Brief report: High incidence of peridiagnosis thromboembolic events in patients with BRAF-mutant lung cancer

INTRODUCTION

We aimed to determine if advanced BRAF-mutant NSCLC has a higher thromboembolic events (TEE) rate than the expected.

METHODS

Between 2008 and 2021, 182 patients with BRAF-mutant advanced NSCLC (BRAF V600E, n = 70; BRAF non-V600E, n = 112) were retrospectively identified from 18 centers in Spain. Patients received chemotherapy (n = 147), immunotherapy (n = 69), targeted therapy (n = 42), and immunotherapy + chemotherapy (n = 26).

RESULTS

Incidence rate of TEE was 26.4 % (95%CI: 19.9 %-32.9 %). A total of 72 TEE were documented among 48 patients, as 18 patients (37.5 %) developed more than one event. Median time to TEE onset was 2 months, 69 % of TEE occurred in the peridiagnostic period (+/- 90 days from cancer diagnosis), and in 16 pts. (33 %) TEE was the form of lung cancer presentation. Although most TEE were only venous (82 %; PE, n = 33; DVT, n = 16), arterial events were reported in 31 % and occurred earlier, or TEE presented in atypical locations (13.9 %). TEE were related to high hospitalization rate (59 %), recurrence (23 %), and mortality (10.4 %) despite appropriate anticoagulant/antiaggregant treatment. Median OS in patients without-TEE was 19.4 months (95%CI: 4.6-34.1), and significantly shorter in patients with arterial-TEE vs venous-TEE vs both of them: 9.9 months (95%CI: 0-23.5) vs 41.7 months (95%CI: 11.3-72.2 m) vs 2.7 months (95%CI: 2.1-3.3), p = 0.001. Neither clinical or molecular features (BRAF V600E/non-V600E), nor cancer treatment was associated to TEE occurrence. Khorana score underperformed to predict thrombosis at cancer diagnosis, as only 19.2 % of patients were classified as high-risk.

CONCLUSIONS

Thrombotic events represent a new clinical feature of BRAF-mutant lung cancer. Patients with almost a 30 % incidence of TEE should be offered systematic anticoagulation.

Genome-wide profiling of non-smoking-related lung cancer cells reveals common RB1 rearrangements associated with histopathologic transformation in EGFR-mutant tumors

BACKGROUND

The etiology and the molecular basis of lung adenocarcinomas (LuADs) in nonsmokers are currently unknown. Furthermore, the scarcity of available primary cultures continues to hamper our biological understanding of non-smoking-related lung adenocarcinomas (NSK-LuADs).

PATIENTS AND METHODS

We established patient-derived cancer cell (PDC) cultures from metastatic NSK-LuADs, including two pairs of matched EGFR-mutant PDCs before and after resistance to tyrosine kinase inhibitors (TKIs), and then performed whole-exome and RNA sequencing to delineate their genomic architecture. For validation, we analyzed independent cohorts of primary LuADs.

RESULTS

In addition to known non-smoker-associated alterations (e.g. RET, ALK, EGFR, and ERBB2), we discovered novel fusions and recurrently mutated genes, including ATF7IP, a regulator of gene expression, that was inactivated in 5% of primary LuAD cases. We also found germline mutations at dominant familiar-cancer genes, highlighting the importance of genetic predisposition in the origin of a subset of NSK-LuADs. Furthermore, there was an over-representation of inactivating alterations at RB1, mostly through complex intragenic rearrangements, in treatment-naive EGFR-mutant LuADs. Three EGFR-mutant and one EGFR-wild-type tumors acquired resistance to EGFR-TKIs and chemotherapy, respectively, and histology on re-biopsies revealed the development of small-cell lung cancer/squamous cell carcinoma (SCLC/LuSCC) transformation. These features were consistent with RB1 inactivation and acquired EGFR-T790M mutation or FGFR3-TACC3 fusion in EGFR-mutant tumors.

CONCLUSIONS

We found recurrent alterations in LuADs that deserve further exploration. Our work also demonstrates that a subset of NSK-LuADs arises within cancer-predisposition syndromes. The preferential occurrence of RB1 inactivation, via complex rearrangements, found in EGFR-mutant tumors appears to favor SCLC/LuSCC transformation under growth-inhibition pressures. Thus RB1 inactivation may predict the risk of LuAD transformation to a more aggressive type of lung cancer, and may need to be considered as a part of the clinical management of NSK-LuADs patients.

Abstract LB-155: Identification of a DNA methylation signature in liquid biopsy for early non-small cell lung cancer (NSCLC) diagnosis

Introduction: Lung cancer is the leading cause worldwide, mainly due to late diagnosis. The aim of this work was to identify a panel of epigenetic biomarkers for improving early diagnosis of lung cancer patients using minimally and non-invasive biological fluids.

Patients and Methods: DNA hypermethylated biomarkers were identified performing a Genome-wide DNA methylation analysis (Infinium 450K array) in Non-small cell lung cancer (NSCLC) primary tumors from two different public databases (Discovery cohorts): CURELUNG FP7 Consortium (237 stage I NSCLC, 25 non-tumoral lung samples) and The Cancer Genome Atlas (TCGA; 350 stage I NSCLC, 62 non-tumoral lung samples). DNA methylation levels of selected candidates were analyzed by pyrosequencing in non- or minimally invasive samples from three independent cohorts of stage I NSCLC patients and non-tumoral controls (Validation cohorts): bronchoalveolar aspirates (82 NSCLC; 29 controls), bronchoalveolar lavages (51 NSCLC; 29 controls) and sputum (72 NSCLC; 26 controls). Combined Receiver Operating Characteristic (ROC) curve was obtained to evaluate the diagnostic utility of the epigenetic signature.

Results: We identified a panel of 4 cancer-specific genes (BCAT1, CDO1, TRIM58 and ZNF177) with CpG island hypermethylation-associated silencing in early stage NSCLC primary tumors. All these genes presented significantly higher mean levels of%methylation (M) in NSCLC primary tumors respect to non-tumoral controls: BCAT1 (NSCLC: M>50%; Controls: M<20%), CDO1 (NSCLC: M>40%; Controls: M<10%), TRIM58 (NSCLC: M>50%; Controls: M<20%) and ZNF177 (NSCLC: M>40%; Controls : M<20%). Importantly, the diagnostic utility of the combination of this 4-gene panel signature was validated in liquid biopsy, showing a very high diagnostic accuracy with areas under the ROC curve (AUC) close to the maximum value: bronchoalveolar aspirates (AUC = 0.91; 95% CI [0.83, 0.98]; p < 0.001), bronchoalveolar lavages (AUC = 0.85; 95% CI [0.78, 0.93]; p < 0.001) and sputum (AUC = 0.93; 95% CI [0.86, 1.0]; p < 0.001).

Conclusions: The herein identified DNA methylation signature could improve, in combination with current diagnostic protocols, the early diagnosis and outcome of NSCLC patients. The high diagnostic accuracy of this signature obtained in liquid biopsy offers a minimally invasive and easy accessible tool for early lung cancer diagnosis.

Citation Format: A Diaz-Lagares, J Mendez-Gonzalez, D Hervas, M Saigi, MJ Pajares, D Garcia, AB Crujeiras, R Lopez-Lopez, R Pio, LM Montuenga, JJ Zulueta, E Nadal, A Rosell, M Esteller, J Sandoval. Identification of a DNA methylation signature in liquid biopsy for early non-small cell lung cancer (NSCLC) diagnosis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-155.