Abstract. CD34 is commonly used as an endothelial cell marker of tumor vessels. However, this marker detects not only newly formed, but also pre-existing large blood vessels. Nestin, a class VI intermediate filament protein, has recently received attention as a marker for detecting newly formed endothelial cells. In this study, whether nestin is a novel angiogenesis marker in colorectal cancer was examined. HCT-15, a human colon cancer cell line, was subcutaneously implanted into the dorsum of nude mice. After the tumor grew, the mice were perfused with fluorescent beads (Fluospheres). Then, the tumor tissues were used for immunofluorescence staining using nestin and the CD34 antibody. Immunohistochemistry was performed with nestin and CD34 on 101 human colorectal cancer tissue samples. Proliferating endothelial cells were detected immunohistochemically by a proliferating cell nuclear antigen (PCNA) antibody. Clinicopathological factors and prognosis were compared between two groups: that with a microvessel density (MVD) higher than the median MVD and that with MVD lower than the median MVD, as detected by nestin and CD34 labellings. Nestin was localized in endothelial cells in small blood vessels (median, 9.06 μm), whereas CD34 was localized in large blood vessels (median, 9.67 μm) in nude mice. The diameter of nestin-positive vessels was smaller than that of CD34-positive vessels in human colorectal cancer. The number ratio of PCNA-positive cells to nestin-positive vascular endothelial cells was higher than that of PCNA-positive to CD34-positive cells (p=0.002). There were no correlations between nestin-positive blood vessels and clinicopathological factors, but the prognosis was worse in the highly nestin-positive MVD group (p=0.071). Nestin is considered a novel angiogenesis marker of proliferating endothelial cells in colorectal cancer tissue.

Lumican is a member of a small leucine-rich proteoglycan family, and it is reportedly overexpressed in human breast cancer. The expression of lumican in the extracellular matrix in breast cancer is associated with a high tumor grade, low estrogen receptor levels and young age. Lumican expression has been previously reported in colorectal cancer, but the role of lumican in the tumor is not well understood. In this study, we examined the expression and role of lumican in advanced colorectal cancer. Immunohistochemical staining was performed on 158 patients who underwent curative surgery for advanced colorectal cancer with lymph node metastasis. In the normal colorectal tissues, lumican immunoreactivity was observed in the fibroblasts and neural cells, but not in the colorectal epithelial cells. Lumican was localized in the cytoplasm of the cancer cells and its overexpression was detected in 99 of the 158 (62.7%) colorectal cancer patients. Clinicopathologically, there was no association of lumican expression with age, sex, histological typing, or venous and lymphatic invasion. However, lumican expression tended to correlate with the spread of lymph node metastasis and the depth of tumor invasion (p=0.136 and 0.135, respectively). Furthermore, the survival rate was significantly lower in patients with a high lumican expression level than in those with a low lumican expression level (p=0.048). These results indicate that lumican expression is a potential prognostic factor in patients with advanced colorectal cancer with nodal metastasis.

Ubiquitin-specific protease 14, also known as the 60 kDa subunit of tRNA-guanine transglycosylase (USP14/ TGT60kD), belongs to the ubiquitin-specific processing protease (UBP) family. USP14/TGT60kD expression in leukemic and colorectal cancer cell lines, and the suppression of such an expression after the induction of cell differentiation have been reported. In the present study, we attempted to clarify whether USP14/TGT60kD overexpression affects the clinicopathological features of colorectal cancer. Immunohistochemically, USP14/TGT60kD was absent or weakly localized in the cytoplasm of normal colorectal epithelial cells. In 18 of 99 (18.2%) colorectal cancer patients, USP14/TGT60kD was strongly detected in the cytoplasm of cancer cells. USP14/TGT60kD expression correlated with pathological stage (P=0.03), and lymph node (P=0.03) and liver (P=0.03) metastases. Furthermore, the percentage of patients strongly positive for USP14/TGT60kD expression increased with pathological stage. The overall survival rate was worse in patients with a high USP14/TGT60kD expression level than in those with a low USP14/TGT60kD expression level. Our results suggest that USP14/TGT60kD also controls the fate of proteins that regulate tumor invasion and metastasis.

Although a pCR was a relatively rare event, a high pCR rate would be helpful to select the regimen and courses of NAC, especially when the pathological response rates are similar.

No abstract