Fig. 5

Pathologic and genetic characteristics and PD-L1 expression of one adenocarcinoma with EGFR coaltered exon 19 frame deletion (E19del) and T790M mutation by amplification refractory mutation system (ARMS) and digital droplet PCR (ddPCR)assays. a A paramount on the adenocarcinoma stained by hematoxylin and eosin. Area I-III were captured for genetic test. b A counterpart of section A were immunohistochemically stained for PD-L1 (SP263). Diffuse PD-L1 expression were found in area B-I and B-II, but negative in area B-III. (c1, d1 and e1) Acinar, solid and micropapillary components were microdisseced from area I, II, and III respectively. (c2, d2 and e2) The target tissues were captured by Laser microdissection. (c3-e3) EGFR mutation were screened by ARMS and wild-typed EGFR was found in acinar and solid area (blue arrow, postive control), whereas mutated in micropapillary area with E19del (red arrow) and T790M (black arrow). (c4-e4) E19del mutation was detected by ddPCR. Laser-captured tissues showed that E19del were absent in acinar and solid areas (c4 and d4, respectively), but present at micropapillary component with the abudance of 48% (e4). (c5-e5) T790M was also tested by ddPCR and acinar and solid components were negative for T790M (c5 and d5, respectively) whereas positive in micropapillary pattern with the abudance of 10% (e5). E19del, exon 19 frame deletion of EGFR; WT, wild type; MR, mutation ratio