Microsatellite unstable gastric cancer with loss of PMS2 expression

(A) Low-power view of an H&E-stained histologic section demonstrating loss of immunohistochemical staining for expression of the PMS2 protein in a microsatellite unstable gastric cancer.
(B) Low-power view of an H&E-stained histologic section demonstrating intact immunohistochemical staining for expression of the PMS2 protein (control).