Impact of EGFR-TKI treatment on the tumor immune microenvironment in EGFR mutation-positive non-small cell lung cancer

Kohsuke Isomoto, Koji Haratani, Hidetoshi Hayashi, Shigeki Shimizu, Shuta Tomida, Takashi Niwa, Toshihide Yokoyama, Yasushi Fukuda, Yasutaka Chiba, Ryoji Kato, Junko Tanizaki, Kaoru Tanaka, Masayuki Takeda, Takashi Ogura, Tadashi Ishida, Akihiko Ito, Kazuhiko Nakagawa

Research output: Contribution to journalArticlepeer-review

129 Citations (Scopus)


Purpose: The impact of EGFR tyrosine kinase inhibitors (TKI) on the tumor immune microenvironment (TME) in non-small cell lung cancer (NSCLC) is unclear. Experimental Design: We retrospectively identified 138 patients with EGFR-mutated NSCLC who underwent rebiopsy after progression during EGFR-TKI treatment. PD-L1 and CD73 expression in tumor cells and tumor-infiltrating lymphocyte (TIL) density at baseline and after progression were determined by IHC. Tumor mutation burden (TMB) was determined by next-generation sequencing. Results: The proportion of patients with a PD-L1 expression level of ≥50% (high) increased from 14% before to 28% after EGFR-TKI (P = 0.0010). Whereas CD8+ and FOXP3+ TIL densities were significantly lower after EGFR-TKI treatment than before, CD8+ TIL density was maintained in tumors with a high PD-L1 expression level. Expression of CD73 in tumor cells after EGFR-TKI treatment was higher than that before in patients with a high PD-L1 expression level. TMB tended to be higher after EGFR-TKI treatment than before (3.3→4.1 mutations/Mbp, P=0.0508). Median progressionfree survival for subsequent treatment with antibodies to PD-1 was longer for patients with a high than for those with a low PD-L1 expression after EGFR-TKI (7.1 vs. 1.7 months, P = 0.0033), and two of five patients whose PD-L1 expression level changed from low to high after EGFR-TKI treatment achieved a PFS of >6 months. Conclusions: EGFR-TKI treatment was associated with changes in the TME of EGFR-mutated NSCLC, and such changes may provide clues for optimization of subsequent PD-1 inhibitor treatment.

Original languageEnglish
Pages (from-to)2037-2046
Number of pages10
JournalClinical Cancer Research
Issue number8
Publication statusPublished - Apr 15 2020

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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