Molecular diagnosis and clinical outcome of a lung cancer patient with TP53-E285K mutated Li-Fraumeni syndrome harboring a somatic EGFR-KDD mutation

Abstract

Objectives: Li-Fraumeni syndrome (LFS) is an autosomal dominant cancer predisposition, mostly caused by germline TP53 mutations. Lung adenocarcinoma (ADC) has been identified as the most frequent LFS-related cancer outside the common LFS core spectrum. EGFR-kinase domain duplication (KDD) is rare in lung cancer and the effective therapy for LFS patients with EGFR-KDD mutated ADC is unclear. This study reports the first case of a TP53-mutated LFS patient with confirmed family history, developing advanced lung ADC harboring EGFR-KDD. Materials and methods: The patient’s lung tumor, lymph nodes, liquid biopsies and germline control sample at various disease stages were subjected to next-generation sequencing (NGS). The TP53 germline mutation was confirmed using the peripheral blood of the patient’s relatives by Sanger sequencing. Results: A rare EGFR-KDD somatic mutation that was missed in the routine EGFR hotspots test, and a TP53-E285K temperature-sensitive germline mutation were identified by NGS. The patient was diagnosed with breast cancer in 2006 and her family cancer history review revealed that seven out of 13 relatives were diagnosed or died from LFS-spectrum cancers before the age of 45 years. Three of the six relatives were positive for the TP53-E285K germline mutation. This patient received multi-line chemotherapy followed by anlotinib, a multi-target tyrosine kinase inhibitor, upon the identification of EGFR-KDD, and achieved an overall survival of 18 months. Conclusions: Our study highlights the importance of NGS in discovering rare genetic alterations to guide treatment decision-making, and provides meaningful insight into the potential treatment options for LFS patients with EGFR-KDD mutations.

Introduction

Li-Fraumeni syndrome (LFS) is a rare autosomal dominant cancer predisposition syndrome characterized by the early onset of multiple tumors. LFS was described in 1969 by Li and Fraumeni, and was subsequently shown to be associated with germline TP53 inactivation mutations [1]. As one of the most prominent tumor suppressor genes, TP53 plays a key role in DNA damage signaling by stimulating cell cycle arrest, apoptosis and DNA repair mechanisms to protect cellular genomic integrity [2]. Therefore, TP53 loss enables the acquisition of additional driver events to accelerate transformation.

Beyond the core LFS spectrum cancers, including sarcoma, breast cancer, brain tumor and adrenal cortical carcinoma, lung adenocarcinoma (ADC) is the most frequently occurring in LFS patients; however, the molecular alteration of LFS-related lung ADC is still unclear and requires further evaluation [3]. Oncogenic mutations of the epidermal growth factor receptor (EGFR) gene occur in approximately 45% of Asian lung ADC patients, among which the most frequent are short in-frame deletions in exon 19 (Ex19del) and point mutations in exon 21 (L858R) [4]. Patients with EGFR-mutated lung cancers generally achieve better clinical outcomes when treated with EGFR tyrosine kinase inhibitors (TKIs) [5].

With the advance of genetic testing techniques, rare EGFR alterations, such as EGFR kinase domain duplication (KDD), are increasingly observed [6]. EGFR-KDD typically consists of an intragenic alteration in EGFR, which leads to the tandem duplication of EGFR exons 18-25 and constitutively activated EGFR signaling [7]. One study reviewed several lung ADC cases with EGFR-KDD alterations and identified significant antitumor responses to EGFR TKI therapies [7]. However, the efficacy of EGFR TKIs for LFS patients with EGFR-KDD was unclear.

Case presentation

A 39-year-old female non-smoker with a diagnosis of breast cancer at the age of 28 years, was diagnosed with stage IV (cT4N2M1b) lung ADC with multiple lymph node metastases in May 2018 (Figure 1). Immunohistochemistry (IHC) staining of a lung tumor biopsy and mammary gland/axillary lymph nodes was positive for the pulmonary ADC markers, TTF-1 and napsin A, but negative for the breast cancer markers, lactoglobulin and GATA-3; thus, confirming that they were lung ADC samples and not recurrent breast cancer samples. Due to a negative result of a PCR-based genetic test for EGFR-L858R, the patient was subsequently administered six cycles of TP therapy (paclitaxel, 30 mg d1 and carboplatin, 750 mg d1) and achieved a partial response (PR) (Figure 1). Paclitaxel monotherapy was used for an additional two cycles for maintenance. However, the patient developed progressive disease (PD) with an enlarged primary tumor in November 2018 (Figure 1B). Therefore, the patient was transitioned to AP treatment (pemetrexed, 1 g d1 and cisplatin, 40 mg d1-3) for four cycles. In March 2019, a CT scan and cerebrospinal fluid (CSF) cytology revealed a progression of the pulmonary lesions and newly-occurring meningeal metastasis, respectively. The patient received combination therapy of gemcitabine (1.6 g d1 and d8) plus nedaplatin (130 mg d2). After four cycles, the patient achieved a stable disease (SD) in July 2019 (Figure 1B), but the meningeal metastasis progression continued. The total survival benefit of multi-line chemotherapy was 13.5 months.

Figure 1.

Representative clinical images obtained during the course of treatment. A. The disease timeline shows the treatments received by the patient and her clinical response. ADC: adenocarcinoma. B. Chest-CT scans show the disease progression following treatment. Tumor lesions are indicated by red arrows. PR: partial response; PD: progressive disease; SD: stable disease.

To seek a more effective treatment strategy, tissues of lung, mammary gland and axillary lymph nodes, which were collected before chemotherapy, accompanied with newly collected CSF and blood biopsies, were subjected to NGS of 425 cancer-relevant-genes in July 2019. Genomic profiling identified an extremely rare EGFR-KDD mutation and a TP53 E285K (c.853G>A) germline mutation in all samples (Supplementary Table 1).

To determine whether the patient was a case of LFS, we investigated her family history and tested for the TP53 E285K germline mutation in blood biopsies provided by six relatives in her family, five of whom had no symptoms of cancer up to date, and one was diagnosed with osteosarcoma at 17 years of age. Family history revealed that the patient’s father died of gastric cancer at the age of 51 years, her three uncles died of lung cancer (age 37 years), mediastinal cancer (age 41 years) and lymphoma (age 42 years), respectively, and her grandfather died of a brain tumor at age 37 years (Figure 2A). TP53 E285K germline mutation screening revealed another three carriers aside from the proband; her younger male cousin (age 39 years), elder female cousin (age 42 years) and her niece with osteosarcoma (Figure 2A, 2B). As an EGFR-KDD alteration was detected by NGS, the patient then received anlotinib, a multi-target TKI, once per day (12 mg) on days 1-14 of a 21-day cycle, but died 4.5 months post-treatment. The patient achieved an overall survival (OS) of 18 months.

Figure 2.

Pedigree of the proband’s family with LFS and TP53 E285K germline mutations. (A) The pedigree of the proband’s family with LFS. Patients labeled with numbers were screened for TP53 E285K mutations. The status of each patient is indicated as wild-type (WT) or as harboring the E285K mutation (E285K). The proband is indicated by an arrow. The numbers below each symbol indicate the following: age of death (d.70y), age at diagnosis of cancers (c.28y) or current age (39y). GC: gastric cancer; BT: brain tumor; LC: lung cancer; PC: pancreatic cancer; MC: mediastinal cancer; BC: breast cancer, ACC: adrenocortical carcinoma; OS: osteosarcoma. (B) The chromatograms of the DNA sequences of the mutated locus in family members who were labeled as II-1 to IV-2, based on to the pedigree in (A). The wild-type sequence was observed in II-1, III-3 and IV-2, while a c. G853A germline transversion was observed in III-1, III-2, III-4 and IV-1.

Discussion

In this report, we described a patient with LFS harboring an EGFR-KDD and TP53 E285K germline mutation who received multi-line chemotherapy, followed by TKI-treatment and achieved an OS of 18 months. EGFR-KDD is an extremely rare oncogenic alteration that occurred in approximately 0.12% of all participants, and 0.24% of EGFR mutation-positive participants in a study of 10,759 NSCLC patients, and could not be detected via traditional PCR-based approaches [7]. Therefore, NGS provided a more precise option for detecting rare gene alterations.

Studies have shown that EGFR-targeted therapies for EGFR-KDD patients achieved significant antitumor responses [7]. Anlotinib, a multi-target TKI, has been reported to significantly improve the OS of patients with refractory NSCLC and benefitted patients with brain metastases [8,9]. Therefore, anlotinib was the choice for our patient, but only achieved 4.5 months of PFS. This may partially due to our patient having a TP53 E285K germline mutation as non-disruptive TP53 mutations are associated with shorter survival in advanced NSCLC treated with TKI [10]. As a strictly temperature-dependent loss of function mutation, E285K is located in the DNA binding domain of TP53 and pathogenic in a cell-based study and an LFS-linked family [11]. A preclinical study suggested that TP53 mutations could reduce gefitinib-induced cell apoptosis via regulation of the Fas (factor-associated suicide) signaling pathway in an NSCLC cell line [12]. However, the underlying mechanisms of the effect of TP53 E285K mutations on TKI treatment needs to be further explored.

The clinical definition of classic LFS includes a proband with a sarcoma at <45 years of age, a first-degree relative with cancer at <45 years of age, and a first- or second-degree relative with any cancer at <45 years of age or a sarcoma at any age [2]. Our patient’s family did not entirely fulfill those criteria, but was defined as LFS-like [2]. For the two TP53 E285K carriers who did not show any symptoms, comprehensive cancer screening and routine medical examinations should be performed.

A recent publication showed that most EGFR-mutant lung cancer carriers with TP53-mutated LFS were female never-smokers, with medical histories of early-onset breast cancer. Such observations are similar to our patient who was diagnosed with breast cancer at the age of 28 years [13]. Despite the paucity of specific recommendations for tumor therapies in LFS patients, minimizing radiation therapy to prevent treatment-related carcinogenesis is recommended. In a report of two lung cancer patients with LFS harboring targetable common EGFR mutations, the disease progressed rapidly during TKI treatment in one case, which indicated that targeted therapy is not suitable for all EGFR-mutated LFS patients [13]. In our case, the patient was treated with multiline chemotherapy and achieved a total survival benefit of 14 months; findings that provided valuable insight into potential treatment options for LFS patients.

Conclusions

In summary, this study reported the first case of a TP53 germline-mutated LFS patient with confirmed family history of advanced lung ADC harboring EGFR-KDD. The patient received multi-line chemotherapy, followed by TKI-treatment and achieved an OS of 18 months. This report highlights the importance of performing comprehensive genomic profiling in discovering rare gene mutations, and providing valuable insights into treatment-decision making for LFS patients with EGFR-KDD alterations. The search for effective therapeutic strategies for such patients with LFS harboring EGFR mutations must also be continued in the future.

Disclosure of conflict of interest

Xue Han and Sisi Liu are employees of Nanjing Geneseeq Technology Inc., China; Xue Wu is an employee of Geneseeq Technology Inc., Canada. The remaining authors declare no conflicts of interest.