We further tested the protein expression level of TGF-β using multiplex immunofluorescence in 70 lung biopsy specimens from initially advanced NSCLC patients with common EGFRΔ19 mutations (n = 30), rare EGFR20ins mutations (n = 10), and without EGFR mutations (WT, n = 30) (Fig. 1C). Here, EGFR is linked to non-small cell lung carcinoma.