Purpose: Plasma TGF-β1 protein levels reportedly may predict the treatment outcomes of lung cancer. We hypothesized that in patients with lung cancer treated with radiation therapy (RT), TGF-β1 levels may correlate with the percentages of CD4⁺ T cells, CD8⁺ T cells, and the CD4⁺/CD8⁺ T cell ratio in peripheral blood.
Patients and methods: Eighty-two lung cancer patients satisfied the inclusion criteria. Platelet-poor plasma was obtained before RT, at the second and fourth weeks during RT, and at the end of RT (pre-, during-, and post-RT, respectively). TGF-β1 was measured via ELISA, while recording the percentages of lymphocyte subsets in peripheral blood. Short-term efficacy was categorized as complete response, partial response, stable disease, or progressive disease.
Results: Patients who had significantly lower TGF-β1 protein levels after RT than pre-RT seemed to have a better short-term effect (P <0.05) than those who had higher TGF-β1 levels. There was a significant association between the TGF-β1 levels and percentages of CD4⁺ T cells, CD8⁺ T cells, or CD4⁺/CD8⁺ T cell ratio during and at the end of RT. Changes in CD3⁺ T cells, B cells, or natural killer cells were not statistically related to the changes in TGF-β1 levels.
Conclusion: Lung cancer patients with TGF-β1 levels in plasma after RT that are below pre-RT levels may experience better short-term efficacy. The underlying mechanism may be related to the influence of TGF-β1 on antitumor immunity.
Keywords: lung cancer, radiotherapy, TGF-β1, lymphocytes, prognosis