Clinical management of epidermal growth factor receptor mutation-positive non-small cell lung cancer patients after progression on previous epidermal growth factor receptor tyrosine kinase inhibitors: the necessity of repeated molecular analysis

The utility of transbronchial rebiopsy for peripheral pulmonary lesions in patients with advanced non-squamous non-small cell lung cancer

Background

Patients treated for non-squamous (non-Sq) non-small cell lung cancer (NSCLC) often require repeat biopsies to determine the optimal subsequent treatment. However, the differences between rebiopsy and initial biopsy in terms of their diagnostic yields and their ability to test the molecular profiles using bronchoscopy with radial endobronchial ultrasound guidance in patients with advanced NSCLC remain unclear. Hence, we aimed to compare the diagnostic yields and ability for molecular analyses of rebiopsies with those of initial biopsies.

Methods

We investigated 301 patients with advanced non-Sq NSCLC who underwent radial endobronchial ultrasound-guided transbronchial biopsy (TBB) for peripheral pulmonary lesions (PPLs) between August 2014 and July 2017. Patients were divided into the rebiopsy and initial biopsy groups: the latter referred to the biopsy that determined the definitive diagnosis. The diagnostic yields and ability for molecular analyses were compared between the two groups, and the factors affecting the TBB diagnostic yield were identified using univariate and multivariate analyses.

Results

The diagnostic yields of the rebiopsy and initial biopsy groups were comparable (86.8 and 90.8%, respectively; p = 0.287). Furthermore, 93.0 and 94.0% of the patients in the rebiopsy and initial biopsy groups, respectively, had adequate specimens for gene profiling and mutational analysis (p = 0.765). The factors that increased the diagnostic yield were a positive bronchus sign (p < 0.001) and tumour location within the internal two-thirds of the lungs (p = 0.026).

Conclusions

The PPL diagnostic yield of the rebiopsy group was as high as that of the initial biopsy group. Hence, TBB for PPLs is feasible for patients requiring rebiopsy as well as for those with initial diagnoses. Adequate, high-quality biopsy specimens can be obtained by transbronchial rebiopsy for molecular testing.

Clinical implication and usefulness of de novo EGFR T790M mutation in lung adenocarcinoma with EGFR-tyrosine kinase inhibitor sensitizing mutation

In total, 102 cases diagnosed as lung adenocarcinoma with EGFR-tyrosine kinase inhibitor (TKI) sensitizing mutations (mEGFR) and had been treated with 1^st ~ 2^nd generation EGFR-TKI alone were enrolled for this study. De novo T790 M status was tested using the tissues at the initial diagnosis and positivity was defined as the ratio of T790 M/wild-type copies over 0.00294 by ddPCR.

Seventy patients (68.6%) harbored the de novo T790 M. De novo T790 M was more frequently detected in cases with EGFR L858 R mutation than those with EGFR exon 19 deletion (E19d) mutations (P = 0.024). Forty-three patients underwent rebiopsy due to disease progression. The cases who experienced progression due to acquired T790 M were more likely to have E19d at initial diagnosis and the presence of de novo T790 M and the ratio of T790 M/wild-type copies did not relate to the emergence of acquired T790 M. On the other hand, the cases with a longer duration of disease-control by EGFR-TKI had higher change to get acquired T790 M mutation (P-value = 0.040).

The presence of de novo T790 M has limitation in predicting disease progression by acquired T790 M, suggesting that identifying de novo T790 M through the ultrasensitive methods may not be necessary identifying patients who would be beneficial by 3rd-generation EGFR-TKI as the 1st line treatment.

Compared to plasma, bronchial washing fluid shows higher diagnostic yields for detecting EGFR-TKI sensitizing mutations by ddPCR in lung cancer

BACKGROUND

The rate of diagnosis of advanced lung adenocarcinoma must be improved. In this study, we compared the detection rates of EGFR-tyrosine kinase inhibitor-sensitizing mutations (mEGFRs) in bronchial washing fluid (BWF) and the plasma of patients with lung adenocarcinoma using the tissue genotype as the standard reference.

METHODS

Paired blood and BWF specimens were collected from 73 patients with lung cancer. The tumor EGFR mutation status was determined by genotyping of the plasma and BWF samples using droplet digital PCR (ddPCR).

RESULTS

The study cohort included 26, 10, 10, and 27 patients with stage I, II, III, and IV disease. Of the 73 cases, 35 had a wild-type EGFR, and 19 had the L858R substitution and exon 19 deletion mutations. The areas under the receiver operator characteristic curves for sensitivity vs. specificity of ddPCR were 0.895 [95% confidence interval (CI): 0.822-0.969] for BWF and 0.686 (95% CI: 0.592-0.780) for plasma (p < 0.001). The fractional abundance was higher in BWF of the mEGFR-positive cases than in the plasma (p = 0.004), facilitating easy threshold setting and discrimination between mEGFR-positive and negative cases. When genotyping results obtained using plasma and BWF were compared for early lung cancer (stages I-IIIA), the diagnostic yields were significantly higher for BWF ddPCR, and the same tendency was observed for the advanced stages, suggesting that the BWF data may reflect the genotype status in early-stage patients.

CONCLUSIONS

The mEGFR genotyping results obtained using BWF showed a higher diagnostic efficacy than did those obtained using the plasma. Thus, BWF-based genotyping may be a useful substitute for that using plasma in lung cancer.

Exosome-based detection of activating and resistance EGFR mutations from plasma of non-small cell lung cancer patients

Non-small cell lung cancer (NSCLC) is the most prevalent form of lung cancer and its molecular landscape has been extensively studied. The most common genetic alterations in NSCLC are mutations within the epidermal growth factor receptor (EGFR) gene, with frequencies between 10-40%. There are several molecular targeted therapies for patients harboring these mutations.

Liquid biopsies constitute a flexible approach to monitor these mutations in real time as opposed to tissue biopsies that represent a single snap-shot in time. However, interrogating cell free DNA (cfDNA) has inherent biological limitations, especially at early or localized disease stages, where there is not enough tumor material released into the patient’s circulation.

We developed a qPCR- based test (ExoDx EGFR) that interrogates mutations within EGFR using Exosomal RNA/DNA and cfDNA (ExoNA) derived from plasma in a cohort of 110 NSCLC patients.

The performance of the assay yielded an overall sensitivity of 90% for L858R, 83% for T790M and 73% for exon 19 indels with specificities of 100%, 100%, and 96% respectively. In a subcohort of patients with extrathoracic disease (M1b and MX) the sensitivities were 92% (L858R), 95% (T790M), and 86% (exon 19 indels) with specificity of 100%, 100% and 94% respectively.

PCC0208027, a novel tyrosine kinase inhibitor, inhibits tumor growth of NSCLC by targeting EGFR and HER2 aberrations

PCC-0208027 is a novel tyrosine kinase inhibitor that has a strong inhibitory effect on epidermal growth factor receptor (EGFR)- or HER2-driven cancers. The aim is to assess the anti-tumor activity of PCC0208027 and related mechanisms in non-small cell lung cancer (NSCLC). We examined the activity of PCC0208027 on various mutated EGFRs, HER2, and HER4. MTT assays, flow cytometry, and Western blotting were used to examine the effects of PCC0208027 on NSCLC cells with different genetic characteristics and relevant molecular mechanisms. Nude mouse xenograft models with HCC827, NCI-H1975, and Calu-3 cells were used to evaluate the in vivo anti-tumor activity of PCC0208027. Results showed that PCC0208027 effectively inhibited the enzyme activity of EGFR family members, including drug-sensitive EGFR mutations, acquired drug-resistant EGFR T790M and EGFR C797S mutations, and wild-type (WT) HER2. PCC0208027 blocked EGFR phosphorylation, thereby downregulating downstream PI3K/AKT and MAPK/ERK signaling pathways and inducing G0/G1 arrest in NSCLC cells. PCC0208027 inhibited tumor growth in mouse xenograft models of HCC827, NCI-H1975, and Calu-3 cells. In summary, our findings suggest that PCC0208027 has the potential to become an oral antineoplastic drug for NSCLC treatment and is worthy of further development.

Re-biopsy and liquid biopsy for patients with non-small cell lung cancer after EGFR-tyrosine kinase inhibitor failure

Background

Re‐biopsy is important for exploring resistance mechanisms, especially for non‐small cell lung cancer (NSCLC) patients who develop resistance to EGFR‐tyrosine kinase inhibitors (TKIs). Liquid biopsy using circulating tumor DNA has come into use for this purpose. This retrospective study investigated the status of re‐biopsy and liquid biopsy in NSCLC patients with EGFR mutations and evaluated their effect on clinical strategies and prognosis.

Methods

Five hundred fifty‐five NSCLC patients with resistance to EGFR‐TKIs were included and divided into three groups: re‐biopsy, liquid biopsy, and no re‐biopsy. Amplification refractory mutation system (ARMS) PCR or super ARMS PCR was used to detect EGFR mutations.

Results

Three hundred eight (55.5%) patients underwent re‐biopsy; 45.5% (140/308) were positive for T790M. The most common re‐biopsy procedure was computed tomography‐guided percutaneous core needle biopsy (60.1%), followed by effusion drainage (29.5%) and superficial lymph node biopsy (6.5%). One hundred eighteen (21.3%) patients underwent liquid biopsy; the T790M detection rate was 41.5% (49/118.) Of the 308 patients who underwent re‐biopsy, 69 were examined for EGFR mutations with plasma. The concordance rate of T790M detection between tissue and plasma was 66.7%. A statistical difference in further treatment after EGFR‐TKI failure was observed among all groups (P = 0.014). Patients in the biopsy groups were more likely to receive third‐generation EGFR‐TKIs. Multivariate analysis showed that re‐biopsy had a significant impact on overall survival (P < 0.001).

Conclusion

Re‐biopsy plays a pivotal role in the management of patients with NSCLC and resistance to EGFR‐TKIs. Liquid biopsy may be an alternative if difficulties performing re‐biopsy exist.

Axl is a novel target of celastrol that inhibits cell proliferation and migration, and increases the cytotoxicity of gefitinib in EGFR mutant non‑small cell lung cancer cells

Gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR‑TKI) is an excellent therapeutic agent to treat EGFR mutation‑positive non‑small cell lung cancer (NSCLC). However, the initial response decreases as chemoresistance develops. In the present study, gefitinib‑resistant EGFR mutant NSCLC PC‑9/GR cells were established to examine the characteristics and mechanisms associated with chemoresistance. Axl expression in PC‑9/GR cells was transcriptionally upregulated, since Axl protein and mRNA expression levels were identified to be increased according to western blot analysis and reverse transcription polymerase chain reaction results. The inhibitory effect of celastrol on Axl protein expression level, cell viability and clonogenicity were identified in parental and gefitinib‑resistant PC‑9 cells. In addition, treatment of PC‑9/GR cells with celastrol and gefitinib in combination was demonstrated to synergistically suppress Axl protein expression level, cell proliferation and migration. Taken together, upregulation of Axl expression seems to be associated with chemoresistance of PC‑9/GR cells. Furthermore, celastrol targets Axl to exert its anticancer effects in order to increase the susceptibility of PC‑9/GR cells to gefitinib and overcome chemoresistance.

Long Noncoding RNA LINC00460 Promotes the Gefitinib Resistance of Nonsmall Cell Lung Cancer Through Epidermal Growth Factor Receptor by Sponging miR-769-5p

The vital roles of long noncoding RNAs (lncRNAs) in the nonsmall cell lung cancer (NSCLC) tumorigenesis are increasingly important. This work aims to investigate the role of lncRNA LINC00460 in the gefitinib resistance of NSCLC cells and discover its relevant mechanism. Our finding reveals that the expression of lncRNA LINC00460 is upregulated in the gefitinib-resistant NSCLC tissue and cells, and closely correlated with advanced tumor stage and clinical poor prognosis outcome. Gain and loss functional assays are performed in gefitinib-resistant NSCLC cells (A549/GR), stating that LINC00460 facilitates the 50% inhibitive concentration of gefitinib for NSCLC cells, multidrug-resistant-related proteins (P-gp, MRP1, and BCRP), as well as the invasion. In vivo, LINC00460 silencing represses the tumor growth. Bioinformatics prediction tools and luciferase analysis confirm that the upregulated LINC00460 sponged miR-769-5p in NSCLC cells; moreover, epidermal growth factor receptor (EGFR) is identified as a direct target gene of miR-769-5p. Verification experiments confirm that the restoration of EGFR could weaken the sensibility of NSCLC cells toward the gefitinib. In conclusion, our result demonstrates that LINC00460 plays a pivotal role in gefitinib resistance of NSCLC cells by targeting EGFR through sponging miR-769-5p. This finding might serve as a therapeutic target for NSCLC.