ABSTRACT
Objective To evaluate the value of high-throughput sequencing(HTS)data reanalysis that does not include ERBB2 copy number variation(CNV)analysis,in identifying ERBB2 amplification in patients with colorectal cancer.Methods The HTS data of 252 cases of colorectal cancer diagnosed by pathological biopsy who received peripheral blood cfDNA HTS detection samples were retrospectively analyzed.According to the HTS data of ERBB2 non-amplified samples judged by immunohistochemistry(IHC)and/or fluorescence in situ hybridization(FISH),the number of chromosome 17(Chr17)reads in the total number of reads was calculated the range of the ratio was initially determined as the threshold for prompting ERBB2 amplification.Suspected positive samples were screened according to thresholds and verified by digital PCR,IHC and FISH.Results The proportion of the number of Chr17 reads accounts for the number of total reads in the 89 cases of ERBB2 non-amplified samples determined by IHC and/or FISH ranged from 0.188 to 0.299(0.239±0.192).Using 0.298(1.25 times the mean)as the threshold indicating ERBB2 amplification,the data of 163 samples were analyzed,of which 7 cases were suspected to be positive,and the ratio ranged from 0.302 to 0.853.Among them,5 cases were determined to be positive by IHC and/or FISH,and 6 cases were confirmed to be positive by digital PCR.The ratio of the number of Chr17 reads to the number of total reads was positively correlated with the ratio of ERBB2/EIF2C1,and the correlation was good(r2=0.909).Conclusion The high-throughput sequencing data that does not cover the ERBB2 CNV analysis has a certain hint value for ERBB2 amplification in patients with colorectal cancer.