Given their good antitumor effects, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are standard first-line therapy for EGFR-sensitive mutations, including exon 19 deletions and exon 21 L858R mutations. EGFR fusion mutations and EGFR amplification are very rare in non-small cell lung cancer (NSCLC). We describe 2 patients with NSCLC harboring EGFR fusion mutations (EGFR-MACF1 and EGFR-GNAT3) combined with EGFR amplification. Both patients received EGFR-TKI treatment, and 1 of them showed an antitumor response.

EGFR mutations are the most important drivers of gene alterations in lung adenocarcinomas and are sensitive to EGFR-TKIs. However, resistance to EGFR-TKIs is inevitable in the majority of EGFR-mutated lung cancer patients. Numerous resistant mechanisms have been revealed to date, and more are still under investigation. Owing to the selective pressure, intratumoral heterogeneity may exist after resistance, especially in patients after multiple lines of treatment. For those patients, it is important to choose therapies focused on the trunk/major clone of the tumor in order to achieve optimal clinical benefit. Here, we will report an EGFR-mutated lung adenocarcinoma patient with heterogeneity of resistant mechanisms including EGFR amplification, large fragment deletion of RB1, and histological transformations after targeted treatments. In our case, EGFR amplification seemed to be the major clone of the resistant mechanism according to the next-generation sequencing (NGS) results of both liquid biopsy monitoring and tissue biopsies. In consideration of the high EGFR amplification level, the patient was administered by combination treatment with EGFR-TKI plus nimotuzumab, an anti-EGFR monoclonal antibody (mAb), and achieved a certain degree of clinical benefit. Our case sheds light on the treatment of EGFR-mutant patients with EGFR amplification and indicates that a combination of EGFR-TKI with anti-EGFR mAb might be one of the possible treatment options based on genetic tests. Moreover, the decision on therapeutic approaches should focus on the major clone of the tumor and should make timely adjustments according to the dynamic changes of genetic characteristics during treatment.

The paradigm for the pharmacological management of advanced non-small cell lung cancer (NSCLC) has been revolutionized by the development of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). Developing resistance to target therapy is unavoidable. Mostly, treatments for single molecular alteration after acquiring EGFR-TKI treatment resistance are well studied. However, there is limited evidence of treatment strategies for complex resistance mechanisms. Presented here is a case of an EGFR-mutated NSCLC patient who developed a complex resistance profile: T790M point mutation and EGFR amplification after first-line EGFR-TKI. This patient was safely treated with a combination of osimertinib and icotinib and achieved a significant clinical response and clear molecular response. Here we present the clinical evidence of the efficacy of osimertinib combined with icotinib in the treatment of EGFR classical mutation along with resistant mutation of T790M point mutation and EGFR amplification.

The histological transformation from epidermal growth factor receptor (EGFR)-mutated adenocarcinoma (ADC) to squamous cell carcinoma (SCC) after tyrosine kinase inhibitor (TKI) treatment is rare. We present a case of a patient who transitioned from early-stage primary lung ADC with partial squamous differentiation, EGFR mutation and amplification, to adrenal gland metastasis as SCC with EGFR amplification disappearance 115-months after surgery, during which gefitinib and local radiotherapy were utilized for the metastasis in the right femoral head and mediastinal lymph nodes. This case might indicate a possible mechanism of EGFR inhibition resistance with SCC transition and EGFR amplification loss from the initially well-responding ADC, especially those with SCC or partial squamous differentiation. The optimal post-progression therapy for ADC-SCC patients is challenging and further studies are needed.

Currently, women with metastatic or recurrent cervical cancer still have very limited treatment options. Despite the rapid advancements in targeted therapies, no targeted therapy was approved for cervical cancer, except for bevacizumab. In the present study, we reported a 52-year-old heavily pre-treated EGFR amplified patient with metastatic cervical squamous cancer who benefited from afatinib with a progression-free survival (PFS) of 5.5 months. The patient was administered with a first-line treatment of chemotherapy and bevacizumab with a PFS of 4.3 months. Subsequently the patient was treated with a second-line regimen of angiogenesis inhibitor apatinib plus chemotherapy and a third-line treatment of pembrolizumab. Genomic profiling revealed significant EGFR amplification in both primary (copy number [CN] =15.9) and metastatic lesions (CN =18). Afatinib monotherapy was then administered as the fourth-line regimen. She achieved partial response (PR) with a PFS of 5.5 months. At disease progression, the CN of EGFR was elevated to 39.9 accompanied by the emergence of PIK3CA amplification (CN =4.2). The patient was treated with everolimus and afatinib and achieved stable disease (SD) after 3 months. To the best of our knowledge, this is the first clinical evidence of an EGFR-amplified metastatic cervical cancer patient benefiting from afatinib as a single agent.