Characterizing gastrointestinal stromal tumors and evaluating neoadjuvant imatinib by sequencing of endoscopic ultrasound-biopsies

Figure 4 Ki-67-immunostaining of gastrointestinal stromal tumors-tumor tissue in three endoscopic ultrasound-biopsies and in the three corresponding resected specimens. Digital photos (magnification × 40): EUS-biopsy-tissue (left) and resected specimen tissue (right). Cell nuclei (brown color) are positive for Ki-67 while other cell nuclei (blue color) are negative for Ki-67. Scale bar equals 50 μm. A and B: Case #18, Neo- group (KIT exon 11 D579del, Ki-67_EUS: 6.6%, Ki-67_SURG: 6.3%); C and D: Case #22, Neo + s group (KIT exon 11 V559D, Ki-67_EUS: 5.6%, Ki-67_SURG 0.3%); E and F: Case #26, Neo + r group (PDGFRA exon 18 p.D842V, Ki-67_EUS: 2.7%, Ki-67_SURG 2.5%). EUS: Endoscopic ultrasound.