EGFR T790M detection in formalin-fixed paraffin-embedded tissues of patients with lung cancer using RNA-based in situ hybridization: A preliminary feasibility study

High-resolution and quantitative spatial analysis reveal intra-ductal phenotypic and functional diversification in pancreatic cancer

A 'classical' and a 'basal-like' subtype of pancreatic cancer have been reported, with differential expression of GATA6 and different dosages of mutant KRAS. We established in situ detection of KRAS point mutations and mRNA panels for the consensus subtypes aiming to project these findings to paraffin-embedded clinical tumour samples for spatial quantitative analysis. We unveiled that, next to inter-patient and intra-patient inter-ductal heterogeneity, intraductal spatial phenotypes exist with anti-correlating expression levels of GATA6 and KRASG12D . The basal-like mRNA panel better captured the basal-like cell states than widely used protein markers. The panels corroborated the co-existence of the classical and basal-like cell states in a single tumour duct with functional diversification, i.e. proliferation and epithelial-to-mesenchymal transition respectively. Mutant KRASG12D detection ascertained an epithelial origin of vimentin-positive cells in the tumour. Uneven spatial distribution of cancer-associated fibroblasts could recreate similar intra-organoid diversification. This extensive heterogeneity with functional cooperation of plastic tumour cells poses extra challenges to therapeutic approaches. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Comparison of afatinib and erlotinib combined with bevacizumab in untreated stage IIIB/IV epidermal growth factor receptor-mutated lung adenocarcinoma patients: a multicenter clinical analysis study

Background:

Although bevacizumab in combination with afatinib or erlotinib is an effective and safe first-line therapy for advanced epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC), there are very few clinical data comparing afatinib and erlotinib combined with bevacizumab. We performed a retrospective multicenter analysis for the comparison of two combination therapies.

Methods:

Between May 2015 and October 2020, data of 135 stage IIIB/IV EGFR-mutated NSCLC patients receiving first-line afatinib or erlotinib combined with bevacizumab combination therapy in Linkou, Keelung, Chiayi, and Kaohsiung Chang Gung Memorial Hospitals were retrieved and retrospectively analyzed.

Results:

In all, 67 patients received afatinib plus bevacizumab, and 68 patients received erlotinib plus bevacizumab. Afatinib combined with bevacizumab had an objective response rate (ORR) of 82.1% and a disease control rate (DCR) of 97.0%, and the ORR and DCR were 83.8 and 95.6%, respectively, in the erlotinib combined with bevacizumab group (p = 0.798 and p = 1.000). The median progression-free survival was 20.7 and 20.3 months for the afatinib plus bevacizumab group and the erlotinib plus bevacizumab group, respectively [hazard ratio (HR) = 1.02; 95% confidence interval (CI), 0.891–1.953; p = 0.167). The overall survival was 41.9 and 51.0 months for the afatinib plus bevacizumab group and erlotinib plus bevacizumab group, respectively (HR = 1.42; 95% CI, 0.829–2.436; p = 0.201). The secondary EGFR-T790M mutation rates after disease progression were 44% in the afatinib plus bevacizumab group and 58.8% in the erlotinib plus bevacizumab group (p = 0.165). Skin toxicity was the most frequent treatment-related adverse event (AE) in both treatment groups. Diarrhea, an AE, occurred significantly more frequently in the afatinib plus bevacizumab group than in the erlotinib plus bevacizumab group (p < 0.05).

Conclusion:

Afatinib combined with bevacizumab was equally as effective as erlotinib combined with bevacizumab for untreated advanced EGFR-mutated NSCLC. Prospective clinical studies that explore bevacizumab combined with afatinib or erlotinib for advanced EGFR-mutated NSCLC are warranted.

Comparison of Multi-Gene Testing Data Between Fresh and Formalin-Fixed Specimens From Core Needle Biopsy in Patients With NSCLC

Purpose: Currently, formalin-fixed paraffin-embedded (FFPE) tissue specimens are the conventional material for gene testing for non-small cell lung cancer (NSCLC) patients. In our study, we aimed to develop a quick gene testing procedure using fresh core needle biopsy samples from NSCLC patients.

Methods: In total, 77 fresh NSCLC samples obtained from core needle biopsy were evaluated by frozen section examination. If the NSCLC diagnosis and adequate tumor cell counts were confirmed by histopathology, the fresh tissues were used to extract DNA and subsequent gene testing by ARMS-PCR. Meanwhile, the paired FFPE core needle biopsy samples from 30 NSCLC patients also underwent gene testing.

Results: In total, 77 fresh samples showed an EGFR mutation rate of 61.0%, higher than the levels in the Asian. Following a comparison of gene testing results with fresh tissues and paired FFPE tissues from the 30 patients, no significant difference in the DNA concentration extracted from fresh tissues and FFPE tissues was found. However, DNA purity was significantly higher in fresh tissues than that in FFPE tissues. Gene testing detected the same gene mutations in 93.3% of cases in fresh tissues and paired FFPE tissues. The gene testing procedure using fresh biopsy samples greatly shortens the waiting time of patients.

Conclusion: The multi-gene mutation testing using fresh core needle biopsy samples from NSCLC patients is a reasonable, achievable, and quick approach. Fresh tissues may serve as a potential alternative to FFPE tissues for gene testing in NSCLC patients.

A Real-World Analysis of Patients with Untreated Metastatic Epidermal Growth Factor Receptor (EGFR)-Mutated Lung Adenocarcinoma Receiving First-Line Erlotinib and Bevacizumab Combination Therapy

INTRODUCTION

The clinical features of patients with metastatic epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma receiving first-line therapy based on erlotinib combined with bevacizumab are unclear. Here, we sought to analyze the clinical features of this patient group.

METHODS

Data were analyzed for the period from January 2015 to August 2019 for 49 patients with metastatic EGFR-mutated lung adenocarcinoma receiving first-line erlotinib-and-bevacizumab combination therapy from the Linkou and Kaohsiung Chang Gung Memorial Hospitals.

RESULTS

The combination of erlotinib and bevacizumab showed an 83.7% objective response rate and a 97.9% disease control rate. The median progression-free survival (PFS) and overall survival (OS) were 22.0 [95% CI (19.7-22.33)] and 47.6 [95% CI (38.87-56.37)] months, respectively, for all patients. The secondary EGFR-T790M mutation rate in the patients with acquired resistance to the combination was 72.4%. No predictive factor associated with the appearance of secondary EGFR-T790M mutations was found. The most frequent adverse event (AE) caused by the combination therapy was dermatitis (100%), and most of the AEs were manageable and grades 1 and 2.

CONCLUSION

Erlotinib combined with bevacizumab is an effective and safe therapy for untreated metastatic EGFR-mutated lung adenocarcinoma. The combination does not alter secondary EGFR-T790M mutations in patients with acquired resistance and is feasible in real-world clinical practice.

Biological significance of KRAS mutant allele expression in ovarian endometriosis

KRAS is the most frequently mutated in ovarian endometriosis. However, it is unclear whether the KRAS mutant allele's mRNA is expressed and plays a biological role in ovarian endometriosis. Here, we performed mutation-specific RNA in situ hybridization to evaluate mutant allele expression of KRAS p.G12V, the most frequently detected mutation in ovarian endometriosis in our previous study, in formalin-fixed paraffin-embedded tissue (FFPE) samples of ovarian endometriosis, cancer cell lines, and ovarian cancers. First, we verified that mutant or wild-type allele of KRAS were expressed in all 5 cancer cell lines and 9 ovarian cancer cases corresponding to the mutation status. Next, we applied this assay to 26 ovarian endometriosis cases, and observed mutant allele expression of KRAS p.G12V in 10 cases. Mutant or wild-type allele of KRAS were expressed in line with mutation status in 12 available endometriosis cases for which KRAS gene sequence was determined. Comparison of clinical features between ovarian endometriosis with KRAS p.G12V mutant allele expression and with KRAS wild-type showed that KRAS p.G12V mutant allele expression was significantly associated with inflammation in ovarian endometriosis. Finally, we assessed the spatial distribution of KRAS mutant allele expression in 5 endometriosis cases by performing multiregional sampling. Intratumor heterogeneity of KRAS mutant allele expression was observed in two endometriosis cases, whereas the spatial distribution of KRAS p.G12V mutation signals were diffuse and homogenous in ovarian cancer. In conclusion, evaluation of oncogene mutant expression will be useful for clarifying the biological significance of oncogene mutations in benign tumors.

The Status of the EGFR T790M Mutation is associated with the Clinical Benefits of Osimertinib Treatment in Non-small Cell Lung Cancer Patients: A Meta-Analysis

Background and Purpose: Pervious studies have demonstrated that the loss of EGFR T790M after Osimertinib treatment may be the cause of Osimertinib resistance. Here, we conducted a meta-analysis to evaluate the association between the persistence of EGFR T790M and the clinical benefits of Osimertinib in non-small cell lung cancer (NSCLC) patients with baseline EGFR T790M mutation.

Experimental design and Methods: PUBMED, EMBASE, and Cochrane databases were searched for eligible studies that provided the survival outcomes including overall survival (OS), progression-free survival (PFS) or time to discontinuation (TTD) data for each patient treated with Osimertinib with the status of the T790M mutation tested after Osimertinib resistance. The hazard ratios (HRs) and their 95% confidence intervals (CI) were calculated for each study.

Results: In total, eight eligible studies were included in the analysis, among which six studies provided the data on PFS, and the other two studies provided the TTD data. Overall, 312 patients (151 patients with the persistence of T790M) were identified. The persistence of T790M was associated with longer PFS (HR, 0.40; 95% CI, 0.19-0.84; P=0.01) and TTD (HR, 0.54; 95% CI, 0.39-0.76; P=0.0004). Furthermore, overall analysis the survival outcomes including PFS and TTD subgroups also showed preferable clinical benefits for patients with the T790M persistence (HR, 0.57; 95%CI, 0.45-0.73; P<0.00001).

Conclusions: Our findings confirm the persistence of T790M is associated with the clinical benefits of Osimertinib in NSCLC patients with baseline EGFR T790M mutation treated with Osimertinib.