Hotspot Mutations Detectable by Next-generation Sequencing in Exhaled Breath Condensates from Patients with Lung Cancer
ANTICANCER RESEARCH
Authors: Youssef, Omar; Knuuttila, Aija; Piirila, Paivi; Bohling, Tom; Sarhadi, Virinder; Knuutila, Sakari
Abstract
Background: Genetic alterations occurring in lung cancer are the basis for defining molecular subtypes and essential for targeted therapies. Exhaled breath condensate (EBC) is a form of non-invasive sample that, amongst components, contains DNA from pulmonary tissue. Nextgeneration sequencing (NGS) was herein used to analyze mutations in EBC from patients with lung cancer. Materials and Methods: EBC was collected from 26 patients with cancer and 20 healthy controls. Amplicon-based sequencing using Ion Ampliseq Colon and Lung Cancer gene panel v2 was applied. Results: The sequencing was successful in 17 patients and 20 controls. EBC from patients revealed 39 hotspot mutations occurring in: adenomatous polyposis coli (APC), v-raf murine sarcoma viral oncogene homolog B (BRAE), discoidin domain receptor tyrosine kinase 2 (DDR2), epidermal growth factor receptor (EGFR), erb-b2 receptor tyrosine kinase 4 (ERBB4), F-box and WD repeat domain containing 7 (FBXW7), fibroblast growth factor receptor 1 (FGER1), FGFR3 (fibroblast growth factor receptor 3), Kirsten rat sarcoma viral oncogene homolog (KRAS), mitogen-activated protein kinase kinase 1 (MAP2K1), met proto-oncogene (MET), neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), phosphatase and tensin homolog (PTEN), ret proto-oncogene (RET), SMAD family member 4 (SMAD4), serine/threonine kinase 11 (STK11), and tumorprotein p53 (TP53) genes. EBC from controls revealed 35 hotspot mutations. The average mutant allele fraction was higher in patients than controls. Conclusion: NGS can identify mutations in EBCs from patients with lung cancer. This could provide a promising non-invasive method for the assessment of gene mutations in lung cancer.
Activating Structural Alterations in MAPK Genes Are Distinct Genetic Drivers in a Unique Subgroup Of Spitzoid Neoplasms
AMERICAN JOURNAL OF SURGICAL PATHOLOGY
Authors: Quan, Victor L.; Zhang, Bin; Mohan, Lauren S.; Shi, Katherine; Isales, Maria C.; Panah, Elnaz; Taxter, Timothy J.; Beaubier, Nike; White, Kevin; Gerami, Pedram
Abstract
Recent studies have described kinase fusions as the most common initiating genomic events in Spitzoid neoplasms. Each rearrangement generates a chimeric protein with constitutive activation of the tyrosine kinase domain, resulting in the development of a Spitzoid neoplasm. Identifying key initiating genomic events and drivers may assist in diagnosis, prognostication, and management. Retrospective, consecutive search of our database between 2009 and 2018 for Spitzoid neoplasms identified 86 cases. Whole transcriptome mRNA and DNA sequencing (1714 genes) detected 9% of cases (8/86) with structural rearrangements in MAPK genes other than BRAF and 47% (40/86) with kinase fusions previously described in Spitzoid neoplasms. We identified in-frame fusions of MAP3K8-DIPC2, MAP3K8-PCDH7, MAP3K8-UBL3, MAP3K8-SVIL (n=6), and ATP2A2-MAP3K3 (n=1) as well as a p.I103_K104 in-frame deletion of MAP2K1 (n=1), in the absence of well-recognized drivers of melanocytic neoplasia. Fluorescence in situ hybridization validated all cases (n=7) with available tissue. Cases occurred in younger patients (median age 18 y). Morphologically, cases were predominantly epithelioid (P=0.0032), often with some melanin pigment (P=0.0047), and high-grade nuclear atypia (P=0.012). A significant proportion were thought to be Spitzoid melanomas (3/8). Average follow-up time was 11 months. One MAP3K8-DIP2C Spitzoid melanoma involved 4/5 sentinel lymph nodes and led to a complete lymph node dissection with unremarkable follow-up at 9 months. One MAP3K8-DIPC2 atypical Spitz tumor raised concern for recurrence at 10 months and was reexcised. We present a distinct subtype of Spitzoid neoplasm characterized by structural alterations in MAPK genes, which are important to recognize given the potential for treatment with MAPK inhibitors in metastatic cases.