RESUMO
BACKGROUND: Patients' who are positive for kinase domain activating mutations in epidermal growth factor receptor (EGFR) gene, constitute 30-40% of non-small cell lung cancer (NSCLC), and are suitable candidates for Tyrosine Kinase Inhibitor based targeted/personalized therapy. In EGFR non-mutated subset, 8-10% that show molecular abnormalities such as EML4-ALK, ROS1-ALK, KIP4-ALK, may also derive the benefit of targeted therapy. However, 40% of NSCLC belong to a grey zone of tumours that are negative for the clinically approved biomarkers for personalized therapy. This pilot study aims to identify and classify molecular subtypes of this group to address the un-met need for new drug targets in this category. Here we screened for known/novel oncogenic driver mutations using a 46 gene Ampliseq Panel V1.0 that includes Ser/Thr/Tyr kinases, transcription factors and tumor suppressors. METHODS: NSCLC with tumor burden of at least 40% on histopathology were screened for 29 somatic mutations in the EGFR kinase domain by real-time polymerase chain reaction methods. 20 cases which were EGFR non-mutated for TK domain mutations were included in this study. DNA Quality was verified from each of the 20 cases by fluorimeter, pooled and subjected to targeted re-sequencing in the Ion Torrent platform. Torrent Suite software was used for next generation sequencing raw data processing and variant calling. RESULTS: The clinical relevance and pathological role of all the mutations/variants that include SNPs and Indels was assessed using polyphen-2/SIFT/PROVEAN/mutation assessor structure function prediction programs. There were 10 pathogenic mutations in six different oncogenes for which annotation was available in the COSMIC database; C420R mutation in PIK3CA, Q472H mutation in vascular endothelial growth factor receptor 2 (VEGFR2) (KDR), C630W and C634R in RET, K367M mutation in fibroblast growth factor receptor 2 (FGFR2), G12C in KRAS and 4 pathogenic mutations in TP53 in the DNA binding domain (E285K, R213L, R175H, V173G). CONCLUSION: Results suggest, a potential role for PIK3CA, VEGFR2, RET and FGFR2 as therapeutic targets in EGFR non-mutated NSCLC that requires further clinical validation.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-ret/genética , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Classe I de Fosfatidilinositol 3-Quinases , Feminino , Genoma Humano , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Terapia de Alvo Molecular , Mutação , Proteínas de Fusão Oncogênica/genética , Polimorfismo de Nucleotídeo Único , Inibidores de Proteínas Quinases/uso terapêuticoRESUMO
BACKGROUND: Epidermal growth factor receptor (EGFR) mutation plays a vital role in the prognosis of patients with lung cancer. However, there is a dearth of studies on EGFR mutation in Indian population. In this retrospective study conducted at a network of tertiary cancer care centers across India, we evaluated the proportion of EGFR mutation in patients with non-small-cell lung carcinomas (NSCLC). MATERIALS AND METHODS: A total of 1036 cases of non-small lung cancer were assessed for EGFR mutation status using Scorpion amplified refractory mutation system real time polymerase chain reaction method from fine needle aspiration cytology core biopsy, pleural fluid and cell blocks. For a few cases, macro dissection of tumor from H and E slides was also performed for EGFR analysis. EGFR Status was assessed for the most commonly known driver mutations in Exons 18, 19, 20 and 21, which contributes to a total of 29 somatic mutations including the resistance mutation T790M. RESULTS: Around 39% of the cohort was female and 61% were male. Mutation was positive in 40.3% and negative (wild type) in 59.7%. There was 1.8% mutation in exon 18, 24.6% in exon 19, 1.6% in exon 20 and 12.8% in exon 21. 38.2% had a mutation in a single site and 1.1% had a mutation in two sites. Overall mutation was significant in females (50.5% vs. 33.9%) compared with males (χ2 = 28.3, P < 0.001). Mutation was significant in exon 21 (16.8% vs. 10.3%, χ2 = 9.44, P = 0.002) and exon 19 (30.7% vs. 20.7%, χ2 = 13.2, P < 0.001) in females compared with males. CONCLUSION: EGFR is expressed differentially/mutated in patients with NSCLC. Further studies to unravel the predictors for acquired genetic alterations of EGFR are needed.