Ten percent of non-small cell lung cancer patients with epidermal growth factor receptor (EGFR) mutations harbor uncommon variants. These mutations are mainly involved in lung adenocarcinomas but are rare in lung squamous cell carcinoma (LSCC). In 2018, the Food and Drug Administration-approved afatinib for this specific patient population. However, there is limited information regarding the effectiveness of afatinib for LSCC with EGFR mutations. This case report documented a unique case of a patient with LSCC, which had a rare compound EGFR mutation (G719C and S768I) and showed significant response to afatinib treatment, with 10 months of progression-free survival. New NTRK1 and RET gene mutations may play a potential role in the development of acquired resistance to afatinib following clinical progression. This case highlights the importance of genetic profiling in patients with LSCC. Although these patients have a low positive rate of EGFR mutations, searching for EGFR mutations in these patients might broaden their treatment options.

We present the case of a 70-year-old never-smoking female patient with epidermal growth factor receptor (EGFR) p.L858R-mutated metastatic non-small cell lung cancer (NSCLC). After three months of first-line treatment with erlotinib, progression occurred and platinum/pemetrexed was initiated, followed by a response for more than two years. After the progression, the molecular testing of a vertebral metastasis revealed a ROS proto-oncogene 1 (ROS1) translocation and a human epidermal growth factor receptor 2 (HER2) p.S310F mutation, in addition to the known EGFR p.L858R mutation. Crizotinib then led to a durable response of 17 months. The molecular retesting of the tumour cells obtained from the recurrent pleural effusion revealed the absence of the ROS1 translocation, whereas the EGFR and HER2 mutations were still present. Afatinib was added to the crizotinib, and the combination treatment resulted in another durable response of more than two years. The patient died more than 7 years after the initial diagnosis of metastatic NSCLC. This case demonstrates that the repeated molecular testing of metastatic NSCLC may identify new druggable genomic alterations that can impact the patient management and improve the patient outcome.

Lung cancer is the most common malignant disease and the leading cause of cancer death in China. Non-small cell lung cancer (NSCLC) accounts for over 80% of all lung cancers, and the probability of NSCLC gene mutations is high, with a wide variety of types. With the development of next-generation sequencing (NGS) detection technology, more and more patients with rare fusion gene mutations are detected. Neuregulin 1 (NRG1) gene is a rare oncogenic driver that can lead to activation of human epidermal growth factor receptor 3 (Her3/ErbB3) mediated pathway, resulting in tumor formation. In this article, we reported a case of mixed NSCLC with CRISPLD2-NRG1 fusion detected by RNA-based NGS, who responsed to Afatinib well after 1 month of treatment, and magnetic resonance imaging (MRI) showed shrinkage of intracranial lesions. Meanwhile, we also compiled previously reported NSCLC patients with NRG1 rare gene fusion mutation, in order to provide effective references for clinical diagnosis and treatment.
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【中文题目：罕见CRISPLD2-NRG1融合突变晚期混合型非小细胞肺癌1例并文献复习】 【中文摘要：肺癌是中国发病率和死亡率最高的恶性肿瘤。非小细胞肺癌（non-small cell lung cancer, NSCLC）占全部肺癌的80%以上，NSCLC的基因突变概率高，并且种类繁多。随着基因检测技术的进步，越来越多的罕见融合基因变异被检测出来。神经调节蛋白1（neuregulin 1, NRG1）可促使人表皮生长因子受体3（human epidermal growth factor receptor 3, Her3/ErbB3）介导的通路激活，从而导致肿瘤形成。本文报道了1例罕见CRISPLD2-NRG1融合突变的晚期混合型NSCLC颅内转移的患者，接受阿法替尼治疗1个月后头部磁共振成像（magnetic resonance imaging, MRI）显示颅内病灶明显缩小，患者对阿法替尼治疗反应良好。同时，我们对以往报道的NRG1基因融合突变的NSCLC病例进行总结，以供临床借鉴。
】 【中文关键词：肺肿瘤；阿法替尼；CRISPLD2-NRG1融合突变】.

暂无摘要。

We present a 70-year-old female patient diagnosed with epidermal growth factor receptor-mutated metastatic non-small cell lung cancer (T4N2M1a), who developed afatinib-induced toxic epidermal necrolysis (TEN). We have also performed a PubMed/Medline literature review to detect other possible cases of TEN/Stevens-Johnson syndrome associated with afatinib treatment and found only 5 other cases reported. To our best knowledge, this is the first case of afatinib-induced TEN successfully treated with cyclosporine.

MET exon14 skipping mutations (METex14s) are rarely reported as a potential resistance mechanism to EGFR tyrosine kinase inhibitors (TKIs). The efficacy of targeted therapy against METex14s emerging after osimertinib resistance is uncertain. Herein, we report a case of EGFR-mutated metastatic lung adenocarcinoma in which METex14 was detected in a re-biopsy upon first-line osimertinib resistance. The patient received capmatinib monotherapy as third-line therapy, which was ineffective, followed by an exceptional response to salvage therapy with afatinib. This report highlights the heterogeneity of EGFR-TKI resistance and that targeting rare resistance mechanisms remains challenging.

暂无摘要。

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) represent first-line standard of care in unresectable EGFR mutation-positive (EGFRm+) non-small cell lung cancer (NSCLC). However, 10-20% of patients with EGFRm+ NSCLC have uncommon EGFR variants, defined as mutations other than L858R substitutions or exon 19 deletions. NSCLC harboring uncommon EGFR mutations may demonstrate lower sensitivity to targeted agents than NSCLC with L858R or exon 19 deletion mutations. Prospective clinical trial data in patients with NSCLC uncommon EGFR mutations are lacking. Afatinib is a second-generation TKI and the only Food and Drug Administration-approved drug for some of the more prevalent uncommon EGFR mutations. We present a series of seven case reports describing clinical outcomes in afatinib-treated patients with NSCLC harboring a diverse range of extremely rare mutations with or without co-mutations affecting other genes. EGFR alterations included compound mutations, P-loop αC-helix compressing mutations, and novel substitution mutations. We also present a case with NSCLC harboring a novel EGFR::CCDC6 gene fusion. Overall, the patients responded well to afatinib, including radiologic partial responses in six patients during treatment. Responses were durable for three patients. The cases presented are in line with a growing body of clinical and preclinical evidence that indicating that NSCLC with various uncommon EGFR mutations, with or without co-mutations, may be sensitive to afatinib.

BACKGROUND: In the current treatment landscape for non-small cell lung cancers, epidermal growth factor receptor-tyrosine kinase inhibitors have emerged as a well-established treatment option for patients with advanced or metastatic disease. This is particularly true for those with commonly occurring epidermal growth factor receptor mutations. However, the therapeutic efficacy of these agents for so-called rare epidermal growth factor receptor mutations, and in particular those characterized by a high degree of complexity, such as double mutations, remains a subject of clinical uncertainty.
METHODS: In this context, we present the case of a 64-year-old man of Moroccan descent, a lifelong non-smoker, diagnosed with metastatic non-small cell lung cancer characterized by a complex epidermal growth factor receptor mutation encompassing L858R and S768I. The patient subsequently underwent afatinib-based treatment, showing notable clinical results. These included a remarkable overall survival of 51 months, with a median progression-free survival of more than 39 months.
CONCLUSIONS: This case report is a compelling testimony to the evolving therapeutic landscape of non-small cell lung cancers, providing valuable insight into the potential therapeutic efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors in the realm of rare and complex epidermal growth factor receptor mutations.

Lung cancer treatment has transitioned fully into the era of immunotherapy, yielding substantial improvements in survival rate for patients with advanced non-small cell lung cancer (NSCLC). In this report, we present a case featuring a rare epidermal growth factor receptor (EGFR) mutation accompanied by high programmed death-ligand 1 (PD-L1) expression, demonstrating remarkable therapeutic efficacy through a combination of immunotherapy and chemotherapy. A 77-year-old male with no family history of cancer suffered from upper abdominal pain for more than half months in August 2020 and was diagnosed with stage IV (cT3N3M1c) lung squamous cell carcinoma (LUSC) harboring both a rare EGFR p.G719C mutation and high expression of PD-L1 (tumor proportion score [TPS] = 90%). Treatment with the second-generation targeted therapy drug Afatinib was initiated on September 25, 2020. However, resistance ensued after 1.5 months of treatment. On November 17, 2020, immunotherapy was combined with chemotherapy (Sintilimab + Albumin-bound paclitaxel + Cisplatin), and a CT scan conducted three months later revealed significant tumor regression with a favorable therapeutic effect. Subsequently, the patient received one year of maintenance therapy with Sintilimab, with follow-up CT scans demonstrating subtle tumor shrinkage (stable disease). This case provides evidence for the feasibility and efficacy of immunotherapy combined with chemotherapy in the treatment of EGFR-mutated and PD-L1 highly expressed LUSC.