Clinicopathological significance of next-generation sequencing technology for detection of gene mutations in lung cancer tissues

Abstract

Objective Based on the next-generation sequencing technology (NGS), to explore the mutations and site distribution of lung cancer related genes, the relationship between mutant genes and clinicopathological features, and its clinical application value. Methods A total of 53 lung cancer tissue samples from bronchoscopy biopsy and surgical resection were collected from the department of Respiratory and Critical Care Medicine of Tangdu Hospital from December 2017 to June 2018. The Illumina next-generation sequencing platform was used to detect a total of 103 mutation hotspots in 22 genes, describing the test results and analyzing the relationship between high frequency mutant genes and clinicopathological features. Results A total of 19 gene mutations were detected in 22 lung cancer-related genes, 71 mutations were detected in 103 lung cancer-associated mutation sites, of which the mutation rates of TP53, EGFR, CDKN2A, KRAS, APC genes were 45.07% (32/71), 9.86%(7/71), 8.45% (6/71), 5.63% (4/71), 4.23% (3/71), the mutation rates of PIK3CA, ERBB4, NTRK1, SMO and KIT were all 2.82% (2/71), and the mutation rates of GNAQ, CTNNB1, MAP2K1, ATM, FGFR3, NOTCH1, CDH1, RB1, HRAS were all 1.41% (1/71). There were 29 cases of TP53 mutations, 3 of which had double site mutations, so TP53 had 32 mutation sites. There were 6 cases of EGFR mutations, 1 of which had a double site mutation, so EGFR had 7 mutation sites. The CDKN2A mutations were all single point mutations. The mutation rates of Val173Glu missense mutation of exon 5 of TP53, Arg273Leu missense mutation of exon 8 and Lys320Ter nonsense mutation of exon 9 were all 6.25%(2/32), and the mutation rates of other sites were 3.13%(1/32). The mutation rates of the Glu746 and Ala750del deletion mutation of exon 19 and the Arg868Leu missense mutation of exon 21 were 42.86%(3/7) and 28.57%(2/7), respectively. Also, the mutation rates of other sites were 14.29%(1/7). Additionally, the mutation rates of all mutation sites of CDKN2A were 16.67%(1/6). The frequency of TP53 mutation was higher in patients with poorly and moderately differentiated lung cancer, and the difference was statistically significant (χ2=7.58, P=0.023). The differences in EGFR mutations between the pathological type (χ2=7.45, P=0.024) and the degree of differentiation (χ2=14.51, P=0.001) were statistically significant. There was no statistically significant difference in different stage (χ2=6.37, P=0.081). Conclusions Illumina next-generation sequencing platform can be used as a detection method for multi-gene mutations in lung cancer. The high frequency of TP53, EGFR and CDKN2A mutations has certain guiding significance for the clinical diagnosis and treatment of lung cancer, but further confirmation of large sample data is needed. Key words: Next-generation sequencing; Lung neoplasms; Tissues; Genes; Pathological significance