Abstract:

Objective To discuss the level of killer cell lectin-like receptor G1 （KLRG1）⁺ natural killer （NK） cells in peripheral blood of patients with non-small cell lung cancer （NSCLC）， to clarify its association with the clinical indicators， and to evaluate its clinical significance. Methods A total of 154 patients with lung adenocarcinoma who underwent surgical treatment in Sichuan Cancer Hospital from 2020 to 2022 were enrolled as the study subjects. The clinical data， such as gender， age， body mass index （BMI）， smoking history， drinking history， family history of tumor， and pathological tumor-node-metastasis （pTNM） stage， and routine blood test indicators 1-2 weeks before surgery were collected. Flow cytometry was used to detect the percentage of KLRG1⁺ NK cells in peripheral blood mononuclear cells （PBMCs）； χ2 test or Fisher’s exact test was used to analyze the association between the percentage of KLRG1⁺ NK cells and clinical characteristics； Mann-Whitney U test or Kruskal-Wallis H test was used to compare the percentages of immune cell subsets among different groups； Spearman rank correlation analysis was used to analyze the correlation between the percentage of KLRG1⁺ NK cells and routine blood test indicators. Results Among the 154 patients， there were 51 males （33.12%） and 103 females （66.88%）； 74 patients （48.05%） were younger than 55 years old， and 80 patients （51.95%） were 55 years old or older. The flow cytometry results showed that the median percentage of KLRG1⁺ NK cells in peripheral blood PBMCs was 17.05% （11.55%-23.98%）. Using this median as the cut-off value， the patients were divided into NK cell low percentage group （≤17.05%） and NK cell high percentage group （>17.05%）. The χ2 test results showed that there was a significant association between gender and the grouping of KLRG1⁺ NK cell percentage （χ2=5.78， P=0.017）， while the percentage of KLRG1⁺ NK cells was not associated with age， BMI， smoking history， drinking history， family history， or pTNM stage （P>0.05）. The median percentage of KLRG1⁺ NK cells was 54.85% （38.20%-69.00%）， and it was not associated with pTNM stage （P>0.05）. The Spearman rank correlation analysis results showed that the percentage of KLRG1⁺ NK cells was significantly positively correlated with platelet （PLT） count （rho=0.18， P=0.024）， and significantly negatively correlated with mean platelet volume （MPV） （rho=-0.24， P=0.008）. Conclusion The percentage of KLRG1⁺ NK cells in peripheral blood of patients with NSCLC has decrease trendency with tumor stage progression， and is related to PLT and MPV. The percentage of peripheral blood KLRG1⁺ NK cells combined with PLT parameters is expected to be a potential biomarker for the evaluation of NSCLC condition.

Key words: Cancer，non-small-cell lung, Killer cell lectin-like receptor G1, Natural killer cells, Platelets, Immuneotherapy