Mutational analysis of pulmonary tumours with neuroendocrine features using targeted massive parallel sequencing: a comparison of a neglected tumour group

Abstract

Background:Lung cancer is the leading cause of cancer-related deaths worldwide. The typical and atypical carcinoid (TC and AC), the large-cell neuroendocrine carcinoma (LCNEC) and the small-cell lung cancers (SCLC) are subgroups of pulmonary tumours that show neuroendocrine differentiations. With the rising impact of molecular pathology in routine diagnostics the interest for reliable biomarkers, which can help to differentiate these subgroups and may enable a more personalised treatment of patients, grows.Methods:A collective of 70 formalin-fixed, paraffin-embedded (FFPE) pulmonary neuroendocrine tumours (17 TCs, 17 ACs, 19 LCNECs and 17 SCLCs) was used to identify biomarkers by high-throughput sequencing. Using the Illumina TruSeq Amplicon-Cancer Panel on the MiSeq instrument, the samples were screened for alterations in 221 mutation hot spots of 48 tumour-relevant genes.Results:After filtering >26 000 detected variants by applying strict algorithms, a total of 130 mutations were found in 29 genes and 49 patients. Mutations in JAK3, NRAS, RB1 and VHL1 were exclusively found in SCLCs, whereas the FGFR2 mutation was detected in LCNEC only. KIT, PTEN, HNF1A and SMO were altered in ACs. The SMAD4 mutation corresponded to the TC subtype. We prove that the frequency of mutations increased with the malignancy of tumour type. Interestingly, four out of five ATM-mutated patients showed an additional alteration in TP53, which was by far the most frequently altered gene (28 out of 130; 22%). We found correlations between tumour type and IASLC grade for ATM- (P=0.022; P=0.008) and TP53-mutated patients (P<0.001). Both mutated genes were also associated with lymph node invasion and distant metastasis (P⩽0.005). Furthermore, PIK3CA-mutated patients with high-grade tumours showed a reduced overall survival (P=0.040) and the mutation frequency of APC and ATM in high-grade neuroendocrine lung cancer patients was associated with progression-free survival (PFS) (P=0.020).Conclusions:The implementation of high-throughput sequencing for the analysis of the neuroendocrine lung tumours has revealed that, even if these tumours encompass several subtypes with varying clinical aggressiveness, they share a number of molecular features. An improved understanding of the biology of neuroendocrine tumours will offer the opportunity for novel approaches in clinical management, resulting in a better prognosis and prediction of therapeutic response.

Current understanding and approach to well differentiated lung neuroendocrine tumors: an update on classification and management

“…ACs had more mutations including PTEN, KIT, FGFR1, and KRAS. As expected, high-grade lung NETs had the highest amount of somatic mutations including TP53, ALK, NRAS, VHL, and RB1 [Vollbrecht et al 2015].…”

“…For example, with regard to activating EGFR mutations, alterations in the TOPO domain were seen in both TCs and ACs. This may lead to activation of the receptor in a similar fashion as seen in non-small cell lung cancer and may be targeted by tyrosine kinase inhibitors (TKIs) such as erlotinib [Vollbrecht et al 2015]. Mechanisms of resistance, however, may develop due to mutations in the PIK3CA gene leading to activation of PI3K signaling which in turn has been associated with failure of TKIs in these patients [Sequist et al 2011].…”

Clinical value of miR-145-5p in NSCLC and potential molecular mechanism exploration: A retrospective study based on GEO, qRT-PCR, and TCGA data

“…NRAS has been found to be mutated in NSCLC. [56][57][58][59] Ma et al 60 found that increased NRAS may lead to acquired resistance to EGFR inhibition in NSCLC patients. In summary, mutated NRAS may play a role in NSCLC, but its precise interaction with miR-145-5p requires further study.…”

Tracking EGFR Mutant Resistance in a Large Cell Neuroendocrine Tumor of the Lung with Activating and Resistance EGFR Mutations Treated with Erlotinib-A Case Report and Literature Review

“…The incidence of actionable EGFR mutants in PLNT may be underreported They have either analyzed mixed neuroendocrine tumor populations or retrospectively analyzed known EGFR mutant lung samples where the proportion of PLNET is likely to be low [10,14]. Larger-scale sequencing studies are required to validate the true frequency of EGFR mutant disease in this population and determine if outcomes in patient population parallel that observed in EGFR mutant lung cancer.…”

“…The limited reports evaluating the frequency of EGFR mutations in PLNT suggest that they are uncommon in this subtype of tumors [9,10].…”