To investigate the presence of integrated Epstein-Barr virus (EBV) DNA in the NK/T cell lymphoma (NKTCL) ge-nome and analyze the integration information in the genome of NKTCL cell lines. Methods: PCR and in situ hybridization were used to detect EBV infection in five EBV (+) NK/T samples and four EBV (-) NK/T samples provided by the biobanks of the First Affiliated Hospi-tal of Zhengzhou University. Whole-genome DNA of the samples was sequenced and subjected to bioinformatics analysis. Whole-ge-nome sequence alignment was used to identify the EBV integration sequence. BLAST analysis was used to compare EBV fasta files of the samples and EBV fasta library. CREST software was used to extract softclip reads, filter all paired reads, and enumerate their distri-bution on chromosomes. The integrated genomics viewer (IGV) was used to compare the distribution of reads in partial regions of chromosome. PCR was used to amplify the high-frequency integration region of the EBV DNA. The amplified fragments were sanger se-quenced. Results: EBV DNA and EBER expression were detected in five EBV (+) NK/T samples but not in the four EBV (-) NK/T samples. Sequencing depth, coverage depth, proportion of coverage, and proportion of alignment all met the requirements for subsequent re-search. Sequence alignment revealed that the captured sequences were viral sequences. Filtered reads were most numerous in EBV (+) NKTCL cell line SNK, YTS, and EBV (+) nasal NKTCL tissue. The reads were non-randomly enriched in chromosome 2. EBV DNA inte-gration in the 400 bp region of chr2:30234084-30234483 caused insertion or deletion in the chr2p23.1 site. Conclusions: EBV DNA is highly integrated in the chr2p23.1 site of EBV (+) NKTCL cells and may affect the expression of related genes.

Objective: To investigate the expression and clinical significance of programmed death-ligand 1 (PD-L1), programmed death-ligand 2 (PD-L2), and their receptor programmed cell death protein 1 (PD-1) in EBV-positive T/NK lymphoproliferative disease [Epstein-Barr virus-positive T/natural killer (NK)-cell lymphoproliferative disease, EBV(+)-T/NK-LPD]. Methods: The pathological paraffin-embedded tissues of 17 patients with EBV(+)-T/NK-LPD from the First Affiliated Hospital of Zhengzhou University from January 2013 to December 2017 were collected. These patients include 12 males and 5 females, aged 10-82 years old, the average age being 29 years, 4 people in gradeⅠ, 7 in gradeⅡ, 3 in gradeⅢ, and 3 people with hydroa vacciniforme-like lymphoproliferative disorders. Immunohistochemical SP method was used to detect the expression of PD-1, PD-L1, and PD-L2 in human EBV(+)-T/NK-LPD tissues. The relationship between PD-1, PD-L1, PD-L2 expression, and clinicopathological parameters, pathological grades and prognosis were analyzed by Fisher's exact probabilities and Spearman rank correlation. Result: After statistical analysis, the results showed that in 17 cases of tissue samples, there were 12 cases with positive PD-1 expression, 6 cases with positive PD-L1 expression and 5 cases with positive PD-L2 expression. There was no significant correlation between PD-1 and PD-L2 expression and prognosis (P>0.05). PD-L1 expression showed a positive correlation with prognosis (P<0.05). There was no significant correlation between the expression of PD-L1 and PD-L2 with age, sex, as well as LDH and Ki-67 levels (P>0.05). Moreover, there was no significant correlation of PD-1 and PD-L2 expression with pathological grade (r=0.141, r=-0.149, both P>0.05). However, there was a negative correlation between the PD-L1 expression and pathological grade (r=-0.563), and the correlation between the PD-L1 ex-pression and pathological grade was statistically significant (P<0.05). Conclusions: PD-1, PD-L1, and PD-L2 are abnormally expressed in the pathological tissues of EBV(+)-T/NK-LPD. Although there was no significant correlation between the expression of PD-1 and prognosis or pathological grade, it was significantly higher in EBV+T/NK-LPD. PD-1/PD-Ls associated signaling pathway is expected to be a potential new target for EBV(+)-T/NK-LPD immunotherapy.