ARID1A expression in gastric adenocarcinoma: Clinicopathological significance and correlation with DNA mismatch repair status

Figure 2 Immunohistochemistry for ARID1A. A: Homogeneous loss of expression. All the tumor cells show no expression, whereas the stromal cells retain the nuclear expression of ARID1A; B: Heterogeneous loss of expression. Most of the tumor cells show no expression, whereas some of the gland-forming tumor cells retain nuclear expression (arrows); C: Homogeneously weak expression. The tumor cells show the reduced expression of ARID1A. Non-neoplastic gastric glandular cells retain the expression (arrowheads); D: Heterogeneously weak expression. Most of the tumor cells exhibit reduced expression, but a subset of tumor cells retain nuclear expression (arrow); E: Retained expression: Tumor cells (arrow) show strong nuclear ARID1A expression, similar to non-neoplastic glandular cells (arrowheads).