The effect of HER2 expression on cisplatin-based chemotherapy in advanced non-small cell lung cancer patients

Management of HER2 alterations in non-small cell lung cancer - The past, present, and future

HER2 mutations, which account for 2-4% of non-small cell lung cancer (NSCLC), are distinct molecular alterations identified via next generation sequencing (NGS). Previously, treatment outcomes in HER2-mutant metastatic NSCLC were dismal, showing limited clinical benefit with platinum-based chemotherapy with or without immunotherapy. In contrast to HER2-altered breast and gastric cancer, HER2-mutant NSCLC does not benefit from HER2 targeting agents such as trastuzumab or TDM1. HER2 mutations are also inherently different from HER2 overexpression and amplification. Currently, trastuzumab deruxtecan, a HER2 targeting antibody drug conjugate (ADC) is the first and only approved treatment option for patients with HER2-mutant metastatic NSCLC after failure with standard treatment. In this review, we summarized the biology of HER2 and detection of HER2 overexpression, amplification and mutations, as well as general landscape of landmark and ongoing clinical trials encompassing from chemotherapy to targeted agents, including tyrosine kinase inhibitors (TKIs), ADCs and investigational agents.

The role of Her-2 in penile squamous cell carcinoma progression and cisplatin chemoresistance and potential for antibody-drug conjugate-based therapy

BACKGROUND

Cisplatin-based chemotherapy has been the first choice for advanced penile squamous cell carcinoma (PSCC) in the last decade, but its utility is limited by the low response rate, systemic toxicity, and chemoresistance, which contribute to a poor prognosis. There is no standard second-line therapy for advanced PSCC. Human epidermal growth factor receptor 2 (Her-2)-targeted antibody-drug conjugates (ADCs) are novel low-toxicity agents which have greatly improved clinical outcomes for several advanced cancers. We aimed to explore the expression pattern, clinical significance, and oncogenic roles of Her-2 and the therapeutic potential of Her-2-targeted ADCs in PSCC.

METHODS

Her-2 immunohistochemistry was performed for the largest single-centre PSCC cohort to date (367 patients). PSCC cell lines, cisplatin-resistant cell lines, subcutaneous xenograft, and footpad metastatic models were used to investigate the biological roles of Her-2 in PSCC progression. Cytotoxicity, apoptosis assays, and western blotting investigated the mechanism of Her-2 induced cisplatin-chemoresistance. The efficacy of Disitamab Vedotin (RC48), a Her-2-targeted ADC, was evaluated in PSCC.

RESULTS

Her-2 was identified as an adverse prognostic indicator associated with advanced Tumor-Node-Metastasis (TNM) stages and poor survival with an immunohistochemical expression rate of approximately 47.7% (1+, 23.2%; 2+, 18.0%; 3+, 6.5%) in PSCC. Her-2 promotes cell proliferation, migration, invasion, tumour progression, and cisplatin resistance in PSCC. Mechanistically, Her-2 inhibits cisplatin-induced cell apoptosis by the activation of Akt phosphorylation at Ser473 and disrupts the balance between proapoptotic and antiapoptotic proteins. Meanwhile, cisplatin-resistant PSCC cells present aggressive oncogenic abilities and Her-2 upregulation. More importantly, RC48 displayed remarkable antitumor activities in both Her2-positive and cisplatin-resistant PSCC tumours.

CONCLUSION

Our study suggests that Her-2 is an available therapeutic biomarker for PSCC. Her-2-targeted ADC might have the potential to improve clinical outcomes in high-risk Her-2-positive advanced PSCC patients and provide precious second-line clinical choice for appropriate cisplatin-based chemoresistance patients.

Antibody Drug Conjugates in Lung Cancer: State of the Current Therapeutic Landscape and Future Developments

While both targeted therapy and immunotherapy-based strategies have emerged as frontline standard-of-care for patients with advanced lung cancer, acquired resistance and disease progression remain inevitable in most cases. Chemotherapy is a common salvage option in this scenario, but is limited by a relatively narrow therapeutic index. The emergence of antibody-drug conjugates (ADCs) offer an appealing alternative. ADCs couple the specificity of a monoclonal antibody with the cytotoxic effects of chemotherapy to facilitate the targeted delivery of cytotoxic payloads directly to cancer cells. Here, we review the general structure and function of ADCs, followed by a discussion of emerging ADCs in lung cancer and the future applications of this increasingly relevant class of novel agents.

Genotype Driven Therapy for Non-Small Cell Lung Cancer: Resistance, Pan Inhibitors and Immunotherapy

Eighty-five percent of patients with lung cancer present with Non-small Cell Lung Cancer (NSCLC). Targeted therapy approaches are promising treatments for lung cancer. However, despite the development of targeted therapies using Tyrosine Kinase Inhibitors (TKI) as well as monoclonal antibodies, the five-year relative survival rate for lung cancer patients is still only 18%, and patients inevitably become resistant to therapy. Mutations in Kirsten Ras Sarcoma viral homolog (KRAS) and epidermal growth factor receptor (EGFR) are the two most common genetic events in lung adenocarcinoma; they account for 25% and 20% of cases, respectively. Anaplastic Lymphoma Kinase (ALK) is a transmembrane receptor tyrosine kinase, and ALK rearrangements are responsible for 3-7% of NSCLC, predominantly of the adenocarcinoma subtype, and occur in a mutually exclusive manner with KRAS and EGFR mutations. Among drug-resistant NSCLC patients, nearly half exhibit the T790M mutation in exon 20 of EGFR. This review focuses on some basic aspects of molecules involved in NSCLC, the development of resistance to treatments in NSCLC, and advances in lung cancer therapy in the past ten years. Some recent developments such as PD-1-PD-L1 checkpoint-based immunotherapy for NSCLC are also covered.

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.

Prognostic and Predictive Values of Metabolic Parameters of 18F-FDG PET/CT in Patients With Non-Small Cell Lung Cancer Treated With Chemotherapy

Objectives:

Increasing interests have been focused on using artificial intelligence (AI) to extend prognostic value of medical imaging. Feature extraction is a critical step for successful application of AI. The aim of this study was to explore several metabolic parameters measured by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) as potential AI features in predicting the effectiveness of chemotherapy in patients with non-small cell lung cancer (NSCLC).

Methods:

A set of metabolic parameters of PET/CT and clinical characteristics were detected from 137 patients with NSCLC treated with at least 1 cycle of chemotherapy. Survival receiver–operating characteristic (ROC) analysis was used to define the more significant parameters chosen for the following survival analysis. Patient survival was analyzed by Kaplan-Meier method, log-rank test, and Cox regression.

Results:

Survival ROC showed that maximum standardized uptake value (SUVmax), metabolic tumor volume 50% (MTV50), and total lesion glycolysis 50% (TLG50) had larger area under the curve, and the optimal cutoff values were 11.72, 4.04, and 34.55, respectively. Univariate and multivariate analyses synergistically showed that late PET/CT stage and MTV50 >4.04 were independent factors of poor survival in patients with NSCLC who received chemotherapy.

Conclusions:

Several potential prognostic biomarkers of PET/CT imaging have been extracted for predicting survival and selecting patients with NSCLC who are more likely to benefit from chemotherapy. The identification may accelerate the development of AI methods to improve treatment outcome for NSCLC.

The force of HER2 - A druggable target in NSCLC?

Since several years targeted therapy has been part of treatment in NSCLC in subsets of patients with specific genetic alterations. One of these alterations involves HER2, a member of the ERBB family of tyrosine kinase receptors. Despite that HER2 alterations in NSCLC have been studied for years, there is still no consensus about subgroup definitions. In this review HER2 alterations in NSCLC are discussed, including diagnostic challenges and treatment strategies. Three principal mechanisms of HER2 alterations can be identified: HER2 protein overexpression, HER2 gene amplification and HER2 gene mutations. There are several methods for the detection of HER2 "positivity" in NSCLC, but no gold standard has been established. Laboratory methods for assessment of HER2 positivity in NSCLC include immunohistochemistry (IHC) for protein overexpression and fluorescent in situ hybridization (FISH) and next generation sequencing (NGS) for genetic alterations. Many trials testing HER2 targeted therapy in HER2 altered NSCLC has not lead to a renewed standard of care for this group of patients. Therefore, today the (re)search on how to analyse, define and treat HER2 alterations in NSCLC continues. Still there is no consensus about HER2 subgroup definitions and results of the many trials studying possible treatment strategies are inconclusive. Future research should focus on the most important missing link, whether all HER2 alterations are relevant oncogenic drivers and whether it should be considered as a therapeutic target in NSCLC.

Design of cyclic and d-amino acids containing peptidomimetics for inhibition of protein-protein interactions of HER2-HER3

HER2 receptors are surface proteins belonging to the epidermal growth factor family of receptors. Their numbers are elevated in breast, lung, and ovarian cancers. HER2-positive cancers are aggressive, have higher mortality rate, and have a poor prognosis. We have designed peptidomimetics that bind to HER2 and block the HER2-mediated dimerization of epidermal growth factor family of receptors. Among these, a symmetrical cyclic peptidomimetic (compound 18) exhibited antiproliferative activity in HER2-overexpressing lung cancer cell lines with IC₅₀ values in the nanomolar concentration range. To improve the stability of the peptidomimetic, d-amino acids were introduced into the peptidomimetic, and several analogs of compound 18 were designed. Among the analogs of compound 18, compound 32, a cyclic, d-amino acid-containing peptidomimetic, was found to have an IC₅₀ value in the nanomolar range in HER2-overexpressing cancer cell lines. The antiproliferative activity of compound 32 was also measured by using a 3D cell culture model that mimics the in vivo conditions. The binding of compound 32 to the HER2 protein was studied by surface plasmon resonance. In vitro stability studies indicated that compound 32 was stable in serum for 48 hours and intact peptide was detectable in vivo for 12 hours. Results from our studies indicated that 1 of the d-amino acid analogs of 18, compound 32, binds to the HER2 extracellular domain, inhibiting the phosphorylation of kinase of HER2.

Evaluating the cost-effectiveness of afatinib after platinum-based therapy for the treatment of squamous non-small-cell lung cancer in France

Background and aims

Lung cancer has the highest mortality rate of all cancers worldwide. Non-small-cell lung cancer (NSCLC) accounts for 85% of all lung cancers and has an extremely poor prognosis. Afatinib is an irreversible ErbB family blocker designed to suppress cellular signaling and inhibit cellular growth and is approved in Europe after platinum-based therapy for squamous NSCLC. The objective of the present analysis was to evaluate the cost-effectiveness of afatinib after platinum-based therapy for squamous NSCLC in France.

Methods

The study population was based on the LUX-Lung 8 trial that compared afatinib with erlotinib in patients with squamous NSCLC. The analysis was performed from the perspective of all health care funders and affected patients. A partitioned survival model was developed to evaluate cost-effectiveness based on progression-free survival and overall survival in the trial. Life expectancy, quality-adjusted life expectancy and direct costs were evaluated over a 10-year time horizon. Future costs and clinical benefits were discounted at 4% annually. Deterministic and probabilistic sensitivity analyses were performed.

Results

Model projections indicated that afatinib was associated with greater life expectancy (0.16 years) and quality-adjusted life expectancy (0.094 quality-adjusted life years [QALYs]) than that projected for erlotinib. The total cost of treatment over a 10-year time horizon was higher for afatinib than erlotinib, EUR12,364 versus EUR9,510, leading to an incremental cost-effectiveness ratio of EUR30,277 per QALY gained for afatinib versus erlotinib. Sensitivity analyses showed that the base case findings were stable under variation of a range of model inputs.

Conclusion

Based on data from the LUX-Lung 8 trial, afatinib was projected to improve clinical outcomes versus erlotinib, with a 97% probability of being cost-effective assuming a willingness to pay of EUR70,000 per QALY gained, after platinum-based therapy in patients with squamous NSCLC in France.

A peptidomimetic with a chiral switch is an inhibitor of epidermal growth factor receptor heterodimerization

Among different types of EGFR dimers, EGFR-HER2 and HER2-HER3 are well known in different types of cancers. Targeting dimerization of EGFR will have a significant impact on cancer therapies. A symmetric peptidomimetic was designed to inhibit the protein-protein interaction of EGFR. The peptidomimetic (Cyclo(1,10)PpR (R) Anapa-FDDF-(R)-Anapa)R, compound 18) was shown to exhibit antiproliferative activity with an IC₅₀ of 194 nM in HER2-expressing breast cancer cell lines and 18 nM in lung cancer cell lines. The peptidomimetic has a Pro-Pro sequence in the structure to stabilize the β-turn and a β-amino acid, amino napthyl propionic acid. To investigate the effect of the chirality of β-amino acid on the structure of the peptide and its antiproliferative activity, diastereoisomers of compound 18 were designed and synthesized. Structure-activity relationships of these compounds indicated that there is a chiral switch at β-amino acid in the designed compound. The peptidomimetic with R configuration at β-amino acid and with a L-Pro-D-Pro sequence was the most active compound (18). Using enzyme complement fragmentation assay and proximity ligation assay, we show that compound 18 inhibits HER2:HER3 and EGFR:HER2 dimerization. Surface plasmon resonance studies suggested that compound 18 binds to the HER2 extracellular domain and in particular to domain IV. The anticancer activity of compound 18 was evaluated using a xenograft model of breast cancer in mice; compound 18 suppressed the tumor growth in mice compared to control. Compound 18 was also shown to have a synergistic effect with erlotinib on EGFR mutated lung cancer cell lines.

Evolution from genetics to phenotype: reinterpretation of NSCLC plasticity, heterogeneity, and drug resistance

Lung cancer is the leading cause of cancer-related deaths worldwide. Targeted therapy is beneficial in most cases, but the development of drug resistance stands as an obstacle to good prognosis. Multiple mechanisms were explored such as genetic alterations, activation of bypass signaling, and phenotypic transition. These intrinsic and/or extrinsic dynamic regulations facilitate tumor cell survival in meeting the demands of signaling under different stimulus. This review introduces lung cancer plasticity and heterogeneity and their correlation with drug resistance. While cancer plasticity and heterogeneity play an essential role in the development of drug resistance, the manipulation of them may bring some inspirations to cancer prognosis and treatment. That is to say, lung cancer plasticity and heterogeneity present us with not only challenges but also opportunities.

Predictors of chemotherapy efficacy in non-small-cell lung cancer: a challenging landscape

BACKGROUND

Conventional cytotoxic chemotherapy (CCC) is the backbone of non-small-cell lung cancer (NSCLC) treatment since decades and still represents a key element of the therapeutic armamentarium. Contrary to molecularly targeted therapies and immune therapies, for which predictive biomarkers of activity have been actively looked for and developed in parallel to the drug development process ('companion biomarkers'), no patient selection biomarker is currently available for CCC, precluding customizing treatment.

MATERIALS AND METHODS

We reviewed preclinical and clinical studies that assessed potential predictive biomarkers of CCC used in NSCLC (platinum, antimetabolites, topoisomerase inhibitors, and spindle poisons). Biomarker evaluation method, analytical validity, and robustness are described and challenged for each biomarker.

RESULTS

The best-validated predictive biomarkers for efficacy are currently ERCC1, RRM1, and TS for platinum agents, gemcitabine and pemetrexed, respectively. Other potential biomarkers include hENT1 for gemcitabine, class III β-tubulin for spindle poisons, TOP2A expression and CEP17 duplication (mostly studied for predicting anthracyclines efficacy) whose applicability concerning etoposide would deserve further evaluation. However, none of these biomarkers has till now been validated prospectively in an appropriately designed and powered randomised trial, and none of them is currently ready for implementation in routine clinical practice.

CONCLUSION

The search for predictive biomarkers to CCC has been proven challenging. If a plethora of biomarkers have been evaluated either in the preclinical or in the clinical setting, none of them is ready for clinical implementation yet. Considering that most mechanisms of resistance or sensitivity to CCC are multifactorial, a combinatorial approach might be relevant and further efforts are required.

Current and future targeted therapies for non-small-cell lung cancers with aberrant EGF receptors

Expression of the EGF receptors (EGFRs) is abnormally high in many types of cancer, including 25% of lung cancers. Successful treatments target mutations in the EGFR tyrosine kinase domain with EGFR tyrosine kinase inhibitors (TKIs). However, almost all patients develop resistance to this treatment, and acquired resistance to first-generation TKI has prompted the clinical development of a second generation of EGFR TKI. Because of the development of resistance to treatment of TKIs, there is a need to collect genomic information about EGFR levels in non-small-cell lung cancer patients. Herein, we focus on current molecular targets that have therapies available as well as other targets for which therapies will be available in the near future.

NSCLC and HER2: between lights and shadows

The therapeutic landscape of non-small-cell lung cancer (NSCLC) has dramatically changed in the last few years with the introduction of molecularly targeted agents, leading to unprecedented results in lung tumors with a paradigmatic shift from a "one size fits all" approach to an histologic and molecular-based approach. The discovery of epidermal growth factor receptor (EGFR) mutations in NSCLC in 2004 and the marked response to the EGFR tyrosine kinase inhibitor gefitinib, in a small subset of patients harboring these genetic abnormalities, stimulated the study of other kinase mutants involvement in NSCLC. The incredible story of ALK rearranged tumors, with the rapid Food and Drug Administration approval of Crizotinib after only 4 years from the discovery of EML4-ALK translocation in NSCLC, has profoundly influenced the concept of drug development in NSCLC, paving the way to a novel series of molecularly selected studies with specific inhibitors. The identification of these oncogenic drivers has dramatically changed the genetic landscape of NSCLC moving away from the old concept of a large indistinct histological entity to a combination of rare clinically relevant molecular subsets. Recently, a renewed interest has been emerging on the human epidermal growth factor-2 (HER2) pathway. Genetic aberrations of this signaling pathway have been reported over time to be associated in NSCLC with different sensitivity to the EGFR tyrosine kinase inhibitors, to have a possible prognostic role and more recently HER2 amplification has been emerged as a possible mechanism in EGFR-mutated tumors of acquired resistance to the EGFR tyrosine kinase inhibitors. In addition, dysregulation of the HER2 pathway, in particular HER2 mutations (mostly, in-frame exon 20 insertions), may represent a possible novel therapeutic target in NSCLC, paving the way for a new generation of targeted agents in NSCLC. Since anecdotal case reports of clinical activity of anti-HER2 agents in NSCLC patients with HER2 mutations, several targeted agents have been evaluated in HER2-mutated patients, generating a growing interest upon this oncogenic driver, leading to the design of molecularly selected trials with anti-HER2 compounds and the rediscover of hastily thrown out drugs, such as neratinib. The aim of this article is to provide an overview of the role of HER2 dysregulation in NSCLCs, trying to throw a light not only on the strengths but also the weaknesses of the studies conducted so far. It is a long way to the clinical implementation of these biomarkers and probably the increasing use of next generation sequencing techniques, the creation of large multi-institutional molecular testing platforms and the design of rationally based trials can get closer personalized medicine in NSCLC.

Impact of HER2 codon 655 polymorphism and expression of HER2 and HER3 in non small cell lung cancer patients

The aim of the study was to assess the expression and significance of HER2 and HER3, and Ile/Val single nucleotide polymorphism (SNP) of HER2 in lung cancer patients. Thirty seven cases of lung cancer were investigated immunohistochemically for HER2 and HER3 expression. PCR followed by restriction fragment length polymorphism (RFLP) was used to analyze the presence of HER-2 SNP at codon 655 in 20 samples. The results were compared with clinical and pathological parameters of investigated patients.We found that 100% of the cases were negative for HER2, 29.7% were with moderate or strong HER3 expression and 70.3% of the tumors-without or with low expression for HER3. Lymph node metastasis were found in 40% of HER3 positive cases (χ(2) = 4.752; p = 0.029). Moderately-differentiated tumors do not express neither of investigated markers (χ(2) = 6.719; p = 0.035). HER2 RFLP-PCR analysis showed genotype AG in five patients (25%) and the rest of 15 cases (75%) had АА (Ile/Ile) genotype. Patients with metastasis had genotype АА (Ile/Ile) in 80% and genotype AG (Ile/Val) in 20% (χ(2) = 2.857; p = 0.091).Our results indicate that SNP in HER2 codon 655 and investigation of HER2 and HER3 expression could be helpful to outline the prognosis for patients with lung adenocarcinoma.

[New targets and new drugs in thoracic oncology]

A number of mechanisms that drive oncogenesis have been deciphered over the last 20 years. The main oncogenic factors in the field of thoracic oncology are mutations of EGFR, KRAS, and EML4-ALK translocation, which are most often reported in adenocarcinomas. However, new molecular targets have been highlighted recently including BRAF mutations, HER2 or PI3K, new translocations such as ROS1 or KIF5B-RET. Molecular abnormalities have also been identified in tumors other than adenocarcinoma (squamous and small cell carcinoma). Therapeutic strategies have been designed to inhibit these signaling pathways including monoclonal antibodies and tyrosine kinase inhibitors. Some of these molecules are now approved as therapies, others are currently undergoing testing in clinical trials. We here present a review of novel targeted agents for lung cancer.

Trastuzumab increases the sensitivity of HER2-amplified human gastric cancer cells to oxaliplatin and cisplatin by affecting the expression of telomere-associated proteins

HER2 amplification occurs in ~20% of gastric cancer (GC) cases; however, in gastric and gastroesophageal junction cancer with HER2 gene amplification, trastuzumab in combination with cisplatin (DDP)-based chemotherapy has been reported to improve the oncological outcome. The aim of the present study was to evaluate the combined antitumor efficacy of trastuzumab and various platinum agents in GC cells and to elucidate mechanisms that may be involved in the interaction between trastuzumab and the platinum agents. The in vitro chemosensitivity of the GC cells to platinum agents was evaluated using the CellTiter 96^® AQueous One Solution Cell Proliferation Assay kit. Treatment with 1.0μg/ml trastuzumab for 48 h significantly increased the sensitivity of NCI-N87 cells with HER2 amplification to oxaliplatin (Oxa) and DDP. This chemosensitivity was most prominent in the NCI-N87 cells, in which the half maximal inhibitory concentration of Oxa and DDP was decreased to ~3.29 and 6.91 times, respectively. The apoptotic effect of the platinum agents was evaluated by double-staining the GC cells with Annexin V-fluorescein isothiocyanate and propodium iodide. Consistent with the chemosensitivity analysis, apoptotic analysis indicated that trastuzumab significantly increased Oxa- and DDP-induced apoptosis in the NCI-N87 cells. Furthermore, the mRNA expression levels of various telomere-associated genes was determined by performing quantitative reverse transcription-polymerase chain reactions in a number of GC cell lines, and revealed that trastuzumab (alone and in combination with DDP) may downregulate the mRNA expression levels of the TPP1, TRF1, TRF2, TRF2IP and POT1 genes. However, western blot analysis demonstrated that trastuzumab (alone and in combination with DDP) may significantly downregulate the protein expression levels of telomeric repeat binding factor 2, protection of telomere 1 and TPP1 (formerly known as TINT1, PTOP and PIP). The results of the present study indicate a potential role of low-dose trastuzumab administration for increasing Oxa and DDP sensitivity in HER2-amplified GC cells, possibly via the downregulation of telomere-associated gene expression.

HER2 status for prognosis and prediction of treatment efficacy in adenocarcinomas: a review

The past few years have seen flourish new biologic parameters for cancer prognosis that are revolutionizing therapeutic strategies. HER-2 is in this perspective a striking example, as it is now a key element for the care of 15-20% of breast cancer. HER-2 overexpression has first been reported as a prognostic factor before its consideration as a main parameter to predict treatment efficacy. However, although HER-2 status is now also used as a prognostic factor for many cancers, its ability to predict the action of trastuzumab in these new contexts is much lower than in breast cancer. In this literature review, we aimed to discuss HER-2 overexpression as a prognostic factor and as a predictive parameter of treatment response in selected solid tumors with a focus on adenocarcinomas.