EGFR-mutated lung cancer in Li-Fraumeni syndrome

Lung cancer in patients who have never smoked - an emerging disease

Lung cancer is the most common cause of cancer-related deaths globally. Although smoking-related lung cancers continue to account for the majority of diagnoses, smoking rates have been decreasing for several decades. Lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths worldwide in 2023, preferentially occurring in women and Asian populations. As smoking rates continue to decline, understanding the aetiology and features of this disease, which necessitate unique diagnostic and treatment paradigms, will be imperative. New data have provided important insights into the molecular and genomic characteristics of LCINS, which are distinct from those of smoking-associated lung cancers and directly affect treatment decisions and outcomes. Herein, we review the emerging data regarding the aetiology and features of LCINS, particularly the genetic and environmental underpinnings of this disease as well as their implications for treatment. In addition, we outline the unique diagnostic and therapeutic paradigms of LCINS and discuss future directions in identifying individuals at high risk of this disease for potential screening efforts.

Defining function of wild-type and three patient-specific TP53 mutations in a zebrafish model of embryonal rhabdomyosarcoma

In embryonal rhabdomyosarcoma (ERMS) and generally in sarcomas, the role of wild-type and loss- or gain-of-function TP53 mutations remains largely undefined. Eliminating mutant or restoring wild-type p53 is challenging; nevertheless, understanding p53 variant effects on tumorigenesis remains central to realizing better treatment outcomes. In ERMS, >70% of patients retain wild-type TP53, yet mutations when present are associated with worse prognosis. Employing a kRASG12D-driven ERMS tumor model and tp53 null (tp53-/-) zebrafish, we define wild-type and patient-specific TP53 mutant effects on tumorigenesis. We demonstrate that tp53 is a major suppressor of tumorigenesis, where tp53 loss expands tumor initiation from <35% to >97% of animals. Characterizing three patient-specific alleles reveals that TP53C176F partially retains wild-type p53 apoptotic activity that can be exploited, whereas TP53P153Δ and TP53Y220C encode two structurally related proteins with gain-of-function effects that predispose to head musculature ERMS. TP53P153Δ unexpectedly also predisposes to hedgehog-expressing medulloblastomas in the kRASG12D-driven ERMS-model.

Distinct NSCLC EGFR Variants in a Family With Li-Fraumeni Syndrome: Case Report

Introduction

Heritable lung cancer may occur in the context of germline TP53 mutations (Li-Fraumeni syndrome). Limited cases of intrafamily tumor genomic characteristics have been reported.

Main concerns, Important Clinical Findings, Primary Diagnoses, Interventions, Outcomes

A 40-year-old woman with no smoking history or known environmental exposure risk was incidentally found to have stage II (T2N1) NSCLC harboring an EGFR exon 19 p.Glu746_Ala750 deletion. Family history was notable for an identical twin sister with colorectal cancer (diagnosed at age 31 y) and a mother with stage I NSCLC harboring an EGFR exon 21 c.2573T>G (p.Leu858Arg) mutation (diagnosed at age 69 y). Genetic testing revealed a germline TP53 c.542G>A (p.Arg181His) mutation in the patient, her mother, and her sister, consistent with Li-Fraumeni syndrome. No germline EGFR mutations were detected.

Conclusion

Shared germline TP53 mutations may be associated with distinct NSCLC somatic EGFR mutations within families with Li-Fraumeni syndrome. Further understanding of the association between genetic cancer syndromes and lung cancer risk may improve early lung cancer detection in populations not otherwise meeting screening eligibility.

Prevalence of the Brazilian TP53 Founder c.1010G>A (p.Arg337His) in Lung Adenocarcinoma: Is Genotyping Warranted in All Brazilian Patients?

In Southern and Southeastern Brazil, there is a germline pathogenic variant with incomplete penetrance located in the oligomerization domain of TP53, c.1010G>A (p.Arg337His). Due to a founder effect, the variant is present in 0.3% of the general population of the region. Recently, this variant was identified in 4.4 and 8.9% of two apparently unselected, single center case series of Brazilian lung adenocarcinoma (LUAD) patients from the Southeastern and Central regions of the country, respectively. In the present study, our aim was to examine TP53 c.1010G>A allele and genotype frequencies in LUAD samples obtained from patients diagnosed in Southern Brazil. A total of 586 LUAD samples (tumor DNA) recruited from multiple centers in the region were tested, and the mutant allele was identified using TaqMan® assays in seven cases (7/586, 1.2%) which were submitted to next generation sequencing analyses for confirmation. Somatic EGFR mutations were more frequent in TP53 c.1010G>A carriers than in non-carriers (57.1 vs. 17.6%, respectively). Further studies are needed to confirm if TP53 c.1010G>A is a driver in LUAD carcinogenesis and to verify if there is a combined effect of EGFR and germline TP53 c.1010G>A. Although variant frequency was higher than observed in the general population, it is less than previously reported in LUAD patients from other Brazilian regions. Additional data, producing regional allele frequency information in larger series of patients and including cost-effectiveness analyses, are necessary to determine if TP53 c.1010G>A screening in all Brazilian LUAD patients is justified.

Breast Cancer Patient with Li-Fraumeni Syndrome: A Case Report Highlighting the Importance of Multidisciplinary Management

Germline mutations in TP53, a tumor suppressor gene, are involved in the development of Li-Fraumeni syndrome, a rare disorder that predisposes carriers to multiple tumors. TP53 mutations have been associated with resistance to treatment and poor prognosis. A young female with the pathogenic germline TP53 mutation c.844C > T (p.R282W) was diagnosed with two metachronous breast tumors, one HER2-negative and the other HER2-positive. She was later diagnosed with synchronous glioblastoma, epidermal growth factor receptor-mutated lung adenocarcinoma, and HER2-negative breast cancer metastases. The patient was treated with local therapies, including brain surgery and radiotherapy, lung surgery, and a bilateral mastectomy, as well as with targeted systemic treatment. She proved to be highly sensitive to systemic therapy, and 13 years after the initial diagnosis of breast cancer and 6 years after the diagnosis of the two new primary tumors and recurrence of a prior cancer, she is alive with an excellent performance status. This surprising positive evolution may well be partly due to the pronged multidisciplinary approach to managing her disease and her extraordinary response to treatment: the lung adenocarcinoma showed excellent response to erlotinib; the breast cancer responded extremely well to eribulin and pegylated liposomal doxorubicin; and the glioblastoma has remained in response to surgery and radiotherapy. Despite harboring a TP53 mutation and having multiple tumors, this patient has shown an unexpectedly favorable evolution. The coordinated participation of a multidisciplinary team and the patient's own extraordinarily high sensitivity to systemic treatment played a major role in this evolution.

Hormone receptor expression correlates with EGFR gene mutation in lung cancer in patients with simultaneous primary breast cancer

Background

The coexistence of double primaries of lung cancer (LC) and breast cancer (BC) are not uncommon in women, but there has been limited research conducted of their molecular association. To decipher the internal pathogenesis of LC in patients with concurrent BC and LC, this study explored the clinical factors and relationship between hormone receptor (HR) expression and epidermal growth factor receptor (EGFR) gene mutation.

Methods

The clinicopathological characteristics of 400 female patients clinically diagnosed with double primary LC and BC at Fudan University Shanghai Cancer Center were collected. Pathological discrimination was performed to further confirm the double primaries in patients with available tissues. LC samples were then examined to detect EGFR gene mutation status by PCR-based assays and HR expression by immunohistochemistry (IHC). As a control cohort, the characteristics of 114 consecutive patients with LC only were compared with the double-primary patient group.

Results

A total of 169 patients were pathologically confirmed with simultaneous LC and BC between January 2010 and October 2018. The dominant LC subtype was adenocarcinoma (ADC) (95.1%), and invasive ductal carcinoma (IDC) was the main BC subtype (71.0%). Synchronous and metachronous double primary BC-LC cases accounted for 39.1% and 60.9% of the patients, respectively. The absence of family cancer history was associated with a shorter interval between the two primary cancer diagnoses. Among 64 patients with EGFR mutations, 34.4% had HR-positive LC tissue, compared with 0/24 (0%) of those with EGFR wild-type LC (P<0.001). All of the patients with positive HR expression harbored an activating EGFR mutation (n=22); however, no correlation was observed in the control cohort.

Conclusions

Double primary BC-LC patients have distinctive clinicopathological features compared to those with LC only. The expression of HRs is significantly correlated with EGFR mutation status of LC tissues.

Inherited lung cancer: a review

Lung cancer is the most common cancer worldwide and has high rates of mortality. The major risk factor associated with this disease is tobacco smoke, but approximately 10%-25% of all lung cancer cases occur in patients who have never smoked. Data suggest that lung cancer in never-smokers has a different molecular profile, tumour microenvironment and epidemiology than that in smokers. Several risk factors have been associated with its occurrence, and the possibility of inherited predisposition is becoming clearer. A better understanding of this disease is essential for the future development of personalised screening, diagnosis and treatment approaches, with consequent reduction of mortality. In this review, we discuss historical studies of lung cancer in never-smokers and the currently available evidence of inherited predisposition to this disease.

Potential genetic modifiers for somatic EGFR mutation in lung cancer: a meta-analysis and literature review

BACKGROUND

Accumulating evidence indicates inherited risk in the aetiology of lung cancer, although smoking exposure is the major attributing factor. Family history is a simple substitute for inherited susceptibility. Previous studies have shown some possible yet conflicting links between family history of cancer and EGFR mutation in lung cancer. As EGFR-mutated lung cancer favours female, never-smoker, adenocarcinoma and Asians, it may be argued that there may be some underlying genetic modifiers responsible for the pathogenesis of EGFR mutation.

METHODS

We searched four databases for all original articles on family history of malignancy and EGFR mutation status in lung cancer published up to July 2018. We performed a meta-analysis by using a random-effects model and odds ratio estimates. Heterogeneity and sensitivity were also investigated. Then we conducted a second literature research to curate case reports of familial lung cancers who studied both germline cancer predisposing genes and their somatic EGFR mutation status; and explored the possible links between cancer predisposing genes and EGFR mutation.

RESULTS

Eleven studies have been included in the meta-analysis. There is a significantly higher likelihood of EGFR mutation in lung cancer patients with family history of cancer than their counterparts without family history, preferentially in Asians (OR = 1.35[1.06-1.71], P = 0.01), those diagnosed with adenocarcinomas ((OR = 1.47[1.14-1.89], P = 0.003) and those with lung cancer-affected relatives (first and second-degree: OR = 1.53[1.18-1.99], P = 0.001; first-degree: OR = 1.76[1.36-2.28, P < 0.0001]). Familial lung cancers more likely have concurrent EGFR mutations along with mutations in their germline cancer predisposition genes including EGFR T790 M, BRCA2 and TP53. Certain mechanisms may contribute to the combination preferences between inherited mutations and somatic ones.

CONCLUSIONS

Potential genetic modifiers may contribute to somatic EGFR mutation in lung cancer, although current data is limited. Further studies on this topic are needed, which may help to unveil lung carcinogenesis pathways. However, caution is warranted in data interpretation due to limited cases available for the current study.

Alternative splicing in lung cancer

Lung cancer has the highest mortality rate of all cancers worldwide. Lung cancer is a very heterogeneous disease that is often diagnosed at later stages which have a poor prognosis. Aberrant alternative splicing patterns found in lung cancer contribute to important cell functions. These include changes in splicing for the BCL2L1, MDM2, MDM4, NUMB and MET genes during lung tumourigenesis, to affect pathways involved in apoptosis, cell proliferation and cellular cohesion. Global analyses of RNASeq datasets suggest there may be many more potentially influential aberrant splicing events that need to be investigated in lung cancer. Changes in expression of the splicing factors that regulate alternative splicing events have also been identified in lung cancer. Of these, changes in expression of QKI, RBM4, RBM5, RBM6, RBM10 and SRSF1 proteins regulate many of the most frequently referenced aberrant splicing events in lung cancer. The expanding list of genes known to be aberrantly spliced in lung cancer along with the altered expression of splicing factors that regulate them are providing new clues as to how lung cancer develops, and how these events can be exploited for better treatment. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.

A Single-Center Retrospective Study of Patients with Double Primary Cancers: Breast Cancer and EGFR-Mutant Non-Small Cell Lung Cancer

BACKGROUND

Second primary malignancies (SPM) in the lung are not common in breast cancer (BC) patients. EGFR-mutant lung cancer (LC) is a separate molecular subset, and the co-existence of EGFR-mutant LC and BC has not been explored. We hypothesized that EGFR-mutant LC patients could have higher rates of primary BC than those with EGFR-wild type (WT).

METHODS

We collected data on clinical and molecular characteristics and outcomes of female patients with LC and a previous or simultaneous history of primary BC treated in our hospital from 2008 to 2014.

RESULTS

Data on treatment, follow-up, and EGFR mutation status were available for 356 patients. 17.7% (11/62) of patients with EGFR mutations had BC, compared to 1.02% (3/294) of EGFR-WT patients (p < 0.001). Both tumors were metachronous in 81.8%, with LC diagnosed 9 years after the diagnosis of BC. 5 of the 6 (83.3%) BC patients treated with radiotherapy developed LC in an area within the radiation field. No EGFR mutations were detected in BC tissue and no HER2 expression was detected in LC samples.

CONCLUSION

SPM in the lung and breast occur more frequently among EGFR-mutant compared to EGFR-WT LC patients. Radiotherapy for BC may increase the risk of developing primary LC.

Germline TP53 Mutation and Clinical Characteristics of Korean Patients With Li-Fraumeni Syndrome

Background

Little is known of the mutation and tumor spectrum of Korean patients with Li-Fraumeni syndrome (LFS). Owing to the rarity of LFS, few cases have been reported in Korea thus far. This study aimed to retrospectively review the mutations and clinical characteristics of Korean patients with LFS.

Methods

TP53 mutation was screened in 89 unrelated individuals at the Samsung Medical Center in Korea, from 2004 to 2015. Six additional mutation carriers were obtained from the literature.

Results

We identified nine different mutations in 14 Korean patients (male to female ratio=0.3:1). Two such frameshift mutations (p.Pro98Leufs^*25, p.Pro27Leufs^*17) were novel. The recurrent mutations were located at codons 31 (n=2; p.Val31Ile), 175 (n=3; p.Arg175His), and 273 (n=4; p.Arg273His and p.Arg273Cys). The median age at the first tumor onset was 25 yr. Ten patients (71%) developed multiple primary tumors. A diverse spectrum of tumors was observed, including breast (n=6), osteosarcoma (n=4), brain (n=4), leukemia (n=2), stomach (n=2), thyroid (n=2), lung (n=2), skin (n=2), bladder (n=1), nasal cavity cancer (n=1), and adrenocortical carcinoma (n=1).

Conclusions

There was considerable heterogeneity in the TP53 mutations and tumor spectrum in Korean patients with LFS. Our results suggest shared and different LFS characteristics between Caucasian and Korean patients. This is the first report on the mutation spectrum and clinical characteristics from the largest series of Korean LFS patients.