Fig. 1

Examples of colonic adenocarcinomas with loss of SATB2 (a, b) and CDX2 (c, d) expression by immunohistochemistry. a, b This patient (Supplementary Table 1, Case 2) had a stage II (pT4a N0) adenocarcinoma of the cecum (a, H&E, ×100) with isolated loss of PMS2 expression and negative SATB2 expression within the tumor (b, ×100). Positive SATB2 expression is seen within adjacent non-neoplastic colonic crypt epithelium (b, right half of image). Positive CDX2 expression was identified within the adenocarcinoma (not shown). This patient did not receive adjuvant chemotherapy, developed tumor recurrence 7 months after surgical resection, and died of disease 17 months after initial presentation. c, d This patient (Supplementary Table 1, Case 1) had a stage II (pT4a N0) adenocarcinoma of the sigmoid colon (c, H&E, ×100) with loss of MSH2 and MSH6 expression and negative CDX2 expression within the tumor (d, ×100). Positive expression is seen within adjacent non-neoplastic colonic crypt epithelium (d, top of image). SATB2-positive expression was identified within the adenocarcinoma (not shown). This patient received adjuvant FOLFOX chemotherapy but developed liver metastasis 12 months after surgical resection and died of disease 22 months after initial presentation