Biallelic Mismatch Repair Deficiency in an Adolescent Female

Figure 2

Immunohistochemical studies for PMS2 deficient adenocarcinoma, 40X. (a) H&E: moderately differentiated adenocarcinoma with crowded glands and minimal stroma. (b) CK7: focal positive immunostaining for CK7. (c) CK20: negative immunostaining for CK20. (d) Villin: focal minimal superficial (brush border) immunostaining for villin. CDX2 was also focally positive (not shown). (e) MLH1: intact nuclear immunostaining for MLH1 (no loss of expression). (f) MSH2: intact nuclear immunostaining for MSH2 (no loss of expression). (g) MSH6: intact nuclear immunostaining for MSH6 (no loss of expression). (h) PMS2: loss of nuclear immunostaining for PMS2 in both tumoral cells and background lymphocytes. Positive tissue control stains were appropriately positive (inset).

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