment to improve prognosis and responses to immunotherapy.

Life after Cell Death-Survival and Survivorship Following Chemotherapy

Simple Summary

Treatment of aggressive cancers often relies on chemotherapy. This treatment has improved survival rates, but while effective at killing cancer cells, inevitably it also kills or alters the function of others. While many of the known effects are transient and resolve after treatment, as survival rates increase, so does our understanding of the long-term health costs that accompany cancer survivors. Here we provide an overview of common long-term morbidities known to be caused by conventional chemotherapy, including the risk of relapse, but more importantly, the cost of quality of life experienced, especially by those who have cancer in early life. We aim to highlight the importance of the development of targeted therapies to replace the use of conventional chemotherapy, but also that of treating the patients along with the disease to enable not only longer but also healthier life after cancer.

Abstract

To prevent cancer cells replacing and outnumbering their functional somatic counterparts, the most effective solution is their removal. Classical treatments rely on surgical excision, chemical or physical damage to the cancer cells by conventional interventions such as chemo- and radiotherapy, to eliminate or reduce tumour burden. Cancer treatment has in the last two decades seen the advent of increasingly sophisticated therapeutic regimens aimed at selectively targeting cancer cells whilst sparing the remaining cells from severe loss of viability or function. These include small molecule inhibitors, monoclonal antibodies and a myriad of compounds that affect metabolism, angiogenesis or immunotherapy. Our increased knowledge of specific cancer types, stratified diagnoses, genetic and molecular profiling, and more refined treatment practices have improved overall survival in a significant number of patients. Increased survival, however, has also increased the incidence of associated challenges of chemotherapy-induced morbidity, with some pathologies developing several years after termination of treatment. Long-term care of cancer survivors must therefore become a focus in itself, such that along with prolonging life expectancy, treatments allow for improved quality of life.

A Reliable and Standardizable Differential PCR and qPCR Methodology Assesses HER2 Gene Amplification in Gastric Cancer

We have applied two PCR techniques, differential PCR (diffPCR) and qPCR for the identification of HER2 gene amplifications in genomic DNA of tumor and distal gastric samples from patients with gastric cancer. The diffPCR technique consists of the simultaneous amplification of the HER2 gene and a housekeeping gene by conventional PCR and the densitometric analysis of the bands obtained. We established a cut-off point based on the mean and standard deviation analyzing the DNA of 30 gastric tissues from patients undergoing non-cancer gastrectomy. diffPCR and qPCR yielded consistent results. HER2-overexpression was detected in 25% of patients and was further confirmed by immunohistochemistry and immunofluorescence. The approaches herein described may serve as complementary and reliable methods to assess HER2 amplification.

Trimodality Approach for Esophageal Malignancies

Trimodality therapy, or the use of concurrent chemoradiation followed by surgery, is the cornerstone of contemporary management of esophageal cancer. This article discusses the landmark trials and most current data to understand the concepts, applications, and outcomes from trimodality therapy in locally advanced esophageal cancer.

The promise of bispecific antibodies: Clinical applications and challenges

The development of cancer therapies using monoclonal antibodies has been successful during the last 30 years. Recently much progress was achieved with technologies involving bispecific and multi-specific antibodies. Bispecific antibodies (BsAbs) are antibodies that bind two distinct epitopes, and a large number of potential clinical applications of BsAbs have been described. Here we review mechanism of action, clinical development and future challenges of BsAbs which could be a serve as a valuable arsenal in cancer patients.

Her2-Positive and Microsatellite Instability Status in Gastric Cancer-Clinicopathological Implications

Gastric cancer (GC) is one of the leading causes of cancer-related death. The combination of new molecular classifications with clinicopathological data could contribute to the individualization of patients and to the development of new therapeutic strategies. We examined the various associations in two molecular types of GC: HER2-positive (human epidermal growth factor receptor 2) and microsatellite instability (MSI), assessing their influence on treatment and prognosis. A retrospective study of 142 GC patients was performed with molecular characterization through HER2 overexpression and DNA repair protein expression for MSI. The percentage of HER2-positive tumors was 13.4%, predominantly in men. Correlations were found with intestinal type, metastases, advanced stages and chemotherapy. Almost 75% of HER2-positive patients died. MSI occurred in 16.2%, associated with advanced age, female sex, distal location and intestinal type. These patients had few metastases and low stages. The percentage of deaths was higher among MSI patients who received perioperative chemotherapy. The determination of HER2 and MSI status in GC is important for their association with specific clinicopathological features and for their prognostic and predictive value.

Near Infrared Photoimmunotherapy; A Review of Targets for Cancer Therapy

Simple Summary

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that uses an antibody-photoabsorber (IRDye700DX) conjugate (APC) that is activated by NIR light irradiation. A major benefit of NIR-PIT is that only APC-bound cancer cells that are exposed to NIR light are killed by NIR-PIT; thus, minimal damage occurs in adjacent normal cells. NIR-PIT has now been applied to many cancers expressing various cell-surface target proteins using monoclonal antibodies designed to bind to them. Moreover, NIR-PIT is not limited to tumor antigens but can also be used to kill specific host cells that create immune-permissive environments in which tumors grow. Moreover, multiple targets can be treated simultaneously with NIR-PIT using a cocktail of APCs. NIR-PIT has great potential to treat a wide variety of cancers by targeting appropriate tumor cells, immune cells, or both, and can be augmented by other immunotherapies.

Abstract

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that uses an antibody-photoabsorber (IRDye700DX) conjugate (APC) that is activated by NIR light irradiation. In September 2020, the first APC and laser system were conditionally approved for clinical use in Japan. A major benefit of NIR-PIT is that only APC-bound cancer cells that are exposed to NIR light are killed by NIR-PIT; thus, minimal damage occurs in adjacent normal cells. These early trials have demonstrated that in addition to direct cell killing, there is a significant therapeutic host immune response that greatly contributes to the success of the therapy. Although the first clinical use of NIR-PIT targeted epidermal growth factor receptor (EGFR), many other targets are suitable for NIR-PIT. NIR-PIT has now been applied to many cancers expressing various cell-surface target proteins using monoclonal antibodies designed to bind to them. Moreover, NIR-PIT is not limited to tumor antigens but can also be used to kill specific host cells that create immune-permissive environments in which tumors grow. Moreover, multiple targets can be treated simultaneously with NIR-PIT using a cocktail of APCs. NIR-PIT can be used in combination with other therapies, such as immune checkpoint inhibitors, to enhance the therapeutic effect. Thus, NIR-PIT has great potential to treat a wide variety of cancers by targeting appropriate tumor cells, immune cells, or both, and can be augmented by other immunotherapies.

Differentiation and Regulation of TH Cells: A Balancing Act for Cancer Immunotherapy

Current success of immunotherapy in cancer has drawn attention to the subsets of T_H cells in the tumor which are critical for activation of anti-tumor response either directly by themselves or by stimulating cytotoxic T cell activity. However, presence of immunosuppressive pro-tumorigenic T_H subsets in the tumor milieu further contributes to the complexity of regulation of T_H cell-mediated immune response. In this review, we present an overview of the multifaceted positive and negative effects of T_H cells, with an emphasis on regulation of different T_H cell subtypes by various immune cells, and how a delicate balance of contradictory signals can influence overall success of cancer immunotherapy. We focus on the regulatory network that encompasses dendritic cell-induced activation of CD4⁺ T_H1 cells and subsequent priming of CD8⁺ cytotoxic T cells, along with intersecting anti-inflammatory and pro-tumorigenic T_H2 cell activity. We further discuss how other tumor infiltrating immune cells such as immunostimulatory T_H9 and T_fh cells, immunosuppressive T_reg cells, and the duality of T_H17 function contribute to tip the balance of anti- vs pro-tumorigenic T_H responses in the tumor. We highlight the developing knowledge of CD4⁺ T_H1 immune response against neoantigens/oncodrivers, impact of current immunotherapy strategies on CD4⁺ T_H1 immunity, and how opposing action of T_H cell subtypes can be explored further to amplify immunotherapy success in patients. Understanding the nuances of CD4⁺ T_H cells regulation and the molecular framework undergirding the balancing act between anti- vs pro-tumorigenic T_H subtypes is critical for rational designing of immunotherapies that can bypass therapeutic escape to maximize the potential of immunotherapy.

Does Specimen Type Have an Impact on HER2 Status in Endometrial Serous Carcinoma? Discordant HER2 Status of Paired Endometrial Biopsy and Hysterectomy Specimens in the Presence of Frequent Intratumoral Heterogeneity

A recent clinical trial showed prolonged progression-free survival in human epidermal growth factor receptor 2 (HER2)-positive advanced stage and recurrent endometrial serous carcinomas when trastuzumab was added to traditional chemotherapy. Approximately one third of these tumors are HER2-positive and have been described to show unique characteristics of HER2 protein expression and gene amplification, including significant intratumoral heterogeneity, in recent studies. However, currently, there are no standard protocols for the selection of optimal specimen type or algorithm for HER2 testing in endometrial serous carcinomas. The current study aimed to evaluate the concordance of HER2 status between endometrial biopsy/curettage and subsequent hysterectomy specimens in endometrial serous carcinoma. A total of 57 patients with endometrial serous carcinoma with available HER2 status were identified during the study period, 14 of which (14/57, 25%) were HER2-positive by immunohistochemistry and/or fluorescent in situ hybridization (FISH). The final study cohort consisted of 40 paired endometrial biopsies/curettings and hysterectomies to include all 14 HER2-positive tumors and 26 selected HER2-negative tumors to represent an equal distribution of HER2 immunohistochemical scores. HER2 FISH was performed on all tumors with an immunohistochemical score of 2+. HER2 immunohistochemical scores, heterogeneity of HER2 expression, FISH results, and the overall HER2 status were compared between the 2 specimen types. HER2 status was successfully assigned in both specimen types in 37 cases, as three specimens showed inadequate FISH signals. Concordant HER2 status was observed in 84% of cases (31/37), with identical HER2 immunohistochemical scores in 65% (26/40) of tumors. Among the 6 tumors with a discordant HER2 status, 2 were HER2 negative in the biopsy and positive in the hysterectomy, and 4 were HER2-positive in the biopsy and negative in the hysterectomy. The false-negative rate would be 15.4% and 26.7% if only the biopsy or only the hysterectomy would be the basis for the result, respectively. Intratumoral heterogeneity of HER2 protein expression was present in 22 tumors (55%), including all cases with a discordant HER2 status. The concordance rate of HER2 status between paired endometrial biopsies/curettings and hysterectomies of endometrial serous carcinoma is lower than the reported rates of breast cancer, and comparable to those of gastric carcinomas. Frequent heterogeneity of HER2 protein expression combined with the possibility of a spatially more heterogenous sampling of endometrial cavity in biopsies and curettings, and the potential differences in specimen handling/fixation between the 2 specimen types may explain our findings. HER2 testing of multiple specimens may help identify a greater proportion of patients eligible for targeted trastuzumab therapy and should be taken into account in future efforts of developing endometrial cancer-specific HER2 testing algorithm.

Trastuzumab deruxtecan for the treatment of HER2-positive advanced gastric cancer: a clinical perspective

Human epidermal growth factor receptor 2 (HER2)-positive gastric cancer is a subtype for which new drugs and specific treatment strategies should be developed. Trastuzumab deruxtecan (T-DXd) is a novel HER2-targeted antibody-drug conjugate containing topoisomerase I inhibitor as a payload. In the randomized phase 2 study (DESTINY-Gastric01) for HER2-positive advanced gastric or gastroesophageal junction cancer (AGC), patients treated with T-DXd showed a significantly higher response rate compared with the chemotherapy of physician's choice, associated with remarkably prolonged progression-free and overall survival. T-DXd also exhibits anti-tumor activity to HER2-negative tumor cells close to HER2-positive cells (so-called bystander killing effect). T-DXd was effective even for HER2-low expressing breast and gastric cancer in several clinical studies. Taking advantage of these strong points and synergism with other cytotoxic, molecular-targeted and immunological agents, it is expected that T-DXd will bring further progression in treatment both for strongly and weakly HER2 positive AGC in various treatment settings including perioperative chemotherapy.

Targeting the PI3K and MAPK pathways to improve response to HER2-targeted therapies in HER2-positive gastric cancer

Background

Aberrant PI3K signalling is implicated in trastuzumab resistance in HER2-positive gastric cancer (GC). The role of PI3K or MEK inhibitors in sensitising HER2-positive GCs to trastuzumab or in overcoming trastuzumab resistance is unclear.

Methods

Using mass spectrometry-based genotyping we analysed 105 hotspot, non-synonymous somatic mutations in PIK3CA and ERBB-family (EGFR, ERBB2, ERBB3 and ERBB4) genes in gastric tumour samples from 69 patients. A panel of gastric cell lines (N87, OE19, ESO26, SNU16, KATOIII) were profiled for anti-proliferative response to the PI3K inhibitor copanlisib and the MEK1/2 inhibitor refametinib alone and in combination with anti-HER2 therapies.

Results

Patients with HER2-positive GC had significantly poorer overall survival compared to HER2-negative patients (15.9 months vs. 35.7 months). Mutations in PIK3CA were only identified in HER2-negative tumours, while ERBB-family mutations were identified in HER2-positive and HER2-negative tumours. Copanlisib had anti-proliferative effects in 4/5 cell lines, with IC50s ranging from 23.4 (N87) to 93.8 nM (SNU16). All HER2-positive cell lines except SNU16 were sensitive to lapatinib (IC50s 0.04 µM–1.5 µM). OE19 cells were resistant to trastuzumab. The combination of lapatinib and copanlisib was synergistic in ESO-26 and OE-19 cells (ED50: 0.83 ± 0.19 and 0.88 ± 0.13, respectively) and additive in NCI-N87 cells (ED50:1.01 ± 0.55). The combination of copanlisib and trastuzumab significantly improved growth inhibition compared to either therapy alone in NCI-N87, ESO26 and OE19 cells (p < 0.05).

Conclusions

PI3K or MEK inhibition alone or in combination with anti-HER2 therapy may represent an improved treatment strategy for some patients with HER2-positive GC, and warrants further investigation in a clinical trial setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02842-1.

PTEN is a predictive biomarker of trastuzumab resistance and prognostic factor in HER2-overexpressing gastroesophageal adenocarcinoma

Poor trastuzumab (Tmab) response of patients with human epidermal growth factor receptor 2-overexpressing gastric or gastroesophageal junction adenocarcinoma (HER2-GEA) is associated with the inhibition of phosphatase and tensin homolog (PTEN) expression. In this multicenter, retrospective observational study, pathological samples of patients with HER2-GEA receiving Tmab-combined chemotherapy were immunohistochemically analyzed for PTEN expression. The primary endpoints were disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). We assessed the effect of conventional chemotherapy and Tmab alone or combined with PI3K pathway inhibitors in vitro in HER2-GEA cells with or without PTEN expression. Twenty-nine and 116 patients were in the PTEN-loss and PTEN-positive groups, respectively. In patients with the target region, DCR was significantly lower in PTEN-loss patients than in PTEN-positive patients (67% and 87%, respectively, p = 0.049). The multivariate analysis demonstrated that PTEN loss was significantly associated with shorter PFS (HR = 1.63, p = 0.035) and OS (HR = 1.83, p = 0.022). PTEN knockdown did not affect the cytostatic effect of 5-FU and cisplatin, whereas Tmab combined with the PI3K/mTOR inhibitor NPV-BEZ235 suppressed PTEN-knockdown cell proliferation. In patients with HER2-GEA, PTEN loss is a predictive biomarker of Tmab resistance and prognostic factor. Molecular-targeted therapy with a PI3K/mTOR inhibitor would be effective for HER2-GEA with PTEN loss.

Molecular Oncology in Management of Colorectal Cancer

Colorectal cancers are the third most common cancers in the world. Management of both primary and metastatic colorectal cancers has evolved over the last couple of decades. Extensive research in molecular oncology has helped us understand and identify these complex intricacies in colorectal cancer biology and disease progression. These advances coupled with improved knowledge on various mutations have helped develop targeted chemotherapeutics and has allowed planning an effective treatment regimen in this era of immunotherapy with precision. The diverse chemotherapeutic and biological agents at our disposal can make decision making a very complex process. Molecular profile, including CIN, RAS, BRAF mutations, microsatellite instability, ctDNA, and consensus molecular subtypes, are some of the important factors which are to be considered while planning an individualized treatment regimen. This article summarizes the current status of molecular oncology in the management of colorectal cancer and should serve as a practical guide for the clinical team.

Clinical development of CAR T cell therapy in China: 2020 update

Chimeric antigen receptor (CAR) T-cell therapy has achieved significant success in the treatment of hematological malignancies. In recent years, fast-growing CAR T clinical trials have actively explored their potential application scenarios. According to the data from the clinicaltrials.gov website, China became the country with the most registered CAR T trials in September 2017. As of June 30, 2020, the number of registered CAR T trials in China has reached 357. In addition, as many as 150 other CAR T trials have been registered on ChiCTR. Although CAR T therapy is flourishing in China, there are still some problems that cannot be ignored. In this review, we aim to systematically summarize the clinical practice of CAR T-cell therapy in China. This review will provide an informative reference for colleagues in the field, and a better understanding of the history and current situation will help us more reasonably conduct research and promote cooperation.

Where to Start and What to Do Next: The Sequencing of Treatments in Metastatic Esophagogastric Cancer

Esophagogastric cancer is associated with rising incidence and high mortality. Nearly 40% of patients have metastatic disease at the time of diagnosis with poor 5-year overall survival. The treatment of squamous cell carcinoma of the esophagus and gastroesophageal adenocarcinoma has started to bifurcate in recent years, owing to the evolving understanding of the biologic and genomic characteristics of these tumors. Incorporation of HER2-directed therapy in the form of monoclonal antibody and antibody-drug conjugate is now standard of care for patients with HER2-positive disease. The addition of immune checkpoint inhibitors to the therapeutic landscape of metastatic esophagogastric cancer is associated with modest improvement in overall survival, and definition of predictive biomarkers of response to checkpoint inhibition remains imprecise. A number of therapeutic targets including FGFR2b, Claudin 18.2, DKK-1, and DNA repair defects are being explored in clinical trials. Similarly, combination immunotherapy and novel HER2-targeting agents, such as bispecific antibody and small-molecule inhibitors, are at various stages of clinical development. Despite the progress made in the field of targeted therapies and checkpoint inhibition, chemotherapy remains an integral part of treatment of metastatic esophagogastric cancer but is associated with considerable toxicity. Clinical trials focusing on minimizing toxicity of currently available therapeutic agents, development of novel biomarker-driven treatment strategies, and overcoming resistance to immune checkpoint inhibition will define the future of this traditionally indelible disease.

Comparative investigation of early-onset gastric cancer

Early-onset gastric cancer (EOGC) is a serious social burden. For patients with EOGC, typically considered as those aged <45 years, the underlying cause of the disease remains unclear. In addition, several misunderstandings of EOGC remain in clinical practice. Upon diagnosis, numerous patients with EOGC are already at an advanced stage (stage IV) of the disease and are unable to benefit from treatment. Moreover, several conclusions and data obtained from different EOGC studies appear to be to contradictory. The literature indicates that the incidence of EOGC is gradually rising, and that EOGC differs from traditional and familial gastric cancer in terms of clinicopathological characteristics. Patients with EOGC typically exhibit low survival rates, poor prognosis, rapid disease progression, a low degree of differentiation (signet-ring cell tumors are common) and rapid lymph node and distant metastasis, among other characteristics. The molecular genetic mechanisms of EOGC are also significantly different from those of traditional gastric cancer. An improved definition of EOCG may provide a reference for clinical diagnosis and treatment, and clear guidelines may serve as a basis for more accurate diagnosis and the development of effective treatment strategies.

Development of a Novel Weighted Ranking Method for Immunohistochemical Quantification of a Heterogeneously Expressed Protein in Gastro-Esophageal Cancers

Simple Summary

High levels of the protein Junctional Adhesion Molecule-A (JAM-A) have been linked with aggressive disease in patients with several different cancers. However, its distribution is often non-uniform (heterogeneous) across tumors, and can be difficult to quantify. JAM-A has also been linked with high levels of HER2 (an important oncogene) in breast tumors, and the development of resistance to HER2-targeted drugs in those patients. Since gastro-esophageal (GE) cancers are often high in HER2 and have also been approved for HER2-targeted drugs, the aim of this study was to investigate if levels of JAM-A and HER2 are linked in GE cancer. JAM-A was expressed very heterogeneously across miniaturized tissue sections called tissue microarrays (TMAs) of GE cancer patients. In this model, therefore, there was no correlation between JAM-A and HER2 expression. However, when we used larger tissue sections and developed a scoring system to account for heterogeneity, a significant correlation between JAM-A and HER2 levels emerged. This work illustrates the importance of taking intra-tumor heterogeneity into account, particularly in an era when analysis of protein levels by this method is increasingly used to select patients for targeted cancer drugs.

Abstract

High expression of Junctional Adhesion Molecule-A (JAM-A) has been linked with poor prognosis in several cancers, including breast cancers overexpressing the human epidermal growth factor receptor-2 (HER2). Furthermore, JAM-A expression has been linked with regulating that of HER2, and associated with the development of resistance to HER2-targeted therapies in breast cancer patients. The purpose of this study was to establish a potential relationship between JAM-A and HER2 in HER2-overexpressing gastro-esophageal (GE) cancers. Interrogation of gene expression datasets revealed that high JAM-A mRNA expression was associated with poorer survival in HER2-positive gastric cancer patients. However, high intra-tumoral heterogeneity of JAM-A protein expression was noted upon immunohistochemical scoring of a GE cancer tissue microarray (TMA), precluding a simple confirmation of any relationship between JAM-A and HER2 at protein level. However, in a test-set of 25 full-face GE cancer tissue sections, a novel weighted ranking system proved effective in capturing JAM-A intra-tumoral heterogeneity and confirming statistically significant correlations between JAM-A/HER2 expression. Given the growing importance of immunohistochemistry in stratifying cancer patients for the receipt of new targeted therapies, this may sound a cautionary note against over-relying on cancer TMAs in biomarker discovery studies of heterogeneously expressed proteins. It also highlights a timely need to develop validated mechanisms of capturing intra-tumoral heterogeneity to aid in future biomarker/therapeutic target development for the benefit of cancer patients.

Detection of ERBB2 amplification in uterine serous carcinoma by next-generation sequencing: an approach highly concordant with standard assays

Uterine serous carcinoma is an aggressive subtype of endometrial cancer that accounts for fewer than 10% of endometrial carcinomas but is responsible for about half of deaths. A subset of cases has HER2 overexpression secondary to ERBB2 gene amplification, and these patients may benefit from anti-HER2 therapies, such as trastuzumab. HER2 protein overexpression is currently assessed by immunohistochemistry (IHC) and ERBB2 gene amplification by fluorescence in situ hybridization (FISH). Targeted next-generation sequencing (NGS) is increasingly used to routinely identify predictive and prognostic molecular abnormalities in endometrial carcinoma. To investigate the ability of a targeted NGS panel to detect ERBB2 amplification, we identified cases of uterine serous carcinoma (n = 93) and compared HER2 expression by IHC and copy number assessed by FISH with copy number status assessed by NGS. ERBB2 copy number status using a combination of IHC and FISH was interpreted using the 2018 ASCO/CAP guidelines for breast carcinoma. ERBB2 amplification by NGS was determined by the relative number of reads mapping to ERBB2 in tumor DNA compared to control nonneoplastic DNA. Cases with copy number ≥6 were considered amplified and copy number <6 were non-amplified. By IHC, 70 specimens were classified as negative (0 or 1+), 19 were classified as equivocal (2+), and 4 were classified as positive (3+). Using combined IHC/FISH, ERBB2 amplification was observed in 8 of 93 cases (9%). NGS identified the same 8 cases with copy number ≥6; all 85 others had copy number <6. In this series, NGS had 100% concordance with combined IHC/FISH in identifying ERBB2 amplification. NGS is highly accurate in detecting ERBB2 amplification in uterine serous carcinoma and provides an alternative to measurement by IHC and FISH.

CT Radiomics for Distinction of Human Epidermal Growth Factor Receptor 2 Negative Gastric Cancer

RATIONALE AND OBJECTIVES

The purpose of this study was to investigate the role of computed tomography (CT) radiomics for the prediction of the human epidermal growth factor 2 (HER2) status in patients with gastric cancer.

METHODS

One hundred and thirty two consecutive patients with advanced gastric cancer undergoing radical gastrectomy were retrospectively reviewed. All patients received preoperative contrast CT examination, and immunohistochemistry results of their HER2 status were available. All the subjects were randomly divided into a training cohort (n = 90) and a test cohort (n = 42). Arterial phase (AP) and portal phase (PP) contrast CT images were retrieved for tumor segmentation and feature extraction. Receiver operating characteristics (ROC) curves and area under the curve (AUC) were used to evaluate the performance of the radiomics classifiers.

RESULTS

Among the 132 patients, a total of 99 patients were HER2 negative, and the remaining 33 patients were border line or positive. The AP radiomics model could distinguish HER2-negative cases with an AUC of 0.756 (95% confidence interval [CI]: 0.656-0.840) in the training cohort, which was confirmed in the test cohort with AUC of 0.830 (95% CI: 0.678-0.930). The PP radiomics model showed AUCs of 0.715 (95% CI: 0.612-0.804) and 0.718 (95% CI: 0.554-0.849) in the training and test cohort for distinction of negative HER2 cases, respectively.

CONCLUSION

Radiomics models based on standard-of-care CT images hold promise for distinguishing HER2-negative gastric cancer.

Perioperative trastuzumab, capecitabine and oxaliplatin in patients with HER2-positive resectable gastric or gastro-oesophageal junction adenocarcinoma: NEOHX phase II trial

INTRODUCTION

Perioperative chemotherapy improves overall survival (OS) and disease-free survival (DFS) compared with surgery alone in patients with resectable gastric adenocarcinoma (GA) or gastro-oesophageal junction adenocarcinoma (GEJA). The addition of trastuzumab to chemotherapy improves outcomes in patients with HER2-positive advanced gastric cancer (GC), and we aimed to explore its role in the perioperative setting.

MATERIAL AND METHODS

This Spanish, multicentre, open-label phase II trial evaluated the efficacy and toxicity of perioperative capecitabine, oxaliplatin and trastuzumab (XELOX-T) in patients with HER2-positive resectable GA or GEJA. The primary end-point was 18-months DFS; and secondary end-points included pathological complete response (pCR) rate, R0 resection rate, OS and toxicity (NCT01130337).

RESULTS

Thirty-six patients were included. After three cycles of preoperative treatment, 14 patients (38% of the intention-to-treat population) had partial response and 18 (50%) had stable disease. Surgery was performed in 31 patients: 28 (90%) had R0 resection, three (9.6%) had a pCR and three (9.6%) died due to surgical complications. A total of 24 patients received post-operative XELOX-T, 22 of whom completed trastuzumab maintenance. Main grade III/IV toxicities included diarrhoea (33%), nausea and vomiting (8%). After a median follow-up of 24.1 months, 18-month DFS was 71% (95% confidence interval [CI], 53-83%); and an update after 102 months of follow-up showed a median OS of 79.9 months and a 60-month OS of 58% (95% CI, 40-73%).

CONCLUSIONS

These data suggest that perioperative XELOX-T in patients with HER2-positive GA and GEJA is feasible and active. Further investigation in randomised studies is warranted.

Autophagy Blockade Limits HER2+ Breast Cancer Tumorigenesis by Perturbing HER2 Trafficking and Promoting Release Via Small Extracellular Vesicles

Autophagy modulation is an emerging strategy for cancer therapy. By deleting an essential autophagy gene or disrupting its autophagy function, we determined a mechanism of HER2+ breast cancer tumorigenesis by directly regulating the oncogenic driver. Disruption of FIP200-mediated autophagy reduced HER2 expression on the tumor cell surface and abolished mammary tumorigenesis in MMTV-Neu mice. Decreased HER2 surface expression was due to trafficking from the Golgi to the endocytic pathways instead of the plasma membrane. Autophagy inhibition led to HER2 accumulation in early and late endosomes associated with intraluminal vesicles and released from tumor cells in small extracellular vesicles (sEVs). Increased HER2 release from sEVs correlated with reduced tumor cell surface levels. Blocking sEVs secretion rescued HER2 levels in tumor cells. Our results demonstrate a role for autophagy to promote tumorigenesis in HER2+ breast cancer. This suggests that blocking autophagy could supplement current anti-HER2 agents for treating the disease.

Trastuzumab deruxtecan for the treatment of patients with HER2-positive gastric cancer

Trastuzumab deruxtecan (T-DXd) is a novel anti-human epidermal growth factor receptor 2 (HER2) antibody–drug conjugate composed of a monoclonal anti-HER2 antibody and a topoisomerase I inhibitor, DX-8951 derivative (an exatecan derivative). T-DXd showed potential anti-tumor activities in HER2-positive gastric cancer cell lines and xenograft models. In the randomized, phase II trial DESTINY-Gastric01, T-DXd demonstrated a significantly higher objective response rate as a primary endpoint and a longer overall survival as a secondary endpoint in patients with pretreated HER2-positive advanced gastric cancer (AGC). Although adverse events caused by T-DXd were generally manageable, approximately 10% of patients experienced treatment-related interstitial lung disease. Based on the results of the DESTINY-Gastric01 trial, T-DXd was approved for HER2-positive pretreated AGC in Japan. This study reviews the preclinical and clinical data of T-DXd for treating HER2-positive gastric cancer.

Feasibility of HER2-Targeted Therapy in Advanced Biliary Tract Cancer: A Prospective Pilot Study of Trastuzumab Biosimilar in Combination with Gemcitabine Plus Cisplatin

The prognosis of advanced biliary tract cancer (BTC) is poor with the standard gemcitabine and cisplatin (GemCis) regimen. Given that the rates of human epidermal growth factor receptor 2 (HER2) positivity in BTC reaches around 15%, HER2-targeted therapy needs further investigation. This study aims to evaluate the preliminary efficacy/safety of first-line trastuzumab-pkrb plus GemCis in patients with advanced BTC. Patients with unresectable/metastatic HER2-positive BTC received trastuzumab-pkrb (on day 1 of each cycle, 8 mg/kg for the first cycle and 6 mg/kg for subsequent cycles), gemcitabine (1000 mg/m² on day 1 and 8) and cisplatin (25 mg/m² on day 1 and 8) every 3 weeks. Of the 41 patients screened, 7 had HER2-positive tumours and 4 were enrolled. The median age was 72.5 years (one male). Primary tumour locations included extrahepatic (N = 2) and intrahepatic (N = 1) bile ducts, and gallbladder (N = 1). Best overall response was a partial response in two patients and stable disease in two patients. Median progression-free survival (PFS) was 6.1 months and median overall survival (OS) was not reached. The most common grade 3 adverse event was neutropenia (75%), but febrile neutropenia did not occur. No patient discontinued treatment due to adverse events. Trastuzumab-pkrb with GemCis showed promising preliminary feasibility in patients with HER2-positive advanced BTC.

Effect of Additional Trastuzumab in Neoadjuvant and Adjuvant Treatment for Patients with Resectable HER2-Positive Gastric Cancer

BACKGROUND

Recent studies have reported a beneficial role of trastuzumab in neoadjuvant treatment (NAT) among resectable gastric cancer (GC) patients; however, the effect of adjuvant treatment (AT) combined with trastuzumab is understudied. We performed a retrospective cohort study to compare chemotherapies with or without trastuzumab among human epidermal growth factor receptor 2-positive (HER2 +) locally advanced GC patients in the AT and NAT settings, respectively.

METHODS

We enrolled 208 HER2 + resected GC patients who underwent perioperative/postoperative treatment in 2010-2019 in a single-centered hospital, including 135 AT patients and 73 NAT patients. We used inverse probability of treatment weighting (IPTW) to balance potential confounding factors between the treatment groups, and estimated the treatment effect of trastuzumab. Pathological and survival outcomes were evaluated.

RESULTS

The number of trastuzumab-exposed patients in the AT and NAT cohorts was 31 (23.0%) and 34 (46.6%), respectively. After IPTW adjustment, AT combined with trastuzumab showed a better overall survival (OS) over chemotherapy alone (p = 0.023). In IPTW-adjusted NAT analysis, trastuzumab-exposed patients had an improvement in tumor pathological regression and downstaging, with lower tumor regression grade scores (p = 0.002), ypTNM stages (p < 0.001), ypN stages (p = 0.035), and ypT stages (p < 0.001). Loss of HER2 positivity following trastuzumab treatment was observed in NAT patients; however, we did not observe any significant effect of trastuzumab on OS (p = 0.126).

CONCLUSIONS

Given the improvement in tumor regression and downstaging among NAT patients, and the OS benefit in AT patients, trastuzumab could be considered a promising treatment for locally advanced HER2 + GC patients. In particular, re-evaluation of HER2 status should be considered following NAT combined with trastuzumab.

HER2 Status in High-Risk Endometrial Cancers (PORTEC-3): Relationship with Histotype, Molecular Classification, and Clinical Outcomes

Simple Summary

HER2 testing in endometrial cancer (EC) has gained renewed interest as a therapeutic target. However, HER2 status has not been investigated in the context of the molecular EC classification. Here, we aimed to determine the clinicopathological features and prognostic significance of the HER2 status in the molecularly classified PORTEC-3 trial population of patients with high-risk EC. HER2 status of 407 high-risk EC was determined by HER2 immunohistochemistry and HER2 dual in situ hybridization. Twenty-four (5.9%) HER2-positive EC of various histological subtypes were identified, including serous (n = 9, 37.5%), endometrioid (n = 6, 25.0%), and clear cell (n = 5, 20.8%). HER2 positivity was highly associated with the p53-abnormal subgroup (p53abn, 23/24 cases; p < 0.0001). The correlation between p53abn and the HER2 status (ρ = 0.438; p < 0.0001) was significantly stronger (p < 0.0001) than between serous histology and the HER2 status (ρ = 0.154; p = 0.002). HER2 status did not have independent prognostic value for survival after correction for the molecular classification. Our study strongly suggests that molecular subclass-directed HER2 testing is superior to histotype-directed testing.

Abstract

HER2 status has not been investigated in the context of the molecular endometrial cancer (EC) classification. Here, we aimed to determine the clinicopathological features and prognostic significance of the HER2 status in the molecularly classified PORTEC-3 trial population of patients with high-risk EC (HREC). HER2 testing was performed on tumor tissues of 407 molecularly classified HREC. HER2 status was determined by HER2 immunohistochemistry (IHC; all cases) and subsequent HER2 dual in situ hybridization for cases with any (in) complete moderate to strong membranous HER2 IHC expression. The Χ² test and Spearman’s Rho correlation coefficient were used to compare clinicopathological and molecular features. The Kaplan–Meier method, log-rank test, and Cox proportional hazards models were used for survival analysis. We identified 24 (5.9%) HER2-positive EC of various histological subtypes including serous (n = 9, 37.5%), endometrioid (n = 6, 25.0%), and clear cell (n = 5, 20.8%). HER2 positivity was highly associated with the p53-abnormal subgroup (p53abn, 23/24 cases; p < 0.0001). The correlation between p53abn and the HER2 status (ρ = 0.438; p < 0.0001) was significantly stronger (p < 0.0001) than between serous histology and the HER2 status (ρ = 0.154; p = 0.002). HER2 status did not have independent prognostic value for survival after correction for the molecular classification. Our study strongly suggests that molecular subclass-directed HER2 testing is superior to histotype-directed testing. This insight will be relevant for future trials targeting HER2.

Human Epidermal Growth Factor Receptor 2 (HER2) in Advanced Gastric Cancer: Current Knowledge and Future Perspectives

The discovery of human epidermal growth factor receptor 2 (HER2) overexpression in 15-20% of gastric adenocarcinomas has been a key advance in the global care of this disease. Validated by the ToGA trial in the first-line setting of advanced HER2-positive (+) gastric cancer (GC), trastuzumab, an anti-HER2 monoclonal antibody (mAb), was the first therapeutic agent to significantly improve the prognosis of these patients. Since these results, many attempts have been made to improve the clinical outcomes of patients with HER2+ GC. However, all the other HER2-targeting molecules have failed to show a survival benefit in large phase III studies. The value of continuing trastuzumab after disease progression has been suggested by several retrospective studies. However, recent results of a randomized phase II trial showed no benefit from this strategy. On the other hand, novel therapeutic methods, such as immunotherapy, are emerging as new tools in the strategy of care of advanced GC, even if their benefit in the specific HER2+ population remains undetermined. Furthermore, substantial progress has been made in the understanding of the mechanisms leading to resistance to anti-HER2 therapies, and in the screening methods to detect them, thus opening new perspectives. The aim of this review was firstly to summarize the existing data on the specific strategy of care of HER2+ advanced GC, and secondly, to describe current knowledge regarding the potential mechanisms of resistance to HER2-targeting therapies. Lastly, we report the prospects for overcoming these potential obstacles, from future therapeutic strategies to new detection methods.

Targeting HER2 Alterations in Non–Small-Cell Lung Cancer: A Comprehensive Review

PURPOSE

HER2 is a critical gene that drives various solid tumors in addition to those of breast cancer. For example, HER2 plays a role in non–small-cell lung cancer (NSCLC). Overexpression, amplification, and point mutations in HER2 have been described in patients with NSCLC; however, the potential roles of these alterations remain unclear.

METHODS

We summarize the evidence regarding the distinct impacts of different HER2 aberrations on antitumor agents. Also, we update the therapeutic efficacy of HER2-targeted agents, including anti-HER2 antibodies, antibody-drug conjugates, and small-molecule tyrosine kinase inhibitors, tested in HER2-aberrant NSCLC.

RESULTS

Although these drugs are not yet standard treatments, certain patients may benefit from these therapies. In this review, we aim to provide an improved understanding of HER2 aberrations in NSCLC, including NSCLC biology and the impacts of each aberration on prognosis and standard treatment. We also highlight the potential of novel anti-HER2 therapies approved by regulatory bodies and those in clinical development.

CONCLUSION

Compared with HER2 amplification or overexpression, HER2 mutations, especially HER2 exon 20 mutations, are emerging as the most clear targetable driver for HER2-directed therapies in lung cancer. De novo and inducible HER2 pathway activation need to be differentially managed. Further investigations with new strategies are needed.

Targeted Molecular Therapies in the Treatment of Esophageal Adenocarcinoma, Are We There Yet?

Esophageal adenocarcinoma is one of the leading causes of cancer-related deaths worldwide. The incidence of esophageal adenocarcinoma has increased at an alarming rate in the Western world and long-term survival remains poor. Current treatment approaches involve a combination of surgery, chemotherapy, and radiotherapy. Unfortunately, standard first-line approaches are met with high rates of recurrence and metastasis. More recent investigations into the distinct molecular composition of these tumors have uncovered key genetic and epigenetic alterations involved in tumorigenesis and progression. These discoveries have driven the development of targeted therapeutic agents in esophageal adenocarcinoma. While many agents have been studied, therapeutics targeting the human epidermal growth factor receptor (HER2) and vascular endothelial growth factor (VEGF) pathways have demonstrated improved survival. More recent advances in immunotherapies have also demonstrated survival advantages with monoclonal antibodies targeting the programmed death ligand 1 (PD-L1). In this review we highlight recent advances of targeted therapies, specifically agents targeting receptor tyrosine kinases, small molecule kinase inhibitors, and immune checkpoint inhibitors. While targeted therapeutics and immunotherapies have significantly improved survival, the benefits are limited to patients whose tumors express biomarkers such as PD-L1 and HER2. Survival remains poor for the remainder of patients with esophageal adenocarcinoma, underscoring the critical need for development of novel treatment strategies.

Pyrotinib enhances the radiosensitivity of HER2‑overexpressing gastric and breast cancer cells

The overexpression or amplification of HER2 has been observed in a significant proportion of both gastric cancer (GC) and breast cancer (BC) cases. Pyrotinib is an irreversible dual (EGFR/HER2) tyrosine kinase inhibitor (TKI), newly evaluated for the treatment of HER2-overexpressing cancer types. As radiotherapy (RT) serves a crucial role in controlling the local recurrence of GC and BC, the present study investigated the impact of pyrotinib on the irradiation response. The current results demonstrated that pyrotinib enhanced the radiosensitivity of HER2-overexpressing GC and BC cells in vitro and in vivo. In both NCI-N87 and SKBR3 cells, pyrotinib suppressed the irradiation-induced HER2 nuclear transport. Furthermore, pyrotinib increased DNA damage induced by irradiation in both cancer cell lines. Pyrotinib also enhanced the cytotoxicity of docetaxel, which may provide a novel strategy for potential drug combinations. Thus, pyrotinib is a promising irradiation sensitizer in patients with HER2-overexpressing GC and BC. The present results provide a theoretical foundation for further clinical evaluation of pyrotinib.

Expression and significance of Her2 and Ki-67 in gastric adenocarcinoma without distant metastasis: a cohort study

Background

The significance of human epidermal growth factor receptor 2 (Her2) and nucleus-associated antigen Ki-67 expression remains controversial in gastric adenocarcinoma (GaC). The aim of this study was to investigate the expression and clinicopathologic and prognostic significance of Her2 and Ki-67 in resected GaC without distant metastasis.

Methods

Malignant tissues and clinicopathologic data were obtained from 195 patients with resected non-metastatic GaC. Immunohistochemistry staining was performed to examine the expression of Her2 and Ki-67; their association with clinicopathologic factors were investigated using logistic regression, and their association with survival was explored using Kaplan–Meier analysis and Cox proportional hazards regression.

Results

Her2 was majorly expressed in cell membrane and Ki-67 in cell nucleus in non-metastatic GaC. Stronger Her2 expression was significantly associated with better tumor differentiation, neurovascular invasion, less advanced pathological tumor (pT) stage, and more advanced pathological node (pN) stage; while Ki-67 expression was not significantly associated with any investigated clinicopathologic factors. Patients with both negative Her2 and negative Ki-67 expression had poorer tumor differentiation, and more advanced pT and pathological tumor-node-metastasis (pTNM) stages; the association with pT and pTNM stages were further confirmed by multivariable analyses, especially in node-negative disease. Her2 or Ki-67 alone was not significantly associated with pTNM stage. A strongly positive (+++) Her2 expression was associated with poorer survival in multivariable analysis only (P = 0.047); while Ki-67 or combined expression was not significantly associated with prognosis.

Conclusions

In non-metastatic GaC, Her2 expression and combined expression of Her2 and Ki-67 were associated with several clinicopathologic factors including tumor differentiation and stage, and only a +++ Her2 expression was associated with poorer prognosis in multivariable analysis with marginal significance in this study; while Ki-67 alone had both limited clinicopathologic and prognostic values.

HBXIP promotes gastric cancer via METTL3-mediated MYC mRNA m6A modification

Gastric cancer (GC) is one of the most common malignancies worldwide with limited treatment options and distinct geographical distribution even in countries such as China. Genetic alterations during its carcinogenesis need urgent elucidation. In this study, we propose an intriguing hypothesis that the hepatitis B X-interacting protein (HBXIP) may function as an oncogene in GC. We harvested 45 GC tissues and matched the paracancerous tissues. The c-myc proto-oncogene (MYC) N6-methyladenosine (m6A) mRNA methylation was detected by m6A RNA immunoprecipitation and dot-blot assays. Expressions of HBXIP, methyltransferase like 3 (METTL3) and MYC were all determined to be upregulated in both GC tissues and cells. Silencing HBXIP led to a decreased expression of METTL3, which inhibited GC cell proliferation, migration and invasion while promoting their apoptosis. Furthermore, METTL3 enhanced MYC m6A methylation and increased MYC translation, which could potentiate the proliferation, migration and invasion of GC cells. Finally, the HBXIP knockdown impeded the tumorigenicity of GC cells in vivo. Based on the findings of this study, we conclude that HBXIP plays an oncogenic role in GC via METTL3-mediated MYC mRNA m6A modification. The study offers a comprehensive understanding of HBXIP as a potential therapeutic target to limit GC progression.

Developing Pathology Measures for the Quality Payment Program-Part II: Overcoming Challenges With Data Capture to Maximize Reimbursement

CONTEXT.—

Quality measures are a cornerstone in measuring physicians' performance within the Centers for Medicare & Medicaid Services' Quality Payment Program (QPP). Clinicians' performance on quality measures and other categories within the QPP determines Medicare part B payment adjustments. Driven by evidence-based clinical practice guidelines, quality measures should focus on high-priority facets of health care, support a desired patient outcome, and address an area with evidence of a gap or variation in provider performance.

OBJECTIVE.—

To meet the goals of the QPP, a broad array of quality measures must be developed that allows pathologists the flexibility to choose activities and measures most meaningful to their practice and patient population while also trying to mitigate the challenges of implementation and data collection.

DESIGN.—

In this second manuscript of the series, we present the development of additional College of American Pathologists-developed quality payment measures for use in the QPP. We also discuss the relationship of quality measure reporting with reimbursement and the challenges with capturing data for quality reporting.

RESULTS.—

The College of American Pathologists identified 23 new measures for quality performance reporting that reflect rigorous clinical evidence and address areas in need of performance improvement.

CONCLUSIONS.—

Development of quality measures is a necessary and ongoing effort within the College of American Pathologists. Increased awareness about pathology-specific issues in measure development and reporting is essential to ensuring pathology's ability to demonstrate value and meaningfully participate in the QPP.

Gastrointestinal cancers: current biomarkers in esophageal and gastric adenocarcinoma

Esophageal and gastric adenocarcinomas are frequently diagnosed at an advanced stage and have a dismal prognosis. Even in patients with potentially curative cancer, nearly 50% will develop recurrent disease despite aggressive treatments. A number of biomarkers currently guide treatment decisions for patients with esophageal and gastric adenocarcinoma and include human epidermal growth factor receptor 2 (HER2) amplification, mismatch repair deficiency/microsatellite instability (dMMR/MSI-H) and program death-ligand 1 (PD-L1) expression. This review will focus on the function, testing and FDA-approved targeted therapies for HER2, dMMR/MSI-H and PD-L1. In addition, a number of novel targets in esophageal and gastric cancer are being studied in clinical trials. Neurotrophic-tropomyosin receptor kinase (NTRK), claudin-18 (CLDN18)/Rho GTPase activating protein 26 (ARHGAP26) gene fusion, fibroblast growth factor receptor (FGFR), lymphocyte-activation gene 3 (LAG3) and T cell immunoglobulin and mucin-domain containing-3 (TIM3) will be briefly reviewed. Despite several biomarkers used in the selection of treatment therapies, treatment outcomes remain poor. Future research efforts will focus on the identification of new biomarkers, moving existing biomarkers into earlier lines of therapy, and evaluating new combinations of existing biomarkers and therapies.

PD-L1 and HER2 Expression in Gastroesophageal Cancer: a Matched Case Control Study

Immunotherapy with check-point inhibitors serves as a promising treatment strategy in patients with upper gastrointestinal (GI) tumors. Human epidermal growth factor receptor 2 (HER2) is the only identified therapeutic target in upper GI tumors, whose potential interaction with programmed death-ligand 1 (PD-L1) is unknown. The aim of this study was the investigation of PD-L1 and HER2 in upper GI tumors. We retrospectively identified patients with HER2 positive gastroesophageal cancers and matched them with a HER2 negative group. We investigated the tumor specimens for HER2 status and PD-L1 expression, with the following assessments being performed: i) staining of tumor cells in terms of tumor proportion score (TPS), ii) staining for tumor-associated immune cells (TAIs), iii) interface pattern and iv) combined positive score (CPS). Both HER2 positive and negative group consisted of 59 patients. Expression of PD-L1 in TAIs and interface pattern were associated with a favorable outcome (p = 0.02, HR = 0.8; p = 0.04, HR = 0.39; respectively) in patients with localized disease, whereas TPS was associated with an unfavorable outcome in patients with advanced tumor (p = 0.02, HR = 1.4). These effects were HER2 independent. PD-L1 expression in its different assessment is equally observed in HER2 positive and negative patients. Future studies will show whether dual inhibition of HER2 and PD-L1 improves survival of this selected patient population.

Preparation and characterization of antibody-drug conjugates acting on HER2-positive cancer cells

Two systems of antibody-drug conjugates (ADCs), noncleavable H32-DM1 and cleavable H32-VCMMAE, were developed by using different linkers and drugs attached to the anti-HER2 antibody H32, which is capable of cell internalization. Activated functional groups, including an N-hydroxysuccinimidyl (NHS) ester and a maleimide, were utilized to make the ADCs. Mass spectrometry, hydrophobic interaction chromatography, polyacrylamide gel electrophoresis, and in vitro cell assays were performed to analyze and optimize the ADCs. Several H32-VCMMAE ADCs were established with higher DARs and greater synthetic yields without compromising potency. The anticancer efficacy of H32-DM1 was 2- to 8-fold greater than that of Kadcyla^®. The efficacy of H32-VCMMAE was in turn better than that of H32-DM1. The anticancer efficacy of these ADCs against N87, SK-BR-3 and BT474 cells was in the following order: H32-VCMMAE series > H32-DM1 series > Kadcyla^®. The optimal DAR for H32-VCMMAE was found to be 6.6, with desirable attributes including good cell penetration, a releasable payload in cancer cells, and high potency. Our results demonstrated the potential of H32-VCMMAE as a good ADC candidate.

Prognostic benefit of conversion surgery for HER2 positive stage IV gastric cancer; a case series study of eleven patients treated with trastuzumab-based chemotherapy

BACKGROUND

Since the ToGA trial, trastuzumab-based chemotherapy is the standard treatment for HER2 positive stage IV gastric cancer. However, it is not yet clear whether surgical resection after trastuzumab-based chemotherapy (conversion surgery) can improve survival of HER2 positive stage IV gastric cancer. The purpose of this study is to evaluate the prognostic benefit of conversion surgery in HER2 positive stage IV gastric cancer patients.

CASE PRESENTATION

We retrospectively investigated the medical records of the patients with HER2 positive (IHC3(+) or IHC2(+)/FISH(+)) stage IV gastric cancer treated with trastuzumab-based chemotherapy as the first line treatment. Overall survival (OS) was compared between patients with conversion surgery and without. Eleven HER2 positive stage IV gastric cancer patients treated with trastuzumab-based chemotherapy as the first line treatment were evaluated. Response rate was 63.6%, and 6 of 11 patients could receive conversion surgery. R0 resection was achieved in four patients. In Kaplan-Meier analysis, patients who received conversion surgery showed significantly better OS than those without surgery (3-year survival rate, 66.7% vs. 20%, P = 0.03). The median OS of patients who achieved R0 resection is 51.8 months.

CONCLUSIONS

Conversion surgery might have a survival benefit for HER2 positive stage IV gastric cancer patients. If curative surgery is technically possible, conversion surgery could be a treatment option for HER2 positive stage IV gastric cancer.

Intratumoral and intertumoral heterogeneity of HER2 immunohistochemical expression in gastric cancer

BACKGROUND

Given the high heterogeneity of tumor tissue in gastric cancer (GC), inaccurate detection of tumor biomarkers will inevitably hamper a precise diagnosis and selection of patients for targeted therapies. Human epidermal growth factor receptor 2 (HER2) has been widely accepted as an underlying treatment biomarker of GC. The objective of this study is to investigate the heterogeneity (both intratumoral and intertumoral) of HER2 expression in GC, and the relationship between heterogeneity and the clinicopathological features.

METHODS

A total of 618 patients with primary gastric adenocarcinoma were recruited, and two formalin-fixed paraffin-embedded (FFPE) tumor-containing blocks of each patient were selected for HER2 immunohistochemical (IHC) assay. Clinicopathological characteristics were recorded, and intratumoral and intertumoral heterogeneity of HER2 IHC expression was determined.

RESULTS

The results indicated that the dual-block assays significantly increased the HER2 overexpression (IHC 2+ and 3+) rate compared with the single paraffin block detection. Approximately 50 % of the cases showed intratumoral HER2 heterogeneity within a single tissue section, and 30.10 % of cases showed intertumoral heterogeneity between a patient's two blocks. Furthermore, intertumoral heterogeneity was associated with tumors of small size (P = 0.029) and distal location (P = 0.032) characters, while the intratumoral heterogeneity was correlated with poorly differentiated carcinomas. Laurén's diffuse type showed a notably higher intratumoral heterogeneity rate, and the mixed type exhibited higher intertumoral HER2 discordance between the dual-block cohorts (P < 0.001). Besides, HER2 heterogenous overexpression was not associated with age, gender, type of resection, lymphatic or venous invasion, perineural invasion or pTNM (P > 0.05) for both cohorts.

CONCLUSION

The research findings in this paper indicate that the intratumoral and intertumoral heterogeneity of HER2 overexpression is common in GC patients, and these variations are associated with certain clinicopathological features. We highly recommend multi-block HER2 assessment for accurate diagnosis of GC.

The Role of HER2 in Self-Renewal, Invasion, and Tumorigenicity of Gastric Cancer Stem Cells

Background

Deregulation of HER2 expression could affect the biological characteristics of gastric cancer cells and treatment option for gastric cancer patients. This research aims to investigate the impact of HER2 on biological characteristics of gastric cancer stem cells (GCSCs) and prognosis of gastric cancer patients.

Methods

HER2 knockdown in GCSCs were constructed by lentivirus transfection. Alterations of proliferation, self-renewal, invasion, migration, colony formation, and tumorigenicity of GCSCs were examined. The changes of gene expressions after HER2 interference in GCSCs were detected by gene microarray. The impact of concentration of serum HER2 and expression of HER2 in tumor tissues on survival of 213 gastric cancer patients was also analyzed.

Results

Down-regulation of HER2 decreased the self-renewal, colony formation, migration, invasion, proliferation, and chemotherapy resistance of GCSCs. However, the tumorigenicity of GCSCs in vivo was increased after down-regulation of HER2. The results of gene microarray showed that HER2 gene might regulate the signal transduction of mTOR, Jak-STAT, and other signal pathways and affect the biological characteristics of GCSCs. Furthermore, survival analyses indicated that patients with high concentration of HER2 in serum had a favorable overall survival. However, there was no significant correlation between expression of HER2 in tumor tissue and overall survival.

Conclusion

Interference of HER2 in GCSCs decreased the capacity of self-renewal, proliferation, colony formation, chemotherapy resistance, invasion, and migration but might increase the tumorigenicity in vivo. Patients with high concentration of HER2 in serum seemed to have a favorable prognosis.

Gastric Cancer Heterogeneity and Clinical Outcomes

Gastric adenocarcinoma is a highly aggressive disease with poor overall survival. The aggressive nature of this disease is in part due to the high intra and inter tumoral heterogeneity and also due to the late diagnosis at presentation. Once progression occurs, treatment is more difficult due to the adaptation of tumors, which acquires resistance to commonly used chemotherapeutics. In this report, using publicly available data sets and pathway analysis, we highlight the vast heterogeneity of gastric cancer by investigating genes found to be significantly perturbed. We found several upregulated genes in the diffuse gastric cancer subtypes share similarity to gastric cancer as a whole which can be explained by the increase in this subtype of gastric cancer throughout the world. We report significant downregulation of genes that are underrepresented within the literature, such as ADH7, GCNT2, and LIF1, while other genes have not been explored within gastric cancer to the best of our knowledge such as METTL7A, MAL, CWD43, and SLC2A12. We identified gender to be another heterogeneous component of this disease and suggested targeted treatment strategies specific to this heterogeneity. In this study, we provide an in-depth exploration of the molecular landscape of gastric cancer in order to shed light onto novel areas of gastric cancer research and explore potential new therapeutic targets.

Antibody-drug conjugates to treat gastric cancer

INTRODUCTION

Despite new treatment options, the long-term prognosis of recurrent or inoperable gastric cancer remains poor. Antibody-drug conjugates (ADCs) are a new class of drugs and have shown promising results in clinical trials.

AREAS COVERED

This review focuses on recent clinical findings and development of ADCs for gastric cancer, and summarizes the relevant resistance mechanisms or future directions of ADCs.

EXPERT OPINION

Novel HER2-ADCs have led to breakthrough results for HER2⁺ gastric cancer; however, several questions remain, especially in clinical settings. Translational research to elucidate ADCs' mechanisms of action or resistance will lead to more sophisticated use of ADCs and combination strategies.

ARPP-19 Mediates Herceptin Resistance via Regulation of CD44 in Gastric Cancer

Purpose

As the first-line drug for treatment of HER2-positive metastatic gastric cancer (GC), Herceptin exhibits significant therapeutic efficacy. However, acquired resistance of Herceptin limits the therapeutic benefit of gastric cancer patients, in which the molecular mechanisms remain to be further determined.

Methods

Quantitative real-time polymerase chain reaction was performed to detect the mRNA levels of ARPP-19 and CD44 in GC cells. Protein levels were determined using Western blot and IHC staining. MTT and soft agar colony formation assays were used to measure cell proliferation. Xenograft model was established to verify the functional role of ARPP-19 in Herceptin resistance in vivo. Sphere formation assay was conducted to determine cell stemness.

Results

We observed ARPP-19 was up-regulated in Herceptin resistance gastric cancer cells NCI-N87-HR and MKN45-HR. The forced expression of ARPP-19 promoted, whereas the silencing of ARPP-19 impaired Herceptin resistance of HER2-positive gastric cancer cells both in vitro and in vivo. Moreover, ARPP-19 significantly enhanced the sphere formation capacity and CD44 expression, CD44 was also a positive factor of Herceptin resistance in HER2-positive gastric cancer cells. In addition, high level of ARPP-19 was positively associated with Herceptin resistance and poor survival rate of gastric cancer patients.

Conclusion

We have demonstrated that ARPP-19 promoted Herceptin resistance of gastric cancer via up-regulation of CD44, our study suggested that ARPP-19 could be a potential diagnostic and therapeutic candidate for HER2-positive gastric cancer.