Fig. 1

CRN5 is over-expressed in human colon cancer and is present in the nucleus of a subset of tumour cells. a Transverse section of normal human colon tissue. Colon epithelium cells (arrowheads) and fibroblasts of the stroma (arrow) did not express CRN5, while tissue-resident lymphocytes exhibited a marked expression of CRN5 (double-arrows). b Section of an adenoma with a low grade (lower right region) and a high grade part (upper left region). In the more benign part only single epithelial cells were faintly positive for CRN5 (white arrowhead). In contrast, all epithelial cells of the high grade part showed a strong cytosolic stain of CRN5 (arrowheads). In both parts stroma fibroblasts were CRN5-negative (arrow), and lymphocytes displayed the marked CRN5 signal (double-arrows). c Section of an adenocarcinoma with virtually all tumour epithelial cells showing a strong cytosolic CRN5 expression (arrowhead). Furthermore, a signal for CRN5 was present in the nuclei of tumour epithelial cells (double-arrowheads). In addition to the lymphocytes (double-arrow), stroma fibroblasts (arrow) were CRN5-positive in the adenocarcinoma. d, e Sections of liver and lymph node metastases, where a strong CRN5 signal intensity was visible in the cytoplasm (arrowheads) and nuclei (double-arrowheads) of the tumour epithelial cells. Tumour stroma cells (arrows) and lymphocytes (double-arrows) also showed CRN5 expression. The images at higher magnification (right column) were taken from the same section except for the high grade adenoma, which was from another tissue specimen