The importance of EGFR mutation testing in squamous cell carcinoma or non-small cell carcinoma favor squamous cell carcinoma diagnosed from small lung biopsies

[Advances of Molecular Targeted Therapy in EGFR-mutated Squamous Cell Lung Cancer]

Non-small cell lung cancer (NSCLC) is a prevalent tumour type in our country, with lung squamous carcinoma being a commonly observed NSCLC subtype besides lung adenocarcinoma. Epidermal growth factor receptor (EGFR) is a significant driver gene in lung cancer, and EGFR mutation frequency is considerably lower in lung squamous carcinoma in comparison to lung adenocarcinoma. Although targeted therapy against EGFR has demonstrated significant advancements in lung adenocarcinoma, while progress in lung squamous carcinoma has been relatively sluggish. This paper reviews recent studies on molecular targeted therapy for EGFR-mutated lung squamous carcinoma and summarises the efficacy of EGFR-tyrosine kinase inhibitors (TKIs) in treating squamous carcinoma of the lung, in order to provide a reference for treating patients with EGFR-mutated squamous carcinoma of the lung.
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Pulmonary squamous cell carcinoma and lymphoepithelial carcinoma - morphology, molecular characteristics and differential diagnosis

Squamous cell carcinoma (SCC) comprises one of the major groups of non-small-cell carcinoma of the lung, and is subtyped into keratinising, non-keratinising and basaloid SCC. SCC can readily be diagnosed using histomorphology alone in keratinising SCC. Confirmatory immunohistochemical analyses should always be applied in non-keratinising and basaloid tumours to exclude differential diagnoses, most prominently adenocarcinoma and high-grade neuroendocrine carcinoma, which may have important therapeutic consequences. According to the World Health Organisation (WHO) classification 2015, the diagnosis of SCC can be rendered in resections of morphologically ambiguous tumours with squamous immunophenotype. In biopsies and cytology preparations in the same setting the current guidelines propose a diagnosis of 'non-small-cell carcinoma, favour SCC' in TTF1-negative and p40-positive tumours to acknowledge a possible sampling bias and restrict extended immunohistochemical evaluation in order to preserve tissue for molecular testing. Most SCC feature a molecular 'tobacco-smoke signature' with enrichment in GG > TT mutations, in line with the strong epidemiological association of SCC with smoking. Targetable mutations are extremely rare but they do occur, in particular in younger and non- or light-smoking patients, warranting molecular investigations. Lymphoepithelial carcinoma (LEC) is a poorly differentiated SCC with a syncytial growth pattern and a usually prominent lymphoplasmacytic infiltrate and frequent Epstein-Barr virus (EBV) association. In this review, we describe the morphological and molecular characteristics of SCC and LEC and discuss the most pertinent differential diagnoses.

Clonal dynamics and Stereo-seq resolve origin and phenotypic plasticity of adenosquamous carcinoma

The genomic origin and development of the biphasic lung adenosquamous carcinoma (ASC) remain inconclusive. Here, we derived potential evolutionary trajectory of ASC through whole-exome sequencing, Stereo-seq, and patient-derived xenografts. We showed that EGFR and MET activating mutations were the main drivers in ASCs. Phylogenetically, these drivers and passenger mutations found in both components were trunk clonal events, confirming monoclonal origination. Comparison of multiple lesions also revealed closer genomic distance between lymph node metastases and the ASC component with the same phenotype. However, as mutational signatures of EGFR-positive lung squamous carcinomas (LUSCs) were more comparable to EGFR-positive ASCs than to wild-type LUSCs, we postulated different origination of these LUSCs, with ASC being the potential intermediate state of driver-positive LUSCs. Spatial transcriptomic profiling inferred transformation from adenocarcinoma to squamous cell carcinoma, which was then histologically captured in vivo. Together, our results explained the development of ASC and provided insights into future clinical decisions.

Ramucirumab plus erlotinib versus placebo plus erlotinib in previously untreated EGFR-mutated metastatic non-small-cell lung cancer (RELAY): exploratory analysis of next-generation sequencing results

BACKGROUND

Ramucirumab plus erlotinib (RAM + ERL) demonstrated superior progression-free survival (PFS) over placebo + ERL (PBO + ERL) in the phase III RELAY study of patients with epidermal growth factor receptor (EGFR)-mutated metastatic non-small-cell lung cancer (EGFR+ mNSCLC; NCT02411448). Next-generation sequencing (NGS) was used to identify clinically relevant alterations in circulating tumor DNA (ctDNA) and explore their impact on treatment outcomes.

PATIENTS AND METHODS

Eligible patients with EGFR+ mNSCLC were randomized 1 : 1 to ERL (150 mg/day) plus RAM (10 mg/kg)/PBO every 2 weeks. Liquid biopsies were to be prospectively collected at baseline, cycle 4 (C4), and postdiscontinuation follow-up. EGFR and co-occurring/treatment-emergent (TE) genomic alterations in ctDNA were analyzed using Guardant360 NGS platform.

RESULTS

In those with valid baseline samples, detectable activating EGFR alterations in ctDNA (aEGFR+) were associated with shorter PFS [aEGFR+: 12.7 months (n = 255) versus aEGFR-: 22.0 months (n = 131); hazard ratio (HR) = 1.87, 95% confidence interval (CI) 1.42-2.51]. Irrespective of detectable/undetectable baseline aEGFR, RAM + ERL was associated with longer PFS versus PBO + ERL [aEGFR+: median PFS (mPFS) = 15.2 versus 11.1 months, HR = 0.63, 95% CI 0.46-0.85; aEGFR-: mPFS = 22.1 versus 19.2 months, HR = 0.80, 95% CI 0.49-1.30]. Baseline alterations co-occurring with aEGFR were identified in 69 genes, most commonly TP53 (43%), EGFR (other than aEGFR; 25%), and PIK3CA (10%). PFS was longer in RAM + ERL, irrespective of baseline co-occurring alterations. Clearance of baseline aEGFR by C4 was associated with longer PFS (mPFS = 14.1 versus 7.0 months, HR = 0.481, 95% CI 0.33-0.71). RAM + ERL improved PFS outcomes, irrespective of aEGFR mutation clearance. TE gene alterations were most commonly in EGFR [T790M (29%), other (19%)] and TP53 (16%).

CONCLUSIONS

Baseline aEGFR alterations in ctDNA were associated with shorter mPFS. RAM + ERL was associated with improved PFS outcomes, irrespective of detectable/undetectable aEGFR, co-occurring baseline alterations, or aEGFR+ clearance by C4. aEGFR+ clearance by C4 was associated with improved PFS outcomes. Monitoring co-occurring alterations and aEGFR+ clearance may provide insights into mechanisms of EGFR tyrosine kinase inhibitor resistance and the patients who may benefit from intensified treatment schedules.

Pathologist-initiated reflex testing for biomarkers in non-small-cell lung cancer: expert consensus on the rationale and considerations for implementation

Biomarker tests in lung cancer have been traditionally ordered by the treating oncologist upon confirmation of an appropriate pathological diagnosis. The delay this introduces prolongs yet further what is already a complex, multi-stage, pre-treatment pathway and delays the start of first-line systemic treatment, which is crucially informed by the results of such analysis. Reflex testing, in which the responsibility for testing for an agreed range of biomarkers lies with the pathologist, has been shown to standardise and expedite the process. Twelve experts discussed the rationale and considerations for implementing reflex testing as standard clinical practice.

Next-generation sequencing clarified why first-line treatment with osimertinib was ineffective in an autopsied case of EGFR-mutated lung squamous cell carcinoma

Epidermal growth factor receptor (EGFR)-mutated squamous cell carcinoma (SCC) is less common than adenocarcinoma. The third-generation EGFR-tyrosine kinase inhibitor, osimertinib, is effective in EGFR-mutated lung adenocarcinoma, but its efficacy in EGFR-mutated lung SCC is unclear. The patient was an 83-year-old male. He was diagnosed with SCC of the lung, and molecular analysis revealed that the tumor was positive for EGFR exon19 deletion. He was treated with osimertinib 80 mg/day. No adverse events were observed, but after 18 days of therapy, he complained of dyspnea, and a computed tomography scan showed enlarged lung cancer. The case was categorized as a progressive disease. The patient died 3 weeks later. The autopsy findings confirmed the diagnosis of lung SCC, with morphology and immunohistochemical staining identical to the tumor obtained by bronchoscopy. Next-generation sequencing showed the presence of TP53 R158L, CDK6, and KRAS amplifications. The current case report shows that next-generation sequencing can explain why osimertinib is ineffective in EGFR-mutated SCC.

Landscape of Genomic Alterations and PD-L1 Expression in Early-Stage Non-Small-Cell Lung Cancer (NSCLC)-A Single Center, Retrospective Observational Study

Precision oncology and immunotherapy have revolutionized the treatment of advanced non-small-cell lung cancer (NSCLC). Emerging studies show that targeted therapies are also beneficial for patients with driver alterations such as epidermal growth factor receptor (EGFR) mutations in early-stage NSCLC (stages I-IIIA). Furthermore, patients with elevated programmed death-ligand 1 (PD-L1) expression appear to respond favorably to adjuvant immunotherapy. To determine the frequency of genomic alterations and PD-L1 status in early-stage NSCLC, we retrospectively analyzed data from 2066 unselected, single-center patients with NSCLC diagnosed using next-generation sequencing and immunohistochemistry. Nine-hundred and sixty-two patients (46.9%) presented with early-stage NSCLC. Of these, 37.0% had genomic alterations for which targeted therapies have already been approved for advanced NSCLC. The frequencies of driver mutations in the early stages were equivalent to those in advanced stages, i.e., the rates of EGFR mutations in adenocarcinomas were 12.7% (72/567) and 12.0% (78/650) in early and advanced NSCLC, respectively (p = 0778). In addition, 46.3% of early-stage NSCLC cases were PD-L1-positive, with a tumor proportion score (TPS) of ≥1%. With comparable frequencies of driver mutations in early and advanced NSCLC and PD-L1 overexpression in nearly half of patients with early-stage NSCLC, a broad spectrum of biomarkers for adjuvant and neoadjuvant therapies is available, and several are currently being investigated in clinical trials.

Efficacy of Osimertinib in Lung Squamous Cell Carcinoma Patients with EGFR Gene Mutation–Case Report and A Literature Review

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and the leading cause of cancer-related mortality worldwide. It is responsible for 80–85% of lung cancer cases. NSCLC can be divided into several groups, led by adenocarcinoma (ADC)–40–50% and squamous cell carcinoma (SCC)–20–30%. The development of new molecular therapies targeting particular abnormalities such as mutations in the EGFR (Epidermal Growth Factor Receptor) gene or ROS1 or ALK genes rearrangements resolved in novel strategies in advanced NSCLC management. EGFR mutation occurs mostly in patients with ADC and those patients are mostly females with no or light smoking history. The hereby presented patient fitted the ADC characteristics, while they were diagnosed with SCC. The unusual diagnosis implied further genetic testing, which established the occurrence of L858R substitution in exon 21 in the EGFR gene. A 63-year-old female was admitted to the unit due to a dry cough, pain in the right chest area and dyspnoea. When diagnosed, the patient had a peripheral mass in the right lung superior lobe (55 × 40 mm), satellite nodules in the apex of the same lung and packets of disintegrating lymph nodes. Positron Emission Tomography (PET-CT) confirmed a diffuse neoplastic process qualified as stage IV on the TNM scale. Due to EGFR gene mutation, the woman was administered osimertinib, however, the treatment did not succeed, and other therapeutic solutions were undertaken. The patient died 10 months after diagnosis. Patients with advanced ADC harboring EGFR mutation can receive osimertinib, a third-generation tyrosine kinase inhibitor (TKI), however, the use of TKIs in SCC remains controversial. In some published cases, osimertinib treatment led to success, in others, the therapy did not result in the expected final effect. Small sample groups and diverse molecular backgrounds indicate the need for further research in this field. Thus, the treatment decision-making process in those patients overall remains extremely demanding and ambiguous.

Real-world characteristics and outcomes of advanced non-small-cell lung cancer patients with EGFR exon 19 deletions or exon 21 mutations

Aim: To estimate real-world (rw) outcomes for first-line therapy in patients with advanced EGF receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC), focusing on specific mutation types. Patients & methods: Retrospective observational study (n = 244 patients). Results: Univariate/multivariate analyses showed longer rw progression-free survival (rwPFS) and rwPFS2 in patients with ex19del versus Leu858Arg mutations. Median overall survival was 12.3 months longer with ex19del versus Leu858Arg mutations (HR: 1.47 [95% CI: 0.96-2.25]; p = 0.074). With EGFR-tyrosine kinase inhibitor monotherapy, unadjusted rwPFS for ex19del mutations was longer than for Leu858Arg mutations (HR: 1.62 [95% CI: 1.03-2.56]; p = 0.036). Conclusion: In this rw cohort of patients with advanced EGFR+ NSCLC, ex19del mutations conferred a prognostic advantage over Leu858Arg mutations, with significantly better rwPFS and rwPFS2.

Analysis of EGFR Mutation Status in Algerian Patients with Non-Small Cell Lung Cancer

Background and objective:

Epidermal growth factor receptor (EGFR) mutation status is used as a predictive biomarker for the tyrosine kinase inhibitors therapy in non-small cell lung cancer (NSCLC). The incidence of EGFR mutations appears to vary according to ethnic and geographical backgrounds. This retrospective study aimed to investigate the EGFR mutation status in Algerian NSCLC patients and its association with clinicopathological features.

Methods:

We examined the presence of EGFR mutations (Exons 19-21) in 58 unselected NSCLC samples using PCR followed by direct sequencing.

Results:

The present study included 53 (91.4%) men and 5 (8.6%) women, with a median age of 59 (ranging from 44 to 94 years old). EGFR mutations were detected in 23 patients, with an overall rate of 39.6%. There were 21 (91.3%) cases with the exon-21 L585R single mutation and two (8.7%) with dual mutations of exon-19 deletions and L585R. EGFR mutations were more frequently found in patients with confirmed adenocarcinoma (14/27, 51.8%) than in non-adenomatous NCSCL subtypes (3/14, 21.4%; p=0.03). Furthermore, early stages of the disease were significantly associated with a higher rate of EGFR mutations (14/27, 51.8%) compared with those at advanced stage (5/21, 23.8%; p=0.02). There were no significant differences in EGFR mutation frequency by age, gender, or smoking status.

Conclusion:

We found that Algerian NSCLC patients exhibited a high rate of EGFR mutations, which was quite similar to that in Asians population rather than Caucasian patients. Thus, TKI-based treatments may be more beneficial for Algerian patients with NSCLC. Further studies using a large number of patients are required to confirm our preliminary findings.

Risk stratification of EGFR+ lung cancer diagnosed with panel-based next-generation sequencing

OBJECTIVE

Panel-based next-generation sequencing (NGS) is increasingly used for the diagnosis of EGFR-mutated non-small-cell lung cancer (NSCLC) and could improve risk assessment in combination with clinical parameters.

MATERIALS AND METHODS

To this end, we retrospectively analyzed the outcome of 400 tyrosine kinase inhibitor (TKI)-treated EGFR⁺ NSCLC patients with validation of results in an independent cohort (n = 130).

RESULTS

EGFR alterations other than exon 19 deletions (non-del19), TP53 co-mutations, and brain metastases at baseline showed independent associations of similar strengths with progression-free (PFS hazard ratios [HR] 2.1-2.3) and overall survival (OS HR 1.7-2.2), in combination defining patient subgroups with distinct outcome (EGFR⁺NSCLC risk Score, "ENS", p < 0.001). Co-mutations beyond TP53 were rarely detected by our multigene panel (<5%) and not associated with clinical endpoints. Smoking did not affect outcome independently, but was associated with non-del19 EGFR mutations (p < 0.05) and comorbidities (p < 0.001). Laboratory parameters, like the blood lymphocyte-to-neutrophil ratio and serum LDH, correlated with the metastatic pattern (p < 0.01), but had no independent prognostic value. Reduced ECOG performance status (PS) was associated with comorbidities (p < 0.05) and shorter OS (p < 0.05), but preserved TKI efficacy. Non-adenocarcinoma histology was also associated with shorter OS (p < 0.05), but rare (2-3 %). The ECOG PS and non-adenocarcinoma histology could not be validated in our independent cohort, and did not increase the range of prognostication alongside the ENS.

CONCLUSIONS

EGFR variant, TP53 status and brain metastases predict TKI efficacy and survival in EGFR⁺ NSCLC irrespective of other currently available parameters ("ENS"). Together, they constitute a practical and reproducible approach for risk stratification of newly diagnosed metastatic EGFR⁺ NSCLC.

Osimertinib for compound EGFR exon 19 deletion/T790M mutated lung squamous cell carcinoma

The role of the epidermal growth factor receptor (EGFR) mutation status testing in lung squamous cell carcinoma (SqCC) remains controversial. Evidence of the effectiveness of osimertinib in SqCC with EGFR T790M mutation is limited. Here, we describe a hitherto unreported case of a stage III SqCC patient with compound mutation of EGFR exon 19 deletion (19Del) and T790M mutation. Pathological complete tumor response was achieved after treatment with osimertinib. We suggest that EGFR mutation testing should be performed in Asian patients who have not been definitively diagnosed with SqCC due to small lung biopsy samples. Osimertinib has shown good efficacy in SqCC harboring a “primary” resistance mechanism (EGFR T790M).

Key points

An unreported case of stage III squamous cell carcinoma with synchronous occurrence of EGFR exon 19 deletion (19Del) and T790M mutation. Complete tumor response was achieved after treatment with osimertinib.

EGFR mutation testing should be performed in Asian patients who are not definitively diagnosed with SqCC due to small lung biopsy samples. Osimertinib has shown good efficacy in SqCC harboring a “primary” resistance mechanism (EGFR T790M).